Public Class frmDGVMerged
 
    Dim dt As DataTable
    Dim noffset As Integer = 0
    Dim showmerged As Boolean = False
 
    Dim WithEvents dgv As New DataGridView _
        With {.Parent = Me, .Dock = DockStyle.Fill}
 
    Private Sub frmDGVMerged_Load(sender As System.Object, _
                    e As System.EventArgs) Handles MyBase.Load
 
        dt = New DataTable
        dt.Columns.Add("SP1", GetType(String))
        dt.Columns.Add("SP2", GetType(String))
        dt.Columns.Add("SP3", GetType(String))
 
        dt.Rows.Add("a1", "a2", "a3")
        dt.Rows.Add("b1", "b2", "b3")
        dt.Rows.Add("c1", "c2", "c3")
 
        dgv.DataSource = dt
    End Sub
 
    Private Sub CellEndEdit(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) _
        Handles dgv.CellEndEdit
 
 
        Dim i As Integer = e.RowIndex
        Dim pcell As clsDGVMergedCells
 
        With dgv
            If Not showmerged Then
                .Rows(i).Cells(noffset) = New clsDGVMergedCells()
                pcell = DirectCast(.Rows(i).Cells(noffset), clsDGVMergedCells)
                pcell.LeftColumn = noffset
                pcell.RightColumn = noffset + 3
                showmerged = True
            Else
                .Rows(i).Cells(noffset) = New DataGridViewTextBoxCell
                showmerged = False
            End If
        End With
    End Sub
 
End Class