Use BackgroundWorker to Format DataGridView

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VB

I have a DataGridView control that I’m filling with data from a database. Since the queries have the possibility of returning a lot of data I decided to use a BackgroundWorker object to pull the data so my application wouldn’t appear to be frozen when the query was running. I can get that to work just fine but it didn’t solve my overall problem. After pulling the data I set the DataGridView’s Datasource to it and then call a method that sets up all kinds of formatting on the DataGridView object. It loops through the columns and rows and does things like set background color, alignment, and tool tips on cells based on the data. This is all quite time consuming and my application appears to freeze up when it runs. However I’m having trouble trying to get this into a BackgroundWorker. I’ve tried two methods...

Method One:
If I pass in my DataGridView object as an argument in the BackgroundWorker I get a cross-threading error when I try to set the DataSource. This is how I've always "packaged" things to go into a background worker and I haven't run into problems before...am I not doing it correctly?

'The class I use to package the DataGridView
Private Class packageFormatGrid
      Public dt As DataTable 'Data to set to the grid
      Public dgv1 As DataGridView 'Data grid
End Class
'The class I package the datagridview in and call backgroundworker from
Private Sub CallFormat(ByRef dt as DataTable)
       Dim package As New packageFormatGrid
       package.dt = dt
       package.dgv1 = dgvOutput
       bgwFormat.RunWorkerAsync(package)
End Sub
'Do Work method...
Private Sub bgwFormat_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwFormat.DoWork
       Dim package As packageFormatGrid = CType(e.Argument, packageFormatGrid)
       package.dgv1.DataSource = package.dt
       'I have other code after this point, but the above statement causes
       'a cross-threading error for dgvOutput, which is the "packaged" dgv1
End Sub

Method Two:
If I declare a new DataGridView object and pass it to the RunWorkerComplete as the result, and there set my real DataGridView equal to it, I don’t get any errors, but my grid simply doesn’t fill with anything.

'Set up a new datagridview object and pass it back to other thread in result
Private Sub bgwFormat_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwFormat.DoWork
       Dim package As packageFormatGrid = CType(e.Argument, packageFormatGrid)
       Dim dgv As New DataGridView
       dgv.DataSource = package.dt
       'method that loops columns and rows and formats the datagrid view object
       FormatOutputGrid(dgv)
       e.Result = dgv
End Sub
'On run worker complete, the code doesn't error out, but my grid doesn't display any data.
'Debugging reveals that it has the correct DataSource, but I can't access cell values
Private Sub bgwFormat_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bgwFormat.RunWorkerCompleted
       Dim dgv As DataGridView = CType(e.Result, DataGridView)
       dgvOutput = dgv
End Sub

It’s Monday, so I’m suspicious that I’m just not thinking clearly and I’m missing something painfully obvious. When I google all I get is articles about pulling the data with a BackgroundWorker and nothing about formatting the grid. Does anyone have any ideas?