将DataTable内容写入到Execl文件中，并且写完后显示给用户

        /// <summary>
        /// 保存为Excel文件
        /// </summary>
        private void btnSaveExcel_Click(object sender, EventArgs e)
        {
            saveFileDialogSaveExcel.Filter = "Excel文件|*.XLS";
            saveFileDialogSaveExcel.InitialDirectory = "C:\\";
            if (saveFileDialogSaveExcel.ShowDialog() == DialogResult.Cancel)
            {
                return;
            }
            else
            {
                string fileName = saveFileDialogSaveExcel.FileName;
                DataTable dt = (DataTable)this.dgvShow.DataSource;
                if (dt != null)
                {
                    //调用基本方法，生成Excel文件
                    SaveExcel(dt, fileName);
                }
                else
                {
                    MessageBox.Show("当前表格中没有数据，不能保存！");
                }
            }
        }

        /// <summary>
        /// 将DataTable保存为Execl的基本方法
        /// </summary>
        /// <param name="fileName">Excel文件路径</param>
        public void SaveExcel(DataTable dt, string fileName)
        {
            int columnIndex=1;
            int rowIndex=1;

            Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
            xlApp.DefaultFilePath = fileName;
            xlApp.DisplayAlerts = true;
            xlApp.SheetsInNewWorkbook = 1;
            Microsoft.Office.Interop.Excel.Workbook xlBook = xlApp.Workbooks.Add(true);

            //将DataTable的列名导入Excel表第一行
            foreach (DataColumn column in dt.Columns)
            {
                xlApp.Cells[rowIndex,columnIndex]=column.ColumnName;
                columnIndex++;
            }

           
            //将DataTable中的数据导入Excel中
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                columnIndex = 1;
                rowIndex++;
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    xlApp.Cells[rowIndex, columnIndex] = dt.Rows[i][j].ToString();
                    columnIndex++;
                }
            }

            xlBook.SaveCopyAs(fileName);
            xlApp = null;
            xlBook = null;
            System.Diagnostics.Process.Start(fileName);
            MessageBox.Show("测试成功：Excel文件保存成功且正常打开！");
        }