public class GetBitmapImageClass

    {

        public  BitmapSource GetImageHttp(string url,int width)

        {

            var image = new BitmapImage();

            int BytesToRead = ;

            if (!string.IsNullOrEmpty(url))

            {

                WebRequest request = WebRequest.Create(new Uri(url, UriKind.Absolute));

                request.Timeout = -;

                WebResponse response = request.GetResponse();

                Stream responseStream = response.GetResponseStream();

                BinaryReader reader = new BinaryReader(responseStream);

                MemoryStream memoryStream = new MemoryStream();

                byte[] bytebuffer = new byte[BytesToRead];

                int bytesRead = reader.Read(bytebuffer, , BytesToRead);

                while (bytesRead > )

                {

                    memoryStream.Write(bytebuffer, , bytesRead);

                    bytesRead = reader.Read(bytebuffer, , BytesToRead);

                }

                image.BeginInit();

                image.DecodePixelWidth = width;

                image.CacheOption = BitmapCacheOption.OnLoad;

                memoryStream.Seek(, SeekOrigin.Begin);

                image.StreamSource = memoryStream;

                image.EndInit();

                image.Freeze();

                memoryStream.Close();

                reader.Close();

                responseStream.Close();

                response.Close();

            }

            return image;

        }

        public BitmapSource GetImageFtp(string url, int width)

        {

            var image = new BitmapImage();

            if (!string.IsNullOrEmpty(url))

            {

                FtpWebRequest reqFtp;

                reqFtp = (FtpWebRequest)FtpWebRequest.Create(new Uri(url));

                reqFtp.Method = WebRequestMethods.Ftp.DownloadFile;

                reqFtp.UseBinary = true;

                FtpWebResponse response = (FtpWebResponse)reqFtp.GetResponse();

                Stream ftpStream = response.GetResponseStream();

                MemoryStream mStream = new MemoryStream();

                ftpStream.CopyTo(mStream);

                mStream.Position = ;

                int length = (int)mStream.Length;

                byte[] returnbyte = new byte[length];

                mStream.Read(returnbyte, , length);

                mStream.Close();

                ftpStream.Close();

                response.Close();

                System.IO.MemoryStream stream = new System.IO.MemoryStream(returnbyte);

                image.BeginInit();

                image.DecodePixelWidth = width;

                image.CacheOption = BitmapCacheOption.OnLoad;

                stream.Seek(, SeekOrigin.Begin);

                image.StreamSource = stream;

                image.EndInit();

                image.Freeze();

                stream.Close();

            }

            return image;

        }

        [DllImport("gdi32.dll", SetLastError = true)]

        private static extern bool DeleteObject(IntPtr hObject);

        public BitmapSource ToBitmapSource(System.Drawing.Bitmap bmp)

        {

            try

            {

                var ptr = bmp.GetHbitmap();

                var source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(

                    ptr, IntPtr.Zero, Int32Rect.Empty, System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

                DeleteObject(ptr);

                return source;

            }

            catch

            {

                return null;

            }

        }

        //获取缩略图

        public BitmapSource GetBitImage(string imageLink)

        {

            //"http://172.17.1.231:8083/3050273262379466760/2017/05/28/09/340800100999/09163448402.jpg?fid=1267520"

            if (imageLink.StartsWith("http://"))

            {

                return GetImageHttp(imageLink,);

            }

            //ftp格式的

            else if (imageLink.StartsWith("ftp://"))

            {

                return GetImageFtp(imageLink, );

            }

        }

        //获取原图

        public BitmapSource GetHightBitImage(string imageLink)

        {

            //"http://172.17.1.231:8083/3050273262379466760/2017/05/28/09/340800100999/09163448402.jpg?fid=1267520"

            if (imageLink.StartsWith("http://"))

            {

                return GetImageHttp(imageLink, );

            }

            //ftp格式的

            else if (imageLink.StartsWith("ftp://"))

            {

                return GetImageFtp(imageLink, );

            }

        }

    }