How to integrate bitcoin payment in ASP.Net?
If you don't want to integrate with a 3rd party bitcoin payment provider you can implement your own payment module for Bitcoin (but also for Litecoin and every Bitcoin-derived altcoin) very easily with BitcoinLib that is written in C#.

Some of BitcoinLib's features:


Fully compatible and up-to-date with Bitcoin 0.9.1 RPC API.
Design-by-contract, service-oriented architecture.
Strongly-typed structures for complex RPC requests and responses.
Implicit JSON casting for all RPC messages.
Extended methods for every-day scenarios where the built-in methods fall short.
Exposure of all RPC API's functionality as well as the extended methods through a single interface.
Fallback mechanism for timed-out RPC requests.
Custom RPC exceptions.
Supports all Bitcoin clones.
Can operate on unlimited daemons with a single library reference.
Litecoin integration included.
Each coin instance can be fully parametrized at run-time and implement its own constants.
Console test client with demo methods implemented in it.
Disconnected raw RPC connector included for quick'n'dirty debugging.
Testnet ready.
Fully configurable.