c# - 在 WPF 中显示 Drawing.Image

Question

我有一个 System.Drawing.Image 的实例。

如何在我的 WPF 应用程序中显示这个？

我试过了，img.Source但这不起作用。

Answer 1

我有同样的问题并通过结合几个答案来解决它。

System.Drawing.Bitmap bmp;
Image image;
...
using (var ms = new MemoryStream())
{
    bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
    ms.Position = 0;

    var bi = new BitmapImage();
    bi.BeginInit();
    bi.CacheOption = BitmapCacheOption.OnLoad;
    bi.StreamSource = ms;
    bi.EndInit();
}

image.Source = bi;
//bmp.Dispose(); //if bmp is not used further. Thanks @Peter

从这个问题和答案

Answer 2

要将图像加载到 WPF 图像控件中，您将需要 System.Windows.Media.ImageSource。

您需要将您的 Drawing.Image 对象转换为 ImageSource 对象：

 public static BitmapSource GetImageStream(Image myImage)
    {
        var bitmap = new Bitmap(myImage);
        IntPtr bmpPt = bitmap.GetHbitmap();
        BitmapSource bitmapSource =
         System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
               bmpPt,
               IntPtr.Zero,
               Int32Rect.Empty,
               BitmapSizeOptions.FromEmptyOptions());

        //freeze bitmapSource and clear memory to avoid memory leaks
        bitmapSource.Freeze();
        DeleteObject(bmpPt);

        return bitmapSource;
    }

DeleteObject 方法的声明。

[DllImport("gdi32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool DeleteObject(IntPtr value);

Answer 3

如果您使用转换器，您实际上可以绑定到Image对象。您只需要创建一个IValueConverter将 转换Image为BitmapSource.

我在转换器中使用了 AlexDrenea 的示例代码来完成实际工作。

[ValueConversion(typeof(Image), typeof(BitmapSource))]
public class ImageToBitmapSourceConverter : IValueConverter
{
    [DllImport("gdi32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    internal static extern bool DeleteObject(IntPtr value);

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is null || !(value is Image myImage))
        {//ensure provided value is valid image.
            return null;
        }

        if (myImage.Height > Int16.MaxValue || myImage.Width > Int16.MaxValue)
        {//GetHbitmap will fail if either dimension is larger than max short value.
            //Throwing here to reduce cpu and resource usage when error can be detected early.
            throw new ArgumentException($"Cannot convert System.Drawing.Image with either dimension greater than {Int16.MaxValue} to BitmapImage.\nProvided image's dimensions: {myImage.Width}x{myImage.Height}", nameof(value));
        }

        using Bitmap bitmap = new Bitmap(myImage); //ensure Bitmap is disposed of after usefulness is fulfilled.
        IntPtr bmpPt = bitmap.GetHbitmap();
        try
        {
            BitmapSource bitmapSource =
             System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                   bmpPt,
                   IntPtr.Zero,
                   Int32Rect.Empty,
                   BitmapSizeOptions.FromEmptyOptions());

            //freeze bitmapSource and clear memory to avoid memory leaks
            bitmapSource.Freeze();
            return bitmapSource;
        }
        finally
        { //done in a finally block to ensure this memory is not leaked regardless of exceptions.
            DeleteObject(bmpPt);
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

在您的 XAML 中，您需要添加转换器。

<utils:ImageToBitmapSourceConverter x:Key="ImageConverter"/>

<Image Source="{Binding ThumbSmall, Converter={StaticResource ImageConverter}}"
                   Stretch="None"/>