Extract icon from exe dll or ico file

Question

I make an application that is similar to windows explorer. The problem is I don't know how to extract the icon from a file. I learn from a post about the same problem in vb. This is the code that I translate from vb to c#: [DllImport(shell32.dll)] public static extern long ExtractIcon(long lngInst string strExeFileName long lngIconIndex); [DllImport(user32.dll)] public static extern long DrawIcon(long lngDC long lngX long lngY long lngIcon); the problem for this codes is What are the lngInst and lngDC in C#? Please help me to do this. Thanks in advanced.

cprie · Answer

I had the same problem when trying to display the correct icons for word docs htmls ....  in my app. the functions i've used for that are ExtractIconEx to load the icons from the files and DestroyIcon to release them. ------------------------ /// /// Function to extract Icons from Dll or Exe file. /// [DllImport(Shell32.dll)] public static extern uint ExtractIconEx(string szFile // file name int iconIndex // icon index System.IntPtr[] iconLarge // large icon array System.IntPtr[] iconSmall // small icon array uint icons ); // number of icons to extract /// /// Function to Release Resources allocated by ExtractIconEx Function. /// [DllImport(user32.dll)] public static extern uint DestroyIcon(System.IntPtr hIcon); ----------------------------- cause i haven't found out how to load the icons directly from the doc (i dont think it's possible) i search the registry for the file extension and the registered icon Namespace for registry : using Microsoft.Win32; ---- heres my function /// /// Search Registry for extension and extract the icon for the extension. /// /// extension for which the bitmap should be found /// (.htm .doc ...) /// if true a icon with size 32x32 is extracted from /// registry; else a icon with size 16x16 is extracted /// bitmap which is registered for this extension or NULL if no one was /// found or a error occured public static System.Drawing.Image FindImage(string filePath bool largeImage) { string fileName = System.IO.Path.GetFileName(filePath).ToLower(); // files extension - used to search the registry string extension = System.IO.Path.GetExtension(filePath).ToLower(); // bitmap which is returned System.Drawing.Bitmap myBitmap = null; RegistryKey regKey = Registry.ClassesRoot; RegistryKey iconKey = null; try { // if file is an icon file load the icon directly from the file if(extension == .ico) myBitmap = largeImage ? new System.Drawing.Bitmap(new Bitmap(filePath) 32 32) : new System.Drawing.Bitmap(new Bitmap(filePath) 16 16); // IntPtr are used in the ExtractIconEx function System.IntPtr[] small = new System.IntPtr[ 1 ]; System.IntPtr[] large = new System.IntPtr[ 1 ]; // open extension subKey regKey = regKey.OpenSubKey( extension ); // get default entry string newKeyName = regKey != null ? regKey.GetValue().ToString() : null; if(newKeyName == null) return null; // set registryKey to ClassesRoot and opens the previous found registry key regKey = Registry.ClassesRoot; regKey = regKey.OpenSubKey( newKeyName ); // get the default icon registry key iconKey = regKey.OpenSubKey(DefaultIcon false); if(iconKey == null) { // if no default icon reg key was found continue search by searching for the open or edit commands // the extension is registered with iconKey = regKey.OpenSubKey(shell false); // if a open subkey exist use it otherwise search for an edit key if(new ArrayList(iconKey.GetSubKeyNames()).Contains(open)) iconKey = iconKey.OpenSubKey(open false); else if(new ArrayList(iconKey.GetSubKeyNames()).Contains(edit)) iconKey = iconKey.OpenSubKey(edit false); // if no open or edit key exists set value to null and a default icon 'll be used else iconKey = null; // return a default bitmap if no one was found if(iconKey == null) { if(largeImage) myBitmap = new Bitmap(new Bitmap( ) 32 32); else myBitmap = new Bitmap(new Bitmap( ) 16 16); return myBitmap; } // otherwise open the command subkey to get the programs exe file from where the icon can be extracted iconKey = iconKey.OpenSubKey(command false); if(iconKey != null) regKey = iconKey; } else regKey = iconKey; // open defaultIcon subkex and get the icon index string iconPath = regKey.GetValue().ToString(); // split the found command into command path (exe) and icon index string[] iconPath1 = iconPath.Split(''); string commandPath = iconPath1[0].Substring(0 iconPath1[0].LastIndexOf(.)+4).Trim('\'); int iconIndex = iconPath1.Length > 1 ? Convert.ToInt32(iconPath1[1]) : 0; // extract the icon from the found exe or dll at found index uint returnvalue = ExtractIconEx(commandPath iconIndex large small 1); // if no icon was found - set return value to default Icon if ( returnvalue == 0 || returnvalue == uint.MaxValue) { if(largeImage) myBitmap = new Bitmap(new Bitmap( ) 32 32); else myBitmap = new Bitmap(new Bitmap( ) 16 16); } // if largeIcon = true  set return value to large Icon if ( largeImage && large[ 0 ] != IntPtr.Zero ) myBitmap = Bitmap.FromHicon(large[0]); // else set return value to small icon else if ( !largeImage && small[ 0 ] != IntPtr.Zero ) { // Icon from registry myBitmap = Bitmap.FromHicon(small[0]); } // destroy icons and free the resources allocated cause this wont be done by the framework if(large[0] != IntPtr.Zero) returnvalue = DestroyIcon(large[0]); if(small[0] != IntPtr.Zero) returnvalue = DestroyIcon(small[0]); } catch(Exception ex) { ex.ToString(); return null; } finally { // close all open registry keys if(regKey != null) regKey.Close(); if(iconKey != null) iconKey.Close(); } // return found Icon return myBitmap; } I have tested it under windows 2000 and winxp. I'm not sure about win 98 cause the registry isn't the same under the diffrent os versions. I hate the registry -> if your code works under win2k it wont do the same under winxp!! Hope this 'll solve your problem or gives you a hint to do it in a better way than i. For questions on that code send me a mail to cprie@web.de prie

Extract icon from exe, dll, or ico file