C# 基础（三十）BitmapImage对象和byte[]之间的互转、BitmapImage和Bitmap的互相转换

一、BitmapImage对象和byte[]之间的互转

参考了https://blog.csdn.net/gooapple/article/details/50616821 

        /// <summary>
        /// byte[]转为BitmapImage
        /// </summary>
        /// <param name="byteArray"></param>
        /// <returns></returns>
        public static BitmapImage ToImage(byte[] byteArray)
        {
            BitmapImage bmp = null;
 
            try
            {
                bmp = new BitmapImage();
                bmp.BeginInit();
                bmp.StreamSource = new MemoryStream(byteArray);
                bmp.EndInit();
            }
            catch
            {
                bmp = null;
            }
 
            return bmp;
        }
 
        /// <summary>
        /// BitmapImage转为byte[]
        /// </summary>
        /// <param name="bmp"></param>
        /// <returns></returns>
        public static byte[] ToByteArray(BitmapImage bmp)
        {
            byte[] ByteArray = null;
 
            try
            {
                Stream stream = bmp.StreamSource;
                if (stream != null && stream.Length > 0)
                {
                    stream.Position = 0;
                    using (BinaryReader br = new BinaryReader(stream))
                    {
                        ByteArray = br.ReadBytes((int)stream.Length);
                    }
                }
            }
            catch
            {
                return null;
            }
 
            return ByteArray;
        }

二、 BitmapImage和Bitmap互换

//将Bitmap对象转换成bitmapImage对象
public BitmapImage ConvertBitmapToBitmapImage(Bitmap bitmap)
{
    MemoryStream stream = new MemoryStream();
    bitmap.Save(stream, ImageFormat.Bmp);
    BitmapImage image = new BitmapImage();
    image.BeginInit();
    image.StreamSource = stream;
    image.EndInit();
    return image;
}


     //将bitmapImage对象转换成Bitmap对象
     public static System.Drawing.Bitmap BitmapImage2Bitmap(BitmapImage bitmapImage)
        {
            using (System.IO.MemoryStream outStream = new System.IO.MemoryStream())
            {
                BitmapEncoder enc = new BmpBitmapEncoder();
                enc.Frames.Add(BitmapFrame.Create(bitmapImage));
                enc.Save(outStream);
                System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(outStream);
 
                return bitmap; 
            }
 
        }

三、实际应用

1、不能用的代码，会遇到调用线程无法访问此对象，因为另一个线程拥有该对象，至今我还不清楚（应该不是 Dispatcher.BeginInvoke 更新UI的问题，可能是两个using的问题）。

代码如下：

  private void video_NewFrame(object sender, Video.NewFrameEventArgs eventArgs)
        {
            try
            {
                BitmapImage bi;
                Byte[] Array;
                using (var bitmap = (Bitmap)eventArgs.Frame.Clone())
                {
                    bi = bitmap.ToBitmapImage();
                    //将BitmapImage转成字节
                    Stream stream = bi.StreamSource;
                    if (stream != null && stream.Length > 0)
                    {                                                          
                        using (BinaryReader br = new BinaryReader(stream))
                        {
                            Array = br.ReadBytes((int)stream.Length);
                        }
                    }
                }     
                bi.Freeze(); // avoid cross thread operations and prevents leaks
                Dispatcher.BeginInvoke(new ThreadStart(delegate { videoPlayer.Source = bi; }));
            }
            catch (Exception exc)
            {
                MessageBox.Show("Error on _videoSource_NewFrame:\n" + exc.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
                StopCamera();
            }
        }

2、去掉里面的using，正常运行

   private void video_NewFrame(object sender, Video.NewFrameEventArgs eventArgs)
        {
            try
            {
                BitmapImage bi;
                Byte[] Array;
                using (var bitmap = (Bitmap)eventArgs.Frame.Clone())
                {
                    bi = bitmap.ToBitmapImage();
                    //将BitmapImage转成字节
                    Stream stream = bi.StreamSource;
                    if (stream != null && stream.Length > 0)
                    {
                        BinaryReader br = new BinaryReader(stream);
                        Array = br.ReadBytes((int)stream.Length);                     
                    }
                }     
                bi.Freeze(); // avoid cross thread operations and prevents leaks
                Dispatcher.BeginInvoke(new ThreadStart(delegate { videoPlayer.Source = bi; }));
            }
            catch (Exception exc)
            {
                MessageBox.Show("Error on _videoSource_NewFrame:\n" + exc.Message, "Error", MessageBoxButton.OK, MessageBoxImage.Error);
                StopCamera();
            }
        }