日历记事本程序设计

主程序：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;

namespace CN
{
    class function
    {
                //连接字符串
        public static string strConn = @"Data Source=jsj34\SQLEXPRESS;Initial Catalog=ClendarNote;Integrated Security=True";
        public SqlConnection conn = new SqlConnection(@"Data Source=jsj34\SQLEXPRESS;Initial Catalog=ClendarNote;Integrated Security=True");
        public static string connstring = ConfigurationSettings.AppSettings["conn"];
        //检测连接是否打开
        public void CheckConnection()
        {
            if (this.conn.State == ConnectionState.Closed)
            {
                this.conn.Open();
            }
        }

        /// <summary>
        /// 非查询命令的执行
        /// </summary>
        /// <param name="sql">表示要执行的命令</param>

        /// <returns>返回值为执行命令之后受影响的行数</returns>
        public int NonQuery(string sql)
        {
       //     conn = new SqlConnection(strConn);
            int a = -1;
            try
            {
                //打开连接
                conn.Open();
                //sql是传递进来的参数 表示要执行的命令
                SqlCommand cmd = new SqlCommand(sql, conn);
                //返回受影响的行数
                a = cmd.ExecuteNonQuery();
            }
            catch
            {

            }
            finally
            {
                //关闭连接
                conn.Close();
            }
            //返回值为执行命令之后受影响的行数
            return a;
        }

        /// <summary>
        /// 查询命令的执行
        /// </summary>