使用VB语言制作登陆界面

Option Explicit

Const MaxLoginTimes As Integer = 3

Private Sub cmdLogin_Click()

    Static loginTimes As Integer

    loginTimes = loginTimes + 1

If loginTimes < MaxLoginTimes Then

    On Error GoTo ppp

    Dim Cn As Connection

    Dim Rs As Recordset

    Dim strSQL As String

    

    Set Cn = New Connection

    Set Rs = New Recordset

    Cn.ConnectionString = " provider=Microsoft.Jet.OLEDB.3.51;Data Source=C:\Users\jf\Desktop\TestExample.mdb"

    Cn.Open

    Rs.ActiveConnection = Cn

    strSQL = "select UserPassword from UserInformation where UserID= '" & Me.txtUserID.Text & "'"

    Rs.Open (strSQL)

    If Rs.EOF = True Then

        MsgBox txtUserID.Text & "不存在"

        Me.txtUserID.SetFocus

        Me.txtUserID.SelStart = 0

        Me.txtUserID.SelLength = Len(Me.txtUserID.Text)

    Else

       If Rs.Fields("UserPassword").Value = Me.txtPassword.Text Then

            MsgBox "登录成功"

            Unload Me

            'frmNew.show

       Else

        MsgBox "密码错误"

       End If

     End If

        

ppp:

    Cn.Close

Else

    MsgBox "亲，您的输入次数超过允许的最大次数", vbCritical, "登录"

End If

End Sub