IHierarchyData.HasChildren Property
Indicates whether the hierarchical data node that the IHierarchyData object represents has any child nodes.
Assembly: System.Web (in System.Web.dll)
The HasChildren property is a convenience property that enables callers to avoid checking the return value of the GetChildren method for null. If the HasChildren property returns true, call the GetChildren method to retrieve an IHierarchicalEnumerable collection of child nodes.
The following code example demonstrates how an ASP.NET hierarchical data-bound control uses an IHierarchyData object in a recursive data-binding method. The items in an IHierarchicalEnumerable collection are enumerated, and for each an IHierarchyData object is retrieved using the GetHierarchyData method. Finally, the HasChildren property is checked to determine whether to recurse. This code example is part of a larger example provided for the HierarchicalDataBoundControl class.
Private Sub RecurseDataBindInternal(ByVal node As TreeNode, _ ByVal enumerable As IHierarchicalEnumerable, _ ByVal depth As Integer) Dim item As Object For Each item In enumerable Dim data As IHierarchyData = enumerable.GetHierarchyData(item) If Not data Is Nothing Then ' Create an object that represents the bound data ' to the control. Dim newNode As New TreeNode() Dim rvnode As New RootViewNode() rvnode.Node = newNode rvnode.Depth = depth ' The dataItem is not just a string, but potentially ' an XML node or some other container. ' If DataTextField is set, use it to determine which ' field to render. Otherwise, use the first field. If DataTextField.Length > 0 Then newNode.Text = DataBinder.GetPropertyValue _ (data, DataTextField, Nothing) Else Dim props As PropertyDescriptorCollection = _ TypeDescriptor.GetProperties(data) ' Set the "default" value of the node. newNode.Text = String.Empty ' Set the true data-bound value of the TextBox, ' if possible. If props.Count >= 1 Then If Not props(0).GetValue(data) Is Nothing Then newNode.Text = props(0).GetValue(data).ToString() End If End If End If Nodes.Add(rvnode) If data.HasChildren Then Dim newEnumerable As IHierarchicalEnumerable = _ data.GetChildren() If Not (newEnumerable Is Nothing) Then RecurseDataBindInternal(newNode, _ newEnumerable, depth + 1) End If End If If MaxDepth < depth Then MaxDepth = depth End If End If Next item End Sub 'RecurseDataBindInternal
Available since 2.0