SoapHttpClientProtocol.BeginInvoke Method

Reference

Definition

Namespace:: System.Web.Services.Protocols

Assembly:: System.Web.Services.dll

Important

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Starts an asynchronous invocation of an XML Web service method using SOAP.

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

protected IAsyncResult BeginInvoke (string methodName, object[] parameters, AsyncCallback callback, object asyncState);

member this.BeginInvoke : string * obj[] * AsyncCallback * obj -> IAsyncResult

Protected Function BeginInvoke (methodName As String, parameters As Object(), callback As AsyncCallback, asyncState As Object) As IAsyncResult

Parameters

methodName: String

The name of the XML Web service method in the derived class that is invoking the BeginInvoke(String, Object[], AsyncCallback, Object) method.

parameters: Object[]

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

callback: AsyncCallback

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

asyncState: Object

Extra information supplied by the caller.

Returns

IAsyncResult

An IAsyncResult that is passed to the EndInvoke(IAsyncResult) method to obtain the return values from the remote method call.

Exceptions

SoapException

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

InvalidOperationException

The request was not valid for the object's current state.

WebException

An error occurred while accessing the network.

Examples

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

#using <System.Web.Services.dll>
#using <System.Xml.dll>
#using <System.dll>

using namespace System::Diagnostics;
using namespace System::Xml::Serialization;
using namespace System;
using namespace System::Web::Services::Protocols;
using namespace System::Web::Services;

namespace MyMath
{

   [System::Web::Services::WebServiceBindingAttribute(Name="MyMathSoap",Namespace="http://www.contoso.com/")]
   public ref class MyMath: public System::Web::Services::Protocols::SoapHttpClientProtocol
   {
   public:

      [System::Diagnostics::DebuggerStepThroughAttribute]
      MyMath()
      {
         this->Url = "http://www.contoso.com/math.asmx";
      }


      [System::Diagnostics::DebuggerStepThroughAttribute]
      [System::Web::Services::Protocols::SoapDocumentMethodAttribute("http://www.contoso.com/Add",
      RequestNamespace="http://www.contoso.com/",ResponseNamespace="http://www.contoso.com/",
      Use=System::Web::Services::Description::SoapBindingUse::Literal,
      ParameterStyle=System::Web::Services::Protocols::SoapParameterStyle::Wrapped)]
      int Add( int num1, int num2 )
      {
         array<Object^>^temp1 = {num1,num2};
         array<Object^>^results = this->Invoke( "Add", temp1 );
         return  *dynamic_cast<int^>(results[ 0 ]);
      }


      [System::Diagnostics::DebuggerStepThroughAttribute]
      System::IAsyncResult^ BeginAdd( int num1, int num2, System::AsyncCallback^ callback, Object^ asyncState )
      {
         array<Object^>^temp2 = {num1,num2};
         return this->BeginInvoke( "Add", temp2, callback, asyncState );
      }


      [System::Diagnostics::DebuggerStepThroughAttribute]
      int EndAdd( System::IAsyncResult^ asyncResult )
      {
         array<Object^>^results = this->EndInvoke( asyncResult );
         return  *dynamic_cast<int^>(results[ 0 ]);
      }

   };

}


namespace MyMath {
    using System.Diagnostics;
    using System.Xml.Serialization;
    using System;
    using System.Web.Services.Protocols;
    using System.Web.Services;

    [System.Web.Services.WebServiceBindingAttribute(Name="MyMathSoap", Namespace="http://www.contoso.com/")]
    public class MyMath : System.Web.Services.Protocols.SoapHttpClientProtocol {

        [System.Diagnostics.DebuggerStepThroughAttribute()]
        public MyMath() {
            this.Url = "http://www.contoso.com/math.asmx";
        }

        [System.Diagnostics.DebuggerStepThroughAttribute()]
        [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://www.contoso.com/Add", RequestNamespace="http://www.contoso.com/", ResponseNamespace="http://www.contoso.com/", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)]
        public int Add(int num1, int num2) {
            object[] results = this.Invoke("Add", new object[] {num1,
                        num2});
            return ((int)(results[0]));
        }

        [System.Diagnostics.DebuggerStepThroughAttribute()]
        public System.IAsyncResult BeginAdd(int num1, int num2, System.AsyncCallback callback, object asyncState) {
            return this.BeginInvoke("Add", new object[] {num1,
                        num2}, callback, asyncState);
        }

        [System.Diagnostics.DebuggerStepThroughAttribute()]
        public int EndAdd(System.IAsyncResult asyncResult) {
            object[] results = this.EndInvoke(asyncResult);
            return ((int)(results[0]));
        }
    }
}

Option Strict On
Option Explicit On

Imports System.Diagnostics
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.Xml.Serialization

Namespace MyMath
    
    <System.Web.Services.WebServiceBindingAttribute(Name:="MyMathSoap", [Namespace]:="http://www.contoso.com/")>  _
    Public Class MyMath
        Inherits System.Web.Services.Protocols.SoapHttpClientProtocol
        
        <System.Diagnostics.DebuggerStepThroughAttribute()>  _
        Public Sub New()
            MyBase.New
            Me.Url = "http://www.contoso.com/math.asmx"
        End Sub
        
        <System.Diagnostics.DebuggerStepThroughAttribute(),  _
         System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://www.contoso.com/Add", RequestNamespace:="http://www.contoso.com/", ResponseNamespace:="http://www.contoso.com/", Use:=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle:=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)>  _
        Public Function Add(ByVal num1 As Integer, ByVal num2 As Integer) As Integer
            Dim results() As Object = Me.Invoke("Add", New Object() {num1, num2})
            Return CType(results(0),Integer)
        End Function
        
        <System.Diagnostics.DebuggerStepThroughAttribute()>  _
        Public Function BeginAdd(ByVal num1 As Integer, ByVal num2 As Integer, ByVal callback As System.AsyncCallback, ByVal asyncState As Object) As System.IAsyncResult
            Return Me.BeginInvoke("Add", New Object() {num1, num2}, callback, asyncState)
        End Function
        
        <System.Diagnostics.DebuggerStepThroughAttribute()>  _
        Public Function EndAdd(ByVal asyncResult As System.IAsyncResult) As Integer
            Dim results() As Object = Me.EndInvoke(asyncResult)
            Return CType(results(0),Integer)
        End Function
    End Class
End Namespace

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

<%@ WebService Language="C#" Class="MyMath"%>
 using System.Web.Services;
 using System;
 
 [WebService(Namespace="http://www.contoso.com/")] 
 public class MyMath {

    [ WebMethod ]
    public int Add(int num1, int num2) {
        return num1+num2;
    }
 }

<%@ WebService Language="VB" Class="MyMath"%>
Imports System.Web.Services
Imports System

<WebService(Namespace:="http://www.contoso.com/")> _
Public Class MyMath
    <WebMethod()> _
    Public Function Add(num1 As Integer, num2 As Integer) As Integer
        Return num1 + num2
    End Function 'Add
End Class 'Math

Remarks

Typically, you would not call the BeginInvoke method directly, unless you were building your own proxy class for an XML Web service.

A proxy class generated by the Web Services Description Language tool (Wsdl.exe) from a Service Description exposes the XML Web service methods as names derived from the proxy class to call the XML Web service methods synchronously. To call the XML Web service methods asynchronously, two additional methods are added to the proxy class for each XML Web service method, one with the Begin prefix added to the name of the XML Web service method and one with the End prefix added.

The proxy class calls the BeginInvoke method to start an asynchronous invocation call to the XML Web service method. For example, if an XML Web service exposes an XML Web service method named Add, the proxy class contains a method named BeginAdd, for starting an invocation to the XML Web service method. Within the code for the BeginAdd, a call is made to the BeginInvoke method and the results are placed into the expected return type for Add.

The methodName is used to find the custom attributes which may have been added to the method, such as SoapDocumentMethodAttribute. SoapDocumentMethodAttribute provides additional information about the derived method that is required for the SOAP protocol.

asyncState is passed into callback and is included in the IAsyncResult that is returned from the BeginInvoke method. The asyncState parameter can be used to pass information about the context of the asynchronous call, specified in the callback parameter, to the delegate that handles the result.

Applies to

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