C# app integration for hardware and WASM module

[brandonharwood14]

Hi Paul, 

Firstly thank you for all the documentation and work you have put in along side all the other contributors of FSUIPC and the WAPI. I'm hoping to gain some insight on the information below.

A bit of backstory before I get to the main talking points:
I am trying to create my own C# application to work in conjunction with my hardware for my company. Where the use of Arduino based microcontrollers or my own custom microcontrollers send serial data via USB to the PC and C# program which in tern translates that into events or appropriate code to be sent to flight simulator. I have completed the program for X-Plane but now moving on to MSFS2020 there are many more hurdles to overcome. I am hoping to use my C# program in conjunction with your WASM module and FSUIPC to achieve all the functionality needed for various avionics units.

From what I can work out some functionality for certain things in FS2020 are achieved via the use of WASM modules, LVars and HVars. I believe are the ones in particular that I would be interested in given my software only needs to send events to the simulator for avionics. GNS530/430, GTN750,650 G1000, G3000 etc.
So my question is how/what is the best way to send this information to the flight simulator. is Calculator code the best way to send not only standard events but also L/Hvars? or as mentioned by John in this thread is the use of Presets the better option.

As for presets, how are they supposed to be typed into the C# code or is there a txt file that needs to be placed somewhere specific and then references in C#?

in VS2022 I have so far been able to connect to FSUIPC and send basic events to the simulator such as turning avionics on and off. selecting the GPS drives nav1. But no matter how hard I try I cannot figure out how to use calculator code nor presets. How is this sent to the simulator and could you please give me a C# example of this? I have been through your example code but still have come up at a loss. sorry!

Any help would be greatly appreciated. 
Thanks - Brandon

[Paul Henty]

Hi Brandon,

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 how/what is the best way to send this information to the flight simulator. is Calculator code the best way to send not only standard events but also L/Hvars? or as mentioned by John in this thread is the use of Presets the better option.

Presets are just containers for calculator code, so they end up executing calculator code eventually. They are useful in the FSUIPC front-end, but if you are using code then it's just an extra step. Also the way you call presets from code via FSUIPC is not very efficient.

If you're using code I would stick to either sending calculator code or using the HVars/LVars directly using the MSFSVariableServices class in my DLL. Which you choose is down to personal preference/convenience/situation. For example, if you're just wanting to read/write a single LVar or activate a single HVar then using the direct method might be easier:

MSFSVariableServices.HVars["MyHVar"].Set();

However, if you've found some complicated calculator code on the web, or in a preset, then you might not want to decode what it's doing and replicated the logic yourself. In this instance it would be easier just to copy the code into your application and send it via MSFSVariableServices.ExecuteCalculateCode()

For aircraft where LVars/HVars are not available you may need to fall back on 'legacy' methods like Events (aka Controls) and Offsets. In this case you need an FSUIPC Connection.

Events/Controls perform actions in the aircraft (Like HVars). Use the FSUIPCConnection.SendControlToFS() feature.

To read data use the Offsets. Some offsets can also be written to.

 

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As for presets, how are they supposed to be typed into the C# code or is there a txt file that needs to be placed somewhere specific and then references in C#?

I don't recommend executing presets themselves from code. It's best to just take the underlying calculator code from the preset and execute that. You can copy it directly into your source code. Alternatively, you can have your application read it from your own text file if you want to be able to modify/add calculator code without recompiling your application. 

 

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How is this sent to the simulator and could you please give me a C# example of this?

If you have not already downloaded the MSFSVariableServices example code project please get it from here:

http://fsuipc.paulhenty.com/#downloads

It doesn't have an example for calculator code but it will show you how to make a connection and use LVars/Hvars directly.

In this thread I give an example of executing calculator code as well as using the same HVar directly. There is also a link to a good website where you can find the underlying calculator code for all the presets.

Feel free to ask further questions. It's a bit confusing if you're coming into this new because there are two systems in use for MSFS: The legacy Events/Controls/Offsets system and the newer LVars/HVars/Calculator code system.

Paul 

[John Dowson]

Note also that if you do want to call a preset (available in FSUIPC) from an FSUIPC client app, you can do this by writing the preset name (preceded by 'P:') to offset 0x7C50.

John

[brandonharwood14]

Thank you both for your support on this topic. I haven't had a chance to test anything yet as we are currently moving homes.

Hopefully have my PC setup properly soon to try this out but I think from your suggestion Paul I will be just executing Calculator Code to set the 'H:xyz' Vars for the applicable Hardware that our customers may have.
I'm thinking I may just put all the applicable HVars into a Text file and read them in C# app.

The reason I've chosen just Calculator Code is, If I'm not mistaken, LVars and HVars have to be accompanied by a file associated with a particular aircraft to be directly linked? instead of the method above where it just blindly tries to send the calculator code and executes it, if the program can?

I believe I will definitely need a connection to FSUIPC for legacy controls too for it seems some autopilot functionality etc. just taking a peak at a particular .ini file by another company that sells similar devices; most of the commands are HVars and some of them legacy events. - This I dont think I will have a problem with as I have already managed to manipulate certain 

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In this thread I give an example of executing calculator code as well as using the same HVar directly. There is also a link to a good website where you can find the underlying calculator code for all the presets.

This link will also helped a lot! thank you. 

One question I have is (hope this isn't a silly one...): does 'Legacy' events just send SimConnect events Via FSUIPC?

Thanks - Brandon

[Paul Henty]

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The reason I've chosen just Calculator Code is, If I'm not mistaken, LVars and HVars have to be accompanied by a file associated with a particular aircraft to be directly linked? 

I believe HVars need a file to be accessed directly by the WASM module. LVars don't need the file. 

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instead of the method above where it just blindly tries to send the calculator code and executes it, if the program can?

I think that's also correct.

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 does 'Legacy' events just send SimConnect events Via FSUIPC?

Probably yes. FSUIPC4 and above uses SimConnect in the background for most things. @John Dowson will be able to confirm.

Paul

[John Dowson]

2 minutes ago, Paul Henty said:

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 does 'Legacy' events just send SimConnect events Via FSUIPC?

Probably yes. FSUIPC4 and above uses SimConnect in the background for most things. @John Dowson will be able to confirm.

Yes - everything goes via SimConnect anyway, either to the FS or the WASM. But you can also send "legacy" events via calculator code, using them as k-type variables.