DataTable和xls文件的相互转换;关闭服务端的Excel进程;用静态类写数据库配置类，数据库操作类;

一、DataTable和xls文件的相互转换;

(1)xls转DataTable

   服务端不必启动Excel.exe进程

  

 /// <summary>
        /// xls文件的某个sheet转成表 
        /// 备注：此方法不会启动服务端的Excel进程
        /// </summary>
        /// <param name="strExcelFileName">xls路径</param>
        /// <param name="strSheetName">xls中的某张sheetName</param>
        /// <returns></returns>
        public static System.Data.DataTable XlsToDataTable(string strExcelFileName, string strSheetName)
        {
            //源的定义
            string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + strExcelFileName + ";" + "Extended Properties='Excel 8.0;HDR=NO;IMEX=1';";
            //Sql语句
            //string strExcel = string.Format("select * from [{0}$]", strSheetName); 这是一种方法
            string strExcel = "select * from   [sheet1$]";

            //定义存放的数据表
            DataSet ds = new DataSet();

            //连接数据源
            OleDbConnection conn = new OleDbConnection(strConn);

            conn.Open();

            //适配到数据源
            OleDbDataAdapter adapter = new OleDbDataAdapter(strExcel, strConn);
            adapter.Fill(ds, strSheetName);
            conn.Close();
            return ds.Tables[strSheetName];
        }

(2)DataTable转xls

   使用服务端的Excel.exe完成工作

  

 /// <summary>
        /// dataTable存成excel表格
        ///  备注：如果strFileName处已经存在文件,则报错
        /// </summary>
        /// <param name="dtSource">dataTable</param>
        /// <param name="strFileName">在服务端完整路径</param>
        public static  void DataTableToExcel(System.Data.DataTable dtSource, string strFileName)
        {
            int rowNum = dtSource.Rows.Count;
            int columnNum = dtSource.Columns.Count;
            int rowIndex = 1;
            int columnIndex = 0;

            if (dtSource == null || string.IsNullOrEmpty(strFileName))
            {
                return;
            }
            if (rowNum > 0)
            {
                Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
                xlApp.DefaultFilePath = "";
                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 dc in dtSource.Columns)
                {
                    columnIndex++;
                    xlApp.Cells[rowIndex, columnIndex] = dc.ColumnName;
                }
                //将DataTable中的数据导入Excel中
                xlApp.Cells.NumberFormat = "@";//设置所有cells格式为字符串。设置类型要在个Cell赋值之前
                for (int i = 0; i < rowNum; i++)
                {
                    rowIndex++;
                    columnIndex = 0;
                    for (int j = 0; j < columnNum; j++)
                    {
                        columnIndex++;
                        xlApp.Cells[rowIndex, columnIndex] = dtSource.Rows[i][j].ToString();
                    }
                }
                xlBook.SaveCopyAs(strFileName);
                //结束Excel进程的代码
                xlBook.Close(false, System.Reflection.Missing.Value, System.Reflection.Missing.Value);//关闭book
                xlApp.Quit();//关闭excel
                Marshal.ReleaseComObject(xlBook);//释放COM组件
                Marshal.ReleaseComObject(xlApp); 
                xlBook = null;//如果有Ragne,Sheet,WorkBooks等对象,也要null
                xlApp = null;

                GC.GetTotalMemory(false);//回收调用xlApp产生的垃圾
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.GetTotalMemory(true);  
               
            }
        }

二、关闭服务端的Excel进程

如果使用NPOI等组件,那么不启动服务端Excel进程即可生成xls文件。如果服务端用Excel进程产生xls文件,那么如下用于关闭Excel.exe进程

    //结束Excel进程的代码
                xlBook.Close(false, System.Reflection.Missing.Value, System.Reflection.Missing.Value);//关闭book
                xlApp.Quit();//关闭excel
                Marshal.ReleaseComObject(xlBook);//释放COM组件
                Marshal.ReleaseComObject(xlApp); 
                xlBook = null;//如果有Ragne,Sheet,WorkBooks等对象,也要null
                xlApp = null;

                GC.GetTotalMemory(false);//回收调用xlApp产生的垃圾
                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.GetTotalMemory(true);

三、用静态类写数据库配置类，数据库操作类;

 配置文件中写连接字符串

  <connetionString>

   <add name="BalloonShopConfiguration" ProviderName="System.Data.SqlClient" ConnectionString="Server=;User Id=;Password=;DataBase=";

 </connetionString>

1.数据库配置类：

    变量:string providerName, string connectionString

    属性：string ProviderName,string ConnectionString

    方法：构造函数（从配置文件connectionString 中读providerName和connectionString,初始化 这两个变量）

2.数据库操作类:

   方法： (1)public static DbCommand CreateCommand() //创建操作数据库的命令

            (2)public static DataTable ExcuteCommand(DbCommand) //执行命令，返回DataTable

 /// <summary>
    /// 通用数据库类
    /// </summary>
     public static class GenericDataAccess
    {
         /// <summary>
         /// 获取datatable
         /// </summary>
         /// <param name="dbCommand">必须已经包含的Conn信息，即是用Conn.CreateCommand()</param>
         /// <returns></returns>
        public static DataTable ExecutSelectCommnd(DbCommand dbCommand)
        {
            DbConnection conn = dbCommand.Connection;
            conn.Open();
            DbDataReader dr = dbCommand.ExecuteReader();
            DataTable dt = new DataTable();
            dt.Load(dr);
            dr.Close();//关闭dr. dataReader是执行效率最高的类。但是，在一个dataReader关闭之前，不能执行其它数据库操作。
            conn.Close();//关闭连接
            return dt;
        }
         /// <summary>
         /// 创建命令
         /// CommandType默认是 StoredProcedure
         /// </summary>
         /// <returns></returns>
        public static DbCommand CreateCommand()
        {
            string providerName = BalloonShopConfiguration.DbProviderName;//获取providerName
            DbProviderFactory fac = DbProviderFactories.GetFactory(providerName);
            DbConnection conn = fac.CreateConnection();
            conn.ConnectionString = BalloonShopConfiguration.DbConnectionString;
            DbCommand command = conn.CreateCommand();//DbCommand 是conn下属Command
            command.CommandType = CommandType.StoredProcedure;
            return command;
        }
    }