Question

public static bool AllNodesChecked(TreeNodeCollection nodes)        
{
    foreach (TreeNode node in nodes)
    {
        if (!node.Checked)
        {
            return false;
        }
        AllNodesChecked(node.Nodes);
    }
    return true;
}

Test tree is

A1(checked) -> B1(unchecked)
A2(checked)
A3(checked)

but it isn’t returning when it hits node B1.

EDIT: Thank you all for helping my tired brain. Recursion should only be attempted early in the day after a cold shower.

Answer 1

You are ignoring the return value of AllNodesChecked in the recursive call:

public static bool AllNodesChecked(TreeNodeCollection nodes)        
{
    foreach (TreeNode node in nodes)
        if (!node.Checked || !AllNodesChecked(node.Nodes))
           return false;
    return true;
}

The return statement only returns from the current method in the call stack to the immediate caller. It doesn’t suddenly return from all other calls above in the call stack.