c# – 如何从URI下载图像并从中创建位图对象？

public void test()
    {
            PostWebClient client = new PostWebClient(callback);
            cookieContainer = new CookieContainer();
            client.cookies = cookieContainer;
            client.download(new Uri("SITE"));
    }

    public void callback(bool error, string res)
    {
            byte[] byteArray = UnicodeEncoding.UTF8.GetBytes(res);

            MemoryStream stream = new MemoryStream( byteArray );
            var tmp = new BitmapImage();
            tmp.SetSource(stream);
    }

我在回调方法的最后一行收到“未指定的错误”.有趣的事实是,如果我使用BitmapImage(新的Uri(“SITE”))它运作良好…(我不能这样做,因为我想从该URL抓取cookie.图像是jpg.

PostWebClient类 – > http://paste.org/53413

System.Net.WebRequest request = 
        System.Net.WebRequest.Create(
        "http://www.microsoft.com//h/en-us/r/ms_masthead_ltr.gif");
    System.Net.WebResponse response = request.GetResponse();
    System.IO.Stream responseStream = 
        response.GetResponseStream();
    Bitmap bitmap2 = new Bitmap(responseStream);

MSDN link for Bitmap