帮助功能超出范围（C＃）

Question

我想拨打CancelAsync，但webClient超出范围。

private void Download_Click(object sender, EventArgs e) 
{ 
    WebClient webClient = new WebClient(); 
} 


private void Button1_Click(object sender, EventArgs e) 
{ 
    webClient.CancelAsync(); 
} 

有人能告诉我如何webClient.CancelAsync()可以从这个事件处理函数中调用请

Answer 1

class .... 
{ 
    WebClient webClient; 

    private void Download_Click(object sender, EventArgs e) 
    { 
     webClient = new WebClient(); 
    } 


    private void Button1_Click(object sender, EventArgs e) 
    { 
     webClient.CancelAsync(); 
    } 

Answer 2

你需要在一个领域的WebClient存储在你的类。