Question

I have a treeview and Checkbox is set true. What I want is that only one checkbox is selected in the whole treeview. How can I do that?

FYI: the treeview is in three level depth.

Answer 1

The simplest way to do that is to set an even handler to your tree view’s AfterCheck event. In this handler you can uncheck all the nodes but the one which just became checked:

void node_AfterCheck(object sender, TreeViewEventArgs e) {
    // only do it if the node became checked:
    if (e.Node.Checked) {
        // for all the nodes in the tree...
        foreach (TreeNode cur_node in e.Node.TreeView.Nodes) {
            // ... which are not the freshly checked one...
            if (cur_node != e.Node) {
                // ... uncheck them
                cur_node.Checked = false;
            }
        }
    }
}

Should work (didn’t try)