/// <summary>
        /// 导出Excel
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnExportExcel_Click(object sender, EventArgs e)
        {
            DataTable dt = this.dgvWaterTicket.DataSource;
            if (dt == null)
            {
                return;
            } 
            if (dt.Rows.Count == 0)
            {                
                return;
            }
            Excel.Application xlApp = new Excel.Application();
            if (xlApp == null)
            {
                MessageBox.Show("请确保您的电脑已经安装Excel", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            xlApp.UserControl = true;
            Excel.Workbooks workbooks = xlApp.Workbooks;
            //根据模版产生新的workbook //Workbook workbook = workbooks.Add("D:\\aa.xls");
            Excel.Workbook workbook = workbooks.Add(Excel.XlWBATemplate.xlWBATWorksheet);
            Excel.Worksheet worksheet = (Excel.Worksheet)workbook.Worksheets[1];//取得sheet1 
            if (worksheet == null)
            {
                MessageBox.Show("请确保您的电脑已经安装Excel", "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            try
            {

                Excel.Range range;
                long totalCount = dt.Rows.Count;
                long rowRead = 0;
                float percent = 0;
                worksheet.Cells[1, 1] = frm.Text;//导出的标题
                worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[1, dt.]).MergeCells = true; //合并单元格---列数
                worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[1, 3]).HorizontalAlignment = Excel.XlVAlign.xlVAlignCenter;//居中对齐
                worksheet.get_Range(worksheet.Cells[1, 3], worksheet.Cells[1, 3]).ColumnWidth = 15;     //列宽
                worksheet.get_Range(worksheet.Cells[1, 2], worksheet.Cells[1, 2]).ColumnWidth = 15;     //列宽
                worksheet.get_Range(worksheet.Cells[1, 1], worksheet.Cells[1, 1]).ColumnWidth = 20;     //列宽

                //写入字段 
                for (int i = 0; i < dt.Columns.Count; i++)
                {
                    worksheet.Cells[2, i + 1] = dt.Columns[i].ColumnName;
                    range = (Excel.Range)worksheet.Cells[2, i + 1];
                    range.Interior.ColorIndex = 15;
                    range.Font.Bold = true;

                }
                //写入数值

                for (int r = 0; r < dt.Rows.Count; r++)
                {
                    for (int i = 0; i < dt.Columns.Count; i++)
                    {
                        worksheet.Cells[r + 3, i + 1] = dt.Rows[r][i];
                    }
                    rowRead++;
                    percent = ((float)(100 * rowRead)) / totalCount;
                    //System.Threading.Thread.Sleep(500);
                    //如果字的数量过多则自动换行。worksheet.Cells[r+1, 4]为worksheet.Cells[行, 列]
                    worksheet.get_Range(worksheet.Cells[r + 3, 4], worksheet.Cells[r + 1, 4]).Columns.WrapText = true;     //自动换行
                    worksheet.get_Range(worksheet.Cells[r + 3, 4], worksheet.Cells[r + 3, 4]).Rows.AutoFit(); //自动加行高
                    //this.Text = "导出数据[" + percent.ToString("0.00") + "%]...";

                }

                range = worksheet.get_Range(worksheet.Cells[2, 1], worksheet.Cells[dt.Rows.Count + 2, dt.Columns.Count]);
                range.BorderAround(Excel.XlLineStyle.xlContinuous, Excel.XlBorderWeight.xlThin, Excel.XlColorIndex.xlColorIndexAutomatic, null);

                range