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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 byte[] UploadData(
	string address,
	string method,
	byte[] 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 address parameter is null.


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


data is null.


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.

     	string uriString;
			Console.Write("\nPlease enter the URI to post data to {for example,} : ");
			uriString = Console.ReadLine();

			// Create a new WebClient instance.
			WebClient myWebClient = new WebClient();
			Console.WriteLine("\nPlease enter the data to be posted to the URI {0}:",uriString);
			string postData = Console.ReadLine();

      // Display the headers in the request
			Console.Write("Resulting Request Headers: ");
			// Apply ASCII Encoding to obtain the string as a byte array.

			byte[] byteArray = Encoding.ASCII.GetBytes(postData);
			Console.WriteLine("Uploading to {0} ...",  uriString);						
			// Upload the input string using the HTTP 1.0 POST method.
			byte[] responseArray = myWebClient.UploadData(uriString,"POST",byteArray);
			// Decode and display the response.
			Console.WriteLine("\nResponse received was {0}",

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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