Excel.Workbooks wbs = Aexcel.Workbooks;
            Excel.Workbook wb = wbs[1];
            Excel.Worksheet ws = null;

            ws = (Excel.Worksheet)wb.Worksheets[str];//str是表单Sheet1
            Excel.Range column1 = ws.get_Range(ws.Cells[1,1] as Excel.Range,ws.Cells[ws.Rows.Count,1] as Excel.Range);//A列
            Excel.Range column2 = ws.get_Range(ws.Cells[1, 2] as Excel.Range, ws.Cells[ws.Rows.Count, 2] as Excel.Range);B列
            Excel.Range column = ws.get_Range(ws.Cells[1,5] as Excel.Range,ws.Cells[ws.Rows.Count,5]as Excel.Range);//C列
            column=column1;
            column1 = column2;
            column2 = column;
            wb.Save();