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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;
using System.Windows.Forms.Layout;
namespace System.Windows.Forms;
public partial class LinkLabel
{
public class LinkCollection : IList
{
private readonly LinkLabel _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.
/// Note this is not Thread Safe - but WinForms has to be run in a STA anyways.
private int _lastAccessedIndex = -1;
public LinkCollection(LinkLabel owner) => _owner = owner.OrThrowIfNull();
public virtual Link this[int index]
{
get
{
return _owner._links[index];
}
set
{
_owner._links[index] = value;
_owner._links.Sort(s_linkComparer);
_owner.InvalidateTextLayout();
_owner.Invalidate();
}
}
object? IList.this[int index]
{
get => this[index];
set
{
if (value is Link link)
{
this[index] = link;
}
else
{
throw new ArgumentException(SR.LinkLabelBadLink, nameof(value));
}
}
}
/// <summary>
/// Retrieves the child control with the specified key.
/// </summary>
public virtual Link? this[string key]
{
get
{
// 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;
}
}
}
[Browsable(false)]
public int Count => _owner._links.Count;
/// <summary>
/// whether we have added a non-trivial link to the collection
/// </summary>
public bool LinksAdded { get; private set; }
object ICollection.SyncRoot => this;
bool ICollection.IsSynchronized => false;
bool IList.IsFixedSize => false;
public bool IsReadOnly => false;
public Link Add(int start, int length)
{
if (length != 0)
{
LinksAdded = true;
}
return Add(start, length, null);
}
public Link Add(int start, int length, object? linkData)
{
if (length != 0)
{
LinksAdded = true;
}
// check for the special case where the list is in the "magic"
// state of having only the default link in it. In that case
// we want to clear the list before adding this link.
if (_owner._links.Count == 1
&& this[0].Start == 0
&& this[0]._length == -1)
{
_owner._links.Clear();
_owner.FocusLink = null;
}
Link l = new(_owner)
{
Start = start,
Length = length,
LinkData = linkData
};
Add(l);
return l;
}
public int Add(Link value)
{
if (value is not null && value.Length != 0)
{
LinksAdded = true;
}
// check for the special case where the list is in the "magic"
// state of having only the default link in it. In that case
// we want to clear the list before adding this link.
if (_owner._links.Count == 1
&& this[0].Start == 0
&& this[0]._length == -1)
{
_owner._links.Clear();
_owner.FocusLink = null;
}
// Set the owner control for this link
value!.Owner = _owner;
_owner._links.Add(value);
if (_owner.AutoSize)
{
LayoutTransaction.DoLayout(_owner.ParentInternal, _owner, PropertyNames.Links);
_owner.AdjustSize();
_owner.Invalidate();
}
if (_owner.Links.Count > 1)
{
_owner._links.Sort(s_linkComparer);
}
_owner.ValidateNoOverlappingLinks();
_owner.UpdateSelectability();
_owner.InvalidateTextLayout();
_owner.Invalidate();
if (_owner.Links.Count > 1)
{
return IndexOf(value);
}
else
{
return 0;
}
}
int IList.Add(object? value)
{
if (value is Link link)
{
return Add(link);
}
else
{
throw new ArgumentException(SR.LinkLabelBadLink, nameof(value));
}
}
void IList.Insert(int index, object? value)
{
if (value is Link link)
{
Add(link);
}
else
{
throw new ArgumentException(SR.LinkLabelBadLink, nameof(value));
}
}
public bool Contains(Link link)
{
return _owner._links.Contains(link);
}
/// <summary>
/// Returns true if the collection contains an item with the specified key, false otherwise.
/// </summary>
public virtual bool ContainsKey(string? key)
{
return IsValidIndex(IndexOfKey(key));
}
bool IList.Contains(object? value)
{
if (value is Link link)
{
return Contains(link);
}
else
{
return false;
}
}
public int IndexOf(Link link)
{
return _owner._links.IndexOf(link);
}
int IList.IndexOf(object? value)
{
if (value is Link link)
{
return IndexOf(link);
}
else
{
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)
{
// 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));
}
/// <summary>
/// Remove all links from the linkLabel.
/// </summary>
public virtual void Clear()
{
bool doLayout = _owner._links.Count > 0 && _owner.AutoSize;
_owner._links.Clear();
if (doLayout)
{
LayoutTransaction.DoLayout(_owner.ParentInternal, _owner, PropertyNames.Links);
_owner.AdjustSize();
_owner.Invalidate();
}
_owner.UpdateSelectability();
_owner.InvalidateTextLayout();
_owner.Invalidate();
}
void ICollection.CopyTo(Array dest, int index)
{
((ICollection)_owner._links).CopyTo(dest, index);
}
public IEnumerator GetEnumerator()
{
if (_owner._links is not null)
{
return _owner._links.GetEnumerator();
}
else
{
return Array.Empty<Link>().GetEnumerator();
}
}
public void Remove(Link value)
{
if (value.Owner != _owner)
{
return;
}
_owner._links.Remove(value);
if (_owner.AutoSize)
{
LayoutTransaction.DoLayout(_owner.ParentInternal, _owner, PropertyNames.Links);
_owner.AdjustSize();
_owner.Invalidate();
}
_owner._links.Sort(s_linkComparer);
_owner.ValidateNoOverlappingLinks();
_owner.UpdateSelectability();
_owner.InvalidateTextLayout();
_owner.Invalidate();
if (_owner.FocusLink is null && _owner._links.Count > 0)
{
_owner.FocusLink = _owner._links[0];
}
}
public void RemoveAt(int index)
{
Remove(this[index]);
}
/// <summary>
/// Removes the child control with the specified key.
/// </summary>
public virtual void RemoveByKey(string? key)
{
int index = IndexOfKey(key);
if (IsValidIndex(index))
{
RemoveAt(index);
}
}
void IList.Remove(object? value)
{
if (value is Link link)
{
Remove(link);
}
}
}
}
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