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这是我第一次尝试创建登录表单。我已经阅读了一些关于它的论坛并自己尝试过。但是，我在尝试表单时遇到了错误。

“运行时错误‘2001’：您取消了之前的操作。”

这是我的代码！突出显示的错误是 DLOOKUP 语句。当我将光标移动到 LanID 时，它似乎为 0。（我想这与它有关？）

Option Compare Database
Option Explicit

Private intLoginAttempts As Integer

Private Sub cmdLogin_Click()
'Check mandatory fields
If IsNull(Me.txtLanID) Or Me.txtLanID = "" Then
   MsgBox "Lan ID is required.", vbOKOnly, "Required Data"
   Me.txtLanID.SetFocus
   Exit Sub
End If

If IsNull(Me.txtPassword) Or Me.txtPassword = "" Then
   MsgBox "Password is required.", vbOKOnly, "Required Data"
   Me.txtPassword.SetFocus
   Exit Sub
End If

'Compare input password and database password
If Me.txtLanID <> "" Then
   If Me.txtPassword = DLookup("Password", "tblUser", "[LanID]=" & Me.txtLanID) Then
      LanID = Me.txtLanID

      'Close Login Page
      DoCmd.Close acForm, "frmUserLogin", acSaveNo

      'Check whether user is an admin
      If Me.txtAdmin = DLookup("Administrator", "tblUser", "[LanID]=" & Me.txtLanID) Then
         If Me.txtAdmin = -1 Then
            DoCmd.OpenForm "frmMenu"
            Else
               DoCmd.OpenForm "frmBack"
         End If
      End If

   Else
      MsgBox "Invalid Password. Try again.", vbOKOnly, "Invalid Entry!"
      Me.txtPassword.SetFocus
   End If
End If

'If user enters incorrect password 3 times
intLoginAttempts = intLoginAttempts + 1
If intLoginAttempts = 3 Then
   MsgBox "You do not have access to the database. Please contact system administrator.", vbCritical, "Restricted Access!"
   Application.Quit
End If
End Sub
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1 回答 1

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如果tblUser.LanID是文本数据类型，Me.txtLanID请用引号括起来以避免DLookup()表达式出错。（您不需要.Value那里，因为它是默认属性。）

DLookup("Password", "tblUser", "[LanID]='" & Me.txtLanID & "'")

如果这不是解释，请DLookup()在“立即”窗口中测试您的表达式（使用Ctrl+去那里g），看看它是否引发错误或返回什么值。

请注意，当您DLookup()在“立即”窗口中进行测试时，请使用 的当前值Me.txtLanID。例如，如果Me.txtLanID包含文本“ foo ”，则像这样测试它...

? DLookup("Password", "tblUser", "[LanID]='foo'")
于 2013-01-24T07:58:12.670 回答