WebClient.UploadFile Method (String, String)


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

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

public byte[] UploadFile(
	string address,
	string fileName


Type: System.String

The URI of the resource to receive the file. For example, ftp://localhost/samplefile.txt.

Type: System.String

The file to send to the resource. For example, "samplefile.txt".

Return Value

Type: System.Byte[]

A Byte array containing the body of the response from the resource.

Exception Condition

The address parameter is null.


The fileName parameter is null.


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


fileName is null, 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.

The UploadFile method sends a local file to a resource. This method uses the STOR command to upload an FTP resource. For an HTTP resource, the POST method is used.

This method blocks while uploading the file. To continue executing while waiting for the server's response, use one of the UploadFileAsync methods.

The POST method is defined by HTTP. If the underlying request does not use HTTP and POST is not understood by the server, 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("\nPlease enter the URI to post data to : ");
String uriString = Console.ReadLine();

// Create a new WebClient instance.
WebClient myWebClient = new WebClient();

Console.WriteLine("\nPlease enter the fully qualified path of the file to be uploaded to the URI");
string fileName = Console.ReadLine();
Console.WriteLine("Uploading {0} to {1} ...",fileName,uriString);

// Upload the file to the URI.
// The 'UploadFile(uriString,fileName)' method implicitly uses HTTP POST method.
byte[] responseArray = myWebClient.UploadFile(uriString,fileName);

// Decode and display the response.
Console.WriteLine("\nResponse Received.The contents of the file uploaded are:\n{0}", 

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="C#" runat=server>
void Page_Load(object sender, EventArgs e) {

	foreach(string f in Request.Files.AllKeys) {
		HttpPostedFile file = Request.Files[f];
		file.SaveAs("c:\\inetpub\\test\\UploadedFiles\\" + file.FileName);

<p> Upload complete.  </p>


to access the local file. Associated enumeration: Read.

.NET Framework
Available since 1.1
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