Access VBA object types

问题

I am trying to build a procedure in my Access project that will accept either a table or a form as part of the argument. If the object is a table then it should check the table's fields; if it's a form then it should it the form's controls.

I've tried using either variant or object variable types for the argument. But either way when I check the VarType() the passed variable is of type object, so I can't distinguish between them. (I'm currently passing a table as a TableDef object by the way.)

I would try overloading the function based on parameter type but apparently that isn't available in VBA (as far as I know from Function Overloading and UDF in Excel VBA. Any suggestions?

回答1:

To test for a certain class in VBA, use a combination of the TypeOf and Is operators:

Sub WishVBAHadOverloads(ByVal Obj As Object)
  If TypeOf Obj Is TableDef Then 
    Dim Def As TableDef
    Set Def = Obj
    ' work with Def... 
    Exit Sub
  End If
  If TypeOf Obj Is Form Then 
    Dim Frm As Form
    Set Frm = Obj
    ' work with Frm... 
    Exit Sub
  End If
  Err.Raise 999, "WishVBAHadOverloads", "Bad argument type - expected a TableDef or Form"
End Sub

来源：https://stackoverflow.com/questions/20664923/access-vba-object-types