How to open Access 2000 using VB6.0

zhoujeff 2000-03-12 04:54:00

I found that the VB6.0 can open the Access 97 without any problem, but how to open Access 2000 with it. thx

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cooler 2000-03-15

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你的运行环境必须安装有access2000。
如果你的程序是在access97中编译的，好像不能用的
必须拿到2000的环境中引用2000的库然后重新编译

shaosx 2000-03-13

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ADO

qianqian 2000-03-12

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你能在这里找到答案 http://qianqian.363.net/qa/an4.htm

sythree 2000-03-12

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在VB中引用“MS ACCESS 9.0”库即可。

1 , TaskBar_v0.5.zip"Form_Taskbar is a control for Visual Basic which, once placed onto a form, makes the form act like the Taskbar (minus the Start Menu)." -- David Newcum2 , RemBuilderplus.zip"Rem Builder will auto load on startup to use Rem Builder; start your Visual Basic program with your project code showing, right click and you should see "Rem Builder".3 , syntax.zipThis is an excellent example of how to highlight HTML code in a rich textbox. I encourage everyone to check it out.4 , status.zipThis example demonstrates how to display text about each control the mouse is currently above.5 , dm10e.zipThis COM object allows you to send SMTP mail from many of the most used applications, including:Active Server Pages (Microsoft IIS or Chili!ASP extensions) Microsoft Visual Basic 4.x/5.x/6.x Microsoft Word, Access, Excel 95/97 (VBA) Windows Scripting Host (cscript / wscript) Perl 5.x for Win32 Inprise Delphi 4 Microsoft Visual C++ 4.x/5.x/6.x Microsoft Visual J++ 1.x/6.0 (Java) 6 , ocxex.zip"This is a quick example I made to show you how to use Events and properties in a OCX."7 , news.exeThis control aids as a complete Newsgroup control. It can post messages and recieve messages through the internet.8 , optiondemo.zipThis example demonstrates how to create realistic Option Buttons in Visual Basic.9 , mencrypt.zipThis ocx allows you to encrypt strings while utilizing a password shift method.10 , listtxt.zipThis shows how to retrieve the text from the current selection in a listbox.11 , list_index.zipThis example tells you if the inputted List Index is selected or not.12 , fade.zipThis is a bas to fade a pictuerbox. Can be used to make a progressbar13 , subcls32.zipThis demonstrates hoe to write a subclassing control. And it has many examples as to how to use the control (included.)14 , djmeter.zipThis is the source for a Progress Bar control. Also includes a helpful example.15 , progress.zipThis is an example on how to use the Progress Bar included with Microsoft's Visual Basic.16 , slider.zip"This is a sample of the Slider control that is part of the Microsoft Windows Common Controls(COMCTL32.OCX). "17 , statusbar.zip"This is a sample of the StatusBar control that is part of the Microsoft Windows Common Controls(COMCTL32.OCX). "18 , tabstrip.zip"This is a sample of the TabStrip control that is part of the Microsoft Windows Common Controls(COMCTL32.OCX). "19 , uncommondialog.zipThis is an alternative to Microsoft's (tm) Common Dialog control by Nick Mancini.20 , ucmdex.zipThis is the example to go with Uncommon Dialog OCX.21 , scroll.zipThis demonstrates how to create an auto-scrolling textbox.22 , splitter.zipThis demonstrates how to "split" controls. This is an excellent example, and I reccomend this file for everyone. 23 , mtymse.zip"This project is a fully working ActiveX control, with code, that allows you to control almost every aspect of the mouse. You can move the mouse, click the buttons and adjust the click time from your application."24 , ucmdsrc.zipThis is the source to my OCX. This demontrates how to create a basic OCX. This will aid anyone who wants to create an OCX.25 , avb-systray.zipThis is a good example to add your programs' icon to the Systray. This Zip also includes a helpful example.26 , cmdex.zipThis is an example of how to use the Common Dialog. This demonstrates most of the event procedures of the CM Dialog control.27 , campbell-reg.zipThis demonstrates how to write and retrieve information from the registry.28 , basChangeCursor.zipThis module demonstrates how to animate your cursor through Visual Basic, and Win32.29 , hdcat.zipThis will grab every file on your hard drive and add its path to a listbox.30 , vbo_bump.zipThis DLL allows programmers to easily draw 3D grippers and lines on Device Contexts (DC). 31 , vbo_user32_bas.zipThis BAS file contains many functions to ease the process of using the USER32 DLL. 32 , vbo_gdi32_bas.zipThis BAS File conatains many functions to ease the process of using the GDI32 DLL. 33 , vbo_button_bas.zipThis bas contains functions to manipulate Button class objects34 , LPT_Port.zipRead/write to LPT parallel port35 , DancingBaby.zipA Dancing Baby Screen Saver Which Dance on A Famous Song Macarena ( With Sound ) A Very Cute Screen Saver ,with source code, If you want more avi files then please mail me.36 , superwriter.zipA complete Wordprocessor, with source code. You can save, open files, print them out, copy, cut, paste, well you know the concept!37 , LogOff.zipThis conveniently placed program allows you to log off from your system tray.38 , ChPass.zipChanges NT Domain Passord. This program has two compenants... a server and a a client. The Server must run on a Domain Controller.39 , Reboot.zipThis conveniently placed program allows you to restart your computer more easily, from your system tray. 40 , analogclock.zipThis is a very good demo OCX for an analog clock. Although quite big in size, this is due to the very good background to the clock face. The analog click itself is very accurate and looks very impressive.41 , edge.zipThis program uses a few API calls/functions to set 3D, sunken and etched effects to an image inside an image control. It also has an example of how to change a label control to a 3D command button.42 , splitpanel2.zipA re-written version of the SplitPanel that David originally put onto this site about a year ago. It basically is a control that you place on a form and you can put other controls on the form and by dragging the splitpanel bar around, it does the resizing for you. 43 , avcontrol.zipThis control takes care of many audio and visual functions needed for game and graphical programmers. You can easily retrieve or change the screen resolution and color depth, play audio CDs and standard wave files 44 , fsocontrol.zipThis demonstration version of this control is a wrapper around the FileSystemObject - and makes using the FSO much easier.45 , slidingtoolbar.zipThis project shows how to implement a sliding toolbar in an application using one quick Kernel32 API function "Sleep". The application is fairly simple and easy to implement. 46 , dcsize.zipWhen this control is put onto a form, it ensures that all other controls retain the correct aspect-ratio from the design time view. Basically, it resize all controls on a form when the form resizes. This code is 100% free.47 , colorchooseocx.zipThis great OCX allows you to have a drop down list of colors to allow your user to choose from. The control itself has all the events and properties that you need.48 , xgraphmeter.zipThis is XGraphMeter, a bargraph/meter control good for displaying constantly changing values such as CPU usage or DUN throughput.49 , dynlistmnu.zipWhile trying to come up with a Dynamic menu in VB, I decided that VBs menu object was just too much of a pain to work with This project contains a form to mimic the functionality that I was looking for.. Part of my design criteria was that the menu form 50 , runtime.zipSupposedly, what this code does cannot be done... But it works. Basically, its a demonstration of how you can change control properties at run-time. If you try it in VB, you will get a runtime error, but this code shows you how to do it. Gilbert says51 , ledbulb.zipThis is a first for this author. Its an OCX which represents a characters in the form of led bulbs.52 , textapiroutines.basContained here is a small set of routines can be used with a Rich Text box (RTF) control. It can be used for other controls as well with minor modifications. You are welcome to change, use and distribute the code as you see fit.53 , xflatbutton.zipFlatButton is an owner-drawn flat button that pops up when the mouse passes over it. This version is text-only, but has flexible color support.54 , urllabel.zipWith the development of the internet and intranet applications, this control could could in more and more useful. Its a hyperlink label which will change color or underline when the mouse goes over it 55 , progbar.zipThis is a great replacement for the standard VB progress bar. Its smooth, totally free (all the source code is here), and more versitile than the one that comes with VB.56 , splitpanel.zipThis little control with full source code is remarkably compact but does a lot of fancy things. It allows you to be able to split panels and handles all the resizing behind it. We couldn't think of how to describe it properly, but 下载 it and try it57,basicreg.zipBasic Save and Retrieve Functions58,proguse.zipKeep Track of a Programs Usage59,millisec.zipCount Time in Milliseconds 60,getday.zipGet the Day of Week that a Day Falls On61,shellend.zipNotify the User when a Shelled Process Ends 62,varlist.zipGet a List of Windows Variables 63,detdisp.zipDetermine Display Colors 64,ctrlntwk.zipControl Panel - Network65,ctrluser.zipControl Panel - User Properties66,ctrltwui.zipControl Panel - TweakUI67,ctrlthm.zipControl Panel - Themes68,ctrltele.zipControl Panel - Telephony69,ctrlsys.zipControl Panel - System Properties70,ctrlscrn.zipControl Panel - Screen Savers71,ctrlreg.zipControl Panel - Regional Settings72,ctrlprnt.zipControl Panel - Printers73,ctrlpwr.zipControl Panel - Power Management74,ctrlpw.zipControl Panel - Passwords75,ctrlodbc.zipControl Panel - ODBC3276,ctrlmm.zipControl Panel - Multimedia77,ctrlmdm.zipControl Panel - Modem78,ctrlkbd.zipControl Panel - Keyboard79,ctrlmous.zipControl Panel - Mouse80,ctrlpoa.zipControl Panel - Post Office Admin81,ctrlotlk.zipControl Panel - Outlook82,ctrljoy.zipControl Panel - Joystick83,ctrlie4.zipControl Panel - Internet Explorer 84,ctrlgame.zipControl Panel - Game Controllers85,ctrlfont.zipControl Panel - Fonts86,ctrlarmp.zip Control Panel - Add/Remove Programs87,ctrlanh.zipControl Panel - Add New Hardware88,ctrlanp.zipControl Panel - Add New Printer89,ctrlaccs.zipControl Panel - Accessibility90,ctrlbrf.zipControl Panel - Create Briefcase91,ctrlcdsk.zipControl Panel - Copy Disk92,ctrlcns.zipControl Panel - Create New Shortcut93,ctrldun.zipControl Panel - Dial-Up Networking94,ctrldisp.zipControl Panel - Display Properties95,RegControl.zipFree Registry ActiveX Control. Read/Write String/Binary/DWord values, Check if key/value exists, CreateKey, Delete key/value and enumerate keys/values!96,MouseEvent.zipThis is a Mouse Event procedure that is pretty cool. It can be used for Web designing. Check it out!97,ShellTrayIcon.zipThe CShellTrayIcon class allows your VB application to set, change and delete icons in the system's tray 98,Reboot2.zipReboot remotely. I wrote this to reboot selected PC's during off hours. It is a standalone application that will display a 10 second countdown. Any open data will try to be saved prior to the shutdown process.99,S-Secure.zipThis is S-Secure.....a security program I've coded for Windows. It has 4 modules each in a separate VB project. 100,DriveSpace.zipThis Program finds and displays the Drive's Space.101,Disable_X.zipThis user control allows you to disable the windows close "X" button. Example program included.102,SetParnt.zipShows how to assign controls to different forms at run time. 103,phone.zipA Cellular Phone Application Uses MSCOMM, Modem and normal telephone lines to make calls. You can use this application to make local as well as International calls. 104,Timer01.zipSimple program demonstrating how to create a stop watch using the Timer control. 105,Bubblesort.zipA simple Bubble Sort code that shows how the program works within a VB program. 106,systray.zipJust another Systray Utility, but worse than the others !!! static, flashing and animated Tray-Icons 107,FolderFiles.zipDemonstrates usage of progress bar and list box controls. Its purpose is to get all the files from a specified folder while showing the progress completed. 108,MultipleDataSets.zipThis is a simple, (1) form VB 6.0 program which demonstrates how to plot multiple sets of data on the same graph using the MSChart Control 6.0 (OLEDB). 109,MthVwPrj.zipMonthView control. Lets users view and set date information via a calendar-like interface. 110,calculator4.zipI know this is wierd but I made a calculator control. Just add it to your control bar, double click, and you can use the calculator when your project is at run-time. Source included.111,GradientButton.zipThis button was created to be an enhanced replacement for Visual Basic's standard command button by adding 2 more Border appearance schemes, 2 more button styles, and hover effects. 112,MSChart.zipMSChart. You can view MSChart in Line graph,Pie , Area, etc.. also you can update data provided in the Grid.. Very interesting must see it... 113,printing_tut.zipI made this for a freind to help him out with some basic Printing, i got the idea from a printing tut i found on the net, so the code is not mine. 114,treeview.zipThis code can as many child nodes to a tree view control and can save the data and structure of the treeview control in a text file. Later the data and structure can be retrieved from the text file and filled in the tree view control by clicking the load button. 115,alarm_clock.zipIt simulates an alarm clock. 116,DesktopByAlexDrankus.zipThis program hides/shows desktop, hides/shows taskbar, hides it self from the ctrl+alt+delete, uses pictures to create the forms (pretty cool forms) and many other functions just place this program and all components in a sub-folder 117,Label3D.zipLabel3D lets you change the Label Face Color Shadow Color ON/OFF Shadow. 118,HotLinks.zip Custom Control which acts like a text box, except the developer can specify hot links in the control which act like web page links allowing users to click them, while allowing the developer full control over the result of the click. 119,custbutt.zipThis application shows how to create non rectangular buttons. 120,grid.zipComplete grid coded in vb. supports : locked rows/columns , fg/bg colors , text alignment , cell-edge styles , different selectionstyles . texbox/dropdown cells , cell icons and lots more... 121,analogmeter.zipCreate your own analog meters using MSPaint. These .bmp or .gif files become your meter face. Use the (analogmeter) subroutine to automatically draw the meter needle over the meter face 122,wheel.zipSpinWheel control to be used in place of either the UpDown control or the ScrollBar control.123,ArielBrowseFolder.zipA browse folder control resembling a combobox. When the dropdown button is clicked, browse through a folder treeview to select a directory. Uses the SHBrowseForFolder function, amongst other APIs. A call back procedure is implemented showing the currently selected folder in the browse for folder dialog. 124,pp_prj.zipThis program shows you how to create a sample project that adds print preview capabilities to your Visual Basic program by using a generic object and the Printer object. 125,popup.zipPopUp buttons with only 4 lines of code. 126,adbevel.zipThe bevel control in Delphi is now available in VB. 127,rainbow.zipCool! Have a ProgressBar like in InstallShield!With free selectable fore- and backcolor and the percent value displayed in the middle!Check it out.128,gb12.zipWell folks. Another version of Gold Button is here. I've added a few things. Here they are: Property descriptions, MaskColor, UseMask, Base Address in OCX, picture will now automatically align with text and when you are in desing mode and OnUp property is bsNone, a Dash-Dot-Dot box is drawn over the button, so you can see th button's area. 129,gb11.zipA new version of Gold Button is here dudes.New version has Picture Property and Skin Support. 130,BIGDOGMEDIA.zipMEDIA PLAYER THAT SUPPORTS FORMATS LIKE MP3,AVI,MPEG,WAV ECT.EXAMPLE OF USING ANIMATION WHEN PLAYER IS LAUNCHED. 131,HTML.zipAn HTML editor with complete VB source code. 132,PrintPreview1.zipPrint Setup, and Print Priview application. 133,RTFEditor.zipRTF text editor, HTML text editor, web browser, and more...Try it. Note, make sure your printer is turned on before running the application. 134,VBExplorer-II.zipVBExplorer file utility application. This application uses the Visual Basic TreeView and ListView controls to create a file management application similar to Windows Explorer.135,resizepic.zipShows how to resize a picture box control on a form at run time.

Contents xvii Web Forms 133 Intellisense 134 Customizing the IDE 135 Customizing the Code Editor 135 Customizing Shortcut Keys 135 Customizing the Toolbars 136 Exercise 3.4 Adding a New Toolbar to the Existing Set 136 Exercise 3.5 Adding Commands to Toolbars 137 Customizing Built-In Commands 137 Exercise 3.6 Creating an Alias 138 Customizing the Start Page 139 Accessibility Options 141 Summary 142 Solutions Fast Track 142 Frequently Asked Questions 143 Chapter 4 Common Language Runtime 145 Introduction 146 Component Architecture 148 Managed Code versus Unmanaged Code 150 Interoperability with Managed Code 152 System Namespace 153 File I/O 155 Drawing 156 Printing 157 Common Type System 158 Type Casting 160 Garbage Collection 163 Object Allocation/Deallocation 164 Close/Dispose 165 Summary 166 Solutions Fast Track 167 Frequently Asked Questions 168 Developing & Deploying… Embrace Your Parameters VB.NET is insistent upon enclosing parameters of function calls within parentheses regardless of whether we are returning a value or whether we are using the Call statement. It makes the code much more readable and is a new standard for VB programmers that is consistent with the standard that nearly all other languages adopted long ago. 153_VBnet_TOC 8/16/01 1:12 PM Page xvii xviii Contents Chapter 5 .NET Programming Fundamentals 171 Introduction 172 Variables 173 Constants 175 Structures 176 Program Flow Control 178 If…Then…Else 178 Select Case 182 While Loops 184 For Loops 186 Arrays 187 Declaring an Array 188 Multidimensional Arrays 189 Dynamic Arrays 191 Functions 192 Object Oriented Programming 196 Inheritance 196 Polymorphism 197 Encapsulation 197 Classes 198 Adding Properties 198 Adding Methods 200 System.Object 201 Constructors 201 Overloading 202 Overriding 203 Shared Members 205 String Handling 206 Error Handling 210 Summary 213 Solutions Fast Track 214 Frequently Asked Questions 217 NOTE When porting Visual Basic applications to Visual Basic .NET, be careful of the lower bounds of arrays. If you are using a for loop to iterate through the array, and it is hard-coded to initialize the counter at 1, the first element will be skipped. Remember that all arrays start with the index of 0. 153_VBnet_TOC 8/16/01 1:12 PM Page xviii Contents xix Chapter 6 Advanced Programming Concepts 219 Introduction 220 Using Modules 221 Utilizing Namespaces 222 Creating Namespaces 222 Understanding the Imports Keyword 226 Implementing Interfaces 229 Delegates and Events 232 Simple Delegates 235 Multicast Delegates 236 Event Programming 236 Handles Keyword 236 Language Interoperability 237 File Operations 239 Directory Listing 239 Data Files 241 Text Files 243 Appending to Files 246 Collections 246 The Drawing Namespace 248 Images 253 Printing 256 Understanding Free Threading 262 SyncLock 263 Summary 265 Solutions Fast Track 265 Frequently Asked Questions 267 Chapter 7 Creating Windows Forms 269 Introduction 270 Application Model 270 Properties 271 Manipulating Windows Forms 275 Properties of Windows Forms 275 Methods of Windows Forms 276 Creating Windows Forms 287 What Are Collections? Collectionsare groups of like objects. Collections are similar to arrays, but they don’t have to be redimensioned. You can use the Addmethod to add objects to a collection. Collections take a little more code to create than arrays do, and sometimes accessing a collection can be a bit slower than an array, but they offer significant advantages because a collection is a group of objects whereby an array is a data type. 153_VBnet_TOC 8/16/01 1:12 PM Page xix xx Contents Displaying Modal Forms 288 Displaying Modeless Forms 289 Displaying Top-Most Forms 289 Changing the Borders of a Form 289 Resizing Forms 291 Setting Location of Forms 292 Form Events 294 Creating Multiple Document Interface Applications 297 Creating an MDI Parent Form 297 Creating MDI Child Forms 298 Exercise 7.1 Creating an MDI Child Form 298 Determining the Active MDI Child Form 299 Arranging MDI Child Forms 299 Adding Controls to Forms 300 Anchoring Controls on Forms 301 Docking Controls on Forms 303 Layering Objects on Forms 304 Positioning Controls on Forms 304 Dialog Boxes 305 Displaying Message Boxes 306 Common Dialog Boxes 306 The OpenFileDialog Control 306 The SaveFileDialog Control 309 The FontDialog Control 311 The ColorDialog Control 313 The PrintDialog Control 315 The PrintPreviewDialog Control 316 The PageSetupDialog Control 321 Creating Dialog Boxes 322 Creating and Working with Menus 323 Adding Menus to a Form 323 Exercise 7.2 Adding a Menu to a Form at Design Time 323 Creating Dialog Boxes 1.Create a form. 2.Set the BorderStyle property of the form to FixedDialog. 3.Set the ControlBox, MinimizeBox, and MaximizeBox properties of the form to False. 4.Customize the appearance of the form appropriately. 5.Customize event handlers in the Code window appropriately. 153_VBnet_TOC 8/16/01 1:12 PM Page xx Contents xxi Dynamically Creating Menus 326 Exercise 7.3 Adding a Menu to a Form at Design Time 326 Adding Status Bars to Forms 328 Adding Toolbars to Forms 330 Data Binding 332 Simple Data Binding 332 Complex Data Binding 333 Data Sources for Data Binding 333 Using the Data Form Wizard 334 Using the Windows Forms Class Viewer 338 Using the Windows Forms ActiveX Control Importer 338 Summary 340 Solutions Fast Track 340 Frequently Asked Questions 344 Chapter 8 Windows Forms Components and Controls 347 Introduction 348 Built-In Controls 348 Label Control 351 LinkLabel Control 354 TextBox Control 357 Button Control 361 CheckBox Control 364 RadioButton Control 365 RichTextBox Control 367 TreeView Control 369 ListBox Control 371 CheckedListBox Control 374 ListView Control 376 ComboBox Control 381 DomainUpDown Control 384 NumericUpDown Control 386 PictureBox Control 388 TrackBar Control 389 Adding Items to a Combo Box at Design-Time 1.Select the ComboBox control on the form. 2.If necessary, use the Viewmenu to open the Properties window. 3.In the Properties window, click the Itemsproperty, then click the ellipsis. 4.In String Collection Editor, type the first item, then press Enter. 5.Type the next items, pressing Enterafter each item. 6.Click OK. 153_VBnet_TOC 8/16/01 1:13 PM Page xxi xxii Contents DateTimePicker Control 391 Panel Control 394 GroupBox Control 396 TabControl Control 397 Creating Custom Windows Components 399 Exercise 8.1:Creating a Custom Windows Component 399 Creating Custom Windows Controls 403 Exercise 8.2:Creating a Custom Windows Control 404 Summary 407 Solutions Fast Track 407 Frequently Asked Questions 408 Chapter 9 Using ADO.NET 409 Introduction 410 Overview of XML 411 XML Documents 411 XSL 411 XDR 412 XPath 412 Understanding ADO.NET Architecture 412 Differences between ADO and ADO.NET 414 XML Support 414 ADO.NET Configuration 415 Remoting in ADO.NET 415 Maintaining State 415 Using the XML Schema Definition Tool 416 Connected Layer 417 DataProviders 418 Connection Strings 418 Exercise 9.1 Creating a Connection String 419 Command Objects 421 DataReader 425 DataSet 426 XML Documents XML documents are the heart of the XML standard. An XML document has at least one element that is delimited with one start tag and one end tag. XML documents are similar to HTML, except that the tags are made up by the author. 153_VBnet_TOC 8/16/01 1:13 PM Page xxii Contents xxiii Disconnected Layer 427 Using DataSet 428 Relational Schema 428 Collection of Tables 430 Data States 431 Populating with the DataSet Command 432 Populating with XML 433 Populating Programmatically 434 Using the SQL Server Data Provider 435 TDS 436 Exercise 9.2 Using TypedDataSet 437 Remoting 439 Data Controls 440 DataGrid 440 Exercise 9.3 Using TypedDataSet and DataRelation 441 DataList 446 Repeater 450 Summary 454 Solutions Fast Track 454 Frequently Asked Questions 457 Chapter 10 Developing Web Applications 459 Introduction 460 Web Forms 461 A Simple Web Form 462 Exercise 10.1 Creating a Simple Web Form 462 How Web Forms Differ from Windows Forms 464 Why Web Forms Are Better Than Classic ASP 465 Adding Controls to Web Forms 467 Exercise 10.2 Adding Web Controls to a Web Form 468 Code Behind 473 NOTE Web form controls not only detect browsers such as Internet Explorer and Netscape, but they also detect devices such as Palm Pilots and cell phones and generate appropriate HTML accordingly. 153_VBnet_TOC 8/16/01 1:13 PM Page xxiii xxiv Contents How Web Form Controls Differ from Windows Form Controls 476 ASP.NET Server Controls 476 Intrinsic Controls 476 Bound Controls 478 Exercise 10.3 Using the DataGrid Control 478 Exercise 10.4 Customizing DataGrid Control 482 Custom Controls 487 Validation Controls 488 Exercise 10.5 Using the Validation Controls 489 Creating Custom Web Form Controls 492 Exercise 10.6 A Simple Custom Control 493 Exercise 10.7 Creating a Composite Custom Control 497 Web Services 504 How Web Services Work 505 Developing Web Services 505 Exercise 10.8 Developing Web Services 507 Web Service Utilities 509 Service Description Language 509 Discovery 510 Proxy Class 510 Consuming Web Services from Web Forms 511 Exercise 10.9 Consuming Web Services from Web Forms 511 Using Windows Forms in Distributed Applications 513 Exercise 10.10 Consuming Web Services from Windows Forms 514 Exercise 10.11 Developing a Sample Application 516 Summary 519 Solutions Fast Track 519 Frequently Asked Questions 521 153_VBnet_TOC 8/16/01 1:13 PM Page xxiv Contents xxv Chapter 11 Optimizing, Debugging, and Testing 523 Introduction 524 Debugging Concepts 524 Debug Menu 528 Watches 529 Breakpoints 531 Exceptions Window 532 Command Window 534 Conditional Compilation 536 Trace 538 Assertions 540 Code Optimization 541 Finalization 542 Transitions 542 Parameter Passing Methods 542 Strings 543 Garbage Collection 544 Compiler Options 544 Optimization Options 544 Output File Options 544 .NET Assembly Options 545 Preprocessor Options 546 Miscellaneous Options 546 Testing Phases and Strategies 546 Unit Testing 547 Integration Testing 547 Beta Testing 547 Regression Testing 548 Stress Testing 548 Monitoring Performance 548 Summary 550 Solutions Fast Track 551 Frequently Asked Questions 552 What Are Watches? Watchesprovide us with a mechanism where we can interact with the actual data that is stored in our programs at runtime. They allow us to see the values of variables and the values of properties on objects. In addition to being able to view these values, you can also assign new values. 153_VBnet_TOC 8/16/01 1:13 PM Page xxv xxvi Contents Chapter 12 Security 553 Introduction 554 Security Concepts 555 Permissions 555 Principal 556 Authentication 557 Authorization 557 Security Policy 558 Type Safety 558 Code Access Security 558 .NET Code Access Security Model 559 Stack Walking 559 Code Identity 561 Code Groups 562 Declarative and Imperative Security 564 Requesting Permissions 565 Demanding Permissions 570 Overriding Security Checks 572 Custom Permissions 576 Role-Based Security 578 Principals 578 WindowsPrincipal 579 GenericPrincipal 580 Manipulating Identity 581 Role-Based Security Checks 583 Security Policies 585 Creating a New Permission Set 588 Modifying the Code Group Structure 593 Remoting Security 600 Cryptography 600 Security Tools 603 Summary 606 Solutions Fast Track 607 Frequently Asked Questions 611 Within the .NET Framework, Three Namespaces Involve Cryptography 1.System.Security .CryptographyThe most important one; resembles the CryptoAPI functionalities. 2.System.Security .Cryptography.X509 certificatesRelates only to the X509 v3 certificate used with Authenticode. 3.System.Security .Cryptography.XmlFor exclusive use within the .NET Framework security system. 153_VBnet_TOC 8/16/01 1:13 PM Page xxvi Contents xxvii Chapter 13 Application Deployment 615 Introduction 616 Packaging Code 617 Configuring the .NET Framework 622 Creating Configuration Files 622 Machine/Administrator Configuration Files 623 Application Configuration Files 625 Security Configuration Files 626 Deploying the Application 629 Common Language Runtime 629 Windows Installer 630 CAB Files 631 Internet Explorer 5.5 632 Resource Files 633 Deploying Controls 637 Summary 639 Solutions Fast Track 640 Frequently Asked Questions 642 Chapter 14 Upgrading Visual Basic Applications to .NET 647 Introduction 648 Considerations Before Upgrading 648 Early Binding of Variables 649 Avoiding Null Propagation 650 Using ADO 651 Using Date Data Type 652 Using Constants 652 Considering Architecture Before Migration 653 Intranet/Internet Applications 653 Internet Information Server (IIS) Applications 654 DHTML Applications 655 ActiveX Documents 655 Client/Server and Multi-Tier Applications 655 Single-Tier Applications 656 Data Access Applications 656 WARNING You should under no circumstance edit the Security.config and Enterprise.config files directly. It is very easy to compromise the integrity of these files. Always use the Code Access Security Policy utility (caspol.exe) or the .NET Configuration tool; these will guard the integrity of the files and will also make a backup copy of the last saved version. 153_VBnet_TOC 8/16/01 1:13 PM Page xxvii xxviii Contents Data Types 657 Variants 657 Integers 658 Dates 658 Boolean 659 Arrays 659 Fixed-Length Strings 660 Windows API Data Types 661 Converting VB Forms to Windows Forms 662 Control Anchoring 664 Keyword Changes 665 Goto 666 GoSub 666 Option Base 666 AND/OR 666 Lset 666 VarPtr 667 StrPtr 667 Def 667 Programming Differences 668 Method Implementation 668 Optional Parameters 668 Static Modifier 669 Return Statement 669 Procedure Calls 670 External Procedure Declaration 671 Passing Parameters 672 ParamArray 672 Overloading 674 References to Unmanaged Libraries 677 Metadata 679 Runtime Callable Wrapper 681 COM Callable Wrapper 682 Properties 684 Working with Property Procedures 684 Control Property Name Changes 685 Default Property 687 Avoiding Null Propagation Nullpropagation means that if Null is used in an expression, the resulting expression is always Null. In previous versions of Visual Basic, the Null value disseminated throughout the expression. 153_VBnet_TOC 8/16/01 1:13 PM Page xxviii Contents xxix Null Usage 690 Understanding Error Handling 690 Exercise 14.1:Using Error Handling 692 Data Access Changes in Visual Basic .NET 693 Dataset and Recordset 694 Application Interoperability 694 Cursor Location 695 Disconnected Access 695 Data Navigation 695 Lock Implementation 696 Upgrading Interfaces 696 Upgrading Interfaces from Visual Basic 6.0 699 Using the Upgrade Tool 703 Exercise 14.2 Using the Upgrade Wizard 703 Summary 708 Solutions Fast Track 709 Frequently Asked Questions 712 Index 713 Contents xiii From the Series Editor xxxi Chapter 1 New Features in Visual Basic .NET 1 Introduction 2 Examining the New IDE 3 Cosmetic Improvements 3 Development Accelerators 5 .NET Framework 6 A Very Brief and Simplified History 6 .NET Architecture 7 ASP.NET 7 Framework Classes 8 .NET Servers 8 Common Language Runtime 8 History 8 Convergence 9 Object-Oriented Language 10 Object-Oriented Concepts 10 Advantages of Object-Oriented Design 11 History of Object Orientation and VB 13 Namespaces 13 Web Applications 13 Web Applications Overview 13 Web Forms 14 Web Services 15 HyperText Transport Protocol 16 Simple Object Access Protocol 17 .NET Architecture .NET Framework ASP.NET Updated ASP Engine Web Forms Engine Framework Classes System.Math, System.Io, System.Data, Etc. Common Language Runtime Memory Management Common Type System Garbage Collection .NET .NET Servers 153_VBnet_TOC 8/16/01 1:12 PM Page xiii xiv Contents Security 17 Type Safety 18 Casting 18 Data Conversion 19 Bitwise Operations 20 New Compiler 20 Compiling an Executable 20 Architecture 21 File Management in Previous Versions of VB 21 File Management 22 Changes from Visual Basic 6.0 23 Variants 23 Variable Lower Bounds 23 Fixed Length Strings 23 NULL Propagation 23 Other Items Removed 24 Function Values 24 Short Circuits 25 Properties and Variables 25 Variable Lengths 25 Get and Set 26 Date Type 26 Default Properties 27 Summary 28 Solutions Fast Track 28 Frequently Asked Questions 31 Chapter 2 The Microsoft .NET Framework 33 Introduction 34 What Is the .NET Framework? 34 Introduction to the Common Language Runtime 35 Using .NET-Compliant Programming Languages 37 Creating Assemblies 39 Using the Manifest 42 Compiling Assemblies 45 Assembly Cache 45 Locating an Assembly 45 153_VBnet_TOC 8/16/01 1:12 PM Page xiv Contents xv Private Assembly Files 51 Shared Assembly Files 51 Understanding Metadata 51 The Benefits of Metadata 52 Identifying an Assembly with Metadata 53 Types 53 Defining Members 54 Using Contracts 54 Assembly Dependencies 55 Unmanaged Assembly Code 55 Reflection 56 Attributes 57 Ending DLL Hell 58 Side-by-Side Deployment 58 Versioning Support 59 Using System Services 60 Exception Handling 60 StackTrace 61 InnerException 61 Message 61 HelpLink 62 Garbage Collection 62 Console I/O 62 Microsoft Intermediate Language 63 The Just-In-Time Compiler 63 Using the Namespace System to Organize Classes 64 The Common Type System 65 Type Safety 68 Relying on Automatic Resource Management 68 The Managed Heap 69 Garbage Collection and the Managed Heap 71 Assigning Generations 77 Utilizing Weak References 77 Security Services 79 Framework Security 80 Granting Permissions 81 NOTE Visualization is still key! Die-hard VB programmers may find themselves having a hard time visualizing all the new concepts in VB.NET (and we all know that proper logic visualization plays a big role in what we do). Something that may help is to think about VB.NET as a completely flexible language that can accommodate Web, console, and desktop use. 153_VBnet_TOC 8/16/01 1:12 PM Page xv xvi Contents Gaining Representation through a Principal 82 Security Policy 83 Summary 85 Solutions Fast Track 85 Frequently Asked Questions 88 Chapter 3 Installing and Configuring VB.NET 91 Introduction 92 Editions 92 Installing Visual Studio .NET 93 Exercise 3.1:Installing Visual Studio .NET 94 Installing on Windows 2000 99 The New IDE 100 Integrated Development Environment Automation Model 100 Add-Ins 104 Exercise 3.2 Creating an Add-In Using the Add-In Wizard 105 Wizards 109 Macros 109 Home Page 110 Project Options 112 Toolbox 116 Child Windows 120 Window Types 122 Arranging Windows 123 Task List 123 Exercise 3.3 Setting Up a Custom Token 124 TaskList Views 124 Locating Code 126 Annotating Code 126 Solution Explorer 127 Properties Window 129 Form Layout Toolbar 130 Hide/Show Code Elements 132 Installing Visual Studio .NET IPhase 1: Installing Windows components IPhase 2: Installing Visual Studio .NET IPhase 3: Checking for service releases 153_VBnet_TOC 8/16/01 1:12 PM Page xvi

1：外文原文 Struts——an open-source MVC implementation This article introduces Struts, a Model-View-Controller implementation that uses servlets and JavaServer Pages (JSP) technology. Struts can help you control change in your Web project and promote specialization. Even if you never implement a system with Struts, you may get some ideas for your future servlets and JSP page implementation. Introduction Kids in grade school put HTML pages on the Internet. However, there is a monumental difference between a grade school page and a professionally developed Web site. The page designer (or HTML developer) must understand colors, the customer, product flow, page layout, browser compatibility, image creation, JavaScript, and more. Putting a great looking site together takes a lot of work, and most Java developers are more interested in creating a great looking object interface than a user interface. JavaServer Pages (JSP) technology provides the glue between the page designer and the Java developer. If you have worked on a large-scale Web application, you understand the term change. Model-View-Controller (MVC) is a design pattern put together to help control change. MVC decouples interface from business logic and data. Struts is an MVC implementation that uses Servlets 2.2 and JSP 1.1 tags, from the J2EE specifications, as part of the implementation. You may never implement a system with Struts, but looking at Struts may give you some ideas on your future Servlets and JSP implementations. Model-View-Controller (MVC) JSP tags solved only part of our problem. We still have issues with validation, flow control, and updating the state of the application. This is where MVC comes to the rescue. MVC helps resolve some of the issues with the single module approach by dividing the problem into three categories: • Model The model contains the core of the application's functionality. The model encapsulates the state of the application. Sometimes the only functionality it contains is state. It knows nothing about the view or controller. • View The view provides the presentation of the model. It is the look of the application. The view can access the model getters, but it has no knowledge of the setters. In addition, it knows nothing about the controller. The view should be notified when changes to the model occur. • Controller The controller reacts to the user input. It creates and sets the model. MVC Model 2 The Web brought some unique challenges to software developers, most notably the stateless connection between the client and the server. This stateless behavior made it difficult for the model to notify the view of changes. On the Web, the browser has to re-query the server to discover modification to the state of the application. Another noticeable change is that the view uses different technology for implementation than the model or controller. Of course, we could use Java (or PERL, C/C++ or what ever) code to generate HTML. There are several disadvantages to that approach: • Java programmers should develop services, not HTML. • Changes to layout would require changes to code. • Customers of the service should be able to create pages to meet their specific needs. • The page designer isn't able to have direct involvement in page development. • HTML embedded into code is ugly. For the Web, the classical form of MVC needed to change. Figure 4 displays the Web adaptation of MVC, also commonly known as MVC Model 2 or MVC 2. The ActionServlet class Do you remember the days of function mappings? You would map some input event to a pointer to a function. If you where slick, you would place the configuration information into a file and load the file at run time. Function pointer arrays were the good old days of structured programming in C. Life is better now that we have Java technology, XML, J2EE, and all that. The Struts Controller is a servlet that maps events (an event generally being an HTTP post) to classes. And guess what -- the Controller uses a configuration file so you don_t have to hard-code the values. Life changes, but stays the same. ActionServlet is the Command part of the MVC implementation and is the core of the Framework. ActionServlet (Command) creates and uses Action, an ActionForm, and ActionForward. As mentioned earlier, the struts-config.xml file configures the Command. During the creation of the Web project, Action and ActionForm are extended to solve the specific problem space. The file struts-config.xml instructs ActionServlet on how to use the extended classes. There are several advantages to this approach: • The entire logical flow of the application is in a hierarchical text file. This makes it easier to view and understand, especially with large applications. • The page designer does not have to wade through Java code to understand the flow of the application. • The Java developer does not need to recompile code when making flow changes. Command functionality can be added by extending ActionServlet. The ActionForm class ActionForm maintains the session state for the Web application. ActionForm is an abstract class that is sub-classed for each input form model. When I say input form model, I am saying ActionForm represents a general concept of data that is set or updated by a HTML form. For instance, you may have a UserActionForm that is set by an HTML Form. The Struts framework will: • Check to see if a UserActionForm exists; if not, it will create an instance of the class. • Struts will set the state of the UserActionForm using corresponding fields from the HttpServletRequest. No more dreadful request.getParameter() calls. For instance, the Struts framework will take fname from request stream and call UserActionForm.setFname(). • The Struts framework updates the state of the UserActionForm before passing it to the business wrapper UserAction. • Before passing it to the Action class, Struts will also conduct form state validation by calling the validation() method on UserActionForm. Note: This is not always wise to do. There might be ways of using UserActionForm in other pages or business objects, where the validation might be different. Validation of the state might be better in the UserAction class. • The UserActionForm can be maintained at a session level. Notes: • The struts-config.xml file controls which HTML form request maps to which ActionForm. • Multiple requests can be mapped UserActionForm. • UserActionForm can be mapped over multiple pages for things such as wizards. The Action class The Action class is a wrapper around the business logic. The purpose of Action class is to translate the HttpServletRequest to the business logic. To use Action, subclass and overwrite the process() method. The ActionServlet (Command) passes the parameterized classes to ActionForm using the perform() method. Again, no more dreadful request.getParameter() calls. By the time the event gets here, the input form data (or HTML form data) has already been translated out of the request stream and into an ActionForm class. Struts, an MVC 2 implementation Struts is a set of cooperating classes, servlets, and JSP tags that make up a reusable MVC 2 design. This definition implies that Struts is a framework, rather than a library, but Struts also contains an extensive tag library and utility classes that work independently of the framework. Figure 5 displays an overview of Struts. Struts overview • Client browser An HTTP request from the client browser creates an event. The Web container will respond with an HTTP response. • Controller The Controller receives the request from the browser, and makes the decision where to send the request. With Struts, the Controller is a command design pattern implemented as a servlet. The struts-config.xml file configures the Controller. • Business logic The business logic updates the state of the model and helps control the flow of the application. With Struts this is done with an Action class as a thin wrapper to the actual business logic. • Model state The model represents the state of the application. The business objects update the application state. ActionForm bean represents the Model state at a session or request level, and not at a persistent level. The JSP file reads information from the ActionForm bean using JSP tags. • View The view is simply a JSP file. There is no flow logic, no business logic, and no model information -- just tags. Tags are one of the things that make Struts unique compared to other frameworks like Velocity. Note: "Think thin" when extending the Action class. The Action class should control the flow and not the logic of the application. By placing the business logic in a separate package or EJB, we allow flexibility and reuse. Another way of thinking about Action class is as the Adapter design pattern. The purpose of the Action is to "Convert the interface of a class into another interface the clients expect. Adapter lets classes work together that couldn_t otherwise because of incompatibility interface" (from Design Patterns - Elements of Reusable OO Software by Gof). The client in this instance is the ActionServlet that knows nothing about our specific business class interface. Therefore, Struts provides a business interface it does understand, Action. By extending the Action, we make our business interface compatible with Struts business interface. (An interesting observation is that Action is a class and not an interface. Action started as an interface and changed into a class over time. Nothing's perfect.) The Error classes The UML diagram also included ActionError and ActionErrors. ActionError encapsulates an individual error message. ActionErrors is a container of ActionError classes that the View can access using tags. ActionErrors is Struts way of keeping up with a list of errors. The ActionMapping class An incoming event is normally in the form of an HTTP request, which the servlet Container turns into an HttpServletRequest. The Controller looks at the incoming event and dispatches the request to an Action class. The struts-config.xml determines what Action class the Controller calls. The struts-config.xml configuration information is translated into a set of ActionMapping, which are put into container of ActionMappings. (If you have not noticed it, classes that end with s are containers) The ActionMapping contains the knowledge of how a specific event maps to specific Actions. The ActionServlet (Command) passes the ActionMapping to the Action class via the perform() method. This allows Action to access the information to control flow. ActionMappings ActionMappings is a collection of ActionMapping objects. Struts pros • Use of JSP tag mechanism The tag feature promotes reusable code and abstracts Java code from the JSP file. This feature allows nice integration into JSP-based development tools that allow authoring with tags. • Tag library Why re-invent the wheel, or a tag library? If you cannot find something you need in the library, contribute. In addition, Struts provides a starting point if you are learning JSP tag technology. • Open source You have all the advantages of open source, such as being able to see the code and having everyone else using the library reviewing the code. Many eyes make for great code review. • Sample MVC implementation Struts offers some insight if you want to create your own MVC implementation. • Manage the problem space Divide and conquer is a nice way of solving the problem and making the problem manageable. Of course, the sword cuts both ways. The problem is more complex and needs more management. Struts cons • Youth Struts development is still in preliminary form. They are working toward releasing a version 1.0, but as with any 1.0 version, it does not provide all the bells and whistles. • Change The framework is undergoing a rapid amount of change. A great deal of change has occurred between Struts 0.5 and 1.0. You may want to download the most current Struts nightly distributions, to avoid deprecated methods. In the last 6 months, I have seen the Struts library grow from 90K to over 270K. I had to modify my examples several times because of changes in Struts, and I am not going to guarantee my examples will work with the version of Struts you download. • Correct level of abstraction Does Struts provide the correct level of abstraction? What is the proper level of abstraction for the page designer? That is the $64K question. Should we allow a page designer access to Java code in page development? Some frameworks like Velocity say no, and provide yet another language to learn for Web development. There is some validity to limiting Java code access in UI development. Most importantly, give a page designer a little bit of Java, and he will use a lot of Java. I saw this happen all the time in Microsoft ASP development. In ASP development, you were supposed to create COM objects and then write a little ASP script to glue it all together. Instead, the ASP developers would go crazy with ASP script. I would hear "Why wait for a COM developer to create it when I can program it directly with VBScript?" Struts helps limit the amount of Java code required in a JSP file via tag libraries. One such library is the Logic Tag, which manages conditional generation of output, but this does not prevent the UI developer from going nuts with Java code. Whatever type of framework you decide to use, you should understand the environment in which you are deploying and maintaining the framework. Of course, this task is easier said than done. • Limited scope Struts is a Web-based MVC solution that is meant be implemented with HTML, JSP files, and servlets. • J2EE application support Struts requires a servlet container that supports JSP 1.1 and Servlet 2.2 specifications. This alone will not solve all your install issues, unless you are using Tomcat 3.2. I have had a great deal of problems installing the library with Netscape iPlanet 6.0, which is supposedly the first J2EE-compliant application server. I recommend visiting the Struts User Mailing List archive (see Resources) when you run into problems. • Complexity Separating the problem into parts introduces complexity. There is no question that some education will have to go on to understand Struts. With the constant changes occurring, this can be frustrating at times. Welcome to the Web. • Where is... I could point out other issues, for instance, where are the client side validations, adaptable workflow, and dynamic strategy pattern for the controller? However, at this point, it is too easy to be a critic, and some of the issues are insignificant, or are reasonable for a 1.0 release. The way the Struts team goes at it, Struts might have these features by the time you read this article, or soon after. Future of Struts Things change rapidly in this new age of software development. In less than 5 years, I have seen things go from cgi/perl, to ISAPI/NSAPI, to ASP with VB, and now Java and J2EE. Sun is working hard to adapt changes to the JSP/servlet architecture, just as they have in the past with the Java language and API. You can obtain drafts of the new JSP 1.2 and Servlet 2.3 specifications from the Sun Web site. Additionally, a standard tag library for JSP files is appearing. 2:外文资料翻译译文 Struts——MVC 的一种开放源码实现本文介绍 Struts，它是使用 servlet 和 JavaServer Pages 技术的一种 Model-View-Controller 实现。Struts 可帮助您控制 Web 项目中的变化并提高专业化水平。尽管您可能永远不会用 Struts 实现一个系统，但您可以将其中的一些思想用于您以后的 servlet 和 JSP 网页的实现中。简介小学生也可以在因特网上发布 HTML 网页。但是，小学生的网页和专业开发的网站有质的区别。网页设计人员（或者 HTML 开发人员）必须理解颜色、用户、生产流程、网页布局、浏览器兼容性、图像创建和 JavaScript 等等。设计漂亮的网站需要做大量的工作，大多数 Java 开发人员更注重创建优美的对象接口，而不是用户界面。JavaServer Pages (JSP) 技术为网页设计人员和 Java 开发人员提供了一种联系钮带。如果您开发过大型 Web 应用程序，您就理解变化这个词的含义。“模型-视图-控制器”(MVC) 就是用来帮助您控制变化的一种设计模式。MVC 减弱了业务逻辑接口和数据接口之间的耦合。Struts 是一种 MVC 实现，它将 Servlet 2.2 和 JSP 1.1 标记（属于 J2EE 规范）用作实现的一部分。尽管您可能永远不会用 Struts 实现一个系统，但了解一下 Struts 或许使您能将其中的一些思想用于您以后的 Servlet 的 JSP 实现中。模型-视图-控制器 (MVC) JSP 标记只解决了部分问题。我们还得处理验证、流程控制和更新应用程序的状态等问题。这正是 MVC 发挥作用的地方。MVC 通过将问题分为三个类别来帮助解决单一模块方法所遇到的某些问题： • Model（模型）模型包含应用程序的核心功能。模型封装了应用程序的状态。有时它包含的唯一功能就是状态。它对视图或控制器一无所知。 • View（视图）视图提供模型的表示。它是应用程序的外观。视图可以访问模型的读方法，但不能访问写方法。此外，它对控制器一无所知。当更改模型时，视图应得到通知。 • Controller（控制器）控制器对用户的输入作出反应。它创建并设置模型。 MVC Model 2 Web 向软件开发人员提出了一些特有的挑战，最明显的就是客户机和服务器的无状态连接。这种无状态行为使得模型很难将更改通知视图。在 Web 上，为了发现对应用程序状态的修改，浏览器必须重新查询服务器。另一个重大变化是实现视图所用的技术与实现模型或控制器的技术不同。当然，我们可以使用 Java（或者 PERL、C/C++ 或别的语言）代码生成 HTML。这种方法有几个缺点： • Java 程序员应该开发服务，而不是 HTML。 • 更改布局时需要更改代码。 • 服务的用户应该能够创建网页来满足它们的特定需要。 • 网页设计人员不能直接参与网页开发。 • 嵌在代码中的 HTML 很难看。对于 Web，需要修改标准的 MVC 形式。图 4 显示了 MVC 的 Web 改写版，通常也称为 MVC Model 2 或 MVC 2。 Struts，MVC 2 的一种实现 Struts 是一组相互协作的类、servlet 和 JSP 标记，它们组成一个可重用的 MVC 2 设计。这个定义表示 Struts 是一个框架，而不是一个库，但 Struts 也包含了丰富的标记库和独立于该框架工作的实用程序类。图 5 显示了 Struts 的一个概览。 Struts 概览 • Client browser（客户浏览器）来自客户浏览器的每个 HTTP 请求创建一个事件。Web 容器将用一个 HTTP 响应作出响应。 • Controller（控制器）控制器接收来自浏览器的请求，并决定将这个请求发往何处。就 Struts 而言，控制器是以 servlet 实现的一个命令设计模式。 struts-config.xml 文件配置控制器。 • 业务逻辑业务逻辑更新模型的状态，并帮助控制应用程序的流程。就 Struts 而言，这是通过作为实际业务逻辑“瘦”包装的 Action 类完成的。 • Model（模型）的状态模型表示应用程序的状态。业务对象更新应用程序的状态。ActionForm bean 在会话级或请求级表示模型的状态，而不是在持久级。JSP 文件使用 JSP 标记读取来自 ActionForm bean 的信息。 • View（视图）视图就是一个 JSP 文件。其中没有流程逻辑，没有业务逻辑，也没有模型信息 -- 只有标记。标记是使 Struts 有别于其他框架（如 Velocity）的因素之一。详细分析 Struts 图 6 显示的是 org.apache.struts.action 包的一个最简 UML 图。图 6 显示了 ActionServlet (Controller)、 ActionForm (Form State) 和 Action (Model Wrapper) 之间的最简关系。 ActionServlet 类您还记得函数映射的日子吗？在那时，您会将某些输入事件映射到一个函数指针上。如果您对此比较熟悉，您会将配置信息放入一个文件，并在运行时加载这个文件。函数指针数组曾经是用 C 语言进行结构化编程的很好方法。现在好多了，我们有了 Java 技术、XML、J2EE，等等。Struts 的控制器是将事件（事件通常是 HTTP post）映射到类的一个 servlet。正如您所料 -- 控制器使用配置文件以使您不必对这些值进行硬编码。时代变了，但方法依旧。 ActionServlet 是该 MVC 实现的 Command 部分，它是这一框架的核心。 ActionServlet (Command) 创建并使用 Action 、 ActionForm 和 ActionForward 。如前所述， struts-config.xml 文件配置该 Command。在创建 Web 项目时，您将扩展 Action 和 ActionForm 来解决特定的问题。文件 struts-config.xml 指示 ActionServlet 如何使用这些扩展的类。这种方法有几个优点： • 应用程序的整个逻辑流程都存储在一个分层的文本文件中。这使得人们更容易查看和理解它，尤其是对于大型应用程序而言。 • 网页设计人员不必费力地阅读 Java 代码来理解应用程序的流程。 • Java 开发人员也不必在更改流程以后重新编译代码。可以通过扩展 ActionServlet 来添加 Command 功能。 ActionForm 类 ActionForm 维护 Web 应用程序的会话状态。 ActionForm 是一个抽象类，必须为每个输入表单模型创建该类的子类。当我说输入表单模型时,是指 ActionForm 表示的是由 HTML 表单设置或更新的一般意义上的数据。例如，您可能有一个由 HTML 表单设置的 UserActionForm 。Struts 框架将执行以下操作： • 检查 UserActionForm 是否存在；如果不存在，它将创建该类的一个实例。 • Struts 将使用 HttpServletRequest 中相应的域设置 UserActionForm 的状态。没有太多讨厌的 request.getParameter() 调用。例如，Struts 框架将从请求流中提取 fname ，并调用 UserActionForm.setFname() 。 • Struts 框架在将 UserActionForm 传递给业务包装 UserAction 之前将更新它的状态。 • 在将它传递给 Action 类之前，Struts 还会对 UserActionForm 调用 validation() 方法进行表单状态验证。注：这并不总是明智之举。别的网页或业务可能使用 UserActionForm ，在这些地方，验证可能有所不同。在 UserAction 类中进行状态验证可能更好。 • 可在会话级维护 UserActionForm 。注： • struts-config.xml 文件控制 HTML 表单请求与 ActionForm 之间的映射关系。 • 可将多个请求映射到 UserActionForm 。 • UserActionForm 可跨多页进行映射，以执行诸如向导之类的操作。 Action 类 Action 类是业务逻辑的一个包装。 Action 类的用途是将 HttpServletRequest 转换为业务逻辑。要使用 Action ，请创建它的子类并覆盖 process() 方法。 ActionServlet (Command) 使用 perform() 方法将参数化的类传递给 ActionForm 。仍然没有太多讨厌的 request.getParameter() 调用。当事件进展到这一步时，输入表单数据（或 HTML 表单数据）已被从请求流中提取出来并转移到 ActionForm 类中。注：扩展 Action 类时请注意简洁。 Action 类应该控制应用程序的流程，而不应该控制应用程序的逻辑。通过将业务逻辑放在单独的包或 EJB 中，我们就可以提供更大的灵活性和可重用性。考虑 Action 类的另一种方式是 Adapter 设计模式。 Action 的用途是“将类的接口转换为客户机所需的另一个接口。Adapter 使类能够协同工作，如果没有 Adapter，则这些类会因为不兼容的接口而无法协同工作。”（摘自 Gof 所著的 Design Patterns - Elements of Reusable OO Software ）。本例中的客户机是 ActionServlet ，它对我们的具体业务类接口一无所知。因此，Struts 提供了它能够理解的一个业务接口，即 Action 。通过扩展 Action ，我们使得我们的业务接口与 Struts 业务接口保持兼容。（一个有趣的发现是， Action 是类而不是接口）。 Action 开始为一个接口，后来却变成了一个类。真是金无足赤。） ActionMapping 类输入事件通常是在 HTTP 请求表单中发生的，servlet 容器将 HTTP 请求转换为 HttpServletRequest 。控制器查看输入事件并将请求分派给某个 Action 类。 struts-config.xml 确定 Controller 调用哪个 Action 类。 struts-config.xml 配置信息被转换为一组 ActionMapping ，而后者又被放入 ActionMappings 容器中。（您可能尚未注意到这一点，以 s结尾的类就是容器） ActionMapping 包含有关特定事件如何映射到特定 Action 的信息。 ActionServlet (Command) 通过 perform() 方法将 ActionMapping 传递给 Action 类。这样就使 Action 可访问用于控制流程的信息。 ActionMappings ActionMappings 是 ActionMapping 对象的一个集合。 Struts 的优点 • JSP 标记机制的使用标记特性从 JSP 文件获得可重用代码和抽象 Java 代码。这个特性能很好地集成到基于 JSP 的开发工具中，这些工具允许用标记编写代码。 • 标记库为什么要另发明一种轮子，或标记库呢？如果您在库中找不到您所要的标记，那就自己定义吧。此外，如果您正在学习 JSP 标记技术，则 Struts 为您提供了一个起点。 • 开放源码您可以获得开放源码的全部优点，比如可以查看代码并让使用库的每个人检查代码。许多人都可以进行很好的代码检查。 • MVC 实现样例如果您希望创建您自己的 MVC 实现，则 Struts 可增加您的见识。 • 管理问题空间分治是解决问题并使问题可管理的极好方法。当然，这是一把双刃剑。问题越来越复杂，并且需要越来越多的管理。 Struts 的缺点 • 仍处于发展初期 Struts 开发仍处于初级阶段。他们正在向着发行版本 1.0 而努力，但与任何 1.0 版本一样，它不可能尽善尽美。 • 仍在变化中这个框架仍在快速变化。Struts 1.0 与 Struts 0.5 相比变化极大。为了避免使用不赞成使用的方法，您可能隔一天就需要下载最新的 Struts。在过去的 6 个月中，我目睹 Struts 库从 90K 增大到 270K 以上。由于 Struts 中的变化，我不得不数次修改我的示例，但我不保证我的示例能与您下载的 Struts 协同工作。 • 正确的抽象级别 Struts 是否提供了正确的抽象级别？对于网页设计人员而言，什么是正确的抽象级别呢？这是一个用 $64K 的文字才能解释清楚的问题。在开发网页的过程中，我们是否应该让网页设计人员访问 Java 代码？某些框架（如 Velocity）说不应该，但它提供了另一种 Web 开发语言让我们学习。在 UI 开发中限制访问 Java 有一定的合理性。最重要的是，如果让网页设计人员使用一点 Java，他将使用大量的 Java。在 Microsoft ASP 的开发中，我总是看到这样的情况。在 ASP 开发中，您应该创建 COM 对象，然后编写少量的 ASP 脚本将这些 COM 对象联系起来。但是，ASP 开发人员会疯狂地使用 ASP 脚本。我会听到这样的话，“既然我可以用 VBScript 直接编写 COM 对象，为什么还要等 COM 开发人员来创建它呢？”通过使用标记库，Struts 有助于限制 JSP 文件中所需的 Java 代码的数量。Logic Tag 就是这样的一种库，它对有条件地生成输出进行管理，但这并不能阻止 UI 开发人员对 Java 代码的狂热。无论您决定使用哪种类型的框架，您都应该了解您要在其中部署和维护该框架的环境。当然，这项任务真是说起来容易做起来难。 • 有限的适用范围 Struts 是一种基于 Web 的 MVC 解决方案，所以必须用 HTML、JSP 文件和 servlet 来实现它。 • J2EE 应用程序支持 Struts 需要支持 JSP 1.1 和 Servlet 2.2 规范的 servlet 容器。仅凭这一点远不能解决您的全部安装问题，除非使用 Tomcat 3.2。我用 Netscape iPlanet 6.0 安装这个库时遇到一大堆问题，按理说它是第一种符合 J2EE 的应用程序服务器。我建议您在遇到问题时访问 Struts 用户邮件列表的归档资料。 • 复杂性在将问题分为几个部分的同时也引入了复杂性。毫无疑问，要理解 Struts 必须接受一定的培训。随着变化的不断加入，这有时会令人很沮丧。欢迎访问本网站。 Struts 的前景在这个软件开发的新时代，一切都变得很快。在不到 5 年的时间内，我已经目睹了从 cgi/perl 到 ISAPI/NSAPI、再到使用 VB 的 ASP、一直到现在的 Java 和 J2EE 的变迁。Sun 正在尽力将新的变化反映到 JSP/servlet 体系结构中，正如他们对 Java 语言和 API 所作的更改一样。您可以从 Sun 的网站获得新的 JSP 1.2 和 Servlet 2.3 规范的草案。此外，一个标准 JSP 标记库即将出现。 3：外文出处 [1]Malcolm Davis. Struts——an open-source MVC implementation [2]IBM System Journal,2006

64位现在比较流行了，所以有很多朋友想把过去用VB6写的Inventor dll插件(32位)做个升级，以便支持64位Inventor。有两种方法可以实现这个目标。一种是把dll插件修改成exe插件，第二种方法是把VB6插件转变成VB.NET插件。Brian的博客对这两种方法有非常详细地介绍。以下转载至：http://modthemachine.typepad.co

本代码引自：http://www.Planet-Source-Code.com/vb/scripts/ShowCode.asp?txtCodeId=45195&lngWId=1CODE: Updated May 1st !!! PLEASE READ THESE COMMENTS AS THEY ARE *VERY* IMPORTANT Hijacking, or Inje

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