c\#SQLHelper(for winForm)구현 코드

using System; 
using System.Collections.Generic; 
using System.Text; 
using System.Collections; 
using System.Data; 
using System.Data.SqlClient; 
using System.Configuration; 
namespace HelloWinForm.DBUtility 
{ 
class SQLHelper 
{ 
#region      
//       
private SqlConnection con; 
/// <summary> 
///            
/// </summary> 
/// <returns></returns> 
public static String GetSqlConnection() 
{ 
String conn = ConfigurationManager.AppSettings["connectionString"].ToString(); 
return conn; 
} 
#endregion 
#region   sql    
/// <summary> 
///        SQL   
/// </summary> 
/// <param name="Sqlstr"></param> 
/// <returns></returns> 
public static int ExecuteSql(String Sqlstr) 
{ 
String ConnStr = GetSqlConnection(); 
using (SqlConnection conn = new SqlConnection(ConnStr)) 
{ 
SqlCommand cmd = new SqlCommand(); 
cmd.Connection = conn; 
cmd.CommandText = Sqlstr; 
conn.Open(); 
cmd.ExecuteNonQuery(); 
conn.Close(); 
return 1; 
} 
} 
/// <summary> 
///       SQL   
/// </summary> 
/// <param name="Sqlstr">SQL  </param> 
/// <param name="param">      </param> 
/// <returns></returns> 
public static int ExecuteSql(String Sqlstr, SqlParameter[] param) 
{ 
String ConnStr = GetSqlConnection(); 
using (SqlConnection conn = new SqlConnection(ConnStr)) 
{ 
SqlCommand cmd = new SqlCommand(); 
cmd.Connection = conn; 
cmd.CommandText = Sqlstr; 
cmd.Parameters.AddRange(param); 
conn.Open(); 
cmd.ExecuteNonQuery(); 
conn.Close(); 
return 1; 
} 
} 
/// <summary> 
///   DataReader 
/// </summary> 
/// <param name="Sqlstr"></param> 
/// <returns></returns> 
public static SqlDataReader ExecuteReader(String Sqlstr) 
{ 
String ConnStr = GetSqlConnection(); 
SqlConnection conn = new SqlConnection(ConnStr);//  DataReader ,     using()  
try 
{ 
SqlCommand cmd = new SqlCommand(); 
cmd.Connection = conn; 
cmd.CommandText = Sqlstr; 
conn.Open(); 
return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);//     Connection 
} 
catch //(Exception ex) 
{ 
return null; 
} 
} 
/// <summary> 
///   SQL         
/// </summary> 
/// <param name="Sqlstr">SQL  </param> 
/// <returns></returns> 
public static DataTable ExecuteDt(String Sqlstr) 
{ 
String ConnStr = GetSqlConnection(); 
using (SqlConnection conn = new SqlConnection(ConnStr)) 
{ 
SqlDataAdapter da = new SqlDataAdapter(Sqlstr, conn); 
DataTable dt = new DataTable(); 
conn.Open(); 
da.Fill(dt); 
conn.Close(); 
return dt; 
} 
} 
/// <summary> 
///   SQL     DataSet 
/// </summary> 
/// <param name="Sqlstr">SQL  </param> 
/// <returns></returns> 
public static DataSet ExecuteDs(String Sqlstr) 
{ 
String ConnStr = GetSqlConnection(); 
using (SqlConnection conn = new SqlConnection(ConnStr)) 
{ 
SqlDataAdapter da = new SqlDataAdapter(Sqlstr, conn); 
DataSet ds = new DataSet(); 
conn.Open(); 
da.Fill(ds); 
conn.Close(); 
return ds; 
} 
} 
#endregion 
#region        
/// <summary> 
///       (   ) 
/// </summary> 
/// <param name="procName">       </param> 
/// <returns>        </returns> 
public int RunProc(string procName) 
{ 
SqlCommand cmd = CreateCommand(procName, null); 
cmd.ExecuteNonQuery(); 
this.Close(); 
return (int)cmd.Parameters["ReturnValue"].Value; 
} 
/// <summary> 
///       (   ) 
/// </summary> 
/// <param name="procName">       </param> 
/// <param name="prams">           </param> 
/// <returns>        </returns> 
public int RunProc(string procName, SqlParameter[] prams) 
{ 
SqlCommand cmd = CreateCommand(procName, prams); 
cmd.ExecuteNonQuery(); 
this.Close(); 
return (int)cmd.Parameters[0].Value; 
} 
/// <summary> 
///       (   ) 
/// </summary> 
/// <param name="procName">       </param> 
/// <param name="dataReader">   </param> 
public void RunProc(string procName, out SqlDataReader dataReader) 
{ 
SqlCommand cmd = CreateCommand(procName, null); 
dataReader = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection); 
} 
/// <summary> 
///       (   ) 
/// </summary> 
/// <param name="procName">       </param> 
/// <param name="prams">           </param> 
/// <param name="dataReader">   </param> 
public void RunProc(string procName, SqlParameter[] prams, out SqlDataReader dataReader) 
{ 
SqlCommand cmd = CreateCommand(procName, prams); 
dataReader = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection); 
} 
/// <summary> 
///   Command           
/// </summary> 
/// <param name="procName">       </param> 
/// <param name="prams">           </param> 
/// <returns>Command  </returns> 
private SqlCommand CreateCommand(string procName, SqlParameter[] prams) 
{ 
//          
Open(); 
//command = new SqlCommand( sprocName, new SqlConnection( ConfigManager.DALConnectionString ) ); 
SqlCommand cmd = new SqlCommand(procName, con); 
cmd.CommandType = CommandType.StoredProcedure; 
//               
if (prams != null) 
{ 
foreach (SqlParameter parameter in prams) 
cmd.Parameters.Add(parameter); 
} 
//   Command   
return cmd; 
} 
/// <summary> 
///        
/// </summary> 
/// <param name="ParamName">   </param> 
/// <param name="DbType">    </param> 
/// <param name="Size">    </param> 
/// <param name="Value">   </param> 
/// <returns>     </returns> 
public SqlParameter MakeInParam(string ParamName, SqlDbType DbType, int Size, object Value) 
{ 
return MakeParam(ParamName, DbType, Size, ParameterDirection.Input, Value); 
} 
/// <summary> 
///        
/// </summary> 
/// <param name="ParamName">   </param> 
/// <param name="DbType">    </param> 
/// <param name="Size">    </param> 
/// <returns>     </returns> 
public SqlParameter MakeOutParam(string ParamName, SqlDbType DbType, int Size) 
{ 
return MakeParam(ParamName, DbType, Size, ParameterDirection.Output, null); 
} 
/// <summary> 
///          
/// </summary> 
/// <param name="ParamName">   </param> 
/// <param name="DbType">    </param> 
/// <param name="Size">    </param> 
/// <param name="Direction">     (  /  )</param> 
/// <param name="Value">   </param> 
/// <returns>     </returns> 
public SqlParameter MakeParam(string ParamName, SqlDbType DbType, Int32 Size, ParameterDirection Direction, object Value) 
{ 
SqlParameter param; 
if (Size > 0) 
{ 
param = new SqlParameter(ParamName, DbType, Size); 
} 
else 
{ 
param = new SqlParameter(ParamName, DbType); 
} 
param.Direction = Direction; 
if (!(Direction == ParameterDirection.Output && Value == null)) 
{ 
param.Value = Value; 
} 
return param; 
} 
#endregion 
#region          
/// <summary> 
///       
/// </summary> 
private void Open() 
{ 
//       
if (con == null) 
{ 
//      using System.Configuration;           
con = new SqlConnection(GetSqlConnection()); 
con.Open(); 
} 
} 
/// <summary> 
///       
/// </summary> 
public void Close() 
{ 
if (con != null) 
con.Close(); 
} 
/// <summary> 
///       
/// </summary> 
public void Dispose() 
{ 
//         
if (con != null) 
{ 
con.Dispose(); 
con = null; 
} 
} 
#endregion 
} 
}

using System; 
using System.Collections.Generic; 
using System.Text; 
using System.Data; 
using System.Data.SqlClient; 
using System.Collections; 
using HelloWinForm.DBUtility; 
namespace HelloWinForm.DAL 
{ 
class Student 
{ 
public string test() 
{ 
string str = ""; 
SqlDataReader dr = SQLHelper.ExecuteReader("select * from Student"); 
while (dr.Read()) 
{ 
str += dr["StudentNO"].ToString(); 
} 
dr.Close(); 
return str; 
} 
} 
}