How to print invoice directly in ASP.NET using C#?

I am currently working on asp.net c# Project on POS(Point Of Sale). i am using javascript function on page load but it populate print dialogue box in google chrome. This is my page load javascript function.

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<script type="text/javascript">         window.onload = function () {             window.print();                     }   script>

I dont want this google chrome print dialog box. how can in print invoice directly on button click...I am stuck at this point. I try my best but did not find. Anyone help regarding this problem. Please help me out

What I have tried:

i used javascipt function. i want some c# function which directly print the invoice.