Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click 
    Dim chFrm As New DataForm(C1TrueDBGrid1) 
    chFrm.ShowDialog() 
End Sub

Public Class DataForm 
    Dim c1Tdbgrid As C1.Win.C1TrueDBGrid.C1TrueDBGrid 
    Public Sub New(ByVal c1TDB As C1.Win.C1TrueDBGrid.C1TrueDBGrid) 
        InitializeComponent() 
        c1Tdbgrid = c1TDB 
        C1TrueDBGrid1.DataSource = <set the Datasource> 
    End Sub 
    Private Sub C1TrueDBGrid1_MouseDoubleClick(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles C1TrueDBGrid1.MouseDoubleClick 
       Dim dr As System.Data.DataRowView = CType(Me.C1TrueDBGrid1(Me.C1TrueDBGrid1.Row), System.Data.DataRowView) 
       Dim rowValues As New StringBuilder 
       For i As Integer = 0 To dr.Row.ItemArray().ToList().Count - 1 
            rowValues.Append(dr.Row.Item(i).ToString()) 
            If (i < dr.Row.ItemArray.ToList().Count - 1) Then 
                rowValues.Append(";") 
            End If 
       Next 
      c1Tdbgrid.AddRow(rowValues.ToString()) 
    End Sub 
End Class