文本框的字符限制

学生系统中的输入文本内容，几乎都会涉及到字符限制问题，需要结合我们的现实生活进行相应的调整。字符限制的类型有多种，将学生系统中遇到的字符限制总结如下，把它们归结到一起，也会方便我们日后的使用。
1、去文本框空格（即当单击text就会有空格存在）：

Private Sub txt？_Click()
       Dim s As String
       s = txtName.Text
       s = Replace(s, " ", "")
       txtName.Text = s
End Sub

2、只能输入汉字：

Private Sub txt？_KeyPress(KeyAscii As Integer)  
    If KeyAscii < 0 or KeyAscii =13 or KeyAscii = 8 Then Exit Sub
    KeyAscii = 0
End Sub

3、限制特殊字符：

A
Private Sub txt？_KeyPress(KeyAscii As Integer)
    If ((KeyAscii >= 48 And KeyAscii <= 57) Or (KeyAscii >= 65 And KeyAscii <= 90) Or _
      (KeyAscii >= 97 And KeyAscii <= 122) Or (KeyAscii = 8)) = flase Then KeyAscii = 0
End Sub


B
Private Sub txt？_KeyPress(KeyAscii As Integer)
    Dim cTemp As String
    cTemp = "`~!@#$%^&*()-=_+[]{};:'|<>/?.‘“”’、，。——+（）《》？,~·……￥！：；【】" & """ '禁止输入特殊的字符"
    If InStr(1, cTemp, Chr(KeyAscii)) <> 0 Then KeyAscii = 0
End Sub

4、只能输入字母和汉字：

Private Sub txt？_KeyPress(KeyAscii As Integer)
     If KeyAscii < 0 Or KeyAscii = 8 Or KeyAscii = 13 Then
         ElseIf Not Chr(KeyAscii) Like "[a-zA-Z]" Then
         KeyAscii = 0
     End If
End Sub

5、只能输入数字：

    Private Sub txt？_KeyPress(KeyAscii As Integer) '只能输入数字
      If KeyAscii = 8 Then
          ElseIf KeyAscii < Asc("0") Or KeyAscii > Asc("9") Then
          KeyAscii = 0
      End If
    End Sub

6、限制粘贴：

If KeyCode = vbKeyV And Shift = vbCtrlMask Then
    txtPassword.Enabled = False
    Clipboard.Clear
    txtPassword.Enabled = True
End If

以上也可用键值直接限制，需要什么直接使用对应的键值即可。

    Private Sub text1_KeyPress(Index As Integer, KeyAscii As Integer)
      Select Case KeyAscii
        Case 48 To 57
        Case 65 To 90
        Case 97 To 122
        Case 8
      Case Else
        KeyAscii = 0
      End Select
   End Sub

7、文本框弹出提示信息：
比如密码输入次数的提示：

If miCout = 1 Then
        MsgBox "您还有两次机会！", 48, "提示"
Exit Sub
End If

又或者能输入什么样的信息、使用什么样的字符、不能如何，都可以适当的给用户做出提示。