主题：可以控制顶格写入么

textchanged事件，写代码

Dim txt As String = e.Sender.Text
If txt > "" Then
    Dim pattern As String = "[ ]"
    Dim str As String = System.Text.RegularExpressions.Regex.Replace(txt , pattern ,"")
    e.Sender.Text = str
    e.sender.SelectionStart = str.Length
End If