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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections;
using System.ComponentModel;
namespace System.Windows.Forms;
public partial class ListView
{
[ListBindable(false)]
public class CheckedListViewItemCollection : IList
{
private readonly ListView _owner;
/// A caching mechanism for key accessor
/// We use an index here rather than control so that we don't have lifetime
/// issues by holding on to extra references.
private int _lastAccessedIndex = -1;
/* C#r: protected */
public CheckedListViewItemCollection(ListView owner)
{
_owner = owner.OrThrowIfNull();
}
/// <summary>
/// Number of currently selected items.
/// </summary>
[Browsable(false)]
public int Count
{
get
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
return _owner.CheckedIndices.Count;
}
}
private ListViewItem[] ItemArray
{
get
{
ListViewItem[] items = new ListViewItem[Count];
int index = 0;
for (int i = 0; i < _owner.Items.Count && index < items.Length; ++i)
{
if (_owner.Items[i].Checked)
{
items[index++] = _owner.Items[i];
}
}
return items;
}
}
/// <summary>
/// Selected item in the list.
/// </summary>
public ListViewItem this[int index]
{
get
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
int itemIndex = _owner.CheckedIndices[index];
return _owner.Items[itemIndex];
}
}
object? IList.this[int index]
{
get
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
return this[index];
}
set
{
throw new NotSupportedException();
}
}
/// <summary>
/// Retrieves the child control with the specified key.
/// </summary>
public virtual ListViewItem? this[string? key]
{
get
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
// We do not support null and empty string as valid keys.
if (string.IsNullOrEmpty(key))
{
return null;
}
// Search for the key in our collection
int index = IndexOfKey(key);
if (IsValidIndex(index))
{
return this[index];
}
else
{
return null;
}
}
}
object ICollection.SyncRoot
{
get
{
return this;
}
}
bool ICollection.IsSynchronized
{
get
{
return false;
}
}
bool IList.IsFixedSize
{
get
{
return true;
}
}
public bool IsReadOnly
{
get
{
return true;
}
}
public bool Contains(ListViewItem? item)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
if (item?.ListView == _owner && item.Checked)
{
return true;
}
else
{
return false;
}
}
bool IList.Contains(object? item)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
if (item is ListViewItem listViewItem)
{
return Contains(listViewItem);
}
else
{
return false;
}
}
/// <summary>
/// Returns true if the collection contains an item with the specified key, false otherwise.
/// </summary>
public virtual bool ContainsKey(string? key)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
return IsValidIndex(IndexOfKey(key));
}
public int IndexOf(ListViewItem item)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
ListViewItem[] items = ItemArray;
for (int index = 0; index < items.Length; ++index)
{
if (items[index] == item)
{
return index;
}
}
return -1;
}
/// <summary>
/// The zero-based index of the first occurrence of value within the entire CollectionBase, if found; otherwise, -1.
/// </summary>
public virtual int IndexOfKey(string? key)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
// Step 0 - Arg validation
if (string.IsNullOrEmpty(key))
{
return -1; // we don't support empty or null keys.
}
// step 1 - check the last cached item
if (IsValidIndex(_lastAccessedIndex))
{
if (WindowsFormsUtils.SafeCompareStrings(this[_lastAccessedIndex].Name, key, /* ignoreCase = */ true))
{
return _lastAccessedIndex;
}
}
// step 2 - search for the item
for (int i = 0; i < Count; i++)
{
if (WindowsFormsUtils.SafeCompareStrings(this[i].Name, key, /* ignoreCase = */ true))
{
_lastAccessedIndex = i;
return i;
}
}
// step 3 - we didn't find it. Invalidate the last accessed index and return -1.
_lastAccessedIndex = -1;
return -1;
}
/// <summary>
/// Determines if the index is valid for the collection.
/// </summary>
private bool IsValidIndex(int index)
{
return (index >= 0) && (index < Count);
}
int IList.IndexOf(object? item)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
if (item is ListViewItem listViewItem)
{
return IndexOf(listViewItem);
}
else
{
return -1;
}
}
int IList.Add(object? value)
{
throw new NotSupportedException();
}
void IList.Clear()
{
throw new NotSupportedException();
}
void IList.Insert(int index, object? value)
{
throw new NotSupportedException();
}
void IList.Remove(object? value)
{
throw new NotSupportedException();
}
void IList.RemoveAt(int index)
{
throw new NotSupportedException();
}
public void CopyTo(Array dest, int index)
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
if (Count > 0)
{
Array.Copy(ItemArray, 0, dest, index, Count);
}
}
public IEnumerator GetEnumerator()
{
if (_owner.VirtualMode)
{
throw new InvalidOperationException(SR.ListViewCantAccessCheckedItemsCollectionWhenInVirtualMode);
}
ListViewItem[] items = ItemArray;
if (items is not null)
{
return items.GetEnumerator();
}
else
{
return Array.Empty<ListViewItem>().GetEnumerator();
}
}
}
}
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