How to convert ObservableCollection<SomeType> back to ObservableCollection<T>?

Question

I am struggling with converion back to generic collection type in generic method with return type.

In this answer is clearly written to avoid

switching on a type in a generic

But in this answer is explained how to do it.

I admit, that I used generics to avoid writing three times the same code for three different return types. Right now the compiler is telling me, that

not all code paths return a value

Example of caller methods caller:

public ObservableCollection<LoadedJockey> Jockeys { get; private set; }

Jockeys = await _updateDataService.UpdateDataAsync(Jockeys, DataUpdateModules.JPlFrom, DataUpdateModules.JPlTo, "updateJockeysPl");

My generic method looks like this:

public async Task<ObservableCollection<T>> UpdateDataAsync<T>(ObservableCollection<T> genericCollection, int idFrom, int idTo, string jobType) where T : IConvertible
        {
            //variables reset here
            _loopCounterProgressBar = 0;
            _idFromProgressBar = idFrom;
            _idToProgressBar = idTo;

            if (typeof(T) == typeof(LoadedHorse))
            {
                //do something here
            }
            else if (typeof(T) == typeof(LoadedJockey))
            {
                //do something here
            }
            else if (typeof(T) == typeof(LoadedHistoricalRace))
            {
                //do something here
            }

            //initial
            SemaphoreSlim throttler = new SemaphoreSlim(_degreeOfParallelism);
            List<Task> tasks = new List<Task>();
            TokenSource = new CancellationTokenSource();
            CancellationToken = TokenSource.Token;
            OnProgressBarTick();

            //run loop
            for (int i = idFrom; i < idTo; i++)
            {
                int id = i;

                tasks.Add(Task.Run(async () =>
                {
                    try
                    {
                        if (CancellationToken.IsCancellationRequested)
                            return;

                        await throttler.WaitAsync(TokenSource.Token);

                        if (jobType.Contains("Horses"))
                        {
                            await //call service method
                        }
                        else if (jobType.Contains("Jockeys"))
                        {
                            await //call service method
                        }
                        else if (jobType.Contains("Historic"))
                        {
                            await //call service method
                        }
                    }
                    catch (Exception e)
                    {

                    }
                    finally
                    {
                        _loopCounterProgressBar++;

                        EventHandler<UpdateBarEventArgs> progressBarTick = _updateProgressEventHandler;

                        OnProgressBarTick();

                        throttler.Release();
                    }
                }));
            }

            try
            {
                await Task.WhenAll(tasks);
            }
            catch (OperationCanceledException)
            {

            }
            finally
            {
                //save results in file when finish

                }
            }
            //here I wanted to return some result depending on T
            if (typeof(T) == typeof(LoadedHorse))
            {
                return (ObservableCollection<T>)Convert.ChangeType(Horses, typeof(ObservableCollection<T>));
            }
            else if (typeof(T) == typeof(LoadedJockey))
            {
                return (ObservableCollection<T>)Convert.ChangeType(Jockeys, typeof(ObservableCollection<T>));
            }
            else if (typeof(T) == typeof(LoadedHistoricalRace))
            {
                return (ObservableCollection<T>)Convert.ChangeType(Races, typeof(ObservableCollection<T>));
            }
        }

As you can see, I expect to receive 3 different types of T. And I think that I covered all of them. My solution is based on this example. I am guessing, that I may Convert wrongly my type to T, but I do not how I am supposed to do it.

Answer 1

As Camilo Terevinto adviced, I added at the end of if else chain else { throw new ArgumentException() } and compiler was pleased.