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WebClient.UploadFile Method (String, String, String)

Uploads the specified local file to the specified resource, using the specified method.

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

Public Function UploadFile ( _
	address As String, _
	method As String, _
	fileName As String _
) As Byte()


Type: System.String

The URI of the resource to receive the file.

Type: System.String

The method used to send the file to the resource. If Nothing, the default is POST for http and STOR for ftp.

Type: System.String

The file to send to the resource.

Return Value

Type: System.Byte()
A Byte array containing the body of the response from the resource.


The address parameter is Nothing.


The fileName parameter is Nothing.


The URI formed by combining BaseAddress, and address is invalid.


fileName is Nothing, is Empty, contains invalid characters, or does not exist.


An error occurred while uploading the file.


There was no response from the server hosting the resource.


The Content-type header begins with multipart.

When address specifies an HTTP resource, the UploadFile method sends a local file to a resource using the HTTP method specified in the method parameter and returns any response from the server. This method blocks while uploading the file. To continue executing while waiting for the server's response, use one of the UploadFileAsync methods.

If the method parameter specifies a verb that is not understood by the server or the address resource, the underlying protocol classes determine what occurs. Typically, a WebException is thrown with the Status property set to indicate the error.

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 member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.

The following code example uploads the specified file to the specified URI using UploadFile. Any response returned by the server is displayed on the console.

            Console.Write(ControlChars.Cr + "Please enter the URL to post data to : ")
            Dim uriString As String = Console.ReadLine()

            ' Create a new WebClient instance. 
            Dim myWebClient As New WebClient()
            Console.WriteLine(ControlChars.Cr & _
                "Please enter the fully qualified path of the file to be uploaded to the URL")

            Dim fileName As String = Console.ReadLine()
            Console.WriteLine("Uploading {0} to {1} ...", fileName, uriString)

            ' Upload the file to the Url using the HTTP 1.0 POST. 
            Dim responseArray As Byte() = myWebClient.UploadFile(uriString, "POST", fileName)

            ' Decode and display the response.
            Console.WriteLine(ControlChars.Cr + "Response Received.The contents of the file uploaded are: " & _
                ControlChars.Cr & "{0}", System.Text.Encoding.ASCII.GetString(responseArray))

The following code example shows an ASP.NET page that can accept posted files and is suitable for use with the UploadFile method. The page must reside on a Web server. Its address provides the value for the address parameter of the UploadFile method.

<%@ Import Namespace="System"%>
<%@ Import Namespace="System.IO"%>
<%@ Import Namespace="System.Net"%>
<%@ Import NameSpace="System.Web"%>

<Script language="VB" runat=server>
    Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)

        Dim f As String
        Dim file
        For Each f In Request.Files.AllKeys
            file = Request.Files(f)
            file.SaveAs("c:\inetpub\test\UploadedFiles\" & file.FileName)
        Next f

    End Sub

<p> Upload complete. </p>

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

© 2015 Microsoft