Public Class MyDataGridCLASS
    Inherits DataGrid
    Private m As New ArrayList

    Public ReadOnly Property MultiSelectedIndex() As Integer()
        Get
            Return m.ToArray(GetType(Integer))
        End Get
    End Property

    Protected Overrides Sub OnMouseDown(ByVal e As System.Windows.Forms.MouseEventArgs)
        Debug.WriteLine("DataGrid has hit")
        Dim posdg As Point = New Point(e.X, e.Y)
        Dim hitDG As DataGrid.HitTestInfo = HitTest(posdg)
        If HitDataGrid(hitDG) Then
            MyBase.OnMouseDown(e)
            Debug.WriteLine("Mousedown has gogogo.....")
        End If
    End Sub

    Private Function HitDataGrid(ByVal Hit As DataGrid.HitTestInfo) As Boolean
        Try
            Select Case Me.ModifierKeys
                Case Keys.Control
                    If Hit.Row > -1 Then
                        If m.IndexOf(Hit.Row) > -1 Then
                            m.Remove(Hit.Row)
                            Me.UnSelect(Hit.Row)
                        Else
                            m.Add(Hit.Row)
                            Me.Select(Hit.Row)
                        End If
                    End If
                    Return False
                Case Keys.Shift
                    If Hit.Row > -1 Then
                        For Each IndexOld As Integer In m
                            Me.UnSelect(IndexOld)
                        Next
          

用控件仅一条指令实现界面换肤和多语言版本 一个用C＃写的词法分析程序