WebClient.OpenWrite Method (String, String) (System.Net)

Microsoft Developer Network

OpenWrite Method (String, String)

.NET Framework Class Library

WebClient..::.OpenWrite Method (String, String)

Opens a stream for writing data to the specified resource, using the specified method.

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

Syntax

Visual Basic (Declaration)

Public Function OpenWrite ( _
    address As String, _
    method As String _
) As Stream

Visual Basic (Usage)

Dim instance As WebClient
Dim address As String
Dim method As String
Dim returnValue As Stream

returnValue = instance.OpenWrite(address, _
    method)

public Stream OpenWrite(
    string address,
    string method
)

Visual C++

public:
Stream^ OpenWrite(
    String^ address, 
    String^ method
)

JScript

public function OpenWrite(
    address : String, 
    method : String
) : Stream

Parameters

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

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

Return Value

Type: System.IO..::.Stream
A Stream used to write data to the resource.

Exceptions

Exception	Condition
WebException	The URI formed by combining BaseAddress, and address is invalid. -or- An error occurred while opening the stream.

Exception

Condition

WebException

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

-or-

An error occurred while opening the stream.

Remarks

The OpenWrite method returns a writable stream that is used to send data to a resource. The underlying request is made with the method specified in the method parameter. The data is sent to the server when you close the stream. This method blocks while opening the stream. To continue executing while waiting for the stream, use one of the OpenWriteAsync methods.

If the method parameter specifies a method 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 specify an absolute address, 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.

Note:
This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

Examples

The following code example reads data from the command line and uses OpenWrite to obtain a stream used to write the data. Note that the Stream returned by OpenWrite must be closed to send the data.

Visual Basic

Dim uriString As String
Console.Write(ControlChars.Cr + "Please enter the URI to post data to : ")
uriString = Console.ReadLine()
Console.WriteLine(ControlChars.Cr + "Please enter the data to be posted to the URI {0}:", uriString)
Dim postData As String = Console.ReadLine()
' Apply ASCII encoding to obtain an array of bytes.
Dim postArray As Byte() = Encoding.ASCII.GetBytes(postData)

' Create a new WebClient instance.
Dim myWebClient As New WebClient()

Console.WriteLine("Uploading to {0} ...", uriString)
Dim postStream As Stream = myWebClient.OpenWrite(uriString, "POST")

postStream.Write(postArray, 0, postArray.Length)

' Close the stream and release resources.
postStream.Close()

Console.WriteLine(ControlChars.Cr + "Successfully posted the data.")

            string uriString;
            Console.Write("\nPlease enter the URI to post data to : ");
            uriString = Console.ReadLine();
            Console.WriteLine("\nPlease enter the data to be posted to the URI {0}:",uriString);
            string postData = Console.ReadLine();
            // Apply ASCII encoding to obtain an array of bytes .
            byte[] postArray = Encoding.ASCII.GetBytes(postData);

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

            Console.WriteLine("Uploading to {0} ...",  uriString);                        
            Stream postStream = myWebClient.OpenWrite(uriString,"POST");
            postStream.Write(postArray,0,postArray.Length);

            // Close the stream and release resources.
            postStream.Close();
            Console.WriteLine("\nSuccessfully posted the data.");

Visual C++

String^ uriString;
Console::Write( "\nPlease enter the URI to post data to: " );
uriString = Console::ReadLine();
Console::WriteLine( "\nPlease enter the data to be posted to the URI {0}:", uriString );
String^ postData = Console::ReadLine();
// Apply ASCII encoding to obtain an array of bytes .
array<Byte>^ postArray = Encoding::ASCII->GetBytes( postData );

// Create a new WebClient instance.
WebClient^ myWebClient = gcnew WebClient;

Console::WriteLine( "Uploading to {0} ...", uriString );
Stream^ postStream = myWebClient->OpenWrite( uriString, "POST" );
postStream->Write( postArray, 0, postArray->Length );

// Close the stream and release resources.
postStream->Close();
Console::WriteLine( "\nSuccessfully posted the data." );

Platforms

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.

Version Information

.NET Framework

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

Reference