主题：[求助]如何实现textbox中的类似foxmail搜索邮件框效果

Enter

If e.Sender.Text = "请输入邮件号" Then
    e.Sender.ForeColor = Color.Black
    e.Sender.Text = ""
End If

Leave

If e.Sender.Text = "" Then
    e.Sender.Text = "请输入邮件号"
    e.Sender.ForeColor = Color.gray
Else
    e.Sender.ForeColor = Color.Black
End If