Automation Link Connection

i want Auto Connection
if 'a’Node and 'b’Node on canvas
if I make 'c’Node on canvas then Connect 'a’Node, it’s automate
How I do this

That depends on how nodes are added to your document.
If the user is drag-and-dropping them from another view, such as a GoPalette, you can implement a GoView.ExternalObjectsDropped event handler. You can look at the GoView.Selection to see what node(s) were dropped. You can look at the GoView.Document to see what node(s) are already there, like ‘a’ Node or ‘b’ Node.
If the user is copy-and-pasting them from any view, you can implement a GoView.ClipboardPasted event handler. Again, look at the GoView.Selection to see what was pasted.
If the user is invoking an application command, such as a button or menu item action, then you must be adding the node programmatically, so you can just create and add the link(s) afterwards.