/// <summary>
/// 添加指定类型的元素到子元素集合的队尾
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="newChild"></param>
/// <returns></returns>
public override T AppendChild <T>(T newChild)
{
if (newChild == null)
{
return(default(T));
}
if (newChild.Parent != null)
{
throw new InvalidOperationException();
}
MetaElement lastChild = this.LastChild;
MetaElement element2 = newChild;
if (lastChild == null)
{
element2.Next = element2;
this._lastChild = element2;
}
else
{
element2.Next = lastChild.Next;
lastChild.Next = element2;
this._lastChild = element2;
}
newChild.Parent = this;
return(newChild);
}
/// <summary>
/// 移除所有的子元素
/// </summary>
public override void RemoveAllChildren()
{
MetaElement element2;
for (MetaElement element = this.FirstChild; element != null; element = element2)
{
element2 = element.NextSibling();
this.RemoveChild <MetaElement>(element);
}
}
/// <summary>
/// 根据下标获取元素
/// </summary>
/// <param name="index"></param>
/// <returns></returns>
public override MetaElement GetItem(int index)
{
if (this._container.HasChildren)
{
for (MetaElement element = this._container.FirstChild; element != null; element = element.NextSibling())
{
if (index == 0)
{
return(element);
}
index--;
}
}
throw new ArgumentOutOfRangeException("index");
}
/// <summary>
/// 添加元素到子元素集合的队尾
/// </summary>
/// <param name="element"></param>
private void AddElement(MetaElement element)
{
element.Parent = this;
if (this._lastChild == null)
{
element.Next = element;
this._lastChild = element;
}
else
{
element.Next = this._lastChild.Next;
this._lastChild.Next = element;
this._lastChild = element;
}
}
/// <summary>
/// 获取枚举器
/// </summary>
/// <returns></returns>
public override IEnumerator <MetaElement> GetEnumerator()
{
if (!this._container.HasChildren || (this._container.FirstChild == null))
{
goto labl_ret;
}
MetaElement firstChild = this._container.FirstChild;
while (firstChild != null)
{
yield return(firstChild);
firstChild = firstChild.NextSibling();
}
labl_ret :;
}
/// <summary>
/// 移除指定类型的子元素
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="oldChild"></param>
/// <returns></returns>
public override T RemoveChild <T>(T oldChild)
{
if (oldChild == null)
{
return(default(T));
}
if (oldChild.Parent != this)
{
throw new InvalidOperationException();
}
T local = oldChild;
MetaElement element = this._lastChild;
if (local == this.FirstChild)
{
if (local == this._lastChild)
{
this._lastChild = null;
}
else
{
MetaElement next = local.Next;
element.Next = next;
}
}
else if (local == this._lastChild)
{
MetaElement element3 = local.PreviousSibling();
MetaElement element4 = local.Next;
element3.Next = element4;
this._lastChild = element3;
}
else
{
MetaElement element5 = local.PreviousSibling();
MetaElement element6 = local.Next;
element5.Next = element6;
}
local.Next = null;
local.Parent = null;
return(local);
}
public ChildElements(MetaElement container)
{
this._container = container;
}