Starts an asynchronous invocation of an XML Web service method using SOAP.
Assembly: System.Web.Services (in System.Web.Services.dll)
member BeginInvoke : methodName:string * parameters:Object * callback:AsyncCallback * asyncState:Object -> IAsyncResult
- Type: System.String
The name of the XML Web service method in the derived class that is invoking the method.
- Type: System.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.
- Type: System.AsyncCallback
The delegate to call when the asynchronous invoke is complete. If callback is a null reference (Nothing in Visual Basic), the delegate is not called.
- Type: System.Object
Extra information supplied by the caller.
Typically, you would not call the 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 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 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 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.
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 method is starting an asynchronous invocation to the Add XML Web service method.
The following code example is the Math XML Web service, from which the preceding proxy class was created.