Programmatically change network adapters setting in .Net

hi dharmendr sir,

I have two button btn1 & btn2, when click on btn1 first network should work, when click on btn2 then automatically change into gateway of 2nd network and 2nd network should working.

I have configured two network 

let suppose 

Ist Network

ip address 192.168.18.19

subnet mask is 255.255.255.0

gateway is     192.168.18.1

2nd network is

ip address 192.168.19.19

subnet mask is 255.255.255.0

gateway is     192.168.19.1