Is there a way to get different sizes of the Windows system icons in .NET?

Question

In particular I'd like to be able to get the small (16 x 16) icons at runtime.

I tried this:

new Icon(SystemIcons.Error, SystemInformation.SmallIconSize)

Which supposedly "attempts to find a version of the icon that matches the requested size", but it's still giving me a 32 x 32 icon. I also tried:

Size iconSize = SystemInformation.SmallIconSize;
Bitmap bitmap = new Bitmap(iconSize.Width, iconSize.Height);
using (Graphics g = Graphics.FromImage(bitmap))
{
    g.DrawIcon(SystemIcons.Error, new Rectangle(Point.Empty, iconSize));
}

But that just scales the 32 x 32 icon down into an ugly 16 x 16.

I've considered just pulling icons out of the VS Image Library, but I really want them to vary dynamically with the OS (XP icons on XP, Vista icons on Vista, etc.). I'm willing to P/Invoke if that's what it takes.

Answer 1

You have to scale them yourself. The SystemIcons, as you found out, only have 32x32. You can easily scale them to 16 or 48 as needed. Use interpolation to get a nice bicubic resize. We've done this many times successfully to create very nice looking 16x16 versions and it works fine whether running XP or Vista or 7.

Size iconSize = SystemInformation.SmallIconSize;
Bitmap bitmap = new Bitmap(iconSize.Width, iconSize.Height);

using (Graphics g = Graphics.FromImage(bitmap))   
{
    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
    g.DrawImage(SystemIcons.Error.ToBitmap(), new Rectangle(Point.Empty, iconSize));   
}

Icon smallerErrorIcon = Icon.FromHandle(bitmap.GetHicon());

Be sure to check out the MSDN example here, especially their use of the DestroyIcon method to clean up the handle when you're done.