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WebClient.UploadData Method (String, Byte[])

Uploads a data buffer to a resource identified by a URI.

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

public byte[] UploadData(
	string address,
	byte[] data


Type: System.String
The URI of the resource to receive the data.
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 sending the data.


There was no response from the server hosting the resource.

The UploadData method sends a data buffer to a resource.

This method uses the STOR command to upload an FTP resource. For an HTTP resource, the POST method is used. If the underlying request 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.

The UploadData method sends the content of data to the server without encoding it. This method blocks while uploading the data. To continue executing while waiting for the server's response, use one of the UploadDataAsync 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 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 to a Byte array and posts the array to the specified server using UploadData. Any response from the server is displayed to 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 data to be posted to the URI {0}:",uriString);
			string postData = Console.ReadLine();
			// Apply ASCII Encoding to obtain the string as a byte array.
			byte[] postArray = Encoding.ASCII.GetBytes(postData);
			Console.WriteLine("Uploading to {0} ...",  uriString);							
			//UploadData implicitly sets HTTP POST as the request method.
			byte[] responseArray = myWebClient.UploadData(uriString,postArray);

			// Decode and display the response.
			Console.WriteLine("\nResponse received was :{0}", Encoding.ASCII.GetString(responseArray));

.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.