C#导入导出EXCEL

摘抄自 http://www.cnblogs.com/daxia/archive/2008/01/08/1030779.html

供学习之用

导入导出EXCEL
#region  导入导出EXCEL
        /**//// <summary> 
        /// 将datatable中的数据导出到指定的excel文件中 
        /// </summary> 
        /// <param name="page">web页面对象</param> 
        /// <param name="tab">包含被导出数据的datatable对象</param> 
        /// <param name="filename">excel文件的名称</param> 
        public static void exportExcel(System.Web.UI.Page page, DataTable tab, string filename)
        {
            System.Web.HttpResponse httpresponse = page.Response;
            System.Web.UI.WebControls.DataGrid datagrid = new System.Web.UI.WebControls.DataGrid();
            datagrid.DataSource = tab.DefaultView;
            datagrid.AllowPaging = false;
            datagrid.HeaderStyle.BackColor = System.Drawing.Color.LightGray;
            datagrid.HeaderStyle.HorizontalAlign = HorizontalAlign.Center;
            datagrid.HeaderStyle.Font.Bold = true;
            datagrid.DataBind();
            httpresponse.AppendHeader("content-disposition", "attachment;filename=" + HttpUtility.UrlDecode(filename, System.Text.Encoding.UTF8)); //filename="*.xls"; 
            httpresponse.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
            httpresponse.ContentType = "application/ms-excel";
            System.IO.StringWriter tw = new StringWriter();
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
            datagrid.RenderControl(hw);

            string filepath = page.Server.MapPath("..") + "\\ExcelFolder\\" + filename;
            System.IO.StreamWriter sw = System.IO.File.CreateText(filepath);
            sw.Write(tw.ToString());
            sw.Close();

            downfileForExcel(httpresponse, filename, filepath);

            httpresponse.End();
        }
        private static bool downfileForExcel(System.Web.HttpResponse response, string filename, string fullpath)
        {
            try
            {
                response.ContentType = "application/octet-stream";

                response.AppendHeader("content-disposition", "attachment;filename=" +
                HttpUtility.UrlDecode(filename, System.Text.Encoding.UTF8) + ";charset=gb2312");
                System.IO.FileStream fs = System.IO.File.OpenRead(fullpath);
                long flen = fs.Length;
                int size = 102400;//每100k同时下载数据 
                byte[] readdata = new byte[size];//指定缓冲区的大小 
                if (size > flen) size = Convert.ToInt32(flen);
                long fpos = 0;
                bool isend = false;
                while (!isend)
                {
                    if ((fpos + size) > flen)
                    {
                        size = Convert.ToInt32(flen - fpos);
                        readdata = new byte[size];
                        isend = true;
                    }
                    fs.Read(readdata, 0, size);//读入一个压缩块 
                    response.BinaryWrite(readdata);
                    fpos += size;
                }
                fs.Close();
                System.IO.File.Delete(fullpath);
                return true;
            }
            catch
            {
                return false;
            }
        }

        /**//// <summary> 
        /// 将指定Excel文件中的数据转换成DataTable对象，供应用程序进一步处理 
        /// </summary> 
        /// <param name="filePath"></param> 
        /// <returns></returns> 
        public static System.Data.DataTable ImportExcel(string filePath)
        {
            System.Data.DataTable rs = new System.Data.DataTable();
            bool canOpen = false;

            OleDbConnection conn = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" +
            "Data Source=" + filePath + ";" +
            "Extended Properties=\"Excel 8.0;\"");

            try//尝试数据连接是否可用 
            {
                conn.Open();
                conn.Close();
                canOpen = true;
            }
            catch { }

            if (canOpen)
            {
                try//如果数据连接可以打开则尝试读入数据 
                {
                    OleDbCommand myOleDbCommand = new OleDbCommand("SELECT * FROM [Sheet1$]", conn);
                    OleDbDataAdapter myData = new OleDbDataAdapter(myOleDbCommand);
                    myData.Fill(rs);
                    conn.Close();
                }
                catch//如果数据连接可以打开但是读入数据失败，则从文件中提取出工作表的名称，再读入数据 
                {
                    string sheetName = GetSheetName(filePath);
                    if (sheetName.Length > 0)
                    {
                        OleDbCommand myOleDbCommand = new OleDbCommand("SELECT * FROM [" + sheetName + "$]", conn);
                        OleDbDataAdapter myData = new OleDbDataAdapter(myOleDbCommand);
                        myData.Fill(rs);
                        conn.Close();
                    }
                }
            }
            else
            {
                System.IO.StreamReader tmpStream = File.OpenText(filePath);
                string tmpStr = tmpStream.ReadToEnd();
                tmpStream.Close();
                rs = GetDataTableFromString(tmpStr);
                tmpStr = "";
            }
            return rs;
        }
        /**//// <summary> 
        /// 将指定Html字符串的数据转换成DataTable对象 --根据“<tr><td>”等特殊字符进行处理 
        /// </summary> 
        /// <param name="tmpHtml">Html字符串</param> 
        /// <returns></returns> 
        private static DataTable GetDataTableFromString(string tmpHtml)
        {
            string tmpStr = tmpHtml;
            DataTable TB = new DataTable();
            //先处理一下这个字符串，删除第一个<tr>之前合最后一个</tr>之后的部分 
            int index = tmpStr.IndexOf("<tr");
            if (index > -1)
                tmpStr = tmpStr.Substring(index);
            else
                return TB;

            index = tmpStr.LastIndexOf("</tr>");
            if (index > -1)
                tmpStr = tmpStr.Substring(0, index + 5);
            else
                return TB;

            bool existsSparator = false;
            char Separator = Convert.ToChar("^");

            //如果原字符串中包含分隔符“^”则先把它替换掉 
            if (tmpStr.IndexOf(Separator.ToString()) > -1)
            {
                existsSparator = true;
                tmpStr = tmpStr.Replace("^", "^$&^");
            }

            //先根据“</tr>”分拆 
            string[] tmpRow = tmpStr.Replace("</tr>", "^").Split(Separator);

            for (int i = 0; i < tmpRow.Length - 1; i++)
            {
                DataRow newRow = TB.NewRow();

                string tmpStrI = tmpRow[i];
                if (tmpStrI.IndexOf("<tr") > -1)
                {
                    tmpStrI = tmpStrI.Substring(tmpStrI.IndexOf("<tr"));
                    if (tmpStrI.IndexOf("display:none") < 0 || tmpStrI.IndexOf("display:none") > tmpStrI.IndexOf(">"))
                    {
                        tmpStrI = tmpStrI.Replace("</td>", "^");
                        string[] tmpField = tmpStrI.Split(Separator);

                        for (int j = 0; j < tmpField.Length - 1; j++)
                        {
                            tmpField[j] = RemoveString(tmpField[j], "<font>");
                            index = tmpField[j].LastIndexOf(">") + 1;
                            if (index > 0)
                            {
                                string field = tmpField[j].Substring(index, tmpField[j].Length - index);
                                if (existsSparator) field = field.Replace("^$&^", "^");
                                if (i == 0)
                                {
                                    string tmpFieldName = field;
                                    int sn = 1;
                                    while (TB.Columns.Contains(tmpFieldName))
                                    {
                                        tmpFieldName = field + sn.ToString();
                                        sn += 1;
                                    }
                                    TB.Columns.Add(tmpFieldName);
                                }
                                else
                                {
                                    newRow[j] = field;
                                }
                            }//end of if(index>0) 
                        }

                        if (i > 0)
                            TB.Rows.Add(newRow);
                    }
                }
            }

            TB.AcceptChanges();
            return TB;
        }

        /**//// <summary> 
        /// 从指定Html字符串中剔除指定的对象 
        /// </summary> 
        /// <param name="tmpHtml">Html字符串</param> 
        /// <param name="remove">需要剔除的对象--例如输入"<font>"则剔除"<font ???????>"和"</font>>"</param> 
        /// <returns></returns> 
        public static string RemoveString(string tmpHtml, string remove)
        {
            tmpHtml = tmpHtml.Replace(remove.Replace("<", "</"), "");
            tmpHtml = RemoveStringHead(tmpHtml, remove);
            return tmpHtml;
        }
        /**//// <summary> 
        /// 只供方法RemoveString()使用 
        /// </summary> 
        /// <returns></returns> 
        private static string RemoveStringHead(string tmpHtml, string remove)
        {
            //为了方便注释，假设输入参数remove="<font>" 
            if (remove.Length < 1) return tmpHtml;//参数remove为空：不处理返回 
            if ((remove.Substring(0, 1) != "<"||remove.Substring(remove.Length - 1) != ">")) 
                return tmpHtml;//参数remove不是<?????>：不处理返回 

            int IndexS = tmpHtml.IndexOf(remove.Replace(">", ""));//查找“<font”的位置 
            int IndexE = -1;
            if (IndexS > -1)
            {
                string tmpRight = tmpHtml.Substring(IndexS, tmpHtml.Length - IndexS);
                IndexE = tmpRight.IndexOf(">");
                if (IndexE > -1)
                    tmpHtml = tmpHtml.Substring(0, IndexS) + tmpHtml.Substring(IndexS + IndexE + 1);
                if (tmpHtml.IndexOf(remove.Replace(">", "")) > -1)
                    tmpHtml = RemoveStringHead(tmpHtml, remove);
            }
            return tmpHtml;
        }

        /**//// <summary> 
        /// 将指定Excel文件中读取第一张工作表的名称 
        /// </summary> 
        /// <param name="filePath"></param> 
        /// <returns></returns> 
        private static string GetSheetName(string filePath)
        {
            string sheetName = "";

            System.IO.FileStream tmpStream = File.OpenRead(filePath);
            byte[] fileByte = new byte[tmpStream.Length];
            tmpStream.Read(fileByte, 0, fileByte.Length);
            tmpStream.Close();

            byte[] tmpByte = new byte[]{Convert.ToByte(11),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0), 
Convert.ToByte(11),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0),Convert.ToByte(0), 
Convert.ToByte(30),Convert.ToByte(16),Convert.ToByte(0),Convert.ToByte(0)};

            int index = GetSheetIndex(fileByte, tmpByte);
            if (index > -1)
            {

                index += 16 + 12;
                System.Collections.ArrayList sheetNameList = new System.Collections.ArrayList();

                for (int i = index; i < fileByte.Length - 1; i++)
                {
                    byte temp = fileByte[i];
                    if (temp != Convert.ToByte(0))
                        sheetNameList.Add(temp);
                    else
                        break;
                }
                byte[] sheetNameByte = new byte[sheetNameList.Count];
                for (int i = 0; i < sheetNameList.Count; i++)
                    sheetNameByte[i] = Convert.ToByte(sheetNameList[i]);

                sheetName = System.Text.Encoding.Default.GetString(sheetNameByte);
            }
            return sheetName;
        }
        /**//// <summary> 
        /// 只供方法GetSheetName()使用 
        /// </summary> 
        /// <returns></returns> 
        private static int GetSheetIndex(byte[] FindTarget, byte[] FindItem)
        {
            int index = -1;

            int FindItemLength = FindItem.Length;
            if (FindItemLength < 1) return -1;
            int FindTargetLength = FindTarget.Length;
            if ((FindTargetLength - 1) < FindItemLength) return -1;

            for (int i = FindTargetLength - FindItemLength - 1; i > -1; i--)
            {
                System.Collections.ArrayList tmpList = new System.Collections.ArrayList();
                int find = 0;
                for (int j = 0; j < FindItemLength; j++)
                {
                    if (FindTarget[i + j] == FindItem[j]) find += 1;
                }
                if (find == FindItemLength)
                {
                    index = i;
                    break;
                }
            }
            return index;
        } 

        #endregion