是个 .在 .Range 由 .Cells 定义时需要吗? [英] Is the . in .Range necessary when defined by .Cells?

问题描述

人们普遍认为这不是最佳实践".

dim rng as range使用此工作簿 '<~~ 可能设置了一个外部工作簿与 .worksheets("sheet1")设置 rng = .range(cells(2, 1), cells(rows.count, 1).end(xlup))以以

定义范围的两个

因此始终建议正确限定您的对象，以便代码可以在任何地方运行

It is pretty much widely accepted that this is not 'best practise'.

dim rng as range
with thisworkbook    '<~~ possibly set an external workbook 
    with .worksheets("sheet1")
        set rng = .range(cells(2, 1), cells(rows.count, 1).end(xlup))
    end with
end with

The two Range.Cells properties that define the scope of the Range object will default to the ActiveSheet property. If this is not Sheet1 (defined as the .Parent in the With ... End With statement), the assignment will fail with,

Run-tim error '1004': Application-defined or object-defined error

Solution: use .Cells not Cells. Case closed.

But...

Is the . necessary in this Range object definition when both the Range.Cells properties inherit the .Parent worksheet property that is defined in the With ... End With statement?

How can this,

dim rng as range
with thisworkbook    '<~~ possibly set an external workbook 
    with .worksheets("sheet1")
        ' define rng as Sheet1!A2 to the last populated cell in Sheet1!A:A
        set rng = .range(.cells(2, 1), .cells(rows.count, 1).end(xlup))  '<~~ .range
    end with
end with
debug.print rng.address(0, 0, external:=true)

... be different from this,

dim rng as range
with thisworkbook    '<~~ possibly set an external workbook 
    with .worksheets("sheet1")
        ' define rng as Sheet1!A2 to the last populated cell in Sheet1!A:A
        set rng = range(.cells(2, 1), .cells(rows.count, 1).end(xlup))  '<~~ range not .range
    end with
end with
debug.print rng.address(0, 0, external:=true)

We use .range when the parameters that define the scope of the range are ambiguous; e.g. .range([A1]) The A1 cell could be from any worksheet and will default to the ActiveSheet property without the .. But why do we need to reference the parent of a range object when the scope that defines it has properly referenced its parent worksheet?

解决方案

My opinion is slightly different here.

YES it is required. You can't always control where the user may run the code from.

Please consider these few test cases

SCENARIO

Workbook has 2 worksheets. Sheet1 and Sheet2

---

TEST 1 (Running from a module)

Both Code give same result

TEST 2 (Running from a Sheet code area of Sheet1)

Both Code give same result

TEST 3 (Running from a Sheet code area of Sheet2)

'~~> This code fails
set rng = range(.cells(2, 1), .cells(rows.count, 1).end(xlup))

You will get Application Defined or Object defined error

And hence it is always advisable to properly qualify your objects so that the code can run from anywhere

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