one pragmatical sqlhelper

namespace ConsoleApplication2
{
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

public class SqlHelper
{
/// <summary>
/// 连接字符串
/// </summary>ConfigurationManager.ConnectionStrings["sqlConn"].ConnectionString;
/// <summary>
/// 准备Command对象
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
private static SqlCommand PrepareCommand(string sql, params SqlParameter[] spms)
{
SqlConnection conn = new SqlConnection(strConn);
SqlCommand cmd = new SqlCommand(sql, conn);
if (spms != null)
cmd.Parameters.AddRange(spms);
return cmd;
}
/// <summary>
/// 提交sql语句执行（增删改）
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns>影响行数</returns>
public static int ExecuteNonQuery(string sql, params SqlParameter[] spms)
{
int result = 0;
SqlCommand cmd = PrepareCommand(sql, spms);
try
{
cmd.Connection.Open();
result = cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
throw new Exception(ex.Message);
}
finally
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
}
return result;
}
/// <summary>
/// 提交sql语句返回首行首列的值
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static object ExecuteScalar(string sql, params SqlParameter[] spms)
{
object result = null;
SqlCommand cmd = PrepareCommand(sql, spms);
try
{
cmd.Connection.Open();
result = cmd.ExecuteScalar();
}
catch (Exception ex)
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
throw new Exception(ex.Message);
}
finally
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
}
return result;
}
/// <summary>
/// 提交sql语句执行（增删改）,bayistuta新增,2011/03/21 17:13
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns>影响行数</returns>
public static int ExecuteNonQuery(string sql, CommandType type, params SqlParameter[] spms)
{
int result = 0;
SqlCommand cmd = PrepareCommand(sql, spms);
cmd.CommandType = type;
try
{
cmd.Connection.Open();
result = cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
throw new Exception(ex.Message);
}
finally
{
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
}
return result;
}
/// <summary>
/// 提交sql语句返回读取器,bayistuta新增,2011/03/25 21:26
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static SqlDataReader ExecuteReader(string sql, CommandType type, params SqlParameter[] spms)
{
SqlDataReader reader = null;
SqlCommand cmd = PrepareCommand(sql, spms);
cmd.CommandType = type;
try
{
cmd.Connection.Open();
//关闭reader对象，其对应的连接对象自动关闭
reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
catch (Exception ex)
{
if (reader != null)
reader.Close();
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
throw new Exception(ex.Message);
}
return reader;
}
/// <summary>
/// 提交sql语句返回读取器
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] spms)
{
SqlDataReader reader = null;
SqlCommand cmd = PrepareCommand(sql, spms);
try
{
cmd.Connection.Open();
//关闭reader对象，其对应的连接对象自动关闭
reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
catch (Exception ex)
{
if (reader != null)
reader.Close();
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
throw new Exception(ex.Message);
}
return reader;
}
/// <summary>
/// 查询实体类对象集合
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static List<T> GetList<T>(string sql, params SqlParameter[] spms)
{
List<T> list = new List<T>();
SqlDataReader reader = ExecuteReader(sql, spms);
while (reader.Read())
{
T t = CreateInstance<T>(reader);
list.Add(t);
}
reader.Close();
return list;
}
/// <summary>
/// 查询单个实体类对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static T GetSingle<T>(string sql, params SqlParameter[] spms)
{
T t = default(T);
SqlDataReader reader = ExecuteReader(sql, spms);
if (reader.Read())
{
t = CreateInstance<T>(reader);
}
reader.Close();
return t;
}

/// <summary>
/// 返回DataTable
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="spms">参数</param>
/// <returns></returns>
public static DataTable GetDataTable(string sql, params SqlParameter[] spms)
{
SqlCommand cmd = PrepareCommand(sql, spms);

SqlDataAdapter da = new SqlDataAdapter(cmd); //创建DataAdapter数据适配器实例
DataSet ds = new DataSet();//创建DataSet实例
da.Fill(ds, "tables");//使用DataAdapter的Fill方法(填充)，调用SELECT命令
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
return ds.Tables[0];
}
/// <summary>
/// 返回DataTable
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="spms">参数</param>
/// <returns></returns>
public static DataTable GetDataTable(string sql, CommandType cmdType, params SqlParameter[] spms)
{
SqlCommand cmd = PrepareCommand(sql, spms);
cmd.CommandType = cmdType;
SqlDataAdapter da = new SqlDataAdapter(cmd); //创建DataAdapter数据适配器实例
DataSet ds = new DataSet();//创建DataSet实例
da.Fill(ds, "tables");//使用DataAdapter的Fill方法(填充)，调用SELECT命令
if (cmd.Connection.State != ConnectionState.Closed)
cmd.Connection.Close();
return ds.Tables[0];
}
/// <summary>
/// 查询记录条数
/// </summary>
/// <param name="sql"></param>
/// <param name="spms"></param>
/// <returns></returns>
public static int GetCount(string sql, params SqlParameter[] spms)
{
return (int)ExecuteScalar(sql, spms);
}
/// <summary>
/// 使用反射根据实体类的构造函数创建实例
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="reader"></param>
/// <returns></returns>
private static T CreateInstance<T>(IDataReader reader)
{
Type type = typeof(T);
T t = (T)Activator.CreateInstance(type, reader);
return t;
}

/// <summary>
/// 防sql注入，替换字符串
/// </summary>
/// <param name="val">需要替换的值</param>
/// <returns>替换后的值</returns>
public static string GetParameterValue(string val)
{
return val.Replace("'", "''").Replace("-", "[-]");
}
}

}