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WebClient.UploadData Method (String, String, Byte())

Uploads a data buffer to the specified resource, using the specified method.

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

Public Function UploadData ( _
	address As String, _
	method As String, _
	data As Byte() _
) As Byte()
Dim instance As WebClient 
Dim address As String 
Dim method As String 
Dim data As Byte()
Dim returnValue As Byte()

returnValue = instance.UploadData(address, _
	method, data)


Type: System.String

The URI of the resource to receive the data.

Type: System.String

The HTTP method used to send the data to the resource. If null, the default is POST for http and STOR for ftp.

Type: System.Byte()

The data buffer to send to the resource.

Return Value

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


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


data is Nothing.


An error occurred while uploading the data.


There was no response from the server hosting the resource.

The UploadData method sends a data buffer 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 data. To continue executing while waiting for the server's response, use one of the UploadDataAsync methods.

The UploadData method sends the content of data to the server without encoding it.

If the method parameter specifies a verb that 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.

The following code example converts a string entered from the console into a byte array and posts the array to the specified server using UploadData. Any response from the server is displayed to the console.

Dim uriString As String
Console.Write(ControlChars.Cr + "Please enter the URI to post data to{for example,} : ")
uriString = Console.ReadLine()

' Create a new WebClient instance. 
Dim myWebClient As New WebClient()
Console.WriteLine(ControlChars.Cr + "Please enter the data to be posted to the URI {0}:", uriString)
Dim postData As String = Console.ReadLine()
myWebClient.Headers.Add("Content-Type", "application/x-www-form-urlencoded")

' Display the headers in the request
Console.Write("Resulting Request Headers: ")

' Apply ASCII Encoding to obtain the string as a byte array. 
Dim byteArray As Byte() = Encoding.ASCII.GetBytes(postData)
Console.WriteLine("Uploading to {0} ...", uriString)
' Upload the input string using the HTTP 1.0 POST method. 
Dim responseArray As Byte() = myWebClient.UploadData(uriString, "POST", byteArray)
' Decode and display the response.
Console.WriteLine(ControlChars.Cr + "Response received was :{0}", Encoding.ASCII.GetString(responseArray))
String* uriString;
Console::Write(S"\nPlease enter the URI to post data to {for example,} : ");
uriString = Console::ReadLine();
// Create a new WebClient instance.
WebClient* myWebClient = new WebClient();
Console::WriteLine(S"\nPlease enter the data to be posted to the URI {0}:", uriString);
String* postData = Console::ReadLine();
myWebClient->Headers->Add(S"Content-Type", S"application/x-www-form-urlencoded");
// Apply ASCII Encoding to obtain the String* as a Byte array.
Byte byteArray[] = Encoding::ASCII->GetBytes(postData);
Console::WriteLine(S"Uploading to {0} ...",  uriString);
// Upload the input String* using the HTTP 1.0 POST method.
Byte responseArray[] = myWebClient->UploadData(uriString, S"POST", byteArray);
// Decode and display the response.
Console::WriteLine(S"\nResponse received was {0}",

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0