FSX How to set COM Active Frequency with SimConnect

[Hans0924]

Hi,
I am developing a tool with SimConnect and C#. I want to set the frequency in my tool and it will help me to set COM1 frequency in fsx, but I got a SIMCONNECT_EXCEPTION_DATA_ERROR during the action. So anyone knows how to fix this? Thanks a lot.

Here is related code:

//Data Definition
SimConnect.AddToDataDefinition(Definitions.SetComFrequency, "COM ACTIVE FREQUENCY:1", "Frequency BCD16", SIMCONNECT_DATATYPE.INT32, 0f, SimConnect.SIMCONNECT_UNUSED);
            SimConnect.RegisterDataDefineStruct<ComFrequency>(Definitions.SetComFrequency);

// ComFrequency Class
[StructLayout(LayoutKind.Sequential, Pack = 1)]
    public class ComFrequency
    {
        public uint Frequency;
    }

// Convert to BCD16
public static uint ToBcd16(uint n)
        {
            uint result = 0;
            var remainder = n%0x10;
            var quotient = n/0x10;
            if (!(quotient == 0 && remainder == 0))
                result += ToBcd16(quotient)*10 + remainder;
            return result;
        }

// Set the frequency
            var radioData = new ComFrequency();
            double freq;
            if (double.TryParse(tbCOM1Frequency.Text, out freq) && (freq >= 117.975) && (freq <= 136f))
            {
                radioData.Frequency = ToBcd16((uint) (freq%100*100 + 0.5));
                SimConnect?.SetDataOnSimObject(Definitions.SetComFrequency, SimConnect.SIMCONNECT_OBJECT_ID_USER, SIMCONNECT_DATA_SET_FLAG.DEFAULT,
                radioData);
            }

 

[JB3DG]

If the aircraft uses a standby com assigned in the aircraft cfg I don't think you can set active direct. I may be wrong though.

 

[Hans0924]

If the aircraft uses a standby com assigned in the aircraft cfg I don't think you can set active direct. I may be wrong though.

Thanks for your reply. I did notice that SimConnect document marks COM Active Frequency:Index as NOT SETTABLE, but the radio panel in FSInn can set the frequency and FSInn connect to FS via SimConnect too.

 

[JB3DG]

They might be using events rather than SetDataOnSimObject

 

[n4gix]

If the aircraft uses a standby com assigned in the aircraft cfg I don't think you can set active direct. I may be wrong though.

You are not wrong. The only way to set active com or nav frequencies is to configure the standby to 0 in the aircraft.cfg file. At that point using the standby set events will in fact set the active frequencies.

It's rather a pain the arse to be frank, but it is what it is!

 

[richbarry]

I've got an example off the net that appears to do it a bit differently. It sets the Standby, then Swaps the Standby and Active frequency. The Standby in the aircraft.cfg does not seem to be set to 0.
I have never had any reason to use the code, but it does appear to work, so unless I've missed something, it may be a better solution.

fsx_simconnect.MapClientEventToSimEvent(EVENT_ID.EVENT_COM1Swap, "COM_STBY_RADIO_SWAP")
fsx_simconnect.MapClientEventToSimEvent(EVENT_ID.EVENT_COM1SBset, "COM_STBY_RADIO_SET")

fsx_simconnect.TransmitClientEvent(DEFINITIONS.Struct1, EVENT_ID.EVENT_COM1SBset, "&H12645", hSimconnect.group1, SIMCONNECT_EVENT_FLAG.GROUPID_IS_PRIORITY)
fsx_simconnect.TransmitClientEvent(DEFINITIONS.Struct1, EVENT_ID.EVENT_COM1Swap, 0, hSimconnect.group1, SIMCONNECT_EVENT_FLAG.GROUPID_IS_PRIORITY)