I'm sure it's because I'm not right.  I have to learn more about threading, and I'm not familiar with Control.Invoke.  I have this code:

Private Sub bwWorker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bwWorker.DoWork

Dim objConnection As SqlConnection = Nothing

Dim objAdapter As SqlDataAdapter = Nothing

Dim dtbData As DataTable = Nothing

Try

objConnection = New SqlConnection(ConnectionStrings("DAS").ConnectionString)

objAdapter = New SqlDataAdapter(e.Argument.ToString(), objConnection)

dtbData = New DataTable

Finally

dtbData = Nothing

objAdapter = Nothing

objConnection = Nothing

End Try

End Sub

The work done by the background worker queries a database and fills a datagrid; I'm doing this because I have a lot of data to load at times.  So, using this approach, how do I implement Control.Invoke?

Let me know if you need more information.

Thanks.

First of all your Finally block is wrong. You need to change it on the following:

Finnally

objConnection.Close()

End Try

You don't need those extra lines.

About your error:

You getting an error in "dgvData.DataSource = dtbData" line.You can't set any setting to any control in BackgroundWorker.DoWork method, so you need to Invoke it.

Use folowing method instead of "dgvData.DataSource = dtbData":

Private Sub SetDataSource(ByVal dtbData as DataTable)

if(dgvData.InvokeRequired) then

Dim del as DataSourceHandler = new DataSourceHandler(AddressOf SetDataSource)

Dim objects(dtbData) as Object

dgvData.Invoke(del, objects)

else

dgvData.DataSource = dtbData

end if

End Sub

Public Delegate Sub DataSourceHandler (ByVal dtbData as DataTable)

Anything in theRunWorkCompleted event(and also the Progress event) will already be executing on the correct thread.

The whole purpose of the BackgroundWorker class is so that you dont have to worry about Control.Invoke().