Q:

How can we integrate our C# code in Drupal CMS

We have C# code, which is backend for us. Now we need it to be used in our website which is developed in Drupal.

A:

As far as I know, there is no easy way to do it. You basically have 2 options:

Rewrite the code in php. It may be not possible to do it however, it depends on what the code does.
Expose c# code as an external webservice (e.g. with WCF) and then consume the webservice. Drupal is able to do it - more info.

