I have got as far page 68 where the illustration shows that ommitting the Title is flagged as an error handled by the TryUpdateModel() helper method. However when I try leaving out the Title and attempt to Save, I get an exception occur in the NerdDinner Designer.cs class:

{
OnTitleChanging(value);
ReportPropertyChanging("Title");
_Title = StructuralObject.SetValidValue(value, false);
ReportPropertyChanged("Title");
OnTitleChanged();
}

which says that value cannot be null

Can anybody help please? Thanks

Hi,
i had a similiar effect but only when Debugging the application. When running the application i did not get such error anymore.

What is the class Designer.cs ?

Thanks, Yes I am debugging. The Designer class is the auto generated class created when the entity .edmx file is created.

It's an unhandled exception warning (not an error). Just press F5 to continue.

You if it really bothers you, you can turn off this feature completely or for a specific namespace. In VS2010, select "Debug", "Exceptions", expand "Common Language Runtime Exceptions", uncheck "User-unhandled" box for the System.Data item.