This property is queried to receive the number of rows in the table. It will only be accessed if SupportsCount returns true. If your data provider doesn't support counting, you don't need to implement this property and may safely throw a NotImplementedException. Be aware however that you won't get a progress bar during printing in this case.

'Declaration
 
ReadOnly Property Count As Integer

int Count {get;}

property int Count {
   int get();
}

public int Count
{
    get { return _dataView.Count; }
}

Public Readonly Property Count() As Integer
    Get
        Return _dataView.Count
    End Get
End Property