DataGridCell empty set DbNull.value

Using wpf: DataGridCell empty set DbNull.value on newest questions tagged wpf – Stack Overflow

I am populating a datagrid with a dataset and I have my dataset verified for nullable values –

My problem is :

When the dataset is validating, it found empty rows and the errors are not displayed.
I would like to define the empty cells with a DBNull.value. Is there any way to do it ?.
I have found a property named TargetNullValue that could work ?

source: http://stackoverflow.com/questions/11247200/datagridcell-empty-set-dbnull-value
Using wpf: using-wpf