Datagridview combobox column unique value each row

We need a wee bit more information.

However, assuming in the form load, I load up a grid with this:

 Dim rst As DataTable = MyRst("SELECT FirstName, LastName, City FROM Customers")  
      
DataGridView1.DataSource = rst  
  
  

And thus we get this for a grid:

Now, it obvious if we have a combo box in a grid, and we want to filter? Then we talking about a cascading combo.

In above, obviously the combo is to ONLY show hotels from the given city.

So, in the row enter event we can do this:

        If DataGridView1.Rows.Count <= 0 Then Exit Sub  
  
        Dim Grow As DataGridViewRow = DataGridView1.Rows(e.RowIndex)  
        Dim Mycombo As DataGridViewComboBoxCell  
        Mycombo = Grow.Cells.Item("FavorateHotel")  
  
        Dim sCity As String = Grow.Cells.Item("City").Value  
  
        Dim strSQL As String = "SELECT HotelName from tblHotels where City = '" & sCity & "'"  
  
        Dim r As DataTable = MyRst(strSQL)  
        Mycombo.Items.Clear()  
        For Each dr As DataRow In r.Rows  
            Mycombo.Items.Add(dr("HotelName"))  
        Next  
  

Now, to be fair - I would suggest using a dataView item that you can filter - but if the "list" of choices is small, then the above is rather fine. But it does mean if a user were to say hold a down arrow key, we would be firing off a new query for every row. So, I used the above row event, but we should in fact use a cell click event.

But , the above is a starting point, and you can work from the above code concepts. They are that for each row, you have to setup the combo box source.

I do believe that the data source persits - so we could (should) check if the combo box already has been given a set of values - thus no need to re-load for each row.

Regards,
Albert D. Kallal (Access MVP 2003-2017)
Edmonton, Alberta Canada