使用DateSet下载Excel

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.IO;

namespace ExcelDownLoad
{
    public delegate void ExcelEventHandler();

    public class ExcelHelper:ISubject
    {
        string processStr = "";
        //public Label label2;

        public string ProcessStr
        {
            get { return processStr; }
            set { processStr = value; }
        }

        #region Kill Special Excel Process

        [DllImport("user32.dll", SetLastError = true)]
        static extern int GetWindowThreadProcessId(IntPtr hWnd, out int lpdwProcessId);


        public void KillSpecialExcel(Microsoft.Office.Interop.Excel.Application m_objExcel)
        {
            try
            {
                if (m_objExcel != null)
                {
                    int lpdwProcessId;
                    GetWindowThreadProcessId(new IntPtr(m_objExcel.Hwnd), out lpdwProcessId);

                    System.Diagnostics.Process.GetProcessById(lpdwProcessId).Kill();
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Delete Excel Process Error:" + ex.Message);
            }
        }

        #endregion

        public void ExportExcel(DataSet ds, string saveFileName)
        {
            if (ds == null) return;
            
            bool fileSaved = false;

            if (saveFileName.IndexOf(":") < 0) return; //被点了取消         
            Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
            if (xlApp == null)
            {
                MessageBox.Show("无法创建Excel对象，您的电脑未安装Excel"); return;
            }
            Microsoft.Office.Interop.Excel.Workbooks workbooks = xlApp.Workbooks;
            Microsoft.Office.Interop.Excel.Workbook workbook = workbooks.Add(Microsoft.Office.Interop.Excel.XlWBATemplate.xlWBATWorksheet);
            Microsoft.Office.Interop.Excel.Worksheet worksheet = (Microsoft.Office.Interop.Excel.Worksheet)workbook.Worksheets[1];
            //取得sheet1      
            Microsoft.Office.Interop.Excel.Range range; 
            string oldCaption = DateTime.Today.ToString("yy-MM-dd");
            long totalCount = ds.Tables[0].Rows.Count; 
            long rowRead = 0; 
            float percent = 0;
            //worksheet.Cells[1, 1] = DateTime.Today.ToString("yy-MM-dd");
            //写入字段      
            for (int i = 0; i < ds.Tables[0].Columns.Count; i++)
            {
                worksheet.Cells[1, i + 1] = ds.Tables[0].Columns[i].ColumnName;
                range = (Microsoft.Office.Interop.Excel.Range)worksheet.Cells[1, i + 1];
                range.Interior.ColorIndex = 15;
                range.Font.Bold = true;
            }
            //写入数值        
            for (int r = 0; r < ds.Tables[0].Rows.Count; r++)
            {
                for (int i = 0; i < ds.Tables[0].Columns.Count; i++)
                {
                    worksheet.Cells[r + 2, i + 1] = ds.Tables[0].Rows[r][i];
                }
                rowRead++;
                percent = ((float)(100 * rowRead)) / totalCount;
                //if (label2 != null)
                //{
                //    label2.Text = "正在导出数据[" + percent.ToString("0.00") + "%]..."; //这里可以自己做一个label用来显示进度.  
                //}
                System.Windows.Forms.Application.DoEvents();
            }
            ////this.lbl_process.Visible = false;
            range = worksheet.get_Range(worksheet.Cells[2, 1], worksheet.Cells[ds.Tables[0].Rows.Count + 1, ds.Tables[0].Columns.Count]);
            range.BorderAround(Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous, Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin, Microsoft.Office.Interop.Excel.XlColorIndex.xlColorIndexAutomatic, null);
            range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideHorizontal].ColorIndex = Microsoft.Office.Interop.Excel.XlColorIndex.xlColorIndexAutomatic;
            range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideHorizontal].LineStyle = Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous;
            range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideHorizontal].Weight = Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin;
            if (ds.Tables[0].Columns.Count > 1)
            {
                range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideVertical].ColorIndex = Microsoft.Office.Interop.Excel.XlColorIndex.xlColorIndexAutomatic;
                range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideVertical].LineStyle = Microsoft.Office.Interop.Excel.XlLineStyle.xlContinuous;
                range.Borders[Microsoft.Office.Interop.Excel.XlBordersIndex.xlInsideVertical].Weight = Microsoft.Office.Interop.Excel.XlBorderWeight.xlThin;
            }
            if (saveFileName != "")
            {
                try
                {
                    workbook.Saved = true;
                    workbook.SaveCopyAs(saveFileName);

                    fileSaved = true;
                }
                catch (Exception ex)
                {
                    fileSaved = false; MessageBox.Show("导出文件时出错,文件可能正被打开！\n" + ex.Message);
                }
            }
            else
            {
                fileSaved = false;
            } 
            xlApp.Quit();
            GC.Collect();//强行销毁          
            if (fileSaved && File.Exists(saveFileName))
            {
                //System.Diagnostics.Process.Start(saveFileName);             
                MessageBox.Show("导出成功！", "通知");
            }
        }

        #region ISubject Members
      
        public event ExcelEventHandler Update;
        public void Notify()
        {
            if (Update != null)
            {
                // 使用事件来通知给订阅者
                Update();
            }
        }

        #endregion
    }
}