学生信息管理系统优化限制

1,只能输入数字

If keyascii = 8 then exit sub
If keyascii <48 or keyascii > 57 then keyascii = 0

2，限制粘贴

If keycode = vbkeyv and shift =vbctrlmask then
Txtpassword. Enabled = false
Clipboard.clear
Txtpassword.enabled = true
End if

3,限制特殊字符，数字，空格，只能输入字母或汉字

Private sub txtcoursename_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

4,提示密码剩余次数，密码只可以输入三次，提醒用户

If miCout = 1 Then      
 MsgBox "您还有两次机会！", 48, "警告"   
 Exit Sub  
  End If          
If miCout = 2 Then     
   MsgBox "您还有一次机会！", 48, "警告"    
Exit Sub    
End If      
  If miCout = 3 Then     
   MsgBox "即将关闭程序！", 48, "警告"     
   Me.Hide    
End If    
Exit Sub

5，入校日期早于出生日

dim borndate as date
dim getdate as date'定义变量'
borndate = trim(txtborndate.text)
getdate = trim(txtborndate.text)
If getdate<=borndate then'进行比较 
MsgBox"入学时间不能早于出生时间，请重新输入",vbOKOnly + vbInformation,"警告"       txtRudate.SetFocus 
Exit Sub
End If 

6,限制字符长度

在属性栏里找到Maxlength更改就好