【WPF】wpf image控件加载网络图片不显示问题，

1、加载网络图片到内存system.drawing.image对象中
2、内存中的image 转Bitmap 再转适合system.windows.controls.image 的BitmapImage类型

为什么：网络延迟，得不到实时的图片信息

            string userHeadPic = "http://123.56.178.100/headpic/7.jpg";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(userHeadPic);
            WebResponse response = request.GetResponse();
            System.Drawing.Image img = System.Drawing.Image.FromStream(response.GetResponseStream());
            Bitmap bitMap = new Bitmap(img);
            BitmapImage bitUserLogo = BitmapToBitmapImage(bitMap);
            SchoolPubData.UserInfo.imgHead.Source = bitUserLogo;
            SchoolPubData.MainForm.ToSchoolSwitchPage();

        public BitmapImage BitmapToBitmapImage(Bitmap bitmap)
        {
            Bitmap bitmapSource = new Bitmap(bitmap.Width, bitmap.Height);
            int i, j;
            for (i = 0; i < bitmap.Width; i++)
                for (j = 0; j < bitmap.Height; j++)
                {
                    System.Drawing.Color pixelColor = bitmap.GetPixel(i, j);
                    System.Drawing.Color newColor = System.Drawing.Color.FromArgb(pixelColor.R, pixelColor.G, pixelColor.B);
                    bitmapSource.SetPixel(i, j, newColor);
                }
            MemoryStream ms = new MemoryStream();
            bitmapSource.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
            BitmapImage bitmapImage = new BitmapImage();
            bitmapImage.BeginInit();
            bitmapImage.StreamSource = new MemoryStream(ms.ToArray());
            bitmapImage.EndInit();
            return bitmapImage;
        }