IHierarchyData.GetParent Method ()

 

Gets an IHierarchyData object that represents the parent node of the current hierarchical node.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)

Function GetParent As IHierarchyData

Return Value

Type: System.Web.UI.IHierarchyData

An IHierarchyData object that represents the parent node of the current hierarchical node.

The IHierarchyData interface does not define a HasParent convenience property, so callers must check the return value of the GetParent method for null to determine whether the current IHierarchyData node is the root node of the hierarchical data structure to which the node belongs.

The following code example demonstrates how to implement the GetParent method in a class that implements the IHierarchyData interface. The FileSystemHierarchyData class wraps a FileSystemInfo object, and the GetParent method implementation checks the type of the FileSystemInfo object, and returns the appropriate parent object based on the type. This code example is part of a larger example provided for the IHierarchyData interface and the HierarchicalDataSourceControl class.

    Public Overridable Function GetChildren() _
        As IHierarchicalEnumerable _
        Implements IHierarchyData.GetChildren

        Dim children As New FileSystemHierarchicalEnumerable()

        If GetType(DirectoryInfo) Is fileSystemObject.GetType() Then
            Dim temp As DirectoryInfo = _
                CType(fileSystemObject, DirectoryInfo)
            Dim fsi As FileSystemInfo
            For Each fsi In temp.GetFileSystemInfos()
                children.Add(New FileSystemHierarchyData(fsi))
            Next fsi
        End If
        Return children
    End Function 'GetChildren


    Public Overridable Function GetParent() As IHierarchyData _
     Implements IHierarchyData.GetParent
        Dim parentContainer As New FileSystemHierarchicalEnumerable()

        If GetType(DirectoryInfo) Is fileSystemObject.GetType() Then
            Dim temp As DirectoryInfo = _
                CType(fileSystemObject, DirectoryInfo)
            Return New FileSystemHierarchyData(temp.Parent)
        ElseIf GetType(FileInfo) Is fileSystemObject.GetType() Then
            Dim temp As FileInfo = CType(fileSystemObject, FileInfo)
            Return New FileSystemHierarchyData(temp.Directory)
        End If
        ' If FileSystemObj is any other kind of FileSystemInfo, ignore it.
        Return Nothing
    End Function 'GetParent
End Class 'FileSystemHierarchyData

.NET Framework
Available since 2.0
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