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在 WPF Image 控件中显示 Bitmap 数据

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方案一： 使用 MemoryStream

先将 Bitmap 储存成 MemoryStream ，然后指定给 BitmapImage 。

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void UpdateImageByMemoryStream()
{

    using (MemoryStream memory = new MemoryStream())
    {

        int w = 0, h = 0;

        MyDll.GetBitmapSize(ref w, ref h);
        System.Drawing.Bitmap bitmap;

        bitmap = new System.Drawing.Bitmap(w, h, System.Drawing.Imaging.PixelFormat.Format32bppArgb);


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

        while (true)
        {
            System.Drawing.Imaging.BitmapData bmpData =
            bitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bitmap.PixelFormat);

            // Get the address of the first line.
            IntPtr ptr = bmpData.Scan0;

            var status = MyDll.GetBitmapData(ptr) >= 0 ? true : false;

            // Unlock the bits.
            bitmap.UnlockBits(bmpData);

            if (status)
            {
    bitmap.Save(memory, System.Drawing.Imaging.ImageFormat.Bmp);
                UpdateUI(() =>
                {
                    memory.Position = 0;
                    BitmapImage bitmapimage = new BitmapImage();
                    bitmapimage.BeginInit();
                    bitmapimage.StreamSource = memory;
                    bitmapimage.CacheOption = BitmapCacheOption.OnLoad;
                    bitmapimage.EndInit();

                    imgPreview.Source = bitmapimage;
                });
            }
        }
    }
}

方案二： 调用 Imaging.CreateBitmapSourceFromHBitmap

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void UpdateImageByBitmap()
{


    int w = 0, h = 0;

    MyDll.GetBitmapSize(ref w, ref h);
    var bitmap = new System.Drawing.Bitmap(w, h, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

    System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height);
    while (true)
    {
        System.Drawing.Imaging.BitmapData bmpData =
            bitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, bitmap.PixelFormat);

        // Get the address of the first line.
        IntPtr ptr = bmpData.Scan0;

        var status = MyDll.GetBitmapData(ptr) >= 0 ? true : false;

        // Unlock the bits.
        bitmap.UnlockBits(bmpData);

        if (status)
            UpdateUI(() =>
            {
                imgPreview.Source = BitmapHelper.BitmapToBitmapSource(bitmap);
            });

    }
}
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public class BitmapHelper
{
    [DllImport("gdi32.dll")]
    private static extern bool DeleteObject(IntPtr hObject);
    public static BitmapSource BitmapToBitmapSource(System.Drawing.Bitmap bitmap)
    {
        IntPtr ptr = bitmap.GetHbitmap();
        BitmapSource result = Imaging.CreateBitmapSourceFromHBitmap(
            ptr, IntPtr.Zero, Int32Rect.Empty, 
            BitmapSizeOptions.FromEmptyOptions());
        //release resource
        DeleteObject(ptr);

        return result;
    }
}

方案三： 使用 WriteableBitmap

注：这个方法会长时间占用 UI 线程。

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void UpdateImageByWriteBitmap()
{
    int w = 0, h = 0;

    MyDll.GetBitmapSize(ref w, ref h);
    var rect = new System.Windows.Int32Rect(0, 0, w, h);

    UpdateUI(() =>
    {
        imgPreview.Source =
            writeBitmap = new WriteableBitmap(rect.Width, rect.Height, 96, 96, PixelFormats.Bgra32, null);
    });
    while (true)
    {
        UpdateUI(() =>
        {
            writeBitmap.Lock();
            if (MyDll.GetBitmapData(writeBitmap.BackBuffer) >= 0)
                writeBitmap.AddDirtyRect(rect);
            writeBitmap.Unlock();
        });
    }
}

MainWindow.xaml.cs

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using System;
using System.IO;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Interop;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace WpfDemo
{
	public partial class MainWindow : Window
	{
		Image imgPreview;
		WriteableBitmap writeBitmap;

		public MainWindow()
		{
			InitializeComponent();
		}

		void UpdateUI(Action x)
		{
			if (imgPreview.Dispatcher.CheckAccess())
			{
				x.Invoke();
			}
			else
			{
				imgPreview.Dispatcher.Invoke(x);
			}
		}

		// ...
	}
}

调用 DLL 获取图片数据

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public class MyDll
{
    // 获取图片大小
    [DllImport("xxx.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]
    public static extern void GetBitmapSize(ref int width, ref int height);

    // 获取图片数据，返回值大于 0 代表成功
    [DllImport("xxx.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Cdecl)]
    public static extern int GetBitmapData(IntPtr desFrameData);
}