Event Handler Issue

[AirPanther]

Good day,

I'm experiencing an issue when writing to an offset from an event delegate. In this case 0x0354 (Transponder). The code below, from the SDK, works PERFECTLY when I call the function from a button, timer tick, etc. However, once I call the same SetTransponder() from an event delegate, the value in FSX only updates refreshes about 20% of the time. The other 80% of the time it doesn't update. What's even stranger is if I immediately read back the offset from FSUIPC, I always get the correct value, even though the value in FSX hasn't changed.  I added a counter to the function to make sure the function was firing, and it accurately increments every time the function is called.

 

private Offset<ushort>  FSUIPC_TransponderCode = new Offset<ushort>(0x0354);
int counter;

UDPConnection.UDPDataReceived += new EventHandler(SetTransponder); // Start UDP listener

SetTransponder ()
{
     FsTransponderCode txHelper = new FsTransponderCode((int)value);
     FSUIPC_TransponderCode.Value = txHelper.ToBCD();
     counter++;
}

 

Output

If I fire this function 15 times from the event handler, and send the results to the Output window I get:

Output Window (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15);

But in FSX, I will see

Transponder Frequency (0001, 0004, 0005, 0010, 0013)

However, If I fire this function from a timer or button I get:

Output Window (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15);

Transponder Frequency (0001,0002,0003,0004,0005,0006,0007,0008,0009........0015)

The function is definitely firing, as I'm getting the correct counter output on each function call AND I'm getting the correct value back if I immediately query FSUIPC. So, any idea why FSX doesn't update consistently when the function is fired by an event?

Thanks much,

Robert

[Paul Henty]

Hi Robert,

It's a bit difficult to tell from the code you've posted.

One thing I'm not clear on is where the process() is happening. I would expect it to be in SetTransponder() after the value is set.

If your process() call is elsewhere (like on a separate timer loop) then it's probably that the UDPDataReceived event is firing faster than the Process() calls. So it's going something like this:
 

FSUIPC_TransponderCode.Value = 1
Process()
FSUIPC_TransponderCode.Value = 2
FSUIPC_TransponderCode.Value = 3
FSUIPC_TransponderCode.Value = 4
Process()

In that case you would only see 1 and 4 set in the sim,

Quote

I'm getting the correct value back if I immediately query FSUIPC

Do you mean the local variable (FSUIPC_TransponderCode.Value)? That will just hold a copy of whatever you've set it to locally.

Or do you mean you've done a Process() call to get the current value back from FSUIPC?

Paul

[AirPanther]

Thank you for your response Paul!

It was running Process() in a separate timer at 15ms intervals, but I also added it as the very next line after writing the transponder code and it does the same thing.

FsTransponderCode txHelper = new FsTransponderCode((int)value);
FSUIPC_TransponderCode.Value = txHelper.ToBCD();
Process();

 

Quote

Do you mean the local variable (FSUIPC_TransponderCode.Value)? That will just hold a copy of whatever you've set it to locally.

Or do you mean you've done a Process() call to get the current value back from FSUIPC?

I am indeed referring to the local variable FSUIPC_TransponderCode.Value, and I've called Process()

Robert

[Paul Henty]

I'm not really sure what's causing this then.

I would put some messages (Debug.WriteLine) in your code to see the timing and the order in which your methods and events are being called. That might give you a clue as to what's going wrong.

Generally, it sounds like UDPConnection.UDPDataReceived is being fired too quickly and FSUIPC/FSX just can't keep up with the requests to change the transponder code.

Paul