转 C# SqlHelper数据库的通用访问代码（sqlclient)

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Collections;
using System.Data.SqlClient;

/// <summary>
/// 数据库的通用访问代码
/// 此类为抽象类，不允许实例化，在应用时直接调用即可
/// </summary>
public abstract class SqlHelper
{
//获取数据库连接字符串，其属于静态变量且只读，项目中所有文档可以直接使用，但不能修改
public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["pubsConnectionString"].ConnectionString;

// 哈希表用来存储缓存的参数信息，哈希表可以存储任意类型的参数。
private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

/// <summary>
///执行一个不需要返回值的SqlCommand命令，通过指定专用的连接字符串。
/// 使用参数数组形式提供参数列表
/// </summary>
/// <remarks>
/// 使用示例：
///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{

SqlCommand cmd = new SqlCommand();

using (SqlConnection conn = new SqlConnection(connectionString))
{
//通过PrePareCommand方法将参数逐个加入到SqlCommand的参数集合中
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();

//清空SqlCommand中的参数列表
cmd.Parameters.Clear();
return val;
}
}

/// <summary>
///执行一条不返回结果的SqlCommand，通过一个已经存在的数据库连接
/// 使用参数数组提供参数
/// </summary>
/// <remarks>
/// 使用示例：
///  int result = ExecuteNonQuery(conn, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个现有的数据库连接</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{

SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}

/// <summary>
/// 执行一条不返回结果的SqlCommand，通过一个已经存在的数据库事物处理
/// 使用参数数组提供参数
/// </summary>
/// <remarks>
/// 使用示例：
///  int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">一个存在的 sql 事物处理</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个数值表示此SqlCommand命令执行后影响的行数</returns>
public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}

/// <summary>
/// 执行一条返回结果集的SqlCommand命令，通过专用的连接字符串。
/// 使用参数数组提供参数
/// </summary>
/// <remarks>
/// 使用示例：
///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个包含结果的SqlDataReader</returns>
public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);

// 在这里使用try/catch处理是因为如果方法出现异常，则SqlDataReader就不存在，
//CommandBehavior.CloseConnection的语句就不会执行，触发的异常由catch捕获。
//关闭数据库连接，并通过throw再次引发捕捉到的异常。
try
{
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch
{
conn.Close();
throw;
}
}

/// <summary>
/// 执行一条返回第一条记录第一列的SqlCommand命令，通过专用的连接字符串。
/// 使用参数数组提供参数
/// </summary>
/// <remarks>
/// 使用示例：
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的数据库连接字符串</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个object类型的数据，可以通过 Convert.To{Type}方法转换类型</returns>
public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();

using (SqlConnection connection = new SqlConnection(connectionString))
{
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}

/// <summary>
/// 执行一条返回第一条记录第一列的SqlCommand命令，通过已经存在的数据库连接。
/// 使用参数数组提供参数
/// </summary>
/// <remarks>
/// 使用示例：
///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个已经存在的数据库连接</param>
/// <param name="commandType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="commandText">存储过程的名字或者 T-SQL 语句</param>
/// <param name="commandParameters">以数组形式提供SqlCommand命令中用到的参数列表</param>
/// <returns>返回一个object类型的数据，可以通过 Convert.To{Type}方法转换类型</returns>
public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}

/// <summary>
/// 缓存参数数组
/// </summary>
/// <param name="cacheKey">参数缓存的键值</param>
/// <param name="cmdParms">被缓存的参数列表</param>
public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)
{
parmCache[cacheKey] = commandParameters;
}

/// <summary>
/// 获取被缓存的参数
/// </summary>
/// <param name="cacheKey">用于查找参数的KEY值</param>
/// <returns>返回缓存的参数数组</returns>
public static SqlParameter[] GetCachedParameters(string cacheKey)
{
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];

if (cachedParms == null)
return null;

//新建一个参数的克隆列表
SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];

//通过循环为克隆参数列表赋值
for (int i = 0, j = cachedParms.Length; i < j; i++)
//使用clone方法复制参数列表中的参数
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();

return clonedParms;
}

/// <summary>
/// 为执行命令准备参数
/// </summary>
/// <param name="cmd">SqlCommand 命令</param>
/// <param name="conn">已经存在的数据库连接</param>
/// <param name="trans">数据库事物处理</param>
/// <param name="cmdType">SqlCommand命令类型 (存储过程， T-SQL语句， 等等。)</param>
/// <param name="cmdText">Command text，T-SQL语句 例如 Select * from Products</param>
/// <param name="cmdParms">返回带参数的命令</param>
private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
{

//判断数据库连接状态
if (conn.State != ConnectionState.Open)
conn.Open();

cmd.Connection = conn;
cmd.CommandText = cmdText;

//判断是否需要事物处理
if (trans != null)
cmd.Transaction = trans;

cmd.CommandType = cmdType;

if (cmdParms != null)
{
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}

/// <summary>
/// 执行查询，返回结果集中的第一行第一列的值，忽略其他行列
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
public static object ExcuteScalar(string sql)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
con.Close();
return cmd.ExecuteScalar();
}
}

/// <summary>
/// 执行查询
/// </summary>
/// <param name="sql">有效的sql语句</param>
/// <param name="param">返回DataReader</param>
/// <returns>返回DataReader</returns>
public static SqlDataReader ExcuteReader(string sql, SqlParameter[] param)
{
SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction);
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
cmd.Parameters.AddRange(param);
SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return reader;
}

/// <summary>
/// 执行查询
/// </summary>
/// <param name="sql">有效的sql语句</param>
/// <returns>返回DataReader</returns>
public static SqlDataReader ExcuteReader(string sql)
{
SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction);
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}

/// <summary>
/// 执行查询的基方法
/// </summary>
/// <param name="sql">有效的sql语句</param>
/// <returns>返回DataTable</returns>
public static DataTable ExcuteDataQuery(string sql)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
con.Open();
SqlDataAdapter sda = new SqlDataAdapter(sql, con);
DataTable table = new DataTable();
sda.Fill(table);
con.Close();
return table;
}
}

/// <summary>
/// 执行增，删，改的基方法
/// </summary>
/// <param name="sql">有效的sql语句</param>
/// <param name="param">参数集合</param>
/// <returns>影响的行数</returns>
public static int ExcuteNonQuery(string sql, SqlParameter[] param)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
if (param != null)
{
cmd.Parameters.AddRange(param);
}
int count = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
con.Close();
return count;
}
}

//每页显示5条数据
static int pageSize = 10;
/// <summary>
/// 查询共有多少行，然后直接返回总页码
/// </summary>
/// <returns></returns>
public static int GetAllBookCount()
{
int num = 0;
int pageCount = 0;
string sql = "select count(0) from TB_BookInfo";
num = Convert.ToInt32(ExcuteScalar(sql));
pageCount = num % pageSize != 0 ? (num / pageSize) + 1 : num / pageSize;
return pageCount;
}

/// <summary>
/// 准备命令
/// </summary>
/// <param name="con"></param>
/// <param name="cmd"></param>
/// <param name="textcmd"></param>
/// <param name="cmdType"></param>
/// <param name="param"></param>
public static void PreparedCommd(SqlConnection con, SqlCommand cmd, string textcmd, CommandType cmdType, SqlParameter[] param)
{
try
{
if (con.State != ConnectionState.Open)
{
con.Open();
}
cmd.Connection = con;
cmd.CommandText = textcmd;
cmd.CommandType = cmdType;

if (param != null)
{
foreach (SqlParameter p in param)
{
cmd.Parameters.Add(p);
}
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}

/// <summary>
/// 执行增、删、改
/// </summary>
/// <param name="textcmd">sql语句或者存储过程</param>
/// <param name="cmdType">类型</param>
/// <param name="param">参数</param>
/// <returns>返回int类型的数据</returns>
public static int ExecuteNonQuery(string textcmd,SqlParameter[] param, CommandType cmdType)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
SqlCommand cmd = new SqlCommand();
PreparedCommd(con, cmd, textcmd, cmdType, param);
int num = cmd.ExecuteNonQuery();
return num;
}
}

/// <summary>
/// 读取一行一列的数据
/// </summary>
/// <param name="textmd"></param>
/// <param name="cmdType"></param>
/// <param name="param"></param>
/// <returns></returns>
public static object ExecuteScalar(string textmd, CommandType cmdType, SqlParameter[] param)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
SqlCommand cmd = new SqlCommand();
PreparedCommd(con, cmd, textmd, cmdType, param);
return cmd.ExecuteScalar();
}
}

/// <summary>
/// 读取一行一列的数据
/// </summary>
/// <param name="textmd"></param>
/// <param name="cmdType"></param>
/// <param name="param"></param>
/// <returns></returns>
public static object ExecuteScalar(string SQL)
{
using (SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction))
{
con.Open();
SqlCommand cmd = new SqlCommand(SQL, con);
return cmd.ExecuteScalar();
}
}

/// <summary>
/// 查询
/// </summary>
/// <param name="textcmd"></param>
/// <param name="cmdType"></param>
/// <param name="param"></param>
/// <returns></returns>
public static SqlDataReader ExecuteReader(string textcmd, CommandType cmdType, SqlParameter[] param)
{
SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction);
SqlCommand cmd = new SqlCommand();
try
{
//PreparedCommd(con, cmd, textcmd, cmdType, param);
SqlDataReader read = cmd.ExecuteReader(CommandBehavior.CloseConnection);
return read;
}
catch (Exception ex)
{
con.Close();
throw new Exception(ex.Message);
}
}

/// <summary>
/// 查询返回DataTable
/// </summary>
/// <param name="sql"></param>
/// <returns></returns>
public static DataTable ExecuteReader(string sql)
{
SqlConnection con = new SqlConnection(ConnectionStringLocalTransaction);
DataTable dt = new DataTable();
try
{
SqlDataAdapter da = new SqlDataAdapter(sql, con);
da.Fill(dt);
}
catch (Exception)
{

throw;
}
return dt;
}

/// <summary>
/// 用户登录
/// </summary>
/// <param name="UserName"></param>
/// <param name="UserPwd"></param>
/// <returns></returns>
public static int CheckLogin(string UserName, string UserPwd)
{
int num = 0;
try
{
string sql = "select * from TB_UserInfo  where [user_Name]='" + UserName + "' and user_pwd='" + UserPwd + "'";
num = Convert.ToInt32(ExecuteScalar(sql));
}
catch (Exception ex)
{
throw ex;
}
return num;
}

}