Question

I need a treeview component with multipleselect. So I downloaded “C# TreeView with multiple selection“. Now I am having trouble removing items. The following code runs fine, but removes nothing:

private void removeToolStripMenuItem_Click(object sender, EventArgs e)
{
    for (int i = 0; i < treeView1.SelectedNodes.Count; i++)
    {
        try
        {
            if (treeView1.Nodes[i].IsSelected)
            {
                treeView1.Nodes[i].Remove();
                i--;
            }
        }
        catch { }
    } 

        treeView1.Update();
        treeView1.Refresh();
}

---

treeView1.SelectedNodes.Remove();

Requires an object, but I don’t know which.

foreach (TreeNode tn in treeView1.SelectedNodes)
            tn.Remove();

Throws an exception because the collection was modified.

Can someone help me out?

Thanks!

Answer 1

Try with a backward loop and use the Remove method on the Nodes collection passing the selected node

private void removeToolStripMenuItem_Click(object sender, EventArgs e) 
{ 
    for (int i = treeView1.SelectedNodes.Count - 1; i >= 0; i--)
    {
        TreeNode n = (TreeNode)treeView1.SelectedNodes[i];
        treeView1.Nodes.Remove(n);
    }
    treeView1.Update(); 
    treeView1.Refresh(); 
} 

Also I don’t think you have to test if the node IsSelected because you are already using the SelectedNodes property. (Really I haven’t checked if this is the case with this customized treeview class, however the name suggest that the nodes included are already selected)