how to restart the windows indexing service catalog in asp.net ?

Question

I m using asp.net to search content in files with windows indexing service Once I add files in my catalog I can perform search But when ever I add new Files or change existing in catalog directory the search operation doesnt perform on added or edited files this can be done in two ways
1- restart the indexing server
2- Restarting my catalog only

How I can restart my catalog Programmatically in vb.net or C#.net

please help me

hyder_master