C# 获取系统关联文件图标完整类

能够通过文件扩展名得到相关连接的ICO,此类也是在别人的基础上修改过来的^-^

class SysFileInfo {
[DllImport("Shell32.dll", EntryPoint = "SHGetFileInfo", SetLastError = true, CharSet = CharSet.Auto)]
private static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbFileInfo, uint uFlags);
[DllImport("User32.dll", EntryPoint = "DestroyIcon")]
private static extern int DestroyIcon(IntPtr hIcon);
#region API 参数的常量定义
private const uint SHGFI_ICON = 0x100;
private const uint SHGFI_LARGEICON = 0x0; //大图标 32×32
private const uint SHGFI_SMALLICON = 0x1; //小图标 16×16
private const uint SHGFI_USEFILEATTRIBUTES = 0x10;
#endregion
/// <summary>
/// 保存文件信息的结构体
/// </summary>
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
struct SHFILEINFO {
public IntPtr hIcon;
public int iIcon;
}
/// <summary>
/// 获取文件类型的关联图标
/// </summary>
/// <param name="fileName">文件类型的扩展名或文件的绝对路径</param>
/// <param name="isLargeIcon">是否返回大图标</param>
/// <returns>获取到的图标</returns>
public static Icon GetIcon(string fileName, bool isLargeIcon) {
SHFILEINFO shfi = new SHFILEINFO();
IntPtr hI;
if (isLargeIcon) {
hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), SHGFI_ICON | SHGFI_USEFILEATTRIBUTES | SHGFI_LARGEICON);
}
else {
hI = SHGetFileInfo(fileName, 0, ref shfi, (uint)Marshal.SizeOf(shfi), SHGFI_ICON | SHGFI_USEFILEATTRIBUTES | SHGFI_SMALLICON);
}
Icon icon = Icon.FromHandle(shfi.hIcon).Clone() as Icon;
DestroyIcon(shfi.hIcon); //释放资源
return icon;
}
}