WPF ElementHost 内存泄露问题

无意中发现，WPF ElementHost 控件如果未正确释放，会存在内存泄露问题。解决方法如下：

xaml代码：

<Grid x:Name="grid">
    <WindowsFormsHost x:Name="host">
        <ElementHost x:Name="elementHost">
            <local:MultiPlayerController x:Name="multiPlayer"></local:MultiPlayerController>
        </ElementHost>
    </WindowsFormsHost>
</Grid>

后台资源释放代码：

public void Dispose()
{
    multiPlayer.StopAll();

    if (elementHost != null)
    {
        FrameworkElement frameworkElement = elementHost.Child as FrameworkElement;
        if (frameworkElement != null)
        {
            // Memory leak workaround: elementHost.Child.SizeChanged -= elementHost.childFrameworkElement_SizeChanged;
            SizeChangedEventHandler handler = (SizeChangedEventHandler)Delegate.CreateDelegate(typeof(SizeChangedEventHandler), elementHost, "childFrameworkElement_SizeChanged");
            frameworkElement.SizeChanged -= handler;
        }

        elementHost.Child = null;
        elementHost.Dispose();
        elementHost = null;
    }
    if (host != null)
    {
        host.Child = null;
        host.Dispose();
        host = null;
    }
    grid.Children.Clear();
}

关键代码：

SizeChangedEventHandler handler = (SizeChangedEventHandler)Delegate.CreateDelegate(typeof(SizeChangedEventHandler), elementHost, "childFrameworkElement_SizeChanged");
frameworkElement.SizeChanged -= handler;

另外 grid.Children.Clear() 也不能省。

参考资料：https://stackoverflow.com/questions/24823103/how-to-clear-memoryleak-from-elementhost-control