帮助超出范围的函数（C＃）

Question

我正在尝试拨打CancelAsync，但webClient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();
}

有人可以告诉我如何从这个事件处理程序中调用webClient.CancelAsync()

Answer 1

您需要将WebClient存储在班级的字段中。

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();
    }