InvokeServerMethodAsync(String,String,CancellationToken,Object[]) Method

Asynchronously invokes the specified static (Shared in Visual Basic) method for execution on the server.

Syntax

Visual Basic
C#

'Declaration
 
Public Overloads Function InvokeServerMethodAsync( _
   ByVal assemblyQualifiedTypeName As String, _
   ByVal methodName As String, _
   ByVal cancellationToken As CancellationToken, _
   ByVal ParamArray userArguments() As Object _
) As Task(Of Object)

'Usage
 
Dim instance As EntityManager
Dim assemblyQualifiedTypeName As String
Dim methodName As String
Dim cancellationToken As CancellationToken
Dim userArguments() As Object
Dim value As Task(Of Object)
 
value = instance.InvokeServerMethodAsync(assemblyQualifiedTypeName, methodName, cancellationToken, userArguments)

public Task<object> InvokeServerMethodAsync( 
   string assemblyQualifiedTypeName,
   string methodName,
   CancellationToken cancellationToken,
   params object[] userArguments
)

Parameters

assemblyQualifiedTypeName: Assembly-qualified type name such as 'MyNamespace.Services, MyAssembly'
methodName: Name of method to be invoked
cancellationToken: CancellationToken to be passed to method
userArguments: Arguments to be passed to method

Exceptions

Exception	Description
System.ArgumentException	Type name must be fully qualified
System.ArgumentException	UserState token must be unique for the client
System.Security.SecurityException	The exception that is thrown when a security error is detected.

Remarks

The method called must be marked with the AllowRpcAttribute and correspond to the ServerMethodDelegate signature. InvokeServerMethodAsync enables a client-side caller to invoke an arbitrary static method on the server using an asynchronous call. An outstanding request can be cancelled using the System.Threading.CancellationToken. This feature is only available in certain editions of DevForce.

Example

// Sample showing asynchronous invocation of server method

// In client class:
private void MakeAsyncCall() {
  EntityManager mgr = new DomainModelEntityManager();
  // Make async call
  Guid myToken = Guid.NewGuid();
  mgr.InvokeServerMethodAsync(new ServerMethodDelegate(Order.GetNumberOfOrdersSlow), 
      InvokeServerMethodAsyncCompleted, myToken, 
 	    new DateTime(1995, 1, 1), new DateTime(1999, 1, 1));
}
private void InvokeServerMethodAsyncCompleted(InvokeServerMethodOperation e) {
  Guid token = (Guid)e.UserState;
  if (!e.Cancelled) {
     MessageBox.Show("my async result = " + Convert.ToInt32(e.Result).ToString());
  }
}

// Sample method defined in Order entity class:
public class Order {
//...

  // ServerMethodDelegate method, called from client
  [AllowRpc]
  public static Object GetNumberOfOrdersSlow(IPrincipal pPrincipal, EntityManager pMgr, params Object[] pArgs) {
     // Sleep to make this slower to show async
     System.Threading.Thread.Sleep(2000);
     DateTime dt1 = pArgs[0] as DateTime;
     DateTime dt2 = pArgs[1] as DateTime;
     return pMgr.Order.Where(o => o.OrderDate >= dt1 && o.OrderDate <= dt2).Count();
  }
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

EntityManager Class
EntityManager Members
Overload List