GenericEnumerator.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Shared / MS / Internal / GenericEnumerator.cs / 1305600 / GenericEnumerator.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//  Microsoft Avalon
//  Copyright (c) Microsoft Corporation, 2001
//
//  File:       GenericEnumerator.cs 
//-----------------------------------------------------------------------------
 
using System; 
using System.Collections;
using System.Diagnostics; 
using System.Windows;
using MS.Utility;

#if PRESENTATION_CORE 
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID; 
#else 
using SR=System.Windows.SR;
using SRID=System.Windows.SRID; 
#endif

namespace MS.Internal
{ 
    /// 
    /// GenericEnumerator 
    ///  
    internal class GenericEnumerator : IEnumerator
    { 
        #region Delegates

        internal delegate int GetGenerationIDDelegate();
 
        #endregion
 
        #region Constructors 

        private GenericEnumerator() 
        {
        }

        internal GenericEnumerator(IList array, GetGenerationIDDelegate getGenerationID) 
        {
            _array     = array; 
            _count     = _array.Count; 
            _position  = -1;
            _getGenerationID = getGenerationID; 
            _originalGenerationID = _getGenerationID();
        }

        #endregion 

        #region Private 
 
        private void VerifyCurrent()
        { 
            if (   (-1 == _position)
                || (_position >= _count))
            {
                throw new InvalidOperationException(SR.Get(SRID.Enumerator_VerifyContext)); 
            }
        } 
 
        #endregion
 
        #region IEnumerator

        /// 
        /// Returns the object at the current location of the key times list. 
        /// Use the strongly typed version instead.
        ///  
        object 
            IEnumerator.Current
        { 
            get
            {
                VerifyCurrent();
 
                return _current;
            } 
        } 

        ///  
        /// Move to the next value in the key times list
        /// 
        /// true if succeeded, false if at the end of the list
        public bool MoveNext() 
        {
            if (_getGenerationID() != _originalGenerationID) 
            { 
                throw new InvalidOperationException(SR.Get(SRID.Enumerator_CollectionChanged));
            } 

            _position++;

            if (_position >= _count) 
            {
                _position = _count; 
 
                return false;
            } 
            else
            {
                Debug.Assert(_position >= 0);
 
                _current = _array[_position];
 
                return true; 
            }
        } 

        /// 
        /// Move to the position before the first value in the list.
        ///  
        public void Reset()
        { 
            if (_getGenerationID() != _originalGenerationID) 
            {
                throw new InvalidOperationException(SR.Get(SRID.Enumerator_CollectionChanged)); 
            }
            else
            {
                _position = -1; 
            }
        } 
 
        #endregion
 
        #region Data

        private IList   _array;
        private object  _current; 
        private int     _count;
        private int     _position; 
        private int     _originalGenerationID; 

        private GetGenerationIDDelegate _getGenerationID; 

        #endregion
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK