SiteMapProvider.GetChildNodes(SiteMapNode) 方法

定义

命名空间:

System.Web

程序集:

System.Web.dll

当在派生类中被重写时，将检索特定 SiteMapNode 的子节点。

public:
 abstract System::Web::SiteMapNodeCollection ^ GetChildNodes(System::Web::SiteMapNode ^ node);

public abstract System.Web.SiteMapNodeCollection GetChildNodes (System.Web.SiteMapNode node);

abstract member GetChildNodes : System.Web.SiteMapNode -> System.Web.SiteMapNodeCollection

Public MustOverride Function GetChildNodes (node As SiteMapNode) As SiteMapNodeCollection

参数

node

SiteMapNode

要检索其所有子节点的 SiteMapNode。

返回

SiteMapNodeCollection

包含指定 SiteMapNodeCollection 的直接子节点的只读 SiteMapNode；如果不存在子节点，则为 null 或空集合。

示例

下面的代码示例演示如何在实现 GetChildNodes 抽象 SiteMapProvider 类的类中实现 方法。 将SimpleTextSiteMapProvider分层父/子关系存储在一个对象中，将所有SiteMapNode对象存储在另一Hashtable个对象中。 方法 GetChildNodes 使用这两 ArrayList 个 对象执行反向查找。

此代码示例是为 SiteMapProvider 类提供的一个更大示例的一部分。

// Implement the GetChildNodes method.
public override SiteMapNodeCollection GetChildNodes(SiteMapNode node)
{
  SiteMapNodeCollection children = new SiteMapNodeCollection();
  // Iterate through the ArrayList and find all nodes that have the specified node as a parent.
  lock (this)
  {
    for (int i = 0; i < childParentRelationship.Count; i++)
    {

      string nodeUrl = ((DictionaryEntry)childParentRelationship[i]).Key as string;

      SiteMapNode parent = GetNode(childParentRelationship, nodeUrl);

      if (parent != null && node.Url == parent.Url)
      {
        // The SiteMapNode with the Url that corresponds to nodeUrl
        // is a child of the specified node. Get the SiteMapNode for
        // the nodeUrl.
        SiteMapNode child = FindSiteMapNode(nodeUrl);
        if (child != null)
        {
          children.Add(child as SiteMapNode);
        }
        else
        {
          throw new Exception("ArrayLists not in sync.");
        }
      }
    }
  }
  return children;
}
protected override SiteMapNode GetRootNodeCore()
{
  return RootNode;
}
// Implement the GetParentNode method.
public override SiteMapNode GetParentNode(SiteMapNode node)
{
  // Check the childParentRelationship table and find the parent of the current node.
  // If there is no parent, the current node is the RootNode.
  SiteMapNode parent = null;
  lock (this)
  {
    // Get the Value of the node in childParentRelationship
    parent = GetNode(childParentRelationship, node.Url);
  }
  return parent;
}

' Implement the GetChildNodes method.
Public Overrides Function GetChildNodes(ByVal node As SiteMapNode) As SiteMapNodeCollection
  Dim children As New SiteMapNodeCollection()
  ' Iterate through the ArrayList and find all nodes that have the specified node as a parent.
  SyncLock Me
    Dim i As Integer
    For i = 0 To childParentRelationship.Count - 1

      Dim de As DictionaryEntry = CType(childParentRelationship(i), DictionaryEntry)
      Dim nodeUrl As String = CType(de.Key, String)

      Dim parent As SiteMapNode = GetNode(childParentRelationship, nodeUrl)

      If Not (parent Is Nothing) AndAlso node.Url = parent.Url Then
        ' The SiteMapNode with the Url that corresponds to nodeUrl
        ' is a child of the specified node. Get the SiteMapNode for
        ' the nodeUrl.
        Dim child As SiteMapNode = FindSiteMapNode(nodeUrl)
        If Not (child Is Nothing) Then
          children.Add(CType(child, SiteMapNode))
        Else
          Throw New Exception("ArrayLists not in sync.")
        End If
      End If
    Next i
  End SyncLock
  Return children
End Function 'GetChildNodes

Protected Overrides Function GetRootNodeCore() As SiteMapNode
  Return RootNode
End Function ' GetRootNodeCore()

' Implement the GetParentNode method.
Public Overrides Function GetParentNode(ByVal node As SiteMapNode) As SiteMapNode
  ' Check the childParentRelationship table and find the parent of the current node.
  ' If there is no parent, the current node is the RootNode.
  Dim parent As SiteMapNode = Nothing
  SyncLock Me
    ' Get the Value of the node in childParentRelationship
    parent = GetNode(childParentRelationship, node.Url)
  End SyncLock
  Return parent
End Function 'GetParentNode

注解

派生自 类的 SiteMapProvider 类必须实现抽象 GetChildNodes 方法。

实施者说明

在派生类中重写 GetChildNodes(SiteMapNode) 方法时，请确保对子节点执行安全修整，并确保返回的集合是只读的。 集合仅包含指定 node的直接子级。

另请参阅

• GetParentNode(SiteMapNode)