Skip to content

Latest commit

 

History

History
108 lines (83 loc) · 3.32 KB

readme.md

File metadata and controls

108 lines (83 loc) · 3.32 KB

ESimConnect Tutorial - Reading FS Value from multiple consumers

Motivation

If you have larger project of modules, you probably get to the situation where each module registers for the same SimVar for repeated requests in the same interval. This may (slightly) decrease the performance. Therefore, it may be useful to have some cache which will store and provide the value on request.

To do so, there is the ValueCacheExtender. This class is an extender over ESimConnect and provides the possibility to register and read out the required SimVar. If the same registration is done multiple times, it caches the value for all other data requests.

Principle

To continue here, we expect you are familiar with ESimConnectSimVarRead tutorial.

Idea:

  • 1The point is - do not register for values directly over ESimConnect, use ValueCacheExtender instead.
  • You can register mutliple times for the same SimVar using ValueCacheExtender. However, under the hood, only one registration is done into the underlying ESimConnect.
  • You have possibility to subscribe to the event informing about the value change - same as for ESimConnect.
  • You can ask for the current SimVar value by calling the appropriate method anytime.

Principle:

  1. Register the SimVar to obtain TypeId.
TypeId typeId = valueCache.Register(
    ESimConnect.Definitions.SimVars.Aircraft.Miscelaneous.AIRSPEED_INDICATED, 
    "Knots");
  1. Subscribe to the appropriate event to be notified about value changes (optionally):
valueCache.ValueChanged += ValueCache_ValueChanged;
  1. Or get the value directly by calling the method (optionally):
double value = valueCache.GetValue(typeId);

Project Set Up

To use this feature in your project, your project must meet following criteria:

  • Project is targeted at .NET 6.0
  • Project is targeted at operating system Windows, version 7.0
  • Project has a ESimConnect.dll in the dependencies.
  • Project has MS SimConnect libraries - and - in the output folder

Example

For the full code, see Program.cs file content.

Firstly, import namespace:

using ESimConnect;

// this variable will later hold the id of registered variable
TypeId? typeId = null;

Next, create the instances of ESimConnect and ValueCachextender:

ESimConnect.ESimConnect simCon = new();
ESimConnect.Extenders.ValueCacheExtender valueCache = new(simCon, SimConnectPeriod.SECOND);

Now, subscribe to the event invoked on value change:

valueCache.ValueChanged += ValueCache_ValueChanged;

Then, open the connection:

simCon.Open();

Register so FS starts sending info about the SimVar value:

typeId = valueCache.Register(
    ESimConnect.Definitions.SimVars.Aircraft.Miscelaneous.AIRSPEED_INDICATED, 
    "Knots", 
    SimConnectSimTypeName.FLOAT64);

Now, you can ask for the value anytime:

while (true)
{
  double value = valueCache.GetValue(typeId.Value);
  Console.WriteLine("Current IAS is: " + value);
  Thread.Sleep(1000);
}

Note, that typeId.Value is there cos typeId is Nullable<TypeId>.

Finally, the code invoked once value has changed:

void ValueCache_ValueChanged(
    ESimConnect.Extenders.ValueCacheExtender.ValueChangeEventArgs e)
{
  if (e.TypeId == typeId)
  {
    Console.WriteLine("New data of IAS captured in the event are: " + e.Value);
  }
}