如何在Webclient DownloadFileCompleted事件中检查文件是否已成功下载？

Question

private void Client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
}

我想检查这两种情况：

1. 如果出现错误，请执行某些操作。

2. 如果文件已成功下载，请执行某些操作。

Answer 1

您可以检查AsyncCompletedEventArgs实例的Error和Cancelled属性：

if (e.Error != null)
{
    // there was an error, do something
}
else if (!e.Cancelled)
{
    // file was downloaded fine and completed, do something
}