System.Web.Services.Protocols.SoapHttpClientProtocol.BeginInvoke Method

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

Syntax

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

Parameters

methodName
The name of the XML Web service method in the derived class that is invoking the SoapHttpClientProtocol.BeginInvoke(string, Object[], AsyncCallback, object) 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.
callback
The delegate to call when the asynchronous invoke is complete. If callback is null, the delegate is not called.
asyncState
Extra information supplied by the caller.

Returns

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

Remarks

Typically, you would not call the SoapHttpClientProtocol.BeginInvoke(string, Object[], AsyncCallback, object) 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 SoapHttpClientProtocol.BeginInvoke(string, Object[], AsyncCallback, object) 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 SoapHttpClientProtocol.BeginInvoke(string, Object[], AsyncCallback, object) 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 System.Web.Services.Protocols.SoapDocumentMethodAttribute. System.Web.Services.Protocols.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 SoapHttpClientProtocol.BeginInvoke(string, Object[], AsyncCallback, object) 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.

Requirements

Namespace: System.Web.Services.Protocols
Assembly: System.Web.Services (in System.Web.Services.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0