WPF - 将位图转换为 ImageSource

Question

我需要将 System.Drawing.Bitmap 转换为 System.Windows.Media.ImageSource 类，以便将其绑定到 WizardPage（扩展 WPF 工具包）的 HeaderImage 控件中。 位图被设置为我编写的程序集的资源。 它被这样引用：

public Bitmap GetBitmap
{
   get
   {
      Bitmap bitmap = new Bitmap(Resources.my_banner);
      return bitmap;
   }
}

public ImageSource HeaderBitmap
{
   get
   {
      ImageSourceConverter c = new ImageSourceConverter();
      return (ImageSource)c.ConvertFrom(GetBitmap);
   }
}

转换器是我here找到的。我在

得到一个 NullReferenceException

return (ImageSource) c.ConvertFrom(Resources.my_banner);

如何初始化 ImageSource 以避免此异常？还是有其他方法？ 之后我想使用它：

<xctk:WizardPage x:Name="StartPage" Height="500" Width="700"
                 HeaderImage="{Binding HeaderBitmap}" 
                 Enter="StartPage_OnEnter"

提前感谢您的任何回答。

Answer 1

void Draw()
{
    System.Drawing.Bitmap bmp = new Bitmap();
    ...
    Image img = new Image();
    img.Source = BitmapToImageSource(bmp)
 }


private BitmapImage BitmapToImageSource(System.Drawing.Bitmap bitmap)
{
    using (MemoryStream memory = new MemoryStream())
    {
        bitmap.Save(memory, System.Drawing.Imaging.ImageFormat.Bmp);
        memory.Position = 0;
        BitmapImage bitmapimage = new BitmapImage();
        bitmapimage.BeginInit();
        bitmapimage.StreamSource = memory;
        bitmapimage.CacheOption = BitmapCacheOption.OnLoad;
        bitmapimage.EndInit();
        return bitmapimage;
    }
}

Answer 2

对其他人来说，这是可行的：

    //If you get 'dllimport unknown'-, then add 'using System.Runtime.InteropServices;'
    [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool DeleteObject([In] IntPtr hObject);

    public ImageSource ImageSourceFromBitmap(Bitmap bmp)
    {
        var handle = bmp.GetHbitmap();
        try
        {
            return Imaging.CreateBitmapSourceFromHBitmap(handle, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());
        }
        finally { DeleteObject(handle); }               
    }

Answer 3

dethSwatch - 感谢您在上面的回答！它帮助很大！在实现它之后，我得到了想要的行为，但我发现我在程序的另一部分遇到了内存/句柄问题。我将代码更改如下，使其更加冗长，问题就消失了。再次感谢！

    [DllImport("gdi32.dll", EntryPoint = "DeleteObject")]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool DeleteObject([In] IntPtr hObject);

    public ImageSource ImageSourceForBitmap(Bitmap bmp)
    {
        var handle = bmp.GetHbitmap();
        try
        {
            ImageSource newSource = Imaging.CreateBitmapSourceFromHBitmap(handle, IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());

            DeleteObject(handle);
            return newSource;
        }
        catch (Exception ex)
        {
            DeleteObject(handle);
            return null;
        }
    }

Answer 4

对我来说最简单的解决方案：

ImageBrush myBrush = new ImageBrush();
var bitmap = System.Drawing.Image.FromFile("pic1.bmp");
Bitmap bitmap = new System.Drawing.Bitmap(image);//it is in the memory now
var bitmapSource = Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(),IntPtr.Zero,Int32Rect.Empty,BitmapSizeOptions.FromEmptyOptions());
myBrush.ImageSource = bitmapSource;
cover.MainGrid.Background = myBrush;
cover.Show();
bitmap.Dispose();

Answer 5

为了搜索者的利益，我基于detailed solution 创建了一个快速转换器。

目前没有问题。

using System;
using System.Drawing;
using System.IO;
using System.Windows.Media.Imaging;

namespace XYZ.Helpers
{
    public class ConvertBitmapToBitmapImage
    {
        /// <summary>
        /// Takes a bitmap and converts it to an image that can be handled by WPF ImageBrush
        /// </summary>
        /// <param name="src">A bitmap image</param>
        /// <returns>The image as a BitmapImage for WPF</returns>
        public BitmapImage Convert(Bitmap src)
        {
            MemoryStream ms = new MemoryStream();
            ((System.Drawing.Bitmap)src).Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
            BitmapImage image = new BitmapImage();
            image.BeginInit();
            ms.Seek(0, SeekOrigin.Begin);
            image.StreamSource = ms;
            image.EndInit();
            return image;
        }
    }
}

Answer 6

我不相信ImageSourceConverter 会从System.Drawing.Bitmap 转换。但是，您可以使用以下内容：

public static BitmapSource CreateBitmapSourceFromGdiBitmap(Bitmap bitmap)
{
    if (bitmap == null)
        throw new ArgumentNullException("bitmap");

    var rect = new Rectangle(0, 0, bitmap.Width, bitmap.Height);

    var bitmapData = bitmap.LockBits(
        rect,
        ImageLockMode.ReadWrite,
        PixelFormat.Format32bppArgb);

    try
    {
        var size = (rect.Width * rect.Height) * 4;

        return BitmapSource.Create(
            bitmap.Width,
            bitmap.Height,
            bitmap.HorizontalResolution,
            bitmap.VerticalResolution,
            PixelFormats.Bgra32,
            null,
            bitmapData.Scan0,
            size,
            bitmapData.Stride);
    }
    finally
    {
        bitmap.UnlockBits(bitmapData);
    }
}

此方案要求源图片为 Bgra32 格式；如果您正在处理其他格式，则可能需要添加转换。