主题：控件颜色问题

请教老师，下面代码怎样写在AfterLoad能打开窗口就触发，现在是放在控件的TextChanged

Dim Tb As WinForm.TextBox = e.Form.Controls("TextBox2")
If Tb.Text = "立项设计" Then
    Tb.BackColor = Color.Green
    Tb.ForeColor = Color.Yellow
Else
    If Tb.Text = "技术标书" Then
        Tb.BackColor = Color.Blue
        Tb.ForeColor = Color.White                
            Else
                If Tb.Text = "" Then
                    Tb.BackColor = Color.WhiteSmoke
                    Tb.ForeColor = Color.Black
         End If
    End If
End If