How to find index of all the nodes in a TreeView?

I am using ASP.NET 4.5 with C#.
I have a TreeView control with several child nodes. While populating the TreeView, I have used ModuleId as node value and ModuleText as node Text.
If the user enters any name, the access rights are returned as ModuleIds.
I want to Check the CheckBoxes of the TreeView with these ModuleIds. To do this, I will require to find the node with this ModuleId in the TreeView.
I tried using:
TreeNode node = TreeView1.FindNode<index>
but with this I am able to find only root nodes. I am not aware of the index of any child node.
So first I want index of all the nodes (parent or child) in a List<int>, then I will use above code to find the node.
How to find index of all the nodes in the TreeView? Parent, Child and further Child.