CollectionViewGroupInternal.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / MS / Internal / Data / CollectionViewGroupInternal.cs / 1 / CollectionViewGroupInternal.cs

                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) 2003 by Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: A CollectionViewGroupInternal, as created by a CollectionView according to a GroupDescription. 
//
// See spec at [....]/connecteddata/Specs/Grouping.mht 
//
//---------------------------------------------------------------------------

using System; 
using System.Collections;       // IEnumerator
using System.ComponentModel;    // PropertyChangedEventArgs, GroupDescription 
using System.Windows;           // DependencyProperty.UnsetValue 
using System.Windows.Data;      // CollectionViewGroup
 
namespace MS.Internal.Data
{
    internal class CollectionViewGroupInternal : CollectionViewGroup
    { 
        #region Constructors
 
        //----------------------------------------------------- 
        //
        //  Constructors 
        //
        //-----------------------------------------------------

        internal CollectionViewGroupInternal(object name, CollectionViewGroupInternal parent) : base(name) 
        {
            _parentGroup = parent; 
        } 

        #endregion Constructors 

        #region Public Properties

        //------------------------------------------------------ 
        //
        //  Public Properties 
        // 
        //-----------------------------------------------------
 
        /// 
        /// Is this group at the bottom level (not further subgrouped).
        /// 
        public override bool IsBottomLevel 
        {
            get { return (_groupBy == null); } 
        } 

        #endregion  Public Properties 

        #region Internal Properties

        //------------------------------------------------------ 
        //
        //  Internal Properties 
        // 
        //------------------------------------------------------
 
        // how this group divides into subgroups
        internal GroupDescription GroupBy
        {
            get { return _groupBy; } 
            set
            { 
                bool oldIsBottomLevel = IsBottomLevel; 

                if (_groupBy != null) 
                    ((INotifyPropertyChanged)_groupBy).PropertyChanged -= new PropertyChangedEventHandler(OnGroupByChanged);

                _groupBy = value;
 
                if (_groupBy != null)
                    ((INotifyPropertyChanged)_groupBy).PropertyChanged += new PropertyChangedEventHandler(OnGroupByChanged); 
 
                if (oldIsBottomLevel != IsBottomLevel)
                { 
                    OnPropertyChanged(new PropertyChangedEventArgs("IsBottomLevel"));
                }
            }
        } 

        // the number of items and groups in the subtree under this group 
        internal int FullCount 
        {
            get { return _fullCount; } 
            set { _fullCount = value; }
        }

        // the most recent index where actvity took place 
        internal int LastIndex
        { 
            get { return _lastIndex; } 
            set { _lastIndex = value; }
        } 

        // the first item (leaf) added to this group.  If this can't be determined,
        // DependencyProperty.UnsetValue.
        internal object SeedItem 
        {
            get 
            { 
                if (ItemCount > 0 && (GroupBy == null || GroupBy.GroupNames.Count == 0))
                { 
                    // look for first item, child by child
                    for (int k=0, n=Items.Count; k 0)
                        {
                            // child is a nonempty subgroup - ask it
                            return subgroup.SeedItem; 
                        }
                        // otherwise child is an empty subgroup - go to next child 
                    } 

                    // we shouldn't get here, but just in case... 
                    return DependencyProperty.UnsetValue;
                }
                else
                { 
                    // the group is empty, or it has explicit subgroups.
                    // In either case, we cannot determine the first item - 
                    // it could have gone into any of the subgroups. 
                    return DependencyProperty.UnsetValue;
                } 
            }
        }

        #endregion Properties 

        #region Internal methods 
 
        //-----------------------------------------------------
        // 
        //  Internal methods
        //
        //------------------------------------------------------
 
        internal void Add(object item)
        { 
            ChangeCounts(item, +1); 
            ProtectedItems.Add(item);
        } 

        internal int Remove(object item, bool returnLeafIndex)
        {
            int index = -1; 
            int localIndex = ProtectedItems.IndexOf(item);
 
            if (localIndex >= 0) 
            {
                if (returnLeafIndex) 
                {
                    index = LeafIndexFromItem(null, localIndex);
                }
 
                ChangeCounts(item, -1);
                ProtectedItems.RemoveAt(localIndex); 
            } 

            return index; 
        }

        internal void Clear()
        { 
            ProtectedItems.Clear();
            FullCount = 1; 
            ProtectedItemCount = 0; 
        }
 
        // return the index of the given item within the list of leaves governed
        // by this group
        internal int LeafIndexOf(object item)
        { 
            int leaves = 0;         // number of leaves we've passed over so far
            for (int k=0, n=Items.Count;  k= groupBy.GroupNames.Count) 
                {
                    parent.Remove(group, false);
                }
            } 
        }
 
        void OnGroupByChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e) 
        {
            OnGroupByChanged(); 
        }

        #endregion Private methods
 
        #region Private fields
 
        //----------------------------------------------------- 
        //
        //  Private fields 
        //
        //------------------------------------------------------

        GroupDescription    _groupBy; 
        CollectionViewGroupInternal _parentGroup;
        int                 _fullCount = 1; 
        int                 _lastIndex; 
        int                 _version;       // for detecting stale enumerators
 
        #endregion Private fields

        #region Private classes
 
        //------------------------------------------------------
        // 
        //  Private classes 
        //
        //----------------------------------------------------- 

        private class LeafEnumerator : IEnumerator
        {
            public LeafEnumerator(CollectionViewGroupInternal group) 
            {
                _group = group; 
                DoReset();  // don't call virtual Reset in ctor 
            }
 
            void IEnumerator.Reset()
            {
                DoReset();
            } 

            void DoReset() 
            { 
                _version = _group._version;
                _index = -1; 
                _subEnum = null;
            }

            bool IEnumerator.MoveNext() 
            {
                // check for invalidated enumerator 
                if (_group._version != _version) 
                    throw new InvalidOperationException();
 
                // move forward to the next leaf
                while (_subEnum == null || !_subEnum.MoveNext())
                {
                    // done with the current top-level item.  Move to the next one. 
                    ++ _index;
                    if (_index >= _group.Items.Count) 
                        return false; 

                    CollectionViewGroupInternal subgroup = _group.Items[_index] as CollectionViewGroupInternal; 
                    if (subgroup == null)
                    {
                        // current item is a leaf - it's the new Current
                        _current = _group.Items[_index]; 
                        _subEnum = null;
                        return true; 
                    } 
                    else
                    { 
                        // current item is a subgroup - get its enumerator
                        _subEnum = subgroup.GetLeafEnumerator();
                    }
                } 

                // the loop terminates only when we have a subgroup enumerator 
                // positioned at the new Current item 
                _current = _subEnum.Current;
                return true; 
            }

            object IEnumerator.Current
            { 
                get
                { 
                    if (_index < 0  ||  _index >= _group.Items.Count) 
                        throw new InvalidOperationException();
                    return _current; 
                }
            }

            CollectionViewGroupInternal _group; // parent group 
            int                 _version;   // parent group's version at ctor
            int                 _index;     // current index into Items 
            IEnumerator         _subEnum;   // enumerator over current subgroup 
            object              _current;   // current item
        } 

        #endregion Private classes
    }
 
}

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

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