LinkedListNode<T>.Previous 属性

定义

命名空间:

System.Collections.Generic

程序集:

System.Collections.dll

Source:

LinkedList.cs

获取 LinkedList<T> 中的上一个节点。

public:
 property System::Collections::Generic::LinkedListNode<T> ^ Previous { System::Collections::Generic::LinkedListNode<T> ^ get(); };

public System.Collections.Generic.LinkedListNode<T>? Previous { get; }

member this.Previous : System.Collections.Generic.LinkedListNode<'T>

Public ReadOnly Property Previous As LinkedListNode(Of T)

属性值

LinkedListNode<T>

对 LinkedList<T> 中的上一个节点的引用；或者如果当前节点是 First 的第一个元素 (LinkedList<T>)，则为 null。

示例

下面的代码示例创建 ， LinkedListNode<T>将其添加到 ， LinkedList<T>并在更改时 LinkedList<T> 跟踪其属性的值。

#using <System.dll>

using namespace System;
using namespace System::Collections::Generic;

public ref class GenericCollection  {

public:
   static void Main()  {

      // Create a new LinkedListNode of type String and displays its properties.
      LinkedListNode<String^>^ lln = gcnew LinkedListNode<String^>( "orange" );
      Console::WriteLine( "After creating the node ...." );
      DisplayProperties( lln );

      // Create a new LinkedList.
      LinkedList<String^>^ ll = gcnew LinkedList<String^>();

      // Add the "orange" node and display its properties.
      ll->AddLast( lln );
      Console::WriteLine( "After adding the node to the empty LinkedList ...." );
      DisplayProperties( lln );

      // Add nodes before and after the "orange" node and display the "orange" node's properties.
      ll->AddFirst( "red" );
      ll->AddLast( "yellow" );
      Console::WriteLine( "After adding red and yellow ...." );
      DisplayProperties( lln );

   }

   static void DisplayProperties( LinkedListNode<String^>^ lln )  {
      if ( lln->List == nullptr )
         Console::WriteLine( "   Node is not linked." );
      else
         Console::WriteLine( "   Node belongs to a linked list with {0} elements.", lln->List->Count );

      if ( lln->Previous == nullptr )
         Console::WriteLine( "   Previous node is null." );
      else
         Console::WriteLine( "   Value of previous node: {0}", lln->Previous->Value );

      Console::WriteLine( "   Value of current node:  {0}", lln->Value );

      if ( lln->Next == nullptr )
         Console::WriteLine( "   Next node is null." );
      else
         Console::WriteLine( "   Value of next node:     {0}", lln->Next->Value );

      Console::WriteLine();
   }

};

int main()
{
    GenericCollection::Main();
}

/*

This code produces the following output.

After creating the node ....
   Node is not linked.
   Previous node is null.
   Value of current node:  orange
   Next node is null.

After adding the node to the empty LinkedList ....
   Node belongs to a linked list with 1 elements.
   Previous node is null.
   Value of current node:  orange
   Next node is null.

After adding red and yellow ....
   Node belongs to a linked list with 3 elements.
   Value of previous node: red
   Value of current node:  orange
   Value of next node:     yellow

*/

using System;
using System.Collections.Generic;

public class GenericCollection  {

   public static void Main()  {

      // Create a new LinkedListNode of type String and displays its properties.
      LinkedListNode<String> lln = new LinkedListNode<String>( "orange" );
      Console.WriteLine( "After creating the node ...." );
      DisplayProperties( lln );

      // Create a new LinkedList.
      LinkedList<String> ll = new LinkedList<String>();

      // Add the "orange" node and display its properties.
      ll.AddLast( lln );
      Console.WriteLine( "After adding the node to the empty LinkedList ...." );
      DisplayProperties( lln );

      // Add nodes before and after the "orange" node and display the "orange" node's properties.
      ll.AddFirst( "red" );
      ll.AddLast( "yellow" );
      Console.WriteLine( "After adding red and yellow ...." );
      DisplayProperties( lln );
   }

   public static void DisplayProperties( LinkedListNode<String> lln )  {
      if ( lln.List == null )
         Console.WriteLine( "   Node is not linked." );
      else
         Console.WriteLine( "   Node belongs to a linked list with {0} elements.", lln.List.Count );

      if ( lln.Previous == null )
         Console.WriteLine( "   Previous node is null." );
      else
         Console.WriteLine( "   Value of previous node: {0}", lln.Previous.Value );

      Console.WriteLine( "   Value of current node:  {0}", lln.Value );

      if ( lln.Next == null )
         Console.WriteLine( "   Next node is null." );
      else
         Console.WriteLine( "   Value of next node:     {0}", lln.Next.Value );

      Console.WriteLine();
   }
}


/*

This code produces the following output.

After creating the node ....
   Node is not linked.
   Previous node is null.
   Value of current node:  orange
   Next node is null.

After adding the node to the empty LinkedList ....
   Node belongs to a linked list with 1 elements.
   Previous node is null.
   Value of current node:  orange
   Next node is null.

After adding red and yellow ....
   Node belongs to a linked list with 3 elements.
   Value of previous node: red
   Value of current node:  orange
   Value of next node:     yellow

*/

Imports System.Collections.Generic

Public Class GenericCollection

    Public Shared Sub Main()

        ' Create a new LinkedListNode of type String and displays its properties.
        Dim lln As New LinkedListNode(Of String)("orange")
        Console.WriteLine("After creating the node ....")
        DisplayProperties(lln)

        ' Create a new LinkedList.
        Dim ll As New LinkedList(Of String)

        ' Add the "orange" node and display its properties.
        ll.AddLast(lln)
        Console.WriteLine("After adding the node to the empty LinkedList ....")
        DisplayProperties(lln)

        ' Add nodes before and after the "orange" node and display the "orange" node's properties.
        ll.AddFirst("red")
        ll.AddLast("yellow")
        Console.WriteLine("After adding red and yellow ....")
        DisplayProperties(lln)

    End Sub

    Public Shared Sub DisplayProperties(lln As LinkedListNode(Of String))

        If lln.List Is Nothing Then
            Console.WriteLine("   Node is not linked.")
        Else
            Console.WriteLine("   Node belongs to a linked list with {0} elements.", lln.List.Count)
        End If 

        If lln.Previous Is Nothing Then
            Console.WriteLine("   Previous node is null.")
        Else
            Console.WriteLine("   Value of previous node: {0}", lln.Previous.Value)
        End If 

        Console.WriteLine("   Value of current node:  {0}", lln.Value)
        
        If lln.Next Is Nothing Then
            Console.WriteLine("   Next node is null.")
        Else
            Console.WriteLine("   Value of next node:     {0}", lln.Next.Value)
        End If 

        Console.WriteLine()

    End Sub

End Class


'This code produces the following output.
'
'After creating the node ....
'   Node is not linked.
'   Previous node is null.
'   Value of current node:  orange
'   Next node is null.
'
'After adding the node to the empty LinkedList ....
'   Node belongs to a linked list with 1 elements.
'   Previous node is null.
'   Value of current node:  orange
'   Next node is null.
'
'After adding red and yellow ....
'   Node belongs to a linked list with 3 elements.
'   Value of previous node: red
'   Value of current node:  orange
'   Value of next node:     yellow