WPF保存控件到图片

/// <summary>
/// 保存控件到图片
/// </summary>
/// <param name="element">控件对象</param>
/// <param name="fileName">文件名</param>
/// <param name="dpi">DPI</param>
public static void SaveControlToPng(FrameworkElement element, string fileName, int dpi = 96)
{
    var size = new System.Windows.Size(element.ActualWidth, element.ActualHeight);
    element.Measure(size);
    element.Arrange(new Rect(new System.Windows.Point(0, 0), size));

    var bitmap = new RenderTargetBitmap(
        (int) size.Width, //width
        (int) size.Height, //height
        dpi, //dpi x
        dpi, //dpi y
        PixelFormats.Pbgra32 // pixelformat
    );
    bitmap.Render(element);

    var encoder = new PngBitmapEncoder();
    encoder.Frames.Add(BitmapFrame.Create(bitmap));

    using (var stream = File.Create(fileName))
    {
        encoder.Save(stream);
    }
}