HttpSimpleClientProtocol::BeginInvoke Method (String^, String^, array<Object^>^, AsyncCallback^, Object^)

 

Starts an asynchronous invocation of a method of an XML Web service.

Namespace:   System.Web.Services.Protocols
Assembly:  System.Web.Services (in System.Web.Services.dll)

protected:
IAsyncResult^ BeginInvoke(
	String^ methodName,
	String^ requestUrl,
	array<Object^>^ parameters,
	AsyncCallback^ callback,
	Object^ asyncState
)

Parameters

methodName
Type: System::String^

The name of the XML Web service method.

requestUrl
Type: System::String^

The URL to use when creating the WebRequest.

parameters
Type: array<System::Object^>^

An array of objects containing the parameters to pass to the XML Web service method. The order of the values in the array corresponds to the order of the parameters in the calling method of the derived class.

callback
Type: System::AsyncCallback^

The delegate to call when the asynchronous method call is complete. If callback is null, the delegate is not called.

asyncState
Type: System::Object^

The additional information supplied by a client.

Return Value

Type: System::IAsyncResult^

An IAsyncResult that can be passed to the EndInvoke method to obtain the return values from the XML Web service method.

Exception Condition
Exception

The request reached the server computer, but was not processed successfully.

The methodName parameter is used to find the types of the parameters and return values of the method that is invoking the BeginInvoke method. It is also used to find custom attributes that may have been added to the method. SoapDocumentMethodAttribute, SoapRpcMethodAttribute, and XmlElementAttribute provide additional information on the derived method that is required for the HTTP protocol.

asyncState is passed into callback and is included in the IAsyncResult that is returned from the BeginInvoke method. It is useful for passing information from the context of the asynchronous call to the handling of the asynchronous result in callback.

The following code example is an ASP.NET Web Form, which calls an XML Web service named Math. Within the EnterBtn_Click function, the Web Form starts and completes an asynchronous invocation of the Add XML Web service method.

No code example is currently available or this language may not be supported.

The following code example is a proxy class generated by the Web Services Description Language tool (Wsdl.exe) for the Math XML Web service below. Within the BeginAdd method of the proxy class, the BeginInvoke method starts an asynchronous invocation of the Add XML Web service method.

namespace MyMath
{
   [XmlRootAttribute("snippet1>",Namespace="http://MyMath/",IsNullable=false)]
   public ref class Math: public HttpGetClientProtocol
   {
   public:
      Math()
      {
         this->Url = "http://www.contoso.com/math.asmx";
      }

      [HttpMethodAttribute(System::Web::Services::Protocols::XmlReturnReader::typeid,
      System::Web::Services::Protocols::UrlParameterWriter::typeid)]
      int Add( String^ num1, String^ num2 )
      {
         array<Object^>^temp0 = {num1,num2};
         return  *dynamic_cast<int^>(this->Invoke( "Add", String::Concat( this->Url, "/Add" ), temp0 ));
      }

      IAsyncResult^ BeginAdd( String^ num1, String^ num2, AsyncCallback^ callback, Object^ asyncState )
      {
         array<Object^>^temp1 = {num1,num2};
         return this->BeginInvoke( "Add", String::Concat( this->Url, "/Add" ), temp1, callback, asyncState );
      }

      int EndAdd( IAsyncResult^ asyncResult )
      {
         return  *dynamic_cast<int^>(this->EndInvoke( asyncResult ));
      }
   };
}

The following code example is the Math XML Web service, from which the preceding proxy class was created.

.NET Framework
Available since 1.1
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