Question

我有一个ms访问数据库，我需要在不同的计算机上运行。我的问题是每台计算机都将后端存储在不同的位置。到目前为止，我只有2台机器在运行，但我知道我需要运行更多机器。我将每台计算机的位置存储在一个公共常量中，并使用简单的If语句将其链接到正确的一个。

 Public Const strFolderDatabasePc1 as string "c:\DatabasePc1"
 Public Const strFolderDatabasePc2 as string "c:\DatabasePc2" 
 ....

是否可以在数据库加载时使用if语句创建Public Const？

 Public Const strFolderDatabase as string
 If Pc1 then
    strFolderDatabase = FolderPc1
 else if Pc2 then
    strFolderDatabase = FolderPc2
 else if Pc3 then
    strFolderDatabase = FolderPc3
 else 
    strError
 EndIf

谢谢。

更新：

到目前为止，我已经编写了以下代码。它包含4个用户。

 'Database Folders
 Public Const MainFolder As String = "\\localhost\c$\User\Main"
 Public Const UserAFolder As String = "\\localhost\c$\User\UserA"
 Public Const UserBFolder As String = "\\localhost\c$\User\UserB"
 Public Function AdminFolder() As String
 AdminFolder = Application.CurrentProject.Path & "\Admin\"
 End Function

 'Database Keys
 Public Const MainUserKey As String = "\\localhost\c$\User\Main\Key.txt"
 Public Const UserAKey As String = "\\localhost\c$\User\UserA\key.txt"
 Public Const UserBKey As String = "\\localhost\c$\User\UserB\key.txt"
 Public Function AdminKey() As String
 AdminFolder = Application.CurrentProject.Path & "\Admin\key.txt"
 End Function

 Public Function FolderExists(ByVal path_ As String) As Boolean
 On Error Resume Next
 FolderExists = (GetAttr(path_) And vbDirectory) = vbDirectory
 On Error GoTo 0
 End Function

 Public Function FileExists(ByVal path_ As String) As Boolean
 On Error Resume Next
 FileExists = (Len(Dir(path_)) > 0)
 On Error GoTo 0
 End Function

 Public Function FolderDatabase()
 If FileExists(AdminKey) And FolderExists(AdminFolder) Then
      'Admin
      FolderDatabase = AdminFolder
 ElseIf FileExists(MainUserKey) And FolderExists(UserMainFolder) Then
      'MainUser
      FolderDatabase = UserMainFolder
 ElseIf FileExists(UserAKey) And FolderExists(UserAFolder) Then
      'UserA
      FolderDatabase = UserAFolder
 ElseIf FileExists(UserBKey) And FolderExists(UserBFolder) Then
      'UserB
      FolderDatabase = UserBFolder
 Else
      'Unknown User
      'Do something else...
 End If
 End Function

在每个表单中使用以下代码。

 Sub Check()
 If FolderExists(FolderDatabase) Then
      '===> User, Continue Loading.
      If Dir(FolderDatabase & "*.*") = "" Then
           '===> Empty Folder.
           'Do something...
      Else
           '===> Files On Folder.
           'Do something...
      End If
 Else
      '===> Not Known User.
      Application.Quit acQuitSaveNone
 End If
 End Sub

我可以用更简单的方式编写或执行此操作吗？谢谢。

PS：我需要在一个地方拥有每个USER的位置，因为我将来可能会更改位置或文件名。此外，我正在使用另外两个不同名称的文件夹，我再次使用上述所有文件夹。

Answer 1

简单来说就是no，但是你可以让一个函数通过传递pc号作为参数来返回正确的路径：

Public Const strFolderDatabasePc1 as string "c:\DatabasePc1"
Public Const strFolderDatabasePc2 as string "c:\DatabasePc2" 

Public Function FolderDatabase(ByVal pcNo As Long) As String
    Select Case pcNo
        Case 1:
            FolderDatabase = strFolderDatabasePc1
        Case 2:    
            FolderDatabase = strFolderDatabasePc2
    End Select
 End Function

然后只需传递所需的电脑号码：

Dim path_ As String
    path_ = FolderDatabase(1)

为了使其更具可读性，请为各种电脑设置Enum。

Public Enum Computers
    Home
    Work
End Enum

Public Function FolderDatabase(ByVal pc As Computers) As String
    Select Case pc
        Case Computers.Home:
            FolderDatabase = strFolderDatabasePc1
        Case Computers.Work:    
            FolderDatabase = strFolderDatabasePc2
    End Select
End Function


Dim path_ As String
    path_ = FolderDatabase(Computers.Home)

Answer 2

没有意义。每台计算机都有自己的C:驱动器，其他人不会看到。

所以你可以简单地使用：

Public Const strFolderDatabasePc As string "c:\DatabasePc"

也就是说，您可能最好使用C:\Users\Public下的文件夹，因为您的数据库文件不是，如Windows所见，应用程序只是文档。 / p>

ms access在加载时创建一个常量

2 个答案: