Method failed after 3310 successes

Question

I inherited the following extension method, which creates an ImageSource object based on the file path

public static class ImageSourceExtensions
{
    [StructLayout(LayoutKind.Sequential)]
    public 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 const uint SHGFI_ICON = 0x100;
    public const uint SHGFI_LARGEICON = 0x0;

    [DllImport("shell32.dll")]
    public static extern IntPtr SHGetFileInfo(string pszPath, uint dwFileAttributes, ref SHFILEINFO psfi, uint cbSizeFileInfo, uint uFlags);

    public static ImageSource GetIconFromFolder(this string filePath)
    {
        SHFILEINFO shinfo = new SHFILEINFO();
        SHGetFileInfo(filePath, 0, ref shinfo, (uint)Marshal.SizeOf(shinfo),
                SHGFI_ICON | SHGFI_LARGEICON);

        using (Icon i = Icon.FromHandle(shinfo.hIcon))
        {
            //Convert icon to a Bitmap source
            ImageSource img = Imaging.CreateBitmapSourceFromHIcon(
                                    i.Handle,
                                    new Int32Rect(0, 0, i.Width, i.Height),
                                    BitmapSizeOptions.FromEmptyOptions());

            return img;
        }
    }
}

This extension method works great for folders and files 3310 times. The following exception was thrown in a call to method 3311:

'Win32 handler that was passed to the icon is invalid or invalid type

This error occurs when using the shinfo.hIcon property .

The error was originally selected in my main application and each time was in a different file. Since then, I have extracted this class in a new project and can get the same error (after the same number of times) by doing this with the click of a button:

String path = @"C:\Generic Folder\Generic Document.pdf";

        for (int i = 0; i <4000; i++)
        {
            ImageSource img = path.GetIconFromFolder();
        }

Does anyone know of an obvious reason for this?

Answer 1

HANDLE s. Windows , ( ), , . , Windows , .

SHGetFileInfo hIcon SHFILEINFO, psfi, , DestroyIcon, .

, PInvoke DestroyIcon shinfo.hIcon .

, FromHandle, :

DestroyIcon Win32 API, .