我可以加快每个循环的速度吗

Question

这段代码似乎很简单，但是运行需要很长时间。我已经制作了一个仅包含基本代码的示例项目，但是它仍然很慢。

我有一个带有按钮和面板的表格。在运行时，面板将动态填充约1700个自定义用户控件。自定义用户控件包含一个面板和一个属性。单击表单上的按钮会使每个用户控件交换其颜色。该操作应该一次全部发生，但是它是如此之慢，以至于我只能一次一行一行地观看每个用户控件开关的颜色

我可以暂停屏幕更新直到每个循环的整体运行之后，而不是一个一个地更新每个面板吗？

用户控制代码...

   Public Class ucBox
    Private _TurnedOn As Boolean
    Public Property TurnedOn() As Boolean
        Get
            Return _TurnedOn
        End Get
        Set(ByVal value As Boolean)
            _TurnedOn = value
            If TurnedOn Then
                PnlBox.BackColor = Color.Red
            Else
                PnlBox.BackColor = Color.LightGray
            End If
        End Set
    End Property

    Private Sub PnlBox_Click(sender As Object, e As EventArgs) Handles PnlBox.Click
        If TurnedOn Then
            TurnedOn = False
        Else
            TurnedOn = True
        End If
    End Sub
End Class

表单代码...

    Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        Dim Rw As Int16 = 0, Col As Int16 = 0, x As Int16
        Dim Box As ucBox
        With btnTest
            .Text = "Test Me"
        End With

        While Rw < PnlMain.Height - 10
            While Col < PnlMain.Width - 10
                Box = New ucBox
                x = x + 1
                With Box
                    .Top = Rw
                    .Left = Col
                    .TurnedOn = False
                    .Name = "Box_" & x
                    Col += .Width + 4

                End With

                PnlMain.Controls.Add(Box)
                Box = Nothing
            End While
            Col = 0
            Rw += 24
            If x > 2000 Then Exit While
        End While
        Debug.Print("There are " & x & " boxes.")
    End Sub

    Private Sub btnTest_Click(sender As Object, e As EventArgs) Handles btnTest.Click
        Dim StartTime As Date = Now

        For Each b As ucBox In PnlMain.Controls
            If b.TurnedOn Then
                b.TurnedOn = False
            Else
                b.TurnedOn = True
            End If
        Next

        Debug.Print("Test took " & Now.Subtract(StartTime).TotalMilliseconds)
    End Sub
End Class

我很感谢任何想法。