VB 2015 : How To prevent Column Ordering between Frozen Columns in DataGridView ?

Question

Hi,

I have a DataGridView Control with a bunch of Columns and Rows.
My task is to have the first 3 Columns Frozen and Fixed in order.
User can't change order on Columns from Column01 to Column03.
User can change order only on Columns from Column04 to Column09.

Here's an example :

        For i As Integer = 1 To 9
            DGV.Columns.Add("Column" & i.ToString.PadLeft(2, "0"c),
                            "Column" & i.ToString.PadLeft(2, "0"c))
        Next
        Dim values As List(Of Object)
        For i As Integer = 1 To 100
            values = New List(Of Object)
            For j As Integer = 1 To 9
                values.Add("Data" & i.ToString.PadLeft(5, "0"c) & "-" & j.ToString)
            Next
            DGV.Rows.Add(values.ToArray)
        Next
        DGV.AllowUserToOrderColumns = True
        DGV.Columns(0).Frozen = True
        DGV.Columns(1).Frozen = True
        DGV.Columns(2).Frozen = True

The problem is that User can still change order between the 3 first Frozen Columns.
What should be done to prevent User to move the Forzen Columns between them ?

Thanks to anyone able to help.

Answer 1

Hi, welcome to Microsoft Q&A. You can refer to the following code.

    Private Sub DGV_MouseUp(sender As Object, e As MouseEventArgs) Handles DGV.MouseUp
        If DGV.Columns(0).DisplayIndex <> 0 OrElse DGV.Columns(1).DisplayIndex <> 1 OrElse DGV.Columns(2).DisplayIndex <> 2 Then
            DGV.Columns(0).DisplayIndex = 0
            DGV.Columns(1).DisplayIndex = 1
            DGV.Columns(2).DisplayIndex = 2
        End If
    End Sub

Best Regards.

Jiachen Li

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Answer 2

You can handle the DataGridView.ColumnDisplayIndexChanged event to prevent the user from changing the order of the first three frozen columns. In the event handler, check if the new display index of any of the first three columns is different from their initial positions. If it's different, set it back to the original position.

Here's the updated code:

Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        For i As Integer = 1 To 9
            DGV.Columns.Add("Column" & i.ToString.PadLeft(2, "0"c),
                            "Column" & i.ToString.PadLeft(2, "0"c))
        Next
        Dim values As List(Of Object)
        For i As Integer = 1 To 100
            values = New List(Of Object)
            For j As Integer = 1 To 9
                values.Add("Data" & i.ToString.PadLeft(5, "0"c) & "-" & j.ToString)
            Next
            DGV.Rows.Add(values.ToArray)
        Next
        DGV.AllowUserToOrderColumns = True
        DGV.Columns(0).Frozen = True
        DGV.Columns(1).Frozen = True
        DGV.Columns(2).Frozen = True

        ' Handle the ColumnDisplayIndexChanged event
        AddHandler DGV.ColumnDisplayIndexChanged, AddressOf DGV_ColumnDisplayIndexChanged
    End Sub

    Private Sub DGV_ColumnDisplayIndexChanged(sender As Object, e As DataGridViewColumnEventArgs)
        ' Check if any of the first three columns changed their display index
        If e.Column.Index < 3 AndAlso e.Column.DisplayIndex <> e.Column.Index Then
            ' Set the display index back to the original position
            e.Column.DisplayIndex = e.Column.Index
        End If
    End Sub
End Class

This code will prevent the user from changing the order of the first three frozen columns. They can still change the order of the remaining columns as needed.