[c#] 從System.Drawing.Bitmap加載WPF BitmapImage



4 Answers

感謝Hallgrim,這裡是我結束的代碼:

ScreenCapture = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
   bmp.GetHbitmap(), 
   IntPtr.Zero, 
   System.Windows.Int32Rect.Empty, 
   BitmapSizeOptions.FromWidthAndHeight(width, height));

我也結束了綁定到BitmapSource,而不是像我原來的問題

Question

我有一個System.Drawing.Bitmap的實例,並希望以System.Windows.Media.Imaging.BitmapImage的形式提供給我的WPF應用程序。

對此最好的方法是什麼?




// at class level;
[System.Runtime.InteropServices.DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObject);    // https://.com/a/1546121/194717


/// <summary> 
/// Converts a <see cref="System.Drawing.Bitmap"/> into a WPF <see cref="BitmapSource"/>. 
/// </summary> 
/// <remarks>Uses GDI to do the conversion. Hence the call to the marshalled DeleteObject. 
/// </remarks> 
/// <param name="source">The source bitmap.</param> 
/// <returns>A BitmapSource</returns> 
public static System.Windows.Media.Imaging.BitmapSource ToBitmapSource(this System.Drawing.Bitmap source)
{
    var hBitmap = source.GetHbitmap();
    var result = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(hBitmap, IntPtr.Zero, System.Windows.Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

    DeleteObject(hBitmap);

    return result;
}



我從這些資源建立起來。 https://.com/a/7035036 https://.com/a/1470182/360211

using System;
using System.Drawing;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;
using System.Security;
using System.Windows;
using System.Windows.Interop;
using System.Windows.Media.Imaging;
using Microsoft.Win32.SafeHandles;

namespace WpfHelpers
{
    public static class BitmapToBitmapSource
    {
        public static BitmapSource ToBitmapSource(this Bitmap source)
        {
            using (var handle = new SafeHBitmapHandle(source))
            {
                return Imaging.CreateBitmapSourceFromHBitmap(handle.DangerousGetHandle(),
                    IntPtr.Zero, Int32Rect.Empty,
                    BitmapSizeOptions.FromEmptyOptions());
            }
        }

        [DllImport("gdi32")]
        private static extern int DeleteObject(IntPtr o);

        private sealed class SafeHBitmapHandle : SafeHandleZeroOrMinusOneIsInvalid
        {
            [SecurityCritical]
            public SafeHBitmapHandle(Bitmap bitmap)
                : base(true)
            {
                SetHandle(bitmap.GetHbitmap());
            }

            [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
            protected override bool ReleaseHandle()
            {
                return DeleteObject(handle) > 0;
            }
        }
    }
}



我花了一些時間才能使轉換工作雙向進行,所以下面是我提出的兩種擴展方法:

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

public static class BitmapConversion {

    public static Bitmap ToWinFormsBitmap(this BitmapSource bitmapsource) {
        using (MemoryStream stream = new MemoryStream()) {
            BitmapEncoder enc = new BmpBitmapEncoder();
            enc.Frames.Add(BitmapFrame.Create(bitmapsource));
            enc.Save(stream);

            using (var tempBitmap = new Bitmap(stream)) {
                // According to MSDN, one "must keep the stream open for the lifetime of the Bitmap."
                // So we return a copy of the new bitmap, allowing us to dispose both the bitmap and the stream.
                return new Bitmap(tempBitmap);
            }
        }
    }

    public static BitmapSource ToWpfBitmap(this Bitmap bitmap) {
        using (MemoryStream stream = new MemoryStream()) {
            bitmap.Save(stream, ImageFormat.Bmp);

            stream.Position = 0;
            BitmapImage result = new BitmapImage();
            result.BeginInit();
            // According to MSDN, "The default OnDemand cache option retains access to the stream until the image is needed."
            // Force the bitmap to load right now so we can dispose the stream.
            result.CacheOption = BitmapCacheOption.OnLoad;
            result.StreamSource = stream;
            result.EndInit();
            result.Freeze();
            return result;
        }
    }
}



我來到這個問題,因為我試圖做同樣的事情,但在我的情況下,位圖來自資源/文件。 我發現最好的解決方案如下面的鏈接所述:

http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.bitmapimage.aspx

// Create the image element.
Image simpleImage = new Image();    
simpleImage.Width = 200;
simpleImage.Margin = new Thickness(5);

// Create source.
BitmapImage bi = new BitmapImage();
// BitmapImage.UriSource must be in a BeginInit/EndInit block.
bi.BeginInit();
bi.UriSource = new Uri(@"/sampleImages/cherries_larger.jpg",UriKind.RelativeOrAbsolute);
bi.EndInit();
// Set the image source.
simpleImage.Source = bi;



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Tags

c# c#   wpf   bitmap