c# - WebClient 似乎不起作用？

Question

我有以下代码:

WebClient client = new WebClient();
client.OpenReadAsync(new Uri("whatever"));
client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);

和:

void client_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
  Stream reply = (Stream)e.Result;
  StreamReader s;
  s = new StreamReader(reply);
  this._code = s.ReadToEnd();
  s.Close();
}

在调试时我可以看到编译器没有进入 client_OpenReadCompleted 事件。错在哪里？我已经尝试使用 DownloadStringCompleted 和 DownloadStringAsync 代替，但这也不起作用。

感谢您的帮助。

Answer 1

您的操作顺序不正确。

//create an instance of webclient
WebClient client = new WebClient();
//assign the event handler
client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted);
//call the read method
client.OpenReadAsync(new Uri("whatever"));