Question

I am using VB.NET 2010 (Visual Basic 2010 Express) on a WPF-based project. I am also using the SQL Server Express built-in to Visual Basic 2010 express.

I have just about finished refining my code for hooking up my wpf-based form to an existing SQL database (agentroster.sdf). I have a global data source (AGENT_ROSTER) connected to this database. Connections are confirmed to work properly.

This is the first part of the code I’m using, irrelevant code omitted,

Dim table_adaptor As New AGENT_ROSTERTableAdaptors.AGENT_ROSTERTableAdaptor
Dim roster_table As New DataTable("roster_table")
Dim rowposition As Integer

Private Sub ROSTER_Loaded...
   table_adaptor.Fill(roster_table)
End Sub

I am getting the following errors:
(In Immediate Window)

A first chance exception of type ‘System.InvalidCastException’ occured in VBP-WORD4WORD.exe

(In Message, pointing to the line: “table_adaptor.Fill(roster_table)’)

InvalidCastException was unhandled
Unable to cast object of type ‘System.Data.DataTable’ to type ‘AGENT_ROSTERDataTable’.

What am I doing wrong, and furthermore, how do I fill roster_table with table_adaptor (or alternate method)?

Answer 1

Assuming that your strongly typed DataSet is called “AGENT_ROSTER”:

Dim table_adaptor As New AGENT_ROSTERTableAdaptors.AGENT_ROSTERTableAdaptor
Dim roster_table As New AGENT_ROSTER.roster_table
table_adaptor.Fill(roster_table)

Have a look at Efficient Coding With Strongly Typed DataSets.