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WebClient.DownloadFile Method (String, String)

Downloads the resource with the specified URI to a local file.

Namespace:  System.Net
Assembly:  System (in System.dll)

'Declaration
Public Sub DownloadFile ( _
	address As String, _
	fileName As String _
)

Parameters

address
Type: System.String

The URI from which to download data.

fileName
Type: System.String

The name of the local file that is to receive the data.

ExceptionCondition
ArgumentNullException

The address parameter is Nothing.

WebException

The URI formed by combining BaseAddress and address is invalid.

-or-

filename is Nothing or Empty.

-or-

The file does not exist.

-or- An error occurred while downloading data.

NotSupportedException

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.

NoteNote

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.

The following code example downloads a file from http://www.contoso.com to the local hard drive.

Dim remoteUri As String = "http://www.contoso.com/library/homepage/images/" 
Dim fileName As String = "ms-banner.gif" 
Dim myStringWebResource As String = Nothing 
' Create a new WebClient instance. 
Dim myWebClient As New WebClient()
' Concatenate the domain with the Web resource filename. Because DownloadFile  
'requires a fully qualified resource name, concatenate the domain with the Web resource file name.
myStringWebResource = remoteUri + fileName
Console.WriteLine("Downloading File ""{0}"" from ""{1}"" ......." + ControlChars.Cr + ControlChars.Cr, fileName, myStringWebResource)
' The DownloadFile() method downloads the Web resource and saves it into the current file-system folder.
myWebClient.DownloadFile(myStringWebResource, fileName)
Console.WriteLine("Successfully Downloaded file ""{0}"" from ""{1}""", fileName, myStringWebResource)
Console.WriteLine((ControlChars.Cr + "Downloaded file saved in the following file system folder:" + ControlChars.Cr + ControlChars.Tab + Application.StartupPath))

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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