如何在Webclient DownloadFileCompleted事件中檢查文件是否成功下載？

Question

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

我要檢查這兩種情況下：

1. 如果有一個錯誤，然後做一些事情。

2. 如果文件成功下載，請執行一些操作。

Answer 1

您可以檢查AsyncCompletedEventArgs實例的Error和Cancelled屬性：

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