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ASP.NET TreeView Sort

, 11 Sep 2011 CPOL
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Easy way to sort nodes in a TreeView using a recursive function.
A few days ago, I needed to sort the nodes of a tree view. The solutions that I found over the Internet did not please me, so I decided to write my own. This solution is a simple recursive function that sorts tree nodes in an alphabetic order.

Create your tree view and add your nodes:

TreeView mytree = new TreeView();
//add your nodes here

Then simply call the sort function with the main node as the argument:

sort(node);

Here is the recursive function:

private void sort(TreeNode node)
{
    foreach (TreeNode n in node.ChildNodes)
        sort(n);
    try
    {
        TreeNode temp = null;
        List<TreeNode> childs = new List<TreeNode>();
        while(node.ChildNodes.Count>0)
        {
            foreach (TreeNode n in node.ChildNodes)
                if (temp == null || n.Text[0] < temp.Text[0])
                    temp = n;
            node.ChildNodes.Remove(temp);
            childs.Add(temp);
            temp = null;
        }
        node.ChildNodes.Clear();
        foreach (TreeNode a in childs)
            node.ChildNodes.Add(a);
    }
    catch { }
}

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

brunofer2007
Software Developer (Senior) Martifer Inovação e Gestão
Portugal Portugal
No Biography provided

Comments and Discussions

 
Suggestioncompare full words PinmemberKlimovec12-Apr-12 2:49 
GeneralHeyy it worked for me. Currently i have a treeview which pop... Pinmemberrjkumar19879-Jan-12 2:27 
GeneralRe: just replace the logical comparison "n.Text[0] < temp.Text[0... Pinmemberbrunofer200714-Jan-12 23:59 
General1-The datasource should be sort not the tree in asp.net. An... PinmemberJoePatent13-Sep-11 8:03 
GeneralRe: 1 - Sometimes a TreeView doesn't have necessarily a datasour... Pinmemberbrunofer200714-Sep-11 0:36 
1 - Sometimes a TreeView doesn't have necessarily a datasource. The nodes could be added manually (that was my case).
 

2 - If you watch carefully the code, you see that recursive function it's only called when a node has childnodes:
 
foreach (TreeNode n in node.ChildNodes)
sort(n);
 
the recursive function is called as many child nodes you have, so you can predict the number of iterations
 

3 - I'll explain this step to you:
 
- temp variable is initialized to null.
 
- for each child node: if the temp is null, temp = childnode.
if temp != null,
if the first character of childNode < fisrt character of Temp, temp = childNode
 
- when you reach the end of for each statment, the Temp variable has the lowest start character node.
 
- add that node to List "childs", this way the list will be filled alphabetically.
 
- delete temp node from child node.

- start all over again (the temp variable is set to null to store again the lowest start letter node).
 
- this cycle stops when there are no more childnodes:
while(node.ChildNodes.Count>0)
 
- then, you simply add again the childnode in the node (alphabetically sorted):
foreach (TreeNode a in childs)
node.ChildNodes.Add(a);
 

4 - and finally, as I mention before, the sort() method for TreeView is not present on WebForms (ASP.NET).
GeneralCould I ask, why can't you use the default TreeView Sort met... PinmemberGeorge Swan11-Sep-11 20:11 
GeneralRe: Hello George, as you can see in the title, this solution is ... Pinmemberbrunofer200711-Sep-11 22:21 

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