SQLHelp

using System;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public static class SQLHelp
{
    private static string constr = ConfigurationManager.ConnectionStrings["constr"].ToString();

    /// <summary>
    /// 用于提交Insert Update Delete 返回受影响的行数
    /// </summary>
    /// <param name="cmdType">操作类型StoreProcdeure 或者是 sql语句</param>
    /// <param name="sql">sql语句或者存储过程的名称</param>
    /// <param name="parameters">参数的数组，没有参数传递为Null值</param>
    /// <returns></returns>
    public static int ExecuteNonQuery(CommandType cmdType, string sql, params SqlParameter[] parameters)
    {
        try
        {
            using (var con = new SqlConnection(constr))
            {
                using (var cmd = new SqlCommand(sql, con))
                {
                    cmd.CommandType = cmdType; 
                    if (parameters != null)  
                    {
                        foreach (var  parameter in parameters)
                        {
                            cmd.Parameters.Add(parameter);
                        }
                    }
                    con.Open();
                    int count = cmd.ExecuteNonQuery();
                    con.Close();
                    return count;
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    /// <summary>
    /// 用于提交select 返回 SqlDataReader ,读取完成后需要关闭SqlDataReader
    /// </summary>
    /// <param name="cmdType">操作类型StoreProcdeure 或者是 sql语句</param>
    /// <param name="sql">sql语句或者存储过程的名称</param>
    /// <param name="parameters">参数的数组，没有参数传递为Null值</param>
    /// <returns></returns>
    public static SqlDataReader ExecuteReader(CommandType cmdType, string sql, params SqlParameter[] parameters)
    {
        try
        {
            var con = new SqlConnection(constr);
            using (var cmd = new SqlCommand(sql, con))
            {
                cmd.CommandType = cmdType; 
                if (parameters != null)  
                {
                    foreach (var  parameter in parameters)
                    {
                        cmd.Parameters.Add(parameter);
                    }
                }
                con.Open();
                //关闭读取器,将自动关闭连接对象
                SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                return dr;
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }


    /// <summary>
    /// 用于提交select中的聚合函数,返回第一行,第一列的值
    /// </summary>
    /// <param name="cmdType">操作类型StoreProcdeure 或者是 sql语句</param>
    /// <param name="sql">sql语句或者存储过程的名称</param>
    /// <param name="parameters">参数的数组，没有参数传递为Null值</param>
    /// <returns></returns>
    public static object ExecuteScalar(CommandType cmdType, string sql, params SqlParameter[] parameters)
    {
        try
        {
            using (var con = new SqlConnection(constr))
            {
                using (var cmd = new SqlCommand(sql, con))
                {
                    cmd.CommandType = cmdType; 
                    if (parameters != null)  
                    {
                        foreach (var  parameter in parameters)
                        {
                            cmd.Parameters.Add(parameter);
                        }
                    }
                    con.Open();
                    object o = cmd.ExecuteScalar();
                    con.Close();
                    return o;
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
    /// <summary>
    /// 用于提交select 返回 DataSet ,数据集中默认只有一张表格
    /// </summary>
    /// <param name="cmdType">操作类型StoreProcdeure 或者是 sql语句</param>
    /// <param name="sql">sql语句或者存储过程的名称</param>
    /// <param name="parameters">参数的数组，没有参数传递为Null值</param>
    /// <returns></returns>
    public static DataSet ExecuteDataSet(CommandType cmdType, string sql, params SqlParameter[] parameters)
    {
        try
        {
            using (var con = new SqlConnection(constr))
            {
                using (var da = new SqlDataAdapter())
                {
                    var cmd = new SqlCommand(sql, con);
                    cmd.CommandType = cmdType; 
                    if (parameters != null)  
                    {
                        foreach (var  parameter in parameters)
                        {
                            cmd.Parameters.Add(parameter);
                        }
                    }
                    da.SelectCommand = cmd;
                    DataSet ds = new DataSet();
                    da.Fill(ds);
                    return ds;
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    #region  List<T> ToList<T>(string cmdText, List<DbParameter> listpar, string connString,IDbHelp db) where T : class, new()
    /// <summary>
    /// 返回一个list
    /// </summary>
    /// <typeparam name="T">实体模型</typeparam>
    /// <param name="cmdType">操作类型StoreProcdeure 或者是 sql语句</param>
    /// /// <param name="sql">sql语句</param>
    /// <param name="parameters">参数列表</param>
    /// <returns></returns>
    public static List<T> ToList<T>(CommandType cmdType, string sql, params SqlParameter[] parameters) where T : class, new()
    {
        using (var read = ExecuteReader(cmdType,sql ,parameters))
        {
            List<T> list = null;
            var type = typeof(T);
            if (read.HasRows)
            {
                list = new List<T>();
            }
            while (read.Read())
            {
                T t = new T();
                foreach (PropertyInfo item in type.GetProperties())
                {
                    for (int i = 0; i < read.FieldCount; i++)
                    {
                        //属性名与查询出来的列名比较
                        if (item.Name.ToLower() != read.GetName(i).ToLower()) continue;
                        object value = read[i];
                        if (value != DBNull.Value)
                        {
                            item.SetValue(t, value, null);
                        }
                        break;
                    }
                }
                //将创建的对象添加到集合中
                list.Add(t);
            }
            return list;
        }
    }
    #endregion


}