IconHandler is a class for getting icons from files and the default associated icons by the extension of the file.
It was originally writtin for a P2P project that never got out, called Kibutz. I decided to add the shell and resource functions becouse of a comment I got here. The const value has also been fixed (check IconSize).
The class includes four simple-to-use functions:
IconFromFile(Filename,IconSize,Index) null will be returned.IconsFromFile(Filename,IconSize) Icon typed array of icons.IconFromExtension(Extension,IconSize) null will be returned.IconFromResource(string ResourceName) /*
/*
* IconHandler - by Gil Schmidt
*
* - Originaly was writtin for a p2p project called Kibutz.
* - The IconFromExtension might give you some problems if it won't find an
* icon for it( try/catch should be used).
*
* [Updated]
*
* - Added Shell function for getting file extension after getting some commet
* about it, check link below.
* (http://www.codeguru.com/Csharp/Csharp/cs_misc/icons/article.php/c4261/)
* - IconFromResource was added for having all the common needed functions for
* handling icons.
* - Readed DestroyIcon and adding GetManagedIcon, after verifying it's needed
* (thanks DrGui and Kenneth Broendum).
* - Removed the IconFromExtension that pulled the icon from the registry
* (IconFromExtensionShell is default now).
* - Fixed IconCount mistake (if the number of icon in the file was 0 and the
* index that was selected was also 0 the ExtractIconEx still got to run and
* crashed (thanks SickLab).
* - Fixed iIcon (it was changed from IntPtr to int. on x64 systems IntPtr is
* 8 bytes which caused the mistake to popup) parameter in SHFILEINFO struct
* (Thanks Stefan Mayr).
*
* contact me at: Gil_Smdt@Hotmail.com
*
*/
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using System.Reflection;
using System.IO;
namespace IconHandler
{
struct SHFILEINFO
{
public IntPtr hIcon;
public int iIcon;
public uint dwAttributes;
[MarshalAs( UnmanagedType.ByValTStr, SizeConst = 260 )]
public string szDisplayName;
[MarshalAs( UnmanagedType.ByValTStr, SizeConst = 80 )]
public string szTypeName;
};
public enum IconSize : uint
{
Large = 0x0, //32x32
Small = 0x1 //16x16
}
//the function that will extract the icons from a file
public class IconHandler
{
const uint SHGFI_ICON = 0x100;
const uint SHGFI_USEFILEATTRIBUTES = 0x10;
[DllImport("Shell32", CharSet=CharSet.Auto)]
internal extern static int ExtractIconEx (
[MarshalAs(UnmanagedType.LPTStr)]
string lpszFile, //size of the icon
int nIconIndex,
//index of the icon (in case we have more
//than 1 icon in the file
IntPtr[] phIconLarge, //32x32 icon
IntPtr[] phIconSmall, //16x16 icon
int nIcons); //how many to get
[DllImport("shell32.dll")]
static extern IntPtr SHGetFileInfo(
string pszPath, //path
uint dwFileAttributes, //attributes
ref SHFILEINFO psfi, //struct pointer
uint cbSizeFileInfo, //size
uint uFlags); //flags
//we need this function to release the unmanaged resource,
//the unmanaged resource will be copies to a managed one and
//it will be returned.
[DllImport("user32.dll", CharSet = CharSet.Auto)]
extern static bool DestroyIcon(IntPtr handle);
//will return an array of icons
public static Icon[] IconsFromFile(string Filename,IconSize Size)
{
int IconCount = ExtractIconEx(Filename,-1,null,null,0);
//checks how many icons.
IntPtr[] IconPtr = new IntPtr[IconCount];
Icon TempIcon;
//extracts the icons by the size that was selected.
if (Size == IconSize.Small)
ExtractIconEx(Filename,0,null,IconPtr,IconCount);
else
ExtractIconEx(Filename,0,IconPtr,null,IconCount);
Icon[] IconList = new Icon[IconCount];
//gets the icons in a list.
for (int i = 0; i < IconCount; i++)
{
TempIcon = (Icon) Icon.FromHandle(IconPtr[i]);
IconList[i] = GetManagedIcon(ref TempIcon);
}
return IconList;
}
//extract one selected by index icon from a file.
public static Icon IconFromFile(
string Filename,IconSize Size,int Index)
{
int IconCount = ExtractIconEx(Filename,-1,null,null,0);
//checks how many icons.
if (IconCount <= 0 || Index >= IconCount) return null;
// no icons were found.
Icon TempIcon;
IntPtr[] IconPtr = new IntPtr[1];
//extracts the icon that we want in the selected size.
if (Size == IconSize.Small)
ExtractIconEx(Filename,Index,null,IconPtr,1);
else
ExtractIconEx(Filename,Index,IconPtr,null,1);
TempIcon = Icon.FromHandle(IconPtr[0]);
return GetManagedIcon(ref TempIcon);
}
public static Icon IconFromExtension(string Extension,IconSize Size)
{
try
{
Icon TempIcon;
//add '.' if nessesry
if (Extension[0] != '.') Extension = '.' + Extension;
//temp struct for getting file shell info
SHFILEINFO TempFileInfo = new SHFILEINFO();
SHGetFileInfo(
Extension,
0,
ref TempFileInfo,
(uint)Marshal.SizeOf(TempFileInfo),
SHGFI_ICON | SHGFI_USEFILEATTRIBUTES | (uint) Size);
TempIcon = (Icon) Icon.FromHandle(TempFileInfo.hIcon);
return GetManagedIcon(ref TempIcon);
}
catch (Exception e)
{
System.Diagnostics.Debug.WriteLine(
"error while trying to get icon for " + Extension +
" :" + e.Message);
return null;
}
}
/*
* this is the built in funcion provided by .Net framework for getting
* a file icon, i thought it's worth mentioning.
*
public static Icon IconFromExtension(string Filename)
{
return Icon.ExtractAssociatedIcon(Filename);
}
*/
public static Icon IconFromResource(string ResourceName)
{
Assembly TempAssembly = Assembly.GetCallingAssembly();
return new Icon(TempAssembly.GetManifestResourceStream(
ResourceName));
}
public static void SaveIconFromImage(
Image SourceImage,string IconFilename,IconSize DestenationIconSize)
{
Size NewIconSize = DestenationIconSize ==
IconSize.Large ? new Size(32,32) : new Size(16,16);
Bitmap RawImage = new Bitmap(SourceImage,NewIconSize);
Icon TempIcon = Icon.FromHandle(RawImage.GetHicon());
FileStream NewIconStream = new FileStream(
IconFilename,FileMode.Create);
TempIcon.Save(NewIconStream);
NewIconStream.Close();
}
public static void SaveIcon(Icon SourceIcon,string IconFilename)
{
FileStream NewIconStream = new FileStream(
IconFilename,FileMode.Create);
SourceIcon.Save(NewIconStream);
NewIconStream.Close();
}
public static Icon GetManagedIcon(ref Icon UnmanagedIcon)
{
Icon ManagedIcon = (Icon) UnmanagedIcon.Clone();
DestroyIcon(UnmanagedIcon.Handle);
return ManagedIcon;
}
}
}
/* EOF */
What got me to write this was that I didn't find anything like this around. It's not complicated code, but when you want to use icons you don't plan on wasting your time dealing with it a lot. So, it's comfortable to have this little piece of code around.
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