在Excel VBA中将对象作为参数传递

Question

How do I pass an object to a private sub as a reference in Excel VBA? Below is what I am trying to do:

Sub main()
    Dim r As Range
    Set r = Sheets("Sheet1").Range(Cells(1, 1), Cells(27, 27))
    r.Select 'this works
    select_cells (r) 'this doesn't work
End Sub

Private Sub select_cells(a As Range)
    a.Select 'prompts Object Required error
End Sub

Answer 1

 select_cells (r) 'this doesn't work 

You can't use parentheses to pass object parameters to a procedure. Just do this:

select_cells r

The archaic, obsolete Call keyword can be used, if you really want to keep the parentheses.

Answer 2

There are severla errors in your code

1. Unqualified range references refer to the ActiveSheet . So

    Set r = Sheets("Sheet1").Range(Cells(1, 1), Cells(27, 27)) 

   will error if Sheet1 is not active.

2. r.Select will error if Sheet1 is not active.

3. select_cells (r) with the brackets is incorrect. Use

    select_cells r 

4. a.Select in the Private Sub will error if Sheet1 is not active.

Here's an modified version

Sub main()
    Dim r As Range
    With Sheets("Sheet1")
        Set r = .Range(.Cells(1, 1), .Cells(27, 27))
    End With
    Debug.Print r.Address ' for diagnostic purposes
    select_cells r
End Sub

Private Sub select_cells(a As Range)
    ' Activate the worksheet first, so you can select a range on it
    a.Worksheet.Select
    a.Select
End Sub

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Note on bracketed parameters

When a Sub or Function parameter is a non-object variable, bracketing the parameter overrides the ByRef / ByVal definition and passes the parameter ByVal

When a Sub or Function parameter is an object variable, bracketing the parameter causes an the default property to be passed to the Sub / Function . In the case of the OP, this is r.Value , which causes a type missmatch.