Excel VBA如何从函数返回null

我有这个功能

Public Function parseEmployee(ByVal employeeId As Integer, _ 
                              ByVal ws As Worksheet) As employee
    Dim emp As New employee
    Dim empRow As Range
    If sheetContainsEmployee(employeeId, ws) Then
        Set empRow = ws.Rows(ws.Columns(ID_COLUMN).Find(employeeId).Row)
        emp.id = employeeId
        emp.Name = empRow.Cells(1, NAME_COLUMN).Value
    Else
        emp = Null ' Heres what I'd like to do
    End If

    parseEmployee = emp
End Function

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如果在工作表中找不到员工，我想返回null，这可能吗？我没有设置对象或变量nblock。错误

只有

变量

可以

为空

，而使用

无

：

Public Function parseEmployee(ByVal employeeId As Integer, _  
                              ByVal ws As Worksheet) As employee 
    Dim emp As New employee 
    Dim empRow As Range 
    If sheetContainsEmployee(employeeId, ws) Then 
        Set empRow = ws.Rows(ws.Columns(ID_COLUMN).Find(employeeId).Row) 
        emp.id = employeeId 
        emp.Name = empRow.Cells(1, NAME_COLUMN).Value 
    Else 
        Set emp = Nothing
    End If 

    Set parseEmployee = emp
End Function 

您将测试的方式：

  Dim emp As employee 
  Set emp = parseEmployee( ... )

  If emp Is Nothing Then
      Debug.Print "No employee returned."
  End If

Ref:

只需使用“”，或“”，您可以尝试使用哪种方法，如下所示：

否则 设置emp=“”“”

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请注意，

之间没有空格。我发现函数不返回任何内容会导致异常

我所做的是编写一个sub，它接受一个ByRef参数，该参数是您的返回值

与此相反：

Public Function test() as SomeClass
     set test = Nothing
End Function

我写道：

Public Sub test(ByRef result as SomeClass)
     result = Nothing
End Sub

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感谢您的回复，我尝试将其设置为nothing，但仍然得到运行时错误91:Object variable或with block variable not set。您需要

set emp=nothing

还将该集合添加到“return”行。