C# ----Excel读取数据之数据引擎方法

        /// <summary>
        /// excel转换为DataTable
        /// </summary>
        /// <param name="filename">excel文件名称</param>
        /// <param name="sheet">excel表单名称</param>
        /// <returns></returns>
        private DataTable ExcelToDataTable(string filename,string sheet)
        {
            DataTable dt = new DataTable();
            //判断文件是否存在
            if (!File.Exists(filename))
            {
                DevExpress.XtraEditors.XtraMessageBox.Show(filename + "file don‘t exist!");
            }
            else
            {
                //文件后缀名获取
                string extension = Path.GetExtension(filename);
                //excel数据引擎连接字符串
                string strConn = "";
                if (extension == ".xls")
                {
                    strConn = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + filename + ";Extended Properties=Excel 8.0;";
                }
                else if (extension == ".xlsx")
                {
                    strConn = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filename + ";Extended Properties=\"Excel 12.0 Xml;HDR=No\"";
                }

                ArrayList sheetList = new ArrayList();
                //获取表单列表
                sheetList = ExcelTables(filename,strConn);
                //如果数据表单名不存在，取EXCEL中第一个数据表单
                if (sheetList.IndexOf(sheet) < 0)
                {
                    sheet = sheetList[0].ToString().Trim();
                }
                //建立excel数据引擎连接
                System.Data.OleDb.OleDbConnection dbconn = new System.Data.OleDb.OleDbConnection(strConn);
                //查询表命令
                System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand("select * from [" + sheet + "$]", dbconn);
                System.Data.OleDb.OleDbDataAdapter adapter = new System.Data.OleDb.OleDbDataAdapter(cmd);
                try
                {
                    if (dbconn.State == ConnectionState.Closed)
                    {
                        dbconn.Open();
                    }
                    adapter.Fill(dt);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (dbconn.State == ConnectionState.Open)
                    {
                        dbconn.Close();
                    }
                }
            }
            return dt;
        }
        /// <summary>
        /// 获取Excel表单列表
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        private ArrayList ExcelTables(string filename,string strConn)
        {
            DataTable dt = new DataTable();
            ArrayList sheetList = new ArrayList();
            //判断文件名是否存在以及连接字符串是否正确
            if (File.Exists(filename)&&!string.IsNullOrEmpty(strConn))
            {
                using (System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(strConn))
                {
                    try
                    {
                        conn.Open();
                        //返回excel数据引擎的架构信息
                        dt = conn.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }

                    int sheetCount = dt.Rows.Count;
                    //获取excel表单列表
                    for (int i = 0; i < sheetCount; i++)
                    {
                        string tablename = dt.Rows[i][2].ToString().Trim().TrimEnd(‘$‘);
                        if (sheetList.IndexOf(tablename) < 0)
                        {
                            sheetList.Add(tablename);
                        }
                    }
                }
            }
            return sheetList;
        }