Csla Reflection Code

razorkai posted on Wednesday, July 12, 2006

Hi guys.

I'm trying to call a static method dynamically and found this code in the Csla MethodCaller class.

    public static object CallMethod(
      object obj, MethodInfo info, params object[] parameters)
    {
      // call a private method on the object
      object result;
      try
      {
        result = info.Invoke(obj, parameters);
      }
      catch (Exception e)
      {
        throw new Csla.Server.CallMethodException(
          info.Name + " " + Resources.MethodCallFailed, e.InnerException);
      }
      return result;
    }

What caught my attention is the parms object[] part as I had not seen it before.  The method I am trying to invoke is actually a Csla Factory method on one of my business objects.  I have all the parameters in a criteria object and so I wrote a method, using the example above, like this:-

public object CallMethod(MethodInfo info, params object[] parameters)
{
      return info.Invoke(null, parameters);
}

The static method I am trying to invoke takes one parameter, a Guid.  If I step into this code I can see I have a valid MethodInfo for the method, and the parameters parameter is correctly identified as MyObject.Criteria.  I can drill down into that and see that the array is one dimension deep and contains a Guid.  However, the code spits out an error that it cannot convert an object of type MyObject.Criteria to a Guid.  The Csla code works great, and everything I can find on this way of calling a method seems to indicate that what I have done should work.  So anyone out there know why it blows up?

TIA.

Final thought:  I just made a quick Test rig to Test this outside my project and get the same result.  Please see attached code.

dean replied on Thursday, July 13, 2006

I don't see any attached code. I want to see how you construct you info object.

Dean

razorkai replied on Friday, July 14, 2006

Weird!  I definitely attached it but it seems it has gone.  Anyway, I figured out that I wasn't thinking straight.  The Factory method I was trying to invoke doesn't take a criteria object but a parameter of type Guid.  Therefore I was never going to invoke it by passing it a Criteria object containing a Guid.  The Csla invokes DataPortal methods within the Business Objects by using this technique, but that works because they expect a Criteria object.  The Csla does not invoke the static methods this way, it is the static methods that end up invoking the DataPortal methods!  Thanks for showing an interest though!