iEndrow = ThisWorkbook.Sheets("Summary").Range("A4").End(xlDown).Row
Range(Cells(iEndrow + 1, "A"), Cells(iEndrow + 1, "A")).FormulaR1C1 = "Total"
Range(Cells(iEndrow + 1, "C"), Cells(iEndrow + 1, "C")).FormulaR1C1 = "=SUM(R[-20]C:R[-1]C)"
"=SUM(R[-20]C:R[-1]C)"这段代码是固定死列数的我怎么才能动态获取到它的列数来sum