You are confusing (or mixing) two different things; Server-client architecture and Remote Desktop Protocol.
First of all, you asked for a server-client model, and requested to get an example for a client built in Android that communications with a server that is Windows Forms applications. Which is in many ways,
impossible. This has been discussed a lot of times on this forum as well, and I would like to give you a few of my previous answers that answer this question well.
Short answer: You need to develop a mechanism to communicate; native TCP communication is best in this case (and
I do not believe your statement of, "
tried to use TCP but everything i have tried has not worked", but you can use Web API or WCF to build a resilient framework of communication.
How to connect Android App with Server[
^]
How Do I Send Android Data To .Net Database.[
^]
How to call web apis from android app ?[
^]
Second part of your question is even more complex, as you are trying to not just connect, but also to trigger functions and interact with the application. That is not simple at all. I would like to give you an idea, use any open source remote desktop protocol client-server based model that you can use here, for example start at:
FreeRDP[
^], then build on top and use it for this. Otherwise, you don't have much options.