帮助解决一个函数超出作用域的问题（C#）

Question

我试图调用CancelAsync，虽然webClient的作用域已经超出了范围。

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


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

请问有人可以展示一下如何在此事件处理程序中调用webClient.CancelAsync()吗？

- James Buttler

Answer 1

你需要在你的类中存储WebClient。

- SLaks

Answer 2

class ....
{
    WebClient webClient;

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


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

- Akram Shahda

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请注意，如果用户在未取消的情况下两次点击下载按钮，则会出现错误。 - CodesInChaos