Question

Suppose I have codes like these

public void Upload (Picture picture)
   try
        {
          //ps is the entity framework
            ps.AddToPictures(picture);
            ps.SaveChanges();

            return picture.PictureId;
        }
        catch (Exception e) {
            //some codes to bound the exception to the model 
        }

How can I present the exceptions to the model and present them in the view?

Answer 1

Use ModelState.AddError.

Example:

catch (Exception e) {
   ModelState.AddError("SomeErrorKey", e.Message);
}

Then in the View:

<%= Html.ValidationMessage("SomeErrorKey") %>

Can’t remember the correct overload for ValidationMessage – so take a look at the different overloads.

I’d recommend using custom exceptions though – you don’t want to display things like “Null reference exception” in your View.

More on ModelState.AddError here.