妖怪问题DBHelper.Query不执行,.

Question

using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;
using BookShop.Models;
namespace BookShop.DAL
{
    public class DBHelp
    {
        public static SqlConnection connection;
        public static SqlConnection Connection
        {
            get
            {
                string connectionString = ConfigurationManager.ConnectionStrings["mybookshop"].ConnectionString;
                if (connection == null)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Closed)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }
                return connection;
            }
        }
        
        public static DataSet Query(string sql)
        {
            DataSet ds = new DataSet();
            try
            {
                SqlCommand com = new SqlCommand(sql, Connection);
                SqlDataAdapter dmp = new SqlDataAdapter(com);
                dmp.Fill(ds);
            }
            catch (System.Data.SqlClient.SqlException ex)
            {
                throw new Exception(ex.Message);
            }
            finally
            {
                Connection.Close();
            }
            return ds;
        }        #region 增，删，改ExecuteNonQuery
        /// <summary>
        /// 单个数据增，删，改
        /// </summary>
        /// <param name="safeSql"></param>
        /// <returns></returns>
        public static int ExecuteCommand(string safeSql)
        {
            try
            {
                using (SqlCommand cmd = new SqlCommand(safeSql, Connection))
                {
                    int result = cmd.ExecuteNonQuery();
                    return result;
                }            }
            catch (SqlException ex)
            {                throw ex;
            }
        }
        #endregion       }    }下面执行的时候,有的时候循环会中断,日志里面记录应该是
查询到数据0.000
查询到数据0.001
查询到数据0.000
查询到数据0.001
查询到数据0.000
........
........
查询到数据0.001
查询到数据0.000到这里停在这里了,再也不往下写了,程序就死在这里,到底是什么问题呀. public DataSet dscommand = new DataSet();
 
            while (true)
            {
                log("查询到数据0.000");//
         dscommand = DBHelper.Query("SELECT  * FROM  dbo.AutoCommand WHERE  CONVERT(VARCHAR(10),CREATTIME,126)=Convert(varchar(10),getdate(),126) and  STATUS=0");
                Thread.Sleep(500);//
                log("查询到数据0.001");//停留500毫秒，等待数据库返回。
            }

Answer 1

你也方法里没用初始化connection。打开connection还有DBHelper中connection不要static

Answer 2

CONVERT(VARCHAR(10),CREATTIME,126)=Convert(varchar(10),getdate(),126)==>datediff(d,CREATTIME,getdate())=0

Answer 3

你也方法里没用初始化connection。打开connection下面是open if (connection == null)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Closed)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }还有DBHelper中connection不要static?要怎么改?
我也是抄的.

Answer 4

晕。总共就3、4条代码，如果不好用Query你就删除了代码而直接写ADO.NET代码就行了。

Answer 5

 public static DataTable ReturnDataTable(string cmdtext)
    {
        SqlConnection cn = new SqlConnection();
        cn.ConnectionString = "链接字符串";
        cn.Open();
        SqlCommand cmd = new SqlCommand();
        DataTable dt = new DataTable();
        cmd = new SqlCommand(cmdtext, cn);
        SqlDataReader dr = null;
        using (dr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
        {            dt.Load(dr);
        }
        return dt;
    }

Answer 6

类中的字段就不要用public了，用public就没有什么意义了