SiteMapProvider.GetChildNodes(SiteMapNode) Método

Definição

Namespace:

System.Web

Assembly:

System.Web.dll

Quando substituído em uma classe derivada, recupera os nós filho de um SiteMapNode específico.

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

Parâmetros

node

SiteMapNode

O SiteMapNode do qual recuperar todos os nós filho.

Retornos

SiteMapNodeCollection

Um SiteMapNodeCollection somente leitura que contém os nós filho imediatos do SiteMapNode especificado, caso contrário, null ou uma coleção vazia, se não existirem nós filho.

Exemplos

O exemplo de código a seguir demonstra como implementar o GetChildNodes método em uma classe que implementa a classe abstrata SiteMapProvider . O SimpleTextSiteMapProvider armazena as relações hierárquicas pai/filho em um Hashtable objeto e todos os SiteMapNode objetos em outro. O GetChildNodes método executa uma pesquisa inversa usando ambos os ArrayList objetos.

Este exemplo de código faz parte de um exemplo maior fornecido para a SiteMapProvider classe.

// 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

Comentários

Classes que derivam da SiteMapProvider classe devem implementar o método abstrato GetChildNodes .

Notas aos Implementadores

Ao substituir o GetChildNodes(SiteMapNode) método em uma classe derivada, certifique-se de executar o corte de segurança nos nós filho e garantir que a coleção retornada seja somente leitura. A coleção contém apenas os filhos imediatos do especificado node.

Confira também

• GetParentNode(SiteMapNode)