How Can I Prevent Memory Leaks When Using WPF's CreateBitmapSourceFromHBitmap()?

Avoiding Memory Leaks in WPF's CreateBitmapSourceFromHBitmap()

Overview

WPF's CreateBitmapSourceFromHBitmap() offers a convenient way to integrate System.Drawing.Bitmap images into WPF applications. However, improper usage can result in significant memory leaks.

The Memory Leak Issue

Repeated calls to CreateBitmapSourceFromHBitmap() without proper cleanup lead to a steady increase in application memory consumption. This stems from the failure to release the underlying GDI bitmap resources associated with the System.Drawing.Bitmap object.

The Solution: Explicit Resource Release

To prevent memory leaks, explicitly delete the GDI bitmap handle after using it with CreateBitmapSourceFromHBitmap(). The following code demonstrates this crucial step:

<code class="language-csharp">[DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObject);

using (System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(1000, 1000))
{
    IntPtr hBitmap = bmp.GetHbitmap();

    try
    {
        var source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());
        // Use the 'source' BitmapSource here...
    }
    finally
    {
        DeleteObject(hBitmap);
    }
}</code>

The using statement ensures the System.Drawing.Bitmap is correctly disposed, even if exceptions occur.

Best Practices

• Dispose Order: Ensure the System.Drawing.Bitmap object is disposed of before the BitmapSource to prevent potential cross-thread access problems.
• Alternative Approach: Consider using WPF's Imaging.CreateBitmapSource() as a preferable alternative. This method inherently manages the underlying bitmap resources, eliminating the need for manual cleanup and reducing the risk of memory leaks.

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