SpecialCells returns different results depending on size of range

Question

i really confuse and curious, why with same coding, just with different data quantity, the output can be really different?

With Sheets("control deck").Range("A2:A5000").SpecialCells(xlCellTypeBlanks)
.FormulaR1C1 = "=r[-1]C"
End With

with

With Sheets("control deck").Range("A2:A50000").SpecialCells(xlCellTypeBlanks)
.FormulaR1C1 = "=r[-1]C"
End With

the first output, fill only the blanks with the copy of cell's value above and the second coding, fill all the range with copy of first cell's value

my data :

>     1111    | abc    |x
>                      |y
>                      |z
>     
>     1112    | def    |R
>                      |S
>                      |T
>                      |U

what i hope come out

 1111 | abc |x 1111 abc |y 1111 abc |z 1112 | def |R 1112 def |S 1112 def |T 1112 def |U 

what came out

  > 1111 | abc |x > 1111 abc |y > 1111 abc |z > > 1111 | abc |R > 1111 abc |S > 1111 abc |T > 1111 abc |U 

anybody know why?

this only happen if the range above 30000 `row

Answer 1

If you are using Excel 2007 or earlier, there is a limit to the number of distinct cell areas SpecialCells can reference of 8192

As an alternative, try this

Sub Demo()
    Dim r As Range
    Dim dat As Variant
    Dim i As Long

    Set r = Sheets("Sheet2").Range("A2:A50000")
    dat = r.FormulaR1C1
    For i = 1 To UBound(dat, 1)
        If dat(i, 1) = "" Then
            dat(i, 1) = "=r[-1]C"
        End If
    Next

    r = dat

End Sub

This will be much faster, too.

Answer 2

特殊细胞中存在一个错误，据称于2010年修复，可以选择8,192个区域。