C# – Sorting child nodes of a treeview after populating the treeview in c# winforms

csortingtreeviewwinforms

I am having trouble sorting child nodes of a treeview in my winforms program. My treeview is populated by some XML files and it uses an internal text inside the xml files as Text property of nodes (So I think I cant sort them before adding them to the tree view, or if it is possible, since the xml files are big in size I dont want to waste the process). A populated treeview in my program looks like this:

enter image description here

As you can guess I want child nodes to sort like (I dont want HBM\D10 to come after HBM\D1) rather I want:

    HBM\D1
    HBM\D2
    HBM\D3
etc...

I have already tried treeView1.Sort() and also adding beginUpdate and endUpdate but I had no suceess 🙁

I am using .NET 4, any tips would be appriciated

ok I sortet it out using Thomas's advice:

    class NodeSorter : IComparer
{
        public int Compare(object x, object y) 
        {         
            TreeNode tx = (TreeNode)x; 
            TreeNode ty = (TreeNode)y;

            if (tx.Text.Length < ty.Text.Length)
            {
                return -1;
            }

            if (tx.Text.Length > ty.Text.Length)
            {
                return 1;
            }

            return 0;
        } 
}

Best Answer

You need to create a custom comparer and assign it to the TreeViewNodeSorter property:

public class NodeSorter : System.Collections.IComparer
{
    public int Compare(object x, object y)
    {
        TreeNode tx = (TreeNode)x;
        TreeNode ty = (TreeNode)y;

        // Your sorting logic here... return -1 if tx < ty, 1 if tx > ty, 0 otherwise
        ...
    }
}


...

treeView.TreeViewNodeSorter = new NodeSorter();
treeView.Sort();

Related Solutions

Winforms treeview, recursively check child nodes problem

The .NET TreeView class heavily customizes mouse handling for the native Windows control in order to synthesize the Before/After events. Unfortunately, they didn't get it quite right. When you start clicking fast, you'll generate double-click messages. The native control responds to a double-click by toggling the checked state for the item, without telling the .NET wrapper about it. You won't get a Before/AfterCheck event.

It's a bug but they won't fix it. The workaround is not difficult, you'll need to prevent the native control from seeing the double-click event. Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox, replacing the existing one.

using System;
using System.Windows.Forms;

class MyTreeView : TreeView {
    protected override void WndProc(ref Message m) {
        // Filter WM_LBUTTONDBLCLK
        if (m.Msg != 0x203) base.WndProc(ref m);
    }
}

C# – Re-Sorting treeview Nodes[0] only after being populated

Use the TreeNode.Level property to figure out how to compare node properties. Like this:

    private void SortButton_Click(object sender, EventArgs e) {
        if (treeView1.TreeViewNodeSorter == null) {
            treeView1.TreeViewNodeSorter = new NodeSorter();
        }
    }
    private class NodeSorter : System.Collections.IComparer {
        public int Compare(object x, object y) {
            TreeNode node1 = (TreeNode)x;
            TreeNode node2 = (TreeNode)y;
            if (node1.Level == 1) {
                return Convert.ToInt32(node1.Tag).CompareTo(Convert.ToInt32(node2.Tag));
            }
            else {
                return node1.Index.CompareTo(node2.Index);
            }
        }
    }

Best Answer

Related Solutions

Winforms treeview, recursively check child nodes problem

C# – Re-Sorting treeview Nodes[0] only after being populated

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