控件输入限制总结

 

  学生和机房完了之后，总是有一些小小的细节之类的东西需要注意，尤其是关于文本框等输入字符限制的问题，最近小编总结了一篇关于文本框限制的博客，此次总结来源于小伙伴们平时的辛苦成果，希望可以帮到你们！

 

     平时我们登录自己的账户，总会输入自己的用户名，自己的账号，卡号，密码等。有着许许多多的限制，说白了都是我们的ASCII码表。你还记得那一年你在三合班一起看的ASCII码表么，我还记得我们在501编了小故事。

ASCII表：

 

  

 1.只能有数字和字母组成：（密码长度不可以超过几位数）

Private Sub Password1_Change()Dim i As IntegerFor i = 1 To Len(Password1.Text)If Len(Password1.Text) >= 16 ThenPassword1.Text = ""MsgBox "密码不会超过16位，请重输", vbOKOnly + vbExclamation, "警告"ElseIf Password1.Text <> "" ThenIf ((Asc(Mid(Password1.Text, i, 1)) < 48) Or ((Asc(Mid(Password1.Text, i, 1)) > 57) And (Asc(Mid(Password1.Text, i, 1)) < 65)) Or ((Asc(Mid(Password1.Text, i, 1)) > 90) And (Asc(Mid(Password1.Text, i, 1)) < 97)) Or (Asc(Mid(Password1.Text, i, 1)) > 122)) ThenMsgBox "密码只能由数字和字母组成，请重输", vbOKOnly + vbExclamation, "警告"Password1.Text = ""End IfEnd IfNext iEnd Sub

2.只能输入数字和Backspace键

Private Sub txtSID_KeyPress(KeyAscii As Integer) If KeyAscii = 8 Then ElseIf KeyAscii < Asc(“0”) Or KeyAscii > Asc(“9”) Then KeyAscii = 0 End If End Sub

3.只能输入大小写英文字母和汉字（包括退格和回车）

Private Sub txtName_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.只能输入汉字

Private Sub txtDirector_KeyPress(KeyAscii As Integer) If KeyAscii < 0 Or KeyAscii = 8 Then Exit Sub KeyAscii = 0 ‘不能输入 End Sub

5.限制字符输入

Private Sub txtUserName_KeyPress(KeyAscii As Integer) Select Case KeyAscii Case 8 Case Asc(“A”) To Asc(“Z”) Case Asc(“0”) To Asc(“9”) Case Asc(“a”) To Asc(“z”) Case Is < 0 Case Else KeyAscii = 0 End Select End Sub

Select Case KeyAscii    Case 8    '无变化,退格键不屏蔽    Case Asc("A") To Asc("z")    Case Asc("0") To Asc("9")    Case Is < 0Case Else ' 除了以上的 都屏蔽    KeyAscii = 0

6.输入的分数（成绩）只能是整型，输入的个数（分数大小）有限。

Private Sub txtResult_Change()Dim strItem(1 To 27) As StringDim m As IntegerDim t(30) As Stringm = m + 1t(m) = txtResultDim i As IntegerFor i = 1 To Len(txtResult.Text)    If Asc(Mid(txtResult.Text, i, 1)) < 48 Or Asc(Mid(txtResult.Text, i, 1)) > 58 Then       MsgBox "成绩只能是整型数字"       txtResult.Text = t(m - 1)       txtResult.SelStart = (m - 1)    End IfNext iIf m > 3 Then m = 1End IfIf Len(txtResult.Text) > 3 Then     MsgBox "分数不能超过3位"     txtResult.Text = t(m - 1)     txtResult.SelStart = (m - 1)End If

7.判断输入的是否是数字：

  If Not IsNumeric(Trim(txtSID.Text)) Then      MsgBox "请输入数字！", vbOKOnly + vbExclamation, "警告"      Exit Sub      txtSID.SetFocus  End If

如果小伙伴们还有其他想法，欢迎讨论。您的采纳就是我收到的最好的礼物！