selecteditemcollection.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 / Framework / System / Windows / Controls / selecteditemcollection.cs / 1305600 / selecteditemcollection.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) 2008 by Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: SelectedItemCollection holds the list of selected items of a Selector. 
//
// 
// History:
//  10/01/2008 : atanask - Created
//
//--------------------------------------------------------------------------- 

using System; 
using System.Collections; 
using System.Collections.ObjectModel;
using System.Windows.Controls.Primitives; 

namespace System.Windows.Controls
{
 
    /// 
    /// This class represent the collection of SelectedItems in Selector. It extends the ObservableCollection by providing methods for bulk selection. 
    ///  
    internal class SelectedItemCollection : ObservableCollection
    { 
        #region Contructors
        /// 
        /// Create a new SelectedItemCollection object which keeps a reference to the corresponding Selector
        ///  
        /// 
        public SelectedItemCollection(Selector selector) 
        { 
            _selector = selector;
        } 
        #endregion

        #region Protected Methods
 
        /// 
        /// Clear all items from the selection. This method modifies the behavior of IList.Clear() 
        ///  
        protected override void ClearItems()
        { 
            if (_updatingSelectedItems)
            {
                foreach (object current in _selector._selectedItems)
                { 
                    _selector.SelectionChange.Unselect(current);
                } 
            } 
            else
            { 
                base.ClearItems();
            }
        }
 
        /// 
        /// Removes an item from the selection. This method modifies the behavior of IList.Remove() and IList.RemoveAt() 
        ///  
        protected override void RemoveItem(int index)
        { 
            if (_updatingSelectedItems)
            {
                _selector.SelectionChange.Unselect(this[index]);
            } 
            else
            { 
                base.RemoveItem(index); 
            }
        } 

        /// 
        /// Inserts an item in the selection
        ///  
        protected override void InsertItem(int index, object item)
        { 
            if (_updatingSelectedItems) 
            {
                // For defered selection we should allow only Add method 
                if (index == Count)
                {
                    _selector.SelectionChange.Select(item, true /* assumeInItemsCollection */);
                } 
                else
                { 
                    throw new InvalidOperationException(SR.Get(SRID.InsertInDeferSelectionActive)); 
                }
            } 
            else
            {
                base.InsertItem(index, item);
            } 
        }
 
        ///  
        /// Sets an item on specified index
        ///  
        protected override void SetItem(int index, object item)
        {
            if (_updatingSelectedItems)
            { 
                throw new InvalidOperationException(SR.Get(SRID.SetInDeferSelectionActive));
            } 
            else 
            {
                base.SetItem(index, item); 
            }
        }

        ///  
        /// Movea an item from one position to another
        ///  
        /// index of the column which is being moved 
        /// index of the column to be move to
        protected override void MoveItem(int oldIndex, int newIndex) 
        {
            if (oldIndex != newIndex)
            {
                if (_updatingSelectedItems) 
                {
                    throw new InvalidOperationException(SR.Get(SRID.MoveInDeferSelectionActive)); 
                } 
                else
                { 
                    base.MoveItem(oldIndex, newIndex);
                }
            }
        } 
        #endregion
 
        #region MiltiSelector methods 

        ///  
        /// Begin tracking selection changes. SelectedItems.Add/Remove will queue up the changes but not commit them until EndUpdateSelecteditems is called.
        /// 
        internal void BeginUpdateSelectedItems()
        { 
            if (_selector.SelectionChange.IsActive || _updatingSelectedItems)
            { 
                throw new InvalidOperationException(SR.Get(SRID.DeferSelectionActive)); 
            }
            _updatingSelectedItems = true; 
            _selector.SelectionChange.Begin();
        }

        ///  
        /// Commit selection changes.
        ///  
        internal void EndUpdateSelectedItems() 
        {
            if (!_selector.SelectionChange.IsActive || !_updatingSelectedItems) 
            {
                throw new InvalidOperationException(SR.Get(SRID.DeferSelectionNotActive));
            }
            _updatingSelectedItems = false; 
            _selector.SelectionChange.End();
        } 
 
        /// 
        /// Returns true after BeginUpdateSelectedItems is called 
        /// 
        internal bool IsUpdatingSelectedItems
        {
            get 
            {
                return _selector.SelectionChange.IsActive || _updatingSelectedItems; 
            } 
        }
 
        #endregion

        #region Private data
 
        // Keep a reference for Selector owner
        private Selector _selector; 
 
        // We need a flag for indicating user bulk selection mode. We cannot re-use SelectionChange.IsActive because there are cases when SelectionChange.IsActive==true and SelectedItems.Add is called internally (End()) to update the collection
        // When EndUpdateSelectedItems() is called we first reset this flag to allow SelectedItems.Add to change the collection 
        private bool _updatingSelectedItems;
        #endregion
    }
 
}

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


                        

                        

                        
                        
                    
                    

                        
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