// Method01:根据索引获取节点
private DbNode <T> GetNodeByIndex(int index)
{
if (index < 0 || index >= this.count)
{
throw new ArgumentOutOfRangeException("index", "索引超出范围");
}
DbNode <T> tempNode = this.head;
for (int i = 0; i < index; i++)
{
tempNode = tempNode.Next;
}
return(tempNode);
}
// Method02:在尾节点后插入新节点
public void AddAfter(T value)
{
DbNode <T> newNode = new DbNode <T>(value);
if (this.head == null)
{
// 如果链表当前为空则置为头结点
this.head = newNode;
}
else
{
DbNode <T> lastNode = this.GetNodeByIndex(this.count - 1);
// 调整插入节点与前驱节点指针关系
lastNode.Next = newNode;
newNode.Prev = lastNode;
}
this.count++;
}
// Method03:在尾节点前插入新节点
public void AddBefore(T value)
{
DbNode <T> newNode = new DbNode <T>(value);
if (this.head == null)
{
// 如果链表当前为空则置为头结点
this.head = newNode;
}
else
{
DbNode <T> lastNode = this.GetNodeByIndex(this.count - 1);
DbNode <T> prevNode = lastNode.Prev;
// 调整倒数第2个节点与插入节点的关系
prevNode.Next = newNode;
newNode.Prev = prevNode;
// 调整倒数第1个节点与插入节点的关系
lastNode.Prev = newNode;
newNode.Next = lastNode;
}
this.count++;
}
// Method04:在指定位置后插入新节点
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
{
DbNode <T> prevNode = this.GetNodeByIndex(index); // 获得插入位置的节点
DbNode <T> nextNode = prevNode.Next; // 获取插入位置的后继节点
tempNode = new DbNode <T>(value);
// 调整插入节点与前驱节点指针关系
prevNode.Next = tempNode;
tempNode.Prev = prevNode;
// 调整插入节点与后继节点指针关系
if (nextNode != null)
{
tempNode.Next = nextNode;
nextNode.Prev = tempNode;
}
}
this.count++;
}
public MyDoubleLinkedList()
{
this.count = 0;
this.head = null;
}