c# - 如何从服务器获取照片并在 Image Control for Wp7 中显示

Question

我正在使用下面的代码。我只是不知道为什么它不起作用。错误消息是:关于此的未指定错误:bmp.SetSource(ms)。

我不熟悉 Wp7 的 HttpWebRequest。感谢您帮助解决这个问题。谢谢。

enter code here


 private void LoadPic()
    {
   HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(@"http://xxxxxx/MyImage.jpg");
        NetworkCredential creds = new NetworkCredential("Username", "Pwd");
        req.Credentials = creds;
        req.Method = "GET";
        req.BeginGetResponse(new AsyncCallback(GetStatusesCallBack), req);
    }

    public void GetStatusesCallBack(IAsyncResult result)
    {
        try
        {
            HttpWebRequest httpReq = (HttpWebRequest)result.AsyncState;
            HttpWebResponse response = (HttpWebResponse)httpReq.EndGetResponse(result);
            Stream myStream = response.GetResponseStream();
            int len = (int)myStream.Length;

            byte[] byt = new Byte[len];
            myStream.Read(byt, 0, len);
            myStream.Close();
            MemoryStream ms = new MemoryStream(byt);
            Deployment.Current.Dispatcher.BeginInvoke(() =>
            {
                BitmapImage bmp = new BitmapImage();
                bmp.SetSource(ms);

                image1.Source = bmp;
            });
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
   }

Answer 1

是否需要将响应流复制到一个字节数组，然后复制到一个MemoryStream？如果没有，您可以执行以下操作:

    Stream myStream = response.GetResponseStream();
    Deployment.Current.Dispatcher.BeginInvoke(() => {
        BitmapImage bmp = new BitmapImage();
        bmp.SetSource(myStream);
        image1.Source = bmp;
    });

如果出于某种原因必须进行复制，则需要循环填充缓冲区:

    Stream myStream = response.GetResponseStream();
    int contentLength = (int)myStream.Length;
    byte[] byt = new Byte[contentLength];
    for (int pos = 0; pos < contentLength; )
    {
        int len = myStream.Read(byt, pos, contentLength - pos);
        if (len == 0)
        {
            throw new Exception("Upload aborted.");
        }
        pos += len;
    }
    MemoryStream ms = new MemoryStream(byt);
    Deployment.Current.Dispatcher.BeginInvoke(() =>
    {
        // same as above
    });

第二部分(略微)改编自 C# bitmap images, byte arrays and streams! .