我正在尝试在 WPF 应用程序中上传文件。如果服务器响应,一切正常,但应用程序将在“不安全”互联网连接的环境中使用。因此,如果第一次尝试失败,我想在短暂休息后重试上传。
我用 async/await 尝试了几件事,最后得到了以下代码。如果服务器正在运行,一切都很好,但如果不是,则程序在 while 循环的第二次迭代中失败并出现 ObjectDisposedException。
有任何想法吗?
private void UploadButton_Click(object sender, RoutedEventArgs e)
{
// build content to send
content = new MultipartFormDataContent();
var filestream = new FileStream(filePath, FileMode.Open);
var fileName = System.IO.Path.GetFileName(filePath);
content.Add(new StreamContent(filestream), "file", fileName);
content.Add(new StringContent(terminal_id.ToString()), "terminal_id");
UploadTask(content);
/*var task_a = new Task(() => UploadTask(content));
task_a.Start();*/
}
private async void UploadTask(HttpContent content)
{
bool success = false;
int counter = 0;
while (counter < 3 && !success)
{
Debug.WriteLine("starting upload");
success = await UploadFileAsync(content);
Debug.WriteLine("finished upload. result " + success.ToString());
//if (!success) System.Threading.Thread.Sleep(5000);
counter++;
}
}
private async Task<bool> UploadFileAsync(HttpContent content)
{
var message = new HttpRequestMessage();
message.Method = HttpMethod.Post;
message.Content = content;
message.RequestUri = new Uri(target_url);
using (HttpClient client = new HttpClient())
{
try
{
HttpResponseMessage res = await client.SendAsync(message);
if (res.IsSuccessStatusCode) return true;
}
catch (HttpRequestException hre)
{
Debug.WriteLine(hre.ToString());
}
return false;
}
}