WebClient.DownloadFile Method (Uri, String)
Downloads the resource with the specified URI to a local file.
Assembly: System (in System.dll)
The address parameter is Nothing.
The fileName parameter is Nothing.
The URI formed by combining BaseAddress and address is invalid.
filename is Nothing or Empty.
The file does not exist.
An error occurred while downloading data.
The method has been called simultaneously on multiple threads.
The DownloadFile method downloads to a local file data from the URI specified by in the address parameter. This method blocks while downloading the resource. To download a resource and continue executing while waiting for the server's response, use one of the DownloadFileAsync methods.
If the BaseAddress property is not an empty string ("") and address does not contain an absolute URI, address must be a relative URI that is combined with BaseAddress to form the absolute URI of the requested data. If the QueryString property is not an empty string, it is appended to address.
This method uses the RETR command to download an FTP resource. For an HTTP resource, the GET method is used.
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.
When using this method in a middle tier application, such as an ASP.NET page, you will receive an error if the account under which the application executes does not have permission to access the file.