Check Contraints on DataTable or DataColumn

[John Hui]

I am trying to implement a Check Contraint on a DataTable
or DataColumn.

To do this, I have tried to inherit from
System.Data.Constraint class. But Visual Studio
automatically includes code into my class telling me to
override a number of pricate funcctions and procedures
for example,

Private Overrides Function CanEnableConstraint() As
Boolean

According to Intellisense, this function is declared
Private Overridable Mustoverride in
System.Data.Constraint class. However, this is
against .NET programming rules. My questions are.

1) How is this possible?

2) How can I inherit from the System.Data.Constraint
class?

3) How do I implement a check constraint?

Thanks for any help.

John