幫助功能超出範圍（C＃）

Question

我想撥打CancelAsync，但webClient超出範圍。

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


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

有人能告訴我如何webClient.CancelAsync()可以從這個事件處理函數中調用請

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

你需要在一個領域的WebClient存儲在你的類。