机房收费系统--登录窗体

在对机房收费系统有了大致的认识后，就开始做登录窗体了。登录窗体是最简单的，但是我们需要先理清思路，最好是能画一个简单的流程图，这样就能理清逻辑，在敲代码的时候就会非常简单。

在这里需要注意以下几点：

1.用户输入信息不能为空：

'查询条件If Trim(txtUserName.Text = "") ThenMsgBox "用户名称不能为空，请重新输入！", vbOKOnly + vbExclamation, "警告"txtUserName.SetFocusElseIf Trim(txtPassword.Text = "") ThenMsgBox "用户密码不能为空，请重新输入！", vbOKOnly + vbExclamation, "警告"txtUserName.SetFocusEnd if

2.限制登录次数：

'记载输入密码次数micount = micount + 1If micount = 1 ThenMsgBox "密码输入错误，您还有两次机会！", 48, "警告"txtPassword.SetFocustxtPassword.Text = ""Exit SubElseIf micount = 2 ThenMsgBox "密码输入错误，您还有一次机会！", 48, "警告"txtPassword.SetFocustxtPassword.Text = ""Exit SubElseIf micount = 3 ThenMsgBox "密码输入错误，程序即将关闭！", 48, "警告"txtPassword.SetFocustxtPassword.Text = ""Me.HideExit SubEnd IfEnd If

3.限制特殊字符：

'限制特殊字符 Private Sub txtUserName_KeyPress(KeyAscii As Integer)Const a As String = "'!','@','#','$','%','^','&','*','(',')','<','>','?',':',' ','{','}','-','+','=','_','[',']',',','.','?','\','|','/',''','’'"KeyAscii = IIf(InStr(a, Chr(KeyAscii)), 0, KeyAscii) End Sub

4.限制不能复制粘贴

'不能复制粘贴 Private Sub txtPassword_KeyDown(KeyCode As Integer, Shift As Integer)If (KeyCode = 86 Or KeyCode = 67 Or KeyCode = 88) And Shift = 2 ThenMsgBox "不能粘贴复制", vbOKOnly + vbExclamation, "警告"txtPassword.Text = ""End If End Sub

5.限制登录权限：

'权限限制If Trim(mrc.Fields(1)) = "一般用户" ThenfrmMain.GeneralUser.Enabled = TruefrmMain.Operator.Enabled = FalsefrmMain.Operator.Visible = FalsefrmMain.Administrator.Enabled = FalsefrmMain.Administrator.Visible = FalseEnd IfIf Trim(mrc.Fields(1)) = "操作员" ThenfrmMain.GeneralUser.Enabled = TruefrmMain.Operator.Enabled = TruefrmMain.Administrator.Enabled = FalsefrmMain.Administrator.Visible = FalseEnd IfIf Trim(mrc.Fields(1)) = "管理员" ThenfrmMain.GeneralUser.Enabled = TruefrmMain.Operator.Enabled = TruefrmMain.Administrator.Enabled = TruefrmMain.Administrator.Visible = TrueEnd If

 

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