invalid variant operation 错误

依赖太阳生存 2013-06-13 07:29:49
invalid variant operation

ADOQuery1->Open();
AnsiString cfh;
cfh=ADOQuery1->FieldValues["ssno"]+DateToStr(Date())+Edit2->Text;
an1= " select * from cure where ";
an1 +=" psno='"+Edit1->Text+"' and cfsno ='"+cfh+"'";
ADOQuery1->SQL->Clear();
ADOQuery1->SQL->Add(an1);
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勉励前行 2013-06-13
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ADOQuery1->FieldValues["ssno"] 得到的是一个 Variant , 如果是 NULL 时,是不能转换成 String 的,就会抛出Variant 转换异常。 但是,使用 AsString 方法,得到的就是字符串,这时是无法区别出字段中是空字符串还是 NULL,NULL及空字符串,印象中一些数据库是没区别,一些有区别。
缘中人 2013-06-13
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ADOQuery1->FieldValues["ssno"] Change To ADOQuery1->FieldByName("ssno")AsString
Delphi 7.1 Update Release Notes=======================================================This file contains important supplemental and late-breakinginformation that may not appear in the main productdocumentation, and supersedes information contained in otherdocuments, including previously installed release notes.Borland recommends that you read this file in its entirety.NOTE: If you are updating a localized version of Delphi 7, visit the Borland Registered User web site to obtain a localized readme file that may contain important late- breaking information not included in this readme file.IMPORTANT: Delphi must be closed before installing this update. =====================================================CONTENTS * INSTALLING THIS UPDATE * UPDATING LOCALIZED VERSIONS OF DELPHI 7 * KNOWN ISSUES * ISSUES ADDRESSED BY THIS UPDATE - IDE - CORE DATABASE - DATASNAP - DBGO (ADO COMPONENTS) - dbExpress - dbExpress COMPONENTS AND DB VCL - dbExpress CORE DRIVER AND METADATA - dbExpress VENDOR ISSUES - dbExpress CERTIFICATION - WEB SNAP - ACTIVEX - COMPILER - RTL - VCL - THIRD PARTY - BOLD FOR DELPHI * VERIFYING THAT THE UPDATE WAS SUCCESSFUL * FILES INSTALLED BY THIS UPDATE =======================================================INSTALLING THIS UPDATE* This update can not be applied to Delphi 7 Architect Trial version. * This update can not be removed after it is installed.* You will need the original Delphi 7 installation CD available to install this update.* To install this update from the CD, insert the CD, and launch the d7_ent_upd1.exe file appropriate for your locale.* To install this update from the Web, double-click the self-executing installation file and follow the prompts. * The Delphi 7 documentation PDF files are available on the update CD.========================================================UPDATING LOCALIZED VERSIONS OF DELPHI 7* This update can be applied only to the English version of Delphi 7. There are separate updates for the German, French and Japanese ver
Version 1.7 ----------- - ADD: Delphi/CBuilder 10.2 Tokyo now supported. - ADD: Delphi/CBuilder 10.1 Berlin now supported. - ADD: Delphi/CBuilder 10 Seattle now supported. - ADD: Delphi/CBuilder XE8 now supported. - ADD: Delphi/CBuilder XE7 now supported. - ADD: Delphi/CBuilder XE6 now supported. - ADD: Delphi/CBuilder XE5 now supported. - ADD: Delphi/CBuilder XE4 now supported. - ADD: Delphi/CBuilder XE3 now supported. - ADD: Delphi/CBuilder XE2 now supported. - ADD: Delphi/CBuilder XE now supported. - ADD: Delphi/CBuilder 2010 now supported. - ADD: Delphi/CBuilder 2009 now supported. - ADD: New demo project FlexCADImport. - FIX: The height of the TFlexRegularPolygon object incorrectly changes with its rotation. - FIX: Added division by zero protect in method TFlexControl.MovePathSegment. - FIX: The background beyond docuemnt wasn't filled when TFlexPanel.DocClipping=True. - FIX: In "Windows ClearType" font rendering mode (OS Windows mode) the "garbage" pixels can appear from the right and from the bottom sides of the painted rectangle of the TFlexText object. - FIX: The result rectangle incorrectly calculated in the TFlexText.GetRefreshRect method. - FIX: Added FPaintCache.rcPaint cleanup in the TFlexPanel.WMPaint method. Now it is possible to define is the drawing take place via WMPaint or via the PaintTo direct call (if rcPaint contain non-empty rectangle then WMPaint in progress). - FIX: The TFlexPanel.FPaintCache field moved in the protected class section. Added rcPaint field in FPaintCache that represents drawing rectangle. - ADD: In the text prcise mode (TFlexText.Precise=True) takes into account the rotation angle (TFlexText.Angle). - FIX: Removed FG_NEWTEXTROTATE directive (the TFlexText Precise mode should be used instead). - FIX: The TFlexRegularPolygon object clones incorrectly drawed in case when TFlexRegularPolygon have alternative brush (gradient, texture). - ADD: Add TFlexPanel.InvalidateControl virtual method which calls from TFle

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