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Sorting TreeNodes

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Article relates to

 RadTreeView v6.x, RadTreeView ASP.NET Ajax

Created by

 Nick, Telerik

Last modified by

 Yana, Telerik

Sorting TreeNodes

RadTreeView's Nodes can easily be sorted by Text/Value using simple server-side code:

[C#] Example

 

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!Page.IsPostBack) 
    { 
        SortNodes(RadTreeView1.Nodes); 
    } 
} 
 
//SortNodes is a recursive method enumerating and sorting all node levels 
private void SortNodes(RadTreeNodeCollection collection) 
{ 
    Sort(collection); 
    foreach (RadTreeNode node in collection) 
    { 
        if (node.Nodes.Count > 0) 
        { 
            SortNodes(node.Nodes); 
        } 
    }         
} 
 
//The Sort method is called for each node level sorting the child nodes 
public void Sort(RadTreeNodeCollection collection) 
{ 
    RadTreeNode[] nodes = new RadTreeNode[collection.Count]; 
    collection.CopyTo(nodes, 0); 
    Array.Sort(nodes, new TreeNodeComparer()); 
    collection.Clear(); 
    collection.AddRange(nodes); 
} 
 
//The TreeNodeComparer class defines the sorting criteria 
class TreeNodeComparer : IComparer 
{ 
    #region IComparer Members 
 
    public int Compare(object x, object y) 
    { 
        RadTreeNode firstNode = (RadTreeNode)x; 
        RadTreeNode secondNode = (RadTreeNode)y; 
 
        return firstNode.Text.CompareTo(secondNode.Text); 
    } 

    #endregion 
} 

 

[VB] Example

 

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) 
    If Not Page.IsPostBack Then 
        SortNodes(RadTreeView1.Nodes) 
    End If 
End Sub 
 
'SortNodes is a recursive method enumerating and sorting all node levels 
Private Sub SortNodes(ByVal collection As RadTreeNodeCollection) 
    Sort(collection) 
    For Each node As RadTreeNode In collection 
        If node.Nodes.Count > 0 Then 
            SortNodes(node.Nodes) 
        End If 
    Next 
End Sub 
 
'The Sort method is called for each node level sorting the child nodes 
Public Sub Sort(ByVal collection As RadTreeNodeCollection) 
    Dim nodes As RadTreeNode() = New RadTreeNode(collection.Count - 1) {} 
    collection.CopyTo(nodes, 0) 
    Array.Sort(nodes, New TreeNodeComparer()) 
    collection.Clear() 
    collection.AddRange(nodes) 
End Sub 
 
'The TreeNodeComparer class defines the sorting criteria 
Class TreeNodeComparer 
    Implements IComparer 
    #region IComparer Members 
 
    Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare
        Dim firstNode As RadTreeNode = DirectCast(x, RadTreeNode) 
        Dim secondNode As RadTreeNode = DirectCast(y, RadTreeNode) 
 
        Return firstNode.Text.CompareTo(secondNode.Text) 
    End Function 
#End Region 
End Class 
 

 

The RadTreeNodeCollection class does not have a CopyTo method. One could use the following method instead, to copy the Nodes from the collection to an Array:

[C#] Example

//Copies the Nodes from the specified collection to the specified array. 
private void Copy(RadTreeNodeCollection collection, RadTreeNode[] nodes) 
{ 
    for (int nodeIndex = 0; nodeIndex < collection.Count; nodeIndex++) 
    { 
        nodes[nodeIndex] = collection[nodeIndex]; 
    } 
} 

 

 

[VB] Example

 

'Copies the Nodes from the specified collection to the specified array. 
Private Sub Copy(ByVal collection As RadTreeNodeCollection, _ 
    ByVal nodes As RadTreeNode()) 
    For nodeIndex As Integer = 0 To collection.Count  - 1
        nodes(nodeIndex) = collection(nodeIndex) 
    Next 
End Sub 

 

Comments

  • fquinty , Sep 4, 2008

    For VS2008, .NET FrameWork 3.5 , here is the good syntax for VB.NET : Class TreeNodeComparer : Implements IComparer Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare Dim firstNode As RadTreeNode = DirectCast(x, RadTreeNode) Dim secondNode As RadTreeNode = DirectCast(y, RadTreeNode) Return firstNode.Text.CompareTo(secondNode.Text) End Function End Class

  • Roel , Oct 4, 2008

    copyTo method in collection in my version is missing. i am using version 6.1.10. help!

  • Tonino , Dec 22, 2008

    In the Copy function for VB the for loop has to be changed from For nodeIndex As Integer = 0 To collection.Count to For nodeIndex As Integer = 0 To collection.Count - 1

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