That's only going to be if the two airlines interline and your segments are on the same PNR.

Or else chances are your bags will get offloaded in DEL and you have to clear immigration simply to pick your bags up from the carousel and then check back into your sri lankan flight. [which may or may not allow e-checkin, and if its on a separate pnr the gate agent at your starting point wont be able to check you into that]