I design a treeview for link to each form in MDIparent form. I'm also design a form for permission. when administrator check checkbox, then user can login to this form else the node of treeview will enable=false. then user cannot go to this page.

1. I wan know how to enable= false for treeview node.

2. how i detect this user and active permission. For example, when the user display is Normal User, then admin node in treeview will enable = false.

for disabling tree_node please check this page
For your second condition on which basis you are giving permissions to users? you will have to check those conditions and then assign permissions to the respective users