SqlDbHelper备份，做项目时方便应用(目前不太全，把自己项目中的逐渐转移过来)

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这是官网新闻左侧类别那部分用到的

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public string ConnectionString = ConfigurationManager.ConnectionStrings["GsWebDbEntities"].ConnectionString;
public myDBHelper()
{
//
//TODO: 在此处添加构造函数逻辑
//
}

public DataSet ExecuteDataset(CommandType commandType, string commandText, params DbParameter[] commandParameters)
{

if ((this.ConnectionString == null) || (this.ConnectionString.Length == 0))
{
throw new ArgumentNullException("ConnectionString");
}
using (DbConnection connection = new SqlConnection(ConnectionString))
{
connection.ConnectionString = this.ConnectionString;
connection.Open();
return this.ExecuteDataset(connection, commandType, commandText, commandParameters);
}
}

 

public DataSet ExecuteDataset(DbConnection connection, CommandType commandType, string commandText, params DbParameter[] commandParameters)
{
if (connection == null)
{
throw new ArgumentNullException("connection");
}
DbCommand command = new SqlCommand();

this.PrepareCommand(command, connection, null, commandType, commandText, commandParameters);
using (DbDataAdapter adapter = new SqlDataAdapter())
{
adapter.SelectCommand = command;
DataSet dataSet = new DataSet();
DateTime now = DateTime.Now;
adapter.Fill(dataSet);
DateTime dtEnd = DateTime.Now;

command.Parameters.Clear();
if (connection.State==ConnectionState.Open)
{
connection.Close();
}


return dataSet;
}
}

 

private void PrepareCommand(DbCommand command, DbConnection connection, DbTransaction transaction, CommandType commandType, string commandText, DbParameter[] commandParameters)
{
if (command == null)
{
throw new ArgumentNullException("command");
}
if ((commandText == null) || (commandText.Length == 0))
{
throw new ArgumentNullException("commandText");
}
if (connection.State != ConnectionState.Open)
{

connection.Open();
}

command.Connection = connection;
command.CommandText = commandText;
if (transaction != null)
{
if (transaction.Connection == null)
{
throw new ArgumentException("The transaction was rollbacked or commited, please provide an open transaction.", "transaction");
}
command.Transaction = transaction;
}
command.CommandType = commandType;
if (commandParameters != null)
{

foreach (DbParameter parameter in commandParameters)
{
if (parameter != null)
{
if (((parameter.Direction == ParameterDirection.InputOutput) || (parameter.Direction == ParameterDirection.Input)) && (parameter.Value == null))
{
parameter.Value = DBNull.Value;
}
command.Parameters.Add(parameter);
}
}

}
}

 

 

 

*****************************************************************************以下来自网络，以上来自自己项目中的整理

using System;

using System.Data; using System.Data.SqlClient;   namespace DbHelper {     public class SqlDbHelper     {         private SqlConnection conn;         private SqlCommand cmd;         private SqlDataReader reader;         private SqlDataAdapter adapter;         private string connectionString = @"server=.;database=student;uid=sa;pwd=scce";           public string ConnectionString         {             get { return this.connectionString; }             set { this.connectionString = value; }         }           /// <summary>         /// 获取一个未打开连接的SqlConnection对象         /// </summary>         /// <returns>SqlConnection对象</returns>         public SqlConnection GetConnection()         {             if (conn != null)                 return this.conn;             return this.conn = new SqlConnection(connectionString);         }           /// <summary>         /// 使用连接字符串获取未打开连接SqlConnection对象         /// </summary>         /// <param name="_connStr">连接字符串</param>         /// <returns>SqlConnection对象</returns>         public SqlConnection GetConnection(string _connStr)         {             if (this.conn != null)                 this.conn.ConnectionString = _connStr;             else                 this.conn = new SqlConnection(_connStr);             return this.conn;         }           /// <summary>         /// 使用指定的Sql语句创建SqlCommand对象         /// </summary>         /// <param name="sqlStr">Sql语句</param>         /// <returns>SqlCommand对象</returns>         private SqlCommand GetCommand(string sqlStr)         {             if (this.conn == null)                 this.conn = GetConnection();             if (this.cmd == null)                 this.cmd = this.GetCommand(sqlStr, CommandType.Text, null);             else             {                 this.cmd.CommandType = CommandType.Text;                 this.cmd.Parameters.Clear();             }             this.cmd.CommandText = sqlStr;             return this.cmd;         }           /// <summary>         /// 使用指定的Sql语句,CommandType,SqlParameter数组创建SqlCommand对象         /// </summary>         /// <param name="sqlStr">Sql语句</param>         /// <param name="type">命令类型</param>         /// <param name="paras">SqlParameter数组</param>         /// <returns>SqlCommand对象</returns>         public SqlCommand GetCommand(string sqlStr, CommandType type, SqlParameter[] paras)         {             if (conn == null)                 this.conn = this.GetConnection();             if (cmd == null)                 this.cmd = conn.CreateCommand();             this.cmd.CommandType = type;             this.cmd.CommandText = sqlStr;             this.cmd.Parameters.Clear();             if (paras != null)                 this.cmd.Parameters.AddRange(paras);             return this.cmd;         }           /// <summary>         /// 执行Sql语句返回受影响的行数         /// </summary>         /// <param name="sqlStr">Sql语句</param>         /// <returns>受影响的行数,失败则返回-1</returns>         public int ExecuteNoQuery(string sqlStr)         {             int line = -1;             CheckArgs(sqlStr);             try { OpenConn(); line = this.ExecuteNonQuery(sqlStr,CommandType.Text,null); }             catch (SqlException e) { throw e; }             return line;         }           /// <summary>         /// 使用指定的Sql语句,CommandType,SqlParameter数组执行Sql语句,返回受影响的行数         /// </summary>         /// <param name="sqlStr">Sql语句</param>         /// <param name="type">命令类型</param>         /// <param name="paras">SqlParameter数组</param>         /// <returns>受影响的行数</returns>         public int ExecuteNonQuery(string sqlStr, CommandType type, SqlParameter[] paras)         {             int line = -1;             CheckArgs(sqlStr);             if (this.cmd == null)                 GetCommand(sqlStr, type, paras);             this.cmd.Parameters.Clear();             this.cmd.CommandText = sqlStr;             this.cmd.CommandType = type;             if(paras != null)                 this.cmd.Parameters.AddRange(paras);             try { OpenConn(); line = this.cmd.ExecuteNonQuery(); }             catch (SqlException e) { throw e; }             return line;         }           /// <summary>         /// 使用指定Sql语句获取dataTable         /// </summary>         /// <param name="sqlStr">Sql语句</param>         /// <returns>DataTable对象</returns>         public DataTable GetDataTable(string sqlStr)         {             CheckArgs(sqlStr);             if (this.conn == null)                 this.conn = GetConnection();             this.adapter = new SqlDataAdapter(sqlStr, this.conn);             DataTable table = new DataTable();             try { adapter.Fill(table); }             catch (SqlException e) { throw e; }             return table;         }           /// <summary>         /// 使用指定的Sql语句获取SqlDataReader         /// </summary>         /// <param name="sqlStr">sql语句</param>         /// <returns>SqlDataReader对象</returns>         public SqlDataReader GetSqlDataReader(string sqlStr)         {             CheckArgs(sqlStr);             if (cmd == null)                 GetCommand(sqlStr);             if(reader != null)                 reader.Dispose();             try { OpenConn(); this.reader = this.cmd.ExecuteReader(); }             catch (SqlException e) { throw e; }             return this.reader;         }           /// <summary>         /// 使用事务执行多条Sql语句         /// </summary>         /// <param name="sqlCommands">sql语句数组</param>         /// <returns>全部成功则返回true否则返回false</returns>         public bool ExecuteSqls(string[] sqlCommands)         {             if (sqlCommands == null)                 throw new ArgumentNullException();             if(this.cmd == null)                 GetCommand(null);             SqlTransaction tran = null;             try             {                 OpenConn();                 tran = this.conn.BeginTransaction();                 this.cmd.Transaction = tran;                 foreach (string sql in sqlCommands)                 {                     if (ExecuteNoQuery(sql) == 0)                     { tran.Rollback(); return false; }                 }             }             catch (SqlException e)             {                 if(tran != null)                     tran.Rollback();                 throw e;             }             tran.Commit();             return true;         }           private void OpenConn()         {             try             {                 if (this.conn.State == ConnectionState.Closed)                     conn.Open();             }             catch (SqlException e) { throw e; }         }           private void CheckArgs(string sqlStr)         {             if (sqlStr == null)                 throw new ArgumentNullException();             if (sqlStr.Length == 0)                 throw new ArgumentOutOfRangeException();         }       } }