ExtractIconEx怎么返回NULL？

vcplusplus2005 2006-08-16 07:41:59

HICON hIcon;
CString strIconPath;
strIconPath = _T("C:\\program files\\FlashGet\\flashget.exe");
ExtractIconEx(strIconPath,128,&hIcon,NULL,1);

我用提图标软件就可以提出来。可是上面的代码却不行。

hIcon为NULL.
这是为什么呢？

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claider 2007-02-07

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vcplusplus2005 2006-08-17

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而且我用其他的抓图标程序，128是能抓出来的

vcplusplus2005 2006-08-17

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不是吧，C:\PROGRA~1\FlashGet\flashget.exe,128
这是我在注册表中找到的键值，难道是假的？
0是可以的。

cybermat 2006-08-17

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我用你的代码试过了，没问题啊，128确实也没超出索引范围。128正好是MFC默认的那个图标

cybermat 2006-08-17

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你把128改成0试过吗？

vcplusplus2005 2006-08-17

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当然不是这个问题，这个我是用其他的软件查出来的

vcplusplus2005 2006-08-17

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顶

cybermat 2006-08-16

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ExtractIconEx的第二个参数是图标在EXE或DLL中的索引，你用128可能是超出索引范围了

C# 根据文件类型获取文件图标 using System; using System.Collections.Generic; using System.Collections; using System.Text; using System.Runtime.InteropServices; using Microsoft.Win32; using System.Drawing; namespace FileTypeAndIcon { ///

/// Structure that encapsulates basic information of icon embedded in a file. ///

public struct EmbeddedIconInfo { public string FileName; public int IconIndex; } public class RegisteredFileType { #region APIs [DllImport("shell32.dll", EntryPoint = "ExtractIconA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)] private static extern IntPtr ExtractIcon(int hInst, string lpszExeFileName, int nIconIndex); [DllImport("shell32.dll", CharSet = CharSet.Auto)] private static extern uint ExtractIconEx(string szFileName, int nIconIndex, IntPtr[] phiconLarge, IntPtr[] phiconSmall, uint nIcons); [DllImport("user32.dll", EntryPoint = "DestroyIcon", SetLastError = true)] private static unsafe extern int DestroyIcon(IntPtr hIcon); #endregion #region CORE METHODS ///

/// Gets registered file types and their associated icon in the system. ///

/// Returns a hash table which contains the file extension as keys, the icon file and param as values. public static Hashtable GetFileTypeAndIcon() { try { // Create a registry key object to represent the HKEY_CLASSES_ROOT registry section RegistryKey rkRoot = Registry.ClassesRoot; //Gets all sub keys' names. string[] keyNames = rkRoot.GetSubKeyNames(); Hashtable iconsInfo = new Hashtable(); //Find the file icon. foreach (string keyName in keyNames) { if (String.IsNullOrEmpty(keyName)) continue; int indexOfPoint = keyName.IndexOf("."); //If this key is not a file exttension(eg, .zip), skip it. if (indexOfPoint != 0) continue; RegistryKey rkFileType = rkRoot.OpenSubKey(keyName); if (rkFileType == null) continue; //Gets the default value of this key that contains the information of file type. object defaultValue = rkFileType.GetValue(""); if (defaultValue == null) continue; //Go to the key that specifies the default icon associates with this file type. string defaultIcon = defaultValue.ToString() + "\\DefaultIcon"; RegistryKey rkFileIcon = rkRoot.OpenSubKey(defaultIcon); if (rkFileIcon != null) { //Get the file contains the icon and the index of the icon in that file. object value = rkFileIcon.GetValue(""); if (value != null) { //Clear all unecessary " sign in the string to avoid error. string fileParam = value.ToString().Replace("\"", ""); iconsInfo.Add(keyName, fileParam); } rkFileIcon.Close(); } rkFileType.Close(); } rkRoot.Close(); return iconsInfo; } catch (Exception exc) { throw exc; } } ///

/// Extract the icon from file. ///

/// The params string, /// such as ex: "C:\\Program Files\\NetMeeting\\conf.exe,1". /// This method always returns the large size of the icon (may be 32x32 px). public static Icon ExtractIconFromFile(string fileAndParam) { try { EmbeddedIconInfo embeddedIcon = getEmbeddedIconInfo(fileAndParam); //Gets the handle of the icon. IntPtr lIcon = ExtractIcon(0, embeddedIcon.FileName, embeddedIcon.IconIndex); //Gets the real icon. return Icon.FromHandle(lIcon); } catch (Exception exc) { throw exc; } } ///

/// Extract the icon from file. ///

/// The params string, /// such as ex: "C:\\Program Files\\NetMeeting\\conf.exe,1". /// /// Determines the returned icon is a large (may be 32x32 px) /// or small icon (16x16 px). public static Icon ExtractIconFromFile(string fileAndParam, bool isLarge) { unsafe { uint readIconCount = 0; IntPtr[] hDummy = new IntPtr[1] { IntPtr.Zero }; IntPtr[] hIconEx = new IntPtr[1] { IntPtr.Zero }; try { EmbeddedIconInfo embeddedIcon = getEmbeddedIconInfo(fileAndParam); if (isLarge) readIconCount = ExtractIconEx(embeddedIcon.FileName, 0, hIconEx, hDummy, 1); else readIconCount = ExtractIconEx(embeddedIcon.FileName, 0, hDummy, hIconEx, 1); if (readIconCount > 0 && hIconEx[0] != IntPtr.Zero) { // Get first icon. Icon extractedIcon = (Icon)Icon.FromHandle(hIconEx[0]).Clone(); return extractedIcon; } else // No icon read return null; } catch (Exception exc) { // Extract icon error. throw new ApplicationException("Could not extract icon", exc); } finally { // Release resources. foreach (IntPtr ptr in hIconEx) if (ptr != IntPtr.Zero) DestroyIcon(ptr); foreach (IntPtr ptr in hDummy) if (ptr != IntPtr.Zero) DestroyIcon(ptr); } } } #endregion #region UTILITY METHODS ///

/// Parses the parameters string to the structure of EmbeddedIconInfo. ///

/// The params string, /// such as ex: "C:\\Program Files\\NetMeeting\\conf.exe,1". /// protected static EmbeddedIconInfo getEmbeddedIconInfo(string fileAndParam) { EmbeddedIconInfo embeddedIcon = new EmbeddedIconInfo(); if (String.IsNullOrEmpty(fileAndParam)) return embeddedIcon; //Use to store the file contains icon. string fileName = String.Empty; //The index of the icon in the file. int iconIndex = 0; string iconIndexString = String.Empty; int commaIndex = fileAndParam.IndexOf(","); //if fileAndParam is some thing likes that: "C:\\Program Files\\NetMeeting\\conf.exe,1". if (commaIndex > 0) { fileName = fileAndParam.Substring(0, commaIndex); iconIndexString = fileAndParam.Substring(commaIndex + 1); } else fileName = fileAndParam; if (!String.IsNullOrEmpty(iconIndexString)) { //Get the index of icon. iconIndex = int.Parse(iconIndexString); if (iconIndex < 0) iconIndex = 0; //To avoid the invalid index. } embeddedIcon.FileName = fileName; embeddedIcon.IconIndex = iconIndex; return embeddedIcon; } #endregion } }

已知程序路径szFilePath HICON hIcon = NULL; ExtractIconEx(szFilePath, 0, NULL, &hIcon, 1); 函数具体怎么用呢？下面我们简单看一下：ExtractIconEx作用从指定的执行文件或DLL中获得图标句柄。原型HICON ExtractIconEx( LPCTSTR lp

从文件中抽取图标，我们可以选择使用ExtractIcon()或ExtractIconEx()，以及ExtractAssociatedIcon(),LoadImage()和SHGetFileInfo()。下面我们比较和对照一下这些函数的能力：函数描述 ExtractIcon() 从一个文件中抽取指定索引位置的图标，索

获取.exe/.dll/.icon文件的Icon图标资源

ExtractIconEx("Explorer.exe", 0, NULL, &hIcon, 1);0：表示我的电脑1：表示...2：表示...// 功能： // 得到系统图标，诸如文件夹，桌面图标 // 参数： // int nIndex 指定图标的索引，可取如下值 // . 0 默认图标 // . 1 默认的 .doc 图标 * // . 2 可执行文件图标 // . 3 关闭的文件夹图标 // . 4 打开的文件夹图标 // . 5 5.25 ' 驱动器图标 //

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