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SoapHttpClientProtocol.Invoke Method

Invokes an XML Web service method synchronously using SOAP.

[Visual Basic]
Protected Function Invoke( _
   ByVal methodName As String, _
   ByVal parameters() As Object _
) As Object()
[C#]
protected object[] Invoke(
 string methodName,
 object[] parameters
);
[C++]
protected: Object* Invoke(
 String* methodName,
 Object* parameters __gc[]
)  __gc[];
[JScript]
protected function Invoke(
   methodName : String,
 parameters : Object[]
) : Object[];

Parameters

methodName
The name of the XML Web service method.
parameters
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.

Return Value

An array of objects containing the return value and any by reference or out parameters of the derived class method.

Exceptions

Exception Type Condition
SoapException The request reached the server computer, but was not processed successfully.

Remarks

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

A proxy class generated by the Wsdl.exe utility for an XML Web service exposes the XML Web service methods as names off of the proxy class. The proxy class calls the Invoke method to invoke an XML Web service method call. For example, if an XML Web service exposes an XML Web service method named Add, the proxy class also contains a method named Add. Within the code for the Add method in the proxy class, a synchronous call is made to the XML Web service method through the Invoke method and then the results are coerced 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 on the derived method which is required for the SOAP protocol.

Example

[Visual Basic, C#, C++] The following example is a proxy class generated by the Wsdl.exe utility for the Math XML Web service below. Within the Add method of the proxy class, the Invoke method is calling the Add XML Web service method.

[Visual Basic] 
Option Strict On
Option Explicit On

Imports System
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


[C#] 

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]));
        }
    }
}


[C++] 
#using <mscorlib.dll>
#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=S"MyMathSoap", Namespace=S"http://www.contoso.com/")]
   public __gc class MyMath : public System::Web::Services::Protocols::SoapHttpClientProtocol {

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

      [System::Diagnostics::DebuggerStepThroughAttribute]
      [System::Web::Services::Protocols::SoapDocumentMethodAttribute(S"http://www.contoso.com/Add",
         RequestNamespace=S"http://www.contoso.com/", ResponseNamespace=S"http://www.contoso.com/",
         Use=System::Web::Services::Description::SoapBindingUse::Literal,
         ParameterStyle=System::Web::Services::Protocols::SoapParameterStyle::Wrapped)]
      int Add(int num1, int num2) {
         Object* temp0 [] = {__box(num1), __box(num2)};
         Object* results[] = this->Invoke(S"Add", temp0);
         return *dynamic_cast<__box int*>(results[0]);
      }

      [System::Diagnostics::DebuggerStepThroughAttribute]
      System::IAsyncResult* BeginAdd(int num1, int num2, System::AsyncCallback* callback, Object* asyncState) {
         Object* temp1 [] = {__box(num1), __box(num2)};
         return this->BeginInvoke(S"Add", temp1, callback, asyncState);
      }

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

[Visual Basic, C#, C++] The following example is the Math XML Web service, from which the above proxy class was created.

[Visual Basic] 
<%@ 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

[C#] 
<%@ 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;
          }
 }

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

See Also

SoapHttpClientProtocol Class | SoapHttpClientProtocol Members | System.Web.Services.Protocols Namespace | SoapDocumentMethodAttribute | WebClientProtocol

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