IHierarchyData.Item Propriété

Définition

Obtient le nœud de données hiérarchique que l'objet IHierarchyData représente.Gets the hierarchical data node that the IHierarchyData object represents.

public:
 property System::Object ^ Item { System::Object ^ get(); };
public object Item { get; }
member this.Item : obj
Public ReadOnly Property Item As Object

Valeur de propriété

Object

Un objet de nœud de données hiérarchiques Object.An Object hierarchical data node object.

Exemples

L’exemple de code suivant montre comment accéder IHierarchyData aux propriétés, vérifier le type d' IHierarchyData un objet à Type l’aide de la propriété et effectuer un cast de l’objet pour effectuer d’autres opérations spécifiques au type.The following code example demonstrates how to access IHierarchyData properties, check the type of an IHierarchyData object using the Type property, and cast the object to perform more type-specific operations. Cet exemple de code fait partie d’un exemple plus complet fourni IHierarchyData pour l’interface.This code example is part of a larger example provided for the IHierarchyData interface.

// Print out the current data node, then iterate through its
// children and do the same.
private void PrintFullChildNodeInfo(IHierarchyData node)
{
    string whitespace = "     ";
    string br = "<BR>";

    Response.Write(node.ToString() + br);
    Response.Write(whitespace + node.Path + br);

    // Check for specific types and perform extended functions.
    if (node.Type == "SiteMapNode")
    {
        // Because SiteMapNode implements the IHierarchyData interface,
        // the IHierarchyData object can be cast directly as a SiteMapNode,
        // rather than accessing the Item property for the object that
        // the Type property identifies.
        SiteMapNode siteNode = node.Item as SiteMapNode;
        Response.Write(whitespace + siteNode.Url + br);
        Response.Write(whitespace + siteNode.Description + br);
    }
    else if (node.Type == "SomeBusinessObject")
    {
        // If the IHierarchyData instance is a wrapper class on a business
        // object of some kind, you can retrieve the business object by using
        // the IHierarchyData.Item property.
        //          SomeBusinessObject busObj = node.Item as SomeBusinessObject;
    }

    if (node.HasChildren)
    {
        IEnumerator children = ((IHierarchicalEnumerable)node.GetChildren()).GetEnumerator();

        while (children.MoveNext())
        {
            // Print out SiteMapNode Titles recursively.
            IHierarchyData hierarchicalNode = node.GetChildren().GetHierarchyData(children.Current);
            PrintFullChildNodeInfo(hierarchicalNode);
        }
    }
}
' Print out the current data node, then iterate through its
' children and do the same.

Private Sub PrintFullChildNodeInfo(ByVal node As IHierarchyData)
    Dim whitespace As String = "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"
    Dim br As String = "<BR>"

    Response.Write(Convert.ToString(node) & br)
    Response.Write(whitespace & node.Path & br)

    ' Check for specific types and perform extended functions.
    If node.Type = "SiteMapNode" Then
        ' Because SiteMapNode implements the IHierarchyData interface,
        ' the IHierarchyData object can be cast directly as a SiteMapNode,
        ' rather than accessing the Item property for the object that
        ' the Type property identifies.
        Dim siteNode As SiteMapNode = CType(node.Item, SiteMapNode)
        Response.Write(whitespace & siteNode.Url & br)
        Response.Write(whitespace & siteNode.Description & br)

    ElseIf node.Type = "SomeBusinessObject Then" Then
        ' If the IHierarchyData instance is a wrapper class on a business
        ' object of some kind, you can retrieve the business object by using
        ' the IHierarchyData.Item property.
        '          SomeBusinessObject busObj = node.Item as SomeBusinessObject;
    End If

    If node.HasChildren Then
        Dim children As IEnumerator = CType(node.GetChildren().GetEnumerator(), IHierarchicalEnumerable)
        While children.MoveNext()
            ' Print out SiteMapNode Titles recursively.
            Dim hierarchicalNode As IHierarchyData = node.GetChildren().GetHierarchyData(children.Current)
            PrintFullChildNodeInfo(hierarchicalNode)
        End While
    End If
End Sub

Remarques

Si de nombreuses classes qui représentent des nœuds de données hiérarchiques SiteMapNode , telles que la IHierarchyData classe, implémentent l’interface directement, les autres classes ne jouent que le rôle de wrapper pour une classe qui n’implémente pas l’interface.While many classes that represent hierarchical data nodes, such as the SiteMapNode class, implement the IHierarchyData interface directly, other classes only act as a wrapper for a class that does not implement the interface. La Item propriété est fournie pour ces situations de design, lorsque les objets métier sont fonctionnellement équivalents à un IHierarchyData objet, mais ne peuvent pas être facilement remaniés.The Item property is provided for these design situations, when business objects are functionally equivalent to an IHierarchyData object but cannot be redesigned easily.

S’applique à

Voir aussi