[RESOLVED] Put ListBox over top cell in DataGridView column

[BrainPain]

I've got this working but there's something I don't understand about it. I have a DataGridView and a listbox. I want to position the listbox to be the same location as the topmost visible cell in the column the mouse is in. The end result will be that a context menu will be provided to show the user the distinct values in that column which is why I want the listbox to show over the column that it's displaying data for, just below the header cell. I'm testing right now using the CellMouseEnter event and the following code is working:

Private Sub dgvItems_CellMouseEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles dgvItems.CellMouseEnter
	If e.ColumnIndex >= 0 Then
		Dim r As System.Drawing.Rectangle = dgvItems.GetCellDisplayRectangle(e.ColumnIndex, 0, True)
		lstDistinctValues.Location = New System.Drawing.Point(r.Left + 9, dgvItems.Top + 69)
		lstDistinctValues.Visible = True
	End If
End Sub

But notice the offsets that I had to use to get the positioning just right. That's my question - why is using the location of the cell putting my textbox so far off from where I want it?

Thanks!

Edit: if I use the rectangle's Y position as the top of the ListBox, the ListBox ends up completely outside the DataGridView which is why I'm using the DataGridView's Y position.

[kareninstructor]

Try this out

If e.ColumnIndex >= 0 Then
    Dim CellPoint As Point = Me.dgvItems.GetCellDisplayRectangle(e.ColumnIndex, _ 
                                                                 e.RowIndex, _ 
                                                                 True).Location
    Dim GridPoint As Point = dgvItems.Location
    Dim PointLocation As Point
    PointLocation.X = GridPoint.X + CellPoint.X
    PointLocation.Y = dgvItems.Top - dgvItems.ColumnHeadersHeight
    Me.lstDistinctValues.Location = PointLocation
    lstDistinctValues.Visible = True
End If

[BrainPain]

Sorry, that's not it either. The x position looks about right but the y position is still quite a bit higher than the top of the DataGridView. I changed your y position from "- dgvitems.ColumnHeadersHeight" to "+ dgvItems.ColumnHeadersHeight" and it was still too high.
I believe the cell's position is relative to the DataGridView that it's in and the ListBox position is relative to the form itself, so that's probably what accounts for the offsets I have to use. I'll probably leave my code as is since it's correctly positioning the ListBox, but do you know if I'll get the same rendering on different pcs and/or resolutions?

[kareninstructor]

Sorry, that's not it either. The x position looks about right but the y position is still quite a bit higher than the top of the DataGridView. I changed your y position from "- dgvitems.ColumnHeadersHeight" to "+ dgvItems.ColumnHeadersHeight" and it was still too high.
I believe the cell's position is relative to the DataGridView that it's in and the ListBox position is relative to the form itself, so that's probably what accounts for the offsets I have to use. I'll probably leave my code as is since it's correctly positioning the ListBox, but do you know if I'll get the same rendering on different pcs and/or resolutions?

Perhaps I misinterperted, the following image shows two different examples where the ListBoxes go exactly where I asked them to go. See attached demo also.

[BrainPain]

Ah, ok maybe we did have a miscommunication. When I said

I want the listbox to show over the column that it's displaying data for, just below the header cell

I meant that I wanted the ListBox to be in front of the column, with it's top just below the header cell of the column. I hadn't really thought of having the ListBox show up above the column header cell instead of below it. Your way might be more appealing on the form. I'll check it out further. Thanks!