Database Helper Class Library to Ease Database Operation

///////////////////////////////////////////////////////////////////////////
// Copyright 2003-2005 Falcon Soon
//
// Author: Soon Chun Boon
// Date: 10 Jan 2004
// Description: 
// Base class for Database Interaction using MS SQL.
// Because this class implements IDisposable, derived classes shouldn't do so.
///////////////////////////////////////////////////////////////////////////

using System;
using System.Data;
using System.Data.SqlClient;

namespace DBHelper.SqlClient
{
    /// <summary>
    /// Abstract base class for Database Interaction classes using MS SQL.
    /// </summary>
    public abstract class SqlDBInteractionBase : DBInteractionBase, IDisposable
    {
        #region Class Member Declarations
            /// <summary>
            /// An instance of connection.
            /// </summary>
            protected	SqlConnection			mcnnMainConnection;

            /// <summary>
            /// Value specifies whether connection is created local.
            /// </summary>
            protected	bool					mbMainConnectionIsCreatedLocal;

            /// <summary>
            /// An instance of SQL connection provider.
            /// </summary>
            protected	SqlConnectionProvider	mobjMainConnectionProvider;

            private		bool					mbIsDisposed;
        #endregion


        /// <summary>
        /// Initializes a new instance of <see cref="DBHelper.SqlClient.SqlDBInteractionBase"/>.
        /// </summary>
        /// <remarks>
        /// When first been initialized, local connection is created.
        /// </remarks>
        public SqlDBInteractionBase()
        {
            // Initialize the class' members.
            InitClass();
        }


        /// <summary>
        /// Initializes class members.
        /// </summary>
        protected override void InitClass()
        {
            // create all the objects and initialize other members.
            base.InitClass();
            mcnnMainConnection = new SqlConnection();
            mbMainConnectionIsCreatedLocal = true;
            mobjMainConnectionProvider = null;
            mbIsDisposed = false;
        }


        /// <summary>
        /// Implements the IDispose' method Dispose.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }


        /// <summary>
        /// Implements the Dispose functionality.
        /// </summary>
        protected virtual void Dispose(bool bIsDisposing)
        {
            // Check to see if Dispose has already been called.
            if(!mbIsDisposed)
            {
                if(bIsDisposing)
                {
                    // Dispose managed resources.
                    if(mbMainConnectionIsCreatedLocal)
                    {
                        // Object is created in this class, so destroy it here.
                        mcnnMainConnection.Close();
                        mcnnMainConnection.Dispose();
                        mbMainConnectionIsCreatedLocal = false;
                    }
                    mobjMainConnectionProvider = null;
                    mcnnMainConnection = null;
                }
            }
            mbIsDisposed = true;
        }
      
        #region Class Property Declarations
        /// <summary>
        /// Specifies the connection provider.
        /// </summary>
        public SqlConnectionProvider MainConnectionProvider
        {
            set
            {
                if(value==null)
                {
                    // Invalid value
                    throw new ArgumentNullException("MainConnectionProvider", "Null passed as value to this property which is not allowed.");
                }

                // A connection provider object is passed to this class.
                // Retrieve the SqlConnection object, if present and create a
                // reference to it. If there is already a MainConnection object
                // referenced by the membervar, destroy that one or simply 
                // remove the reference, based on the flag.
                if(mcnnMainConnection!=null)
                {
                    // First get rid of current connection object. Caller is responsible
                    if(mbMainConnectionIsCreatedLocal)
                    {
                        // Is local created object, close it and dispose it.
                        mcnnMainConnection.Close();
                        mcnnMainConnection.Dispose();
                    }
                    // Remove reference.
                    mcnnMainConnection = null;
                }
                mobjMainConnectionProvider = (SqlConnectionProvider)value;
                mcnnMainConnection = (SqlConnection)mobjMainConnectionProvider.DBConnection;
                mbMainConnectionIsCreatedLocal = false;
            }
        }

        /// <summary>
        /// Specifies the connection string.
        /// </summary>
        public override string ConnectionString
        {
            get
            {
                return (base.ConnectionString);
            }
            set
            {
                base.ConnectionString = value;
                mcnnMainConnection.ConnectionString = value;
            }
        }
        #endregion
    }
}