检查前端和后端Access数据库之间的有效连接

Question

我有一个Access数据库应用程序，分为前端和后端。后端位于所有用户都可以访问的共享网络驱动器上。我的问题是，当用户启动这个应用程序的前端时，他们没有连接到后端，因为共享驱动器可能没有在本地安装，启动应用程序时显示的初始表单没有打开，让用户质疑发生了什么。我已经有代码来检查后端是否连接了，尽管出于某种原因，当它没有连接时，介绍屏幕表单永远不会显示，access应用程序就在那里

Private Sub Form_Open(Cancel As Integer)
    Dim strBackEndPath, LResult As String
    Dim i, j, lenPath As Integer

    'initialize variable status to 0
    Me.BEDB_Status = 0
    'define what to check in backend database
    strBackEndPath = CurrentDb.TableDefs("VersionInfo-Available").Connect

    ' Now remove the datebase  & password prefix
    j = InStrRev(strBackEndPath, "=") + 1
    strBackEndPath = Mid(strBackEndPath, j)

    'Checking access to Backend database files...
    Me.MessageText = "Checking access to Backend database files..."
    On Error Resume Next
    LResult = Dir(strBackEndPath)
    'Set status to Length of LResult
    Me.BEDB_Status = Len(LResult)

    'Check length of BEDB_Status, if greater than 0, backend is connected. If 0, backend is not connected.
    If Me.BEDB_Status > 0 Then
        'length is greater than 0 so continue opening the app
        DoCmd.OpenForm "IntroScreen"
    Else
        'length is 0 so backend is not connected. Alert user and quit the app
        Me.MessageText = "The database isn't currently accessible. Program will now exit. Please ask the support team for assistance"
        DoCmd.Quit acQuitSaveNone
    End If

End Sub

Answer 1

实现了Gustav的建议，使用On Load事件而不是On Open事件以及他的IsLinkedTable功能，它运行良好。

谢谢古斯塔夫。

Answer 2

尝试打开其中一个链接表并忽略错误可能更简单、更快：

Public Function IsLinkedTable(ByVal TableName As String) As Boolean

    Dim LinkOk  As Boolean

    On Error Resume Next
    LinkOk = (DCount("*", TableName) >= 0)

    IsLinkedTable = LinkOk

End Function

并使用表单的OnLoad事件，因为这允许表单打开。