Question

我的ms-access表单上有以下VBA代码

Option Compare Database
Option Explicit

Public Function GetUserName() As String
    Dim obj1 As Object
    Dim GetEmpID As String
    Set obj1 = CreateObject("WScript.Network")
    GetUserName = DLookup("[BAFUser]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
    GetEmpID = DLookup("[EmpID]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
    Set obj1 = Nothing
End Function

Private Sub Form_Load()
    Me.EmpName.Value = GetUserName
    Me.EmpID.Value = GetEmpID
End Sub

我可以使用GetUserName子信息中的Load()获取值，但无法使用GetEmpID获取值。

可能的原因是什么？我该如何解决？

提前致谢。

Answer 1

选项1：创建模块级变量，您在函数中设置（现在是子级，因为它没有返回值）

 Option Compare Database
 Option Explicit

 Dim UserName as String
 Dim EmpID as String

 Public Sub GetValues()
  Dim obj1 As Object

  Set obj1 = CreateObject("WScript.Network")
  UserName = DLookup("[BAFUser]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
  EmpID = DLookup("[EmpID]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
  Set obj1 = Nothing
 End Sub

Private Sub Form_Load()
    Call GetValues() 'Invoke the function to set values
    Me.EmpName.Value = UserName 'retrieve values from module level variables
    Me.EmpID.Value = EmpID
 End Sub

选项2：创建ByRef变量。

 Option Compare Database
 Option Explicit

 Public Sub GetValues(ByRef UserName as String, ByRef EmpID as String) 
  Dim obj1 As Object

  Set obj1 = CreateObject("WScript.Network")
  UserName = DLookup("[BAFUser]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
  EmpID = DLookup("[EmpID]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
  Set obj1 = Nothing
 End Sub

Private Sub Form_Load()
   Dim UserName as String
   Dim EmpID as String
    Call GetValues(UserName, EmpId) 'Invoke the function to set values of local variables.
    Me.EmpName.Value = UserName 'retrieve values from function scoped variables.
    Me.EmpID.Value = EmpID
 End Sub

警告：从内存中键入内容。可能需要进行小的修正。

Answer 2

您可以随时在函数中使用ByRef。

Option Compare Database
Option Explicit

Public Function GetUserName(ByRef GetEmpID as string) as string
dim obj1 as object

Set obj1 = CreateObject("WScript.Network")

GetUserName = DLookup("[BAFUser]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")
GetEmpID = DLookup("[EmpID]", "BAF_User", "[BRID] = '" & obj1.UserName & "'")

If not obj1 is nothing then
    Set obj1 = Nothing
End If
End Function

Private Sub Form_Load()
Dim GetEmpID as string

GetEmpID = "None"

Me.EmpName.value = GetUserName(GetEmpID)
Me.EmpID.Value = GetEmpID
End Sub

ByRef传递用于将变量存储在内存中的地址。一旦传递了地址而不是仅传递了值，地址上发生的任何更改都将在整个项目中对变量进行。

有关ByVal和ByRef的更多详细说明，请参阅以下网站： http://www.cpearson.com/excel/byrefbyval.aspx

无法在MS-Access中的子中使用函数的变量

2 个答案: