如何让函数返回空对像

Question

If isExisting Then
        Set searchCustomerByID = re_customer
    Else
        Set searchCustomerByID = Null //这句出错
    End IfsearchCustomerByID是function name

Answer 1

Set searchCustomerByID = empty
这样行不行

Answer 2

searchCustomerByID 返回的是一個什麼來著呀?把代碼貼來LOOK一下

Answer 3

function searchCustomerByID as variant
end function
把返回类型改为变体型
searchCustomerByID = Null 就正确了

Answer 4

Set searchCustomerByID =nothing

Answer 5

Public Function searchCustomerByID(ByVal id As String) As customer
    
    Dim re_customer As customer
    Dim isExisting As Boolean
    Set re_customer = New customer
    Set in_util = New util
    Set db = OpenDatabase("", False, False, "ODBC;DSN=CTIDSN;UID=sa;PWD=;TIMEOUT=180")
    
    Dim sqlcmd As String
        
    sqlcmd = "select * from Customer where  "
    If Form1.Check_UT Then
        sqlcmd = sqlcmd & " UCASE(RTrim(Ltrim(customer_id) ) )"
    Else
        sqlcmd = sqlcmd & "customer_id"
    End If
    sqlcmd = sqlcmd & " = " & in_util.addQuote(Trim(UCase(id)))
    
    'MsgBox (sqlcmd)
    
    
    Set rs = db.OpenRecordset(sqlcmd)
    If rs.EOF Then
        isExisting = False
    Else
        'MsgBox ("FIND")
        re_customer.id = rs![customer_id]
        re_customer.last_name = rs![CUSTOMER_LAST_NAME]
        re_customer.phone = rs![PHONE_NUMBER]
        re_customer.pps_no = rs![pps_no]
        isExisting = True
    End If
    
    'Close all of connection
    rs.Close
    Set rs = Nothing
    db.Close
    Set db = Nothing
    
    'If isExisting Then
        Set searchCustomerByID = re_customer
    'Else
    '    Set searchCustomerByID = re_customer
    'End If
End Function

Answer 6

Set searchCustomerByID = nothing可以通过
下面是调用的代码
        Set re_customer = gb_CustomerDB.searchCustomerByID(customer_id)
        
        If re_customer Then  //这句又应怎写?
            MsgBox ("Can not find the customer,Customer ID:" & customer_id)
        Else
            Form1.Command_Update.Enabled = True
            Call setUpCustomerInfo(re_customer)
        End If

Answer 7

你既然知道Set rs = Nothing
为什么不知道
Set searchCustomerByID =nothing
？

Answer 8

Public Function searchCustomerByID(ByVal id As String) As customer
    
    Dim re_customer As customer
    'Dim isExisting As Boolean
    
    Set in_util = New util
    Set db = OpenDatabase("", False, False, "ODBC;DSN=CTIDSN;UID=sa;PWD=;TIMEOUT=180")
    
    Dim sqlcmd As String
        
    sqlcmd = "select * from Customer where  "
    If Form1.Check_UT Then
        sqlcmd = sqlcmd & " UCASE(RTrim(Ltrim(customer_id) ) )"
    Else
        sqlcmd = sqlcmd & "customer_id"
    End If
    sqlcmd = sqlcmd & " = " & in_util.addQuote(Trim(UCase(id)))
    
    'MsgBox (sqlcmd)
    
    
    Set rs = db.OpenRecordset(sqlcmd)
    'If rs.EOF Then
        'isExisting = False
    'Else
      If Not rs.Eof Then
        'MsgBox ("FIND")
         Set re_customer = New customer
        re_customer.id = rs![customer_id]
        re_customer.last_name = rs![CUSTOMER_LAST_NAME]
        re_customer.phone = rs![PHONE_NUMBER]
        re_customer.pps_no = rs![pps_no]
        'isExisting = True
         Set searchCustomerByID = re_customer
         Set re_customer = Nothing
    End If
    
    'Close all of connection
     
    Set in_util = Nothing
    rs.Close
    Set rs = Nothing
    db.Close
    Set db = Nothing
    
    'If isExisting Then
    '    Set searchCustomerByID = re_customer
    'Else
    '    Set searchCustomerByID = re_customer
    'End If
End Function
下面是调用的代码
        Set re_customer = gb_CustomerDB.searchCustomerByID(customer_id)
        
        If re_customer is nothing Then  
            MsgBox ("Can not find the customer,Customer ID:" & customer_id)
        Else
            Form1.Command_Update.Enabled = True
            Call setUpCustomerInfo(re_customer)
        End If