WebClient::UploadValues Method (String^, String^, NameValueCollection^)


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Uploads the specified name/value collection to the resource identified by the specified URI, using the specified method.

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

array<unsigned char>^ UploadValues(
	String^ address,
	String^ method,
	NameValueCollection^ data


Type: System::String^

The URI of the resource to receive the collection.

Type: System::String^

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

Type: System.Collections.Specialized::NameValueCollection^

The NameValueCollection to send to the resource.

Return Value

Type: array<System::Byte>^

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

Exception Condition

The address parameter is null.


The data parameter is null.


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


data is null.


An error occurred while opening the stream.


There was no response from the server hosting the resource.


The Content-type header value is not null and is not application/x-www-form-urlencoded.

The UploadValues method sends a NameValueCollection to a resource using the 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 UploadValuesAsync methods.

If the Content-type header is null, the UploadValues method sets it to application/x-www-form-urlencoded.

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 in the .NET Framework.

The following code example gathers information from the user (name, age, and address) and posts the values to the server using UploadValues. Any response from the server is displayed on the console.

Console::Write( "\nPlease enter the URL to post data to: " );
String^ uriString = Console::ReadLine();

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

// Create a new NameValueCollection instance to hold some custom parameters to be posted to the URL.
NameValueCollection^ myNameValueCollection = gcnew NameValueCollection;

Console::WriteLine( "Please enter the following parameters to be posted to the URI" );
Console::Write( "Name: " );
String^ name = Console::ReadLine();

Console::Write( "Age: " );
String^ age = Console::ReadLine();

Console::Write( "Address: " );
String^ address = Console::ReadLine();

// Add necessary parameter/value pairs to the name/value container.
myNameValueCollection->Add( "Name", name );
myNameValueCollection->Add( "Address", address );
myNameValueCollection->Add( "Age", age );
Console::WriteLine( "\nUploading to {0} ...", uriString );

// Upload the NameValueCollection.
array<Byte>^ responseArray = myWebClient->UploadValues( uriString, "POST", myNameValueCollection );

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

.NET Framework
Available since 1.1
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