DataGridView导出Excel

  /// <summary>
        /// 将传入的数据保存在同一个Excel应用程序中
        /// </summary>
        public void dgvToExcelNEW(DataGridView datadgvMain, string _nameM, DataGridView datadgvDay, string _nameDay, DataGridView datadgvDetail, string _nameDetail)
        {
            Application app = new Microsoft.Office.Interop.Excel.Application();
            Workbook wb = app.Workbooks.Add(System.Reflection.Missing.Value);
            
            Worksheet ws = null;
            if (datadgvDay.RowCount >= 1)
            {
                if (datadgvDetail.RowCount >= 1)
                {
                    ws = newWeeksheet(datadgvDetail, _nameDetail, wb, ws,1);
                    ws = newWeeksheet(datadgvDay, _nameDay, wb, ws, 2);
                    ws = newWeeksheet(datadgvMain, _nameM, wb, ws, 3);
                }
                else
                {
                    ws = newWeeksheet(datadgvDay, _nameDay, wb, ws, 1);
                    ws = newWeeksheet(datadgvMain, _nameM, wb, ws, 2);
                }
            }
            else
            {
                ws = newWeeksheet(datadgvMain, _nameM, wb, ws,1);
            }
            app.Visible = true;
        }