MaskedTextBox 控件欢迎你。
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.ToolTip1.IsBalloon = True
Me.MaskedTextBox1.Mask = "00-00-0000"
End Sub
MaskedTextBox 类 (System.Windows.Forms)
https://msdn.microsoft.com/zh-cn/library/system.windows.forms.maskedtextbox(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2
要手动输入“-”吗,还不如直接时间插件给用户选择