i want to add the check box to the child node of a certain parent node in the tree view in my application...How should i add it?
The TreeView API only allows you to add/remove checkboxes for EVERY node. If that's what you want, then the answer is easy - use the TreeView's CheckBoxes property.
If you want a checkbox for a particular node in the tree only, then it gets tricky. .NET doesn't directly support that. You can get the tree to accept it using Win32 message overrides, see the link below for a solution elsewhere:
http://dotnetfollower.com/wordpress/2011/05/winforms-treeview-hide-checkbox-of-treenode/