WebClient does not support concurrent I/O operations

Question

How can I get this error from with in the DownloadStringCompleted Event? Doesn\'t that mean, it\'s finished? Is there another event I can fire this from?

I get this

Answer 1

The WebClient only supports a single operations, it cannot download multiple files. You haven't shown your code, but my guess is that you are somehow firing a new request before the old is completed. My bet is that WebClient.IsBusy is true when you attempt to perform another fetch.

See the following thread:

wb.DownloadFileAsync throw "WebClient does not support concurrent I/O operations." exception