Convert System.Drawing.Icon to System.Media.ImageSource

Question

I've got an IntPtr marshaled across an unmanaged/managed boundary that corresponds to an Icon Handle. Converting it to an Icon is trivial via the FromHandle() method, and this was satisfactory until recently.

Basically, I've got enough thread weirdness going on now that the MTA/STA dance I've been playing to keep a hosted WinForm from breaking the primary (WPF-tastic) UI of the application is too brittle to stick with. So the WinForm has got to go.

So, how can I get an ImageSource version of an Icon?

Note, I've tried ImageSourceConverter to no avail.

As an aside, I can get the underlying resource for some but not all of the icons involved and they generally exist outside of my application's assembly (in fact, they often exist in unmanaged dll's).

score 97 · Answer 1 · answered Jul 05 '11 at 09:54

97

Simple conversion method without creating any extra objects:

    public static ImageSource ToImageSource(this Icon icon)
    {
        ImageSource imageSource = Imaging.CreateBitmapSourceFromHIcon(
            icon.Handle,
            Int32Rect.Empty,
            BitmapSizeOptions.FromEmptyOptions());

        return imageSource;
    }

answered Jul 05 '11 at 09:54

Byte

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This solution seems more elegant than the one using Imaging.CreateBitmapSourceFromHBitmap. There's no need to create an unmanaged bitmap (and then have to remember to dispose of it) when Imaging can create the BitmapSource from the Icon handle directly. – Richard Walters Oct 19 '11 at 18:40
1

You're dragging in the obsolete `System.Drawing` to WPF... and if you are a WPF purist, this is a no-go. – Andy Feb 09 '17 at 14:55
`CreateBitmapSourceFromHIcon` lives in the `System.Windows.Interop` namespace so be sure to add your Using or Import statement. – Fütemire Jun 26 '17 at 22:46
1

@Andy I don't see how that's relevant given that OP is already using `System.Drawing.Icon` – radj307 May 16 '22 at 01:16
@radj -- read his question. Specifically *I've got an IntPtr marshaled across an unmanaged/managed boundary that corresponds to an Icon Handle.* He doesn't bring in `System.Drawing.Icon`. So there is no reason to use `System.Drawing` at all. Look at *@Justin Davis*' answer. That's the correct way. – Andy Jun 10 '22 at 00:39
@Andy In the second half of that paragraph OP mentions the *`FromHandle`* method, which I understood to be `System.Drawing.Icon.FromHandle(IntPtr)`; although I do agree that the answer you mentioned is a better approach, and I apologize if I came off as rude in my original comment. – radj307 Jun 12 '22 at 15:36

score 60 · Accepted Answer · edited Apr 20 '10 at 19:57

60

Try this:

Icon img;

Bitmap bitmap = img.ToBitmap();
IntPtr hBitmap = bitmap.GetHbitmap();

ImageSource wpfBitmap =
     Imaging.CreateBitmapSourceFromHBitmap(
          hBitmap, IntPtr.Zero, Int32Rect.Empty, 
          BitmapSizeOptions.FromEmptyOptions());

UPDATE: Incorporating Alex's suggestion and making it an extension method:

internal static class IconUtilities
{
    [DllImport("gdi32.dll", SetLastError = true)]
    private static extern bool DeleteObject(IntPtr hObject);

    public static ImageSource ToImageSource(this Icon icon)
    {            
        Bitmap bitmap = icon.ToBitmap();
        IntPtr hBitmap = bitmap.GetHbitmap();

        ImageSource wpfBitmap = Imaging.CreateBitmapSourceFromHBitmap(
            hBitmap,
            IntPtr.Zero,
            Int32Rect.Empty,
            BitmapSizeOptions.FromEmptyOptions());

        if (!DeleteObject(hBitmap))
        {
            throw new Win32Exception();
        }

        return wpfBitmap;
    }
}

Then you can do:

ImageSource wpfBitmap = img.ToImageSource();

edited Apr 20 '10 at 19:57

Jeff Moser

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answered Jul 14 '09 at 20:23

Kenan E. K.

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After doing this conversion, you should use the DeleteObject( IntPtr hObject ) call in gdi32.dll on the hBitmap to avoid a memory leak. – Alex Feb 05 '10 at 14:43
Even the updated solution might be causing the "Parameter is not valid" issue http://blog.lavablast.com/post/2007/11/The-Mysterious-Parameter-Is-Not-Valid-Exception.aspx in some certain situations, I'd need to investigate more though. It might be safer to use Darren's solution instead – Jeff Moser Apr 28 '10 at 14:59
I looked around the internet for quite sometime in efforts to get an answer to this solution. Most recommend using "Resource" rather than "Embedded Resource" to their project. The problem with that is if you do not wish to distribute & conceal the resourced info within the project, you will need to embed them. What was interesting to note was the of the resource being returned. In WPF for example, to set an Icon on the window it requires an type. Accessing the "Properties.Resource." has a native GDI type and will need to be converted to Windows.Media. – Latency Feb 22 '17 at 15:55
If you use an icon for the main application, it puts it local to the project anyway. Such is the case, if you wish to share this with your MainWindow icon, just use Icon="pack://application:,,,/MyApp;component/image.ico"> in the XAML which will embed it into the assembly just the same. – Latency Feb 22 '17 at 16:04

score 10 · Answer 3 · edited Jan 07 '11 at 09:43

10

MemoryStream iconStream = new MemoryStream();
myForm.Icon.Save(iconStream);
iconStream.Seek(0, SeekOrigin.Begin);
_wpfForm.Icon = System.Windows.Media.Imaging.BitmapFrame.Create(iconStream);

edited Jan 07 '11 at 09:43

Sam

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answered Aug 28 '09 at 14:35

Darren

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Do you need to dispose of the MemoryStream? – devios1 Jul 28 '10 at 01:27
should use Dispose on stream and for some reason this gives me very low quality, black and white images. anyone else has this problem? – Patrick Klug May 03 '11 at 01:18
1

@Patrick, I also had issues using a MemoryStream and getting very low quality output. I used [this solution](http://stackoverflow.com/a/6580799/947171) by Byte (from below). – Jon Peterson Aug 06 '13 at 20:52
You don't need to dispose a MemoryStream, it doesn't do anything except marking it as disposed: http://referencesource.microsoft.com/#mscorlib/system/io/memorystream.cs,0b83d17ca69bf8ea,references. However it will improve performance of the GC slightly since Stream.Dispose will remove it from the finalization queue. – poizan42 Sep 12 '16 at 08:50

score 10 · Answer 4 · answered Oct 27 '10 at 08:30

10

When using disposable streams it is almost always recommended to use 'using' blocks to force correct releasing of resources.

using (MemoryStream iconStream = new MemoryStream())
{
   icon.Save(iconStream);
   iconStream.Seek(0, SeekOrigin.Begin);

   this.TargetWindow.Icon = System.Windows.Media.Imaging.BitmapFrame.Create(iconStream);
}

Where icon is the source System.Drawing.Icon, and this.TargetWindow is the target System.Windows.Window.

answered Oct 27 '10 at 08:30

Derek Bartram

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getting really low quality image with this method – user230910 Mar 20 '16 at 06:31
MemoryStream.Dispose doesn't free anything though, http://referencesource.microsoft.com/#mscorlib/system/io/memorystream.cs,0b83d17ca69bf8ea,references – poizan42 Sep 12 '16 at 08:38
This causes my WPF application to crash with disposing exception. So, Windows needs that memory stream later on when displaying the icon. You need to keep that memory stream alive throughout your window's life. and dispose of it when the window has closed. – Andy Feb 09 '17 at 14:52
I fixed it... use this format and you can dispose of the memory stream as in the above sample: `BitmapFrame.Create(iconStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad)` – Andy Feb 09 '17 at 15:09

score 2 · Answer 5 · answered Jul 04 '16 at 18:52

Taking from some above this has created the highest quality of icons for my self. Loading the icons from a byte array. I use cache onload because if you don't you will get a disposed exception when you dispose the memory stream.

   internal static ImageSource ToImageSource(this byte[] iconBytes)
    {
        if (iconBytes == null)
            throw new ArgumentNullException(nameof(iconBytes));
        using (var ms = new MemoryStream(iconBytes))
        {
            return BitmapFrame.Create(ms, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
        }
    }

score 0 · Answer 6 · answered May 09 '16 at 12:39

Somehow similar example, only tuned from developer's use cases...

    [DllImport("shell32.dll")]
    public static extern IntPtr ExtractIcon(IntPtr hInst, string file, int nIconIndex);

    [DllImport("user32.dll", SetLastError = true)]
    static extern bool DestroyIcon(IntPtr hIcon);

    /// <summary>
    /// Gets application icon from main .exe.
    /// </summary>
    /// <param name="setToObject">object to which to set up icon</param>
    /// <param name="bAsImageSource">true if get it as "ImageSource" (xaml technology), false if get it as "Icon" (winforms technology)</param>
    /// <returns>true if successful.</returns>
    public bool GetIcon(object setToObject, bool bAsImageSource)
    {
        String path = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
        path = Path.Combine(path, "yourmainexecutableName.exe");
        int iIconIndex = 0;

        // If your application contains multiple icons, then
        // you could change iIconIndex here.

        object o2set = null;
        IntPtr hIcon = ExtractIcon(IntPtr.Zero, path, iIconIndex);
        if (hIcon == IntPtr.Zero)
            return false;

        Icon icon = (Icon)Icon.FromHandle(hIcon);
        if (bAsImageSource)
        {
            o2set = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                icon.ToBitmap().GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, 
                System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
        } else {
            icon = (Icon)icon.Clone();
        }

        DestroyIcon(hIcon);
        setToObject.GetType().GetProperty("Icon").SetValue(setToObject, o2set);
        return true;
    } //GetIcon

score -1 · Answer 7 · answered Sep 22 '15 at 09:53

There is a really simple solution to this problem.

Steps:

(1) add image to resources in solution explorer -> resources.resx (2) edit image properties inside "Resources" directory in solution explorer and change "Build action" to "Resource"

In xaml, add the following...

Icon="resources/name of image" (where "name of image" is the name of the image you added to resources - see point (1).

Convert System.Drawing.Icon to System.Media.ImageSource

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