private DbNode <T> GetNodeByIndex(int index)
{
if (index < 0 || index >= this.Count)
{
throw new ArgumentOutOfRangeException("index", "索引超出范围");
}
DbNode <T> result = this.head;
for (int i = 0; i < index; i++)
{
result = result.Next;
}
return(result);
}
/// <summary>
/// 尾节点之后插入新节点
/// </summary>
/// <param name="value"></param>
public void AddAfter(T value)
{
DbNode <T> newNode = new DbNode <T>(value);
if (this.head == null)
{
this.head = newNode;
}
else
{
DbNode <T> lastNode = GetNodeByIndex(this.Count - 1);
lastNode.Next = newNode;
newNode.Prev = lastNode;
}
this.Count++;
}
/// <summary>
/// 尾节点之前插入
/// </summary>
/// <param name="value"></param>
public void AddBefore(T value)
{
DbNode <T> newNode = new DbNode <T>(value);
if (this.head == null)
{
this.head = newNode;
}
else
{
DbNode <T> lastNode = GetNodeByIndex(this.Count - 1); //尾节点
DbNode <T> lastPrevNode = lastNode.Prev; //尾节点的前一个节点
lastPrevNode.Next = newNode;
newNode.Prev = lastPrevNode;
newNode.Next = lastNode;
lastNode.Prev = newNode;
}
this.Count++;
}
public void RemoveAt(int index)
{
if (index == 0)
{
this.head = this.head.Next;
this.head.Prev = null;
}
else
{
DbNode <T> deleteNode = GetNodeByIndex(index);
DbNode <T> prveNode = deleteNode.Prev;
DbNode <T> nextNode = deleteNode.Next;
prveNode.Next = nextNode;
if (nextNode != null)//判断是否是尾节点
{
nextNode.Prev = prveNode;
}
deleteNode = null;
}
this.Count--;
}
public void InsertAfter(int index, T value)
{
DbNode <T> tempNode;
if (index == 0)
{
if (this.head == null)
{
tempNode = new DbNode <T>(value);
this.head = tempNode;
}
else
{
tempNode = new DbNode <T>(value);
tempNode.Next = this.head;
this.head.Prev = tempNode;
this.head = tempNode;
}
}
else
{
tempNode = new DbNode <T>(value);
DbNode <T> indexNode = GetNodeByIndex(index);
DbNode <T> nextIndexNode = indexNode.Next;
indexNode.Next = tempNode;
tempNode.Prev = indexNode;
//是否尾节点
if (nextIndexNode != null)
{
tempNode.Next = nextIndexNode;
nextIndexNode.Prev = tempNode;
}
}
this.Count++;
}
public DoublelinkedList()
{
this.head = null;
this.Count = 0;
}
