asp.net mvc: more info on UpdateModel exception

Hi,

i sometimes get an error with the UpdateModel function. However, i can't seem to locate the exact message which field(s) is/are causing the problem. For example this one: "The model of type 'Enquete' was not successfully updated."

it has an innerexception of NULL, and no further description. Is there a way to find out what is causing the problem?

Michel

EDIT: i see this in my output window: "A first chance exception of type 'System.InvalidOperationException' occurred in System.Web.Mvc.dll"

From stackoverflow

• Steve Sanderson has a wonderful article on using the MVC source to help you debug your application.

  I think this will help you get more info.

  Kindness,

  Dan

  Michel : that indeed worked, but debugging the mvc source is not an easy thing (well, debugging is, but understanding it is another story)

• Just a wild guess: You are trying to bind null to a value type. Check in your model for int, float, DateTime, structs, ... data types that you try to bind to null.

  Michel : i'll look into that, InvalidOperationException does give me a hint that way, you're right. So when i want to be absolutely sure there is no error i have to create a very 'loose' or 'forgiving' model in which you can place any data, and then validate that model and THEN i put it in my business model. Because when the user enters an empty value for a non-nullable int it raises an exception for UpdateModel(). This leaves me with an annoying update from the viewmodel to the businesmodel...