Asp.Net(c#)データベース操作クラス

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
namespace Mysqlserver
{
    /// <summary>
    /// SqlServerDataBase      
    /// </summary>
    public class SqlServerDataBase
    {
        private string strError = null;
        private int intCount = 0;
        public SqlServerDataBase()
        {
            //
            // TODO:            
            //
        }
        /// <summary>
        ///     DBConn，       
        /// </summary>
        /// <returns></returns>
        public SqlConnection DBconn()
        {
            string strConn = "Server=(local);Database=GlobalMeetings;Uid=sa;pwd=";
            try
            {
                return new SqlConnection(strConn);
            }
            catch (Exception)
            {
                return null;
            }
        }
        /// <summary>
        ///     ErrorMessage，      
        /// </summary>
        public string ErrorMessage
        {
            get
            {
                return strError;
            }
        }

        /// <summary>
        ///               
        /// </summary>
        /// <param name="strSelect">    </param>
        /// <param name="SqlConn">     </param>
        /// <returns>      DataSet  ，    null</returns>
        public DataSet Select(string SelectString, SqlConnection sqlConn)
        {
            strError = "";
            SqlConnection conn;
            if (sqlConn == null)
            {
                conn = DBconn();
            }
            else
            {
                conn = sqlConn;
            }
            try
            {
                //               ，     
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
                SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
                SqlCommand selectCommand = new SqlCommand(SelectString, conn);
                selectCommand.CommandType = CommandType.Text;
                mySqlDataAdapter.SelectCommand = selectCommand;
                DataSet myDS = new DataSet();
                mySqlDataAdapter.Fill(myDS);
                return myDS;
            }
            catch (Exception e)
            {
                strError = "      ：" + e.Message;
                return null;
            }
            finally
            {
                if (conn.State != ConnectionState.Closed)
                {
                    conn.Close();
                }
            }
        }
        /// <summary>
        ///      
        /// </summary>
        /// <param name="UpdateString">Update Sql  </param>
        /// <param name="SqlConn">     </param>
        /// <returns>      true</returns>
        public bool Update(string UpdateString, SqlConnection SqlConn)
        {
            return udiDataBase(UpdateString, SqlConn);
        }
        /// <summary>
        ///          
        /// </summary>
        /// <param name="DeleteString">Delete Sql  </param>
        /// <param name="SqlConn">     </param>
        /// <returns>      true</returns>
        public bool Delete(string DeleteString, SqlConnection SqlConn)
        {
            return udiDataBase(DeleteString, SqlConn);
        }
        /// <summary>
        ///         
        /// </summary>
        /// <param name="InsertString">Insert Sql  </param>
        /// <param name="SqlConn">     </param>
        /// <returns>      true</returns>
        public bool Insert(string InsertString, SqlConnection SqlConn)
        {
            return udiDataBase(InsertString, SqlConn);
        }
        /// <summary>
        ///   Sql       
        /// </summary>
        /// <param name="UDIString">    </param>
        /// <param name="SqlConn">     </param>
        /// <returns>       true</returns>
        public bool udiDataBase(string UDIString, SqlConnection SqlConn)
        {
            strError = "";
            SqlConnection conn;
            if (SqlConn == null)
            {
                conn = DBconn();
            }
            else
            {
                conn = SqlConn;
            }
            try
            {
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
                SqlCommand cmd = new SqlCommand(UDIString, conn);
                cmd.CommandType = CommandType.Text;
                intCount = cmd.ExecuteNonQuery();
                return !(intCount < 1);
            }
            catch (Exception e)
            {
                strError = "       ：" + e.Message;
                return false;
            }
            finally
            {
                if (conn.State != ConnectionState.Closed)
                {
                    conn.Close();
                }
            }
        }
    }
}