Resolved Invoke tasks repeatedly but only if previous task completed

[fakeNoose]

Hey Everyone

I'm using the below to find all children classes of an abstract base class and then instantiate each of them and add that instance to a list.

What I'm wanting to be able to do is loop through that list of instances and run a Task that is part of the abstract base class for each instance every second, but I only want to run that task if the previous task run a second ago is completed. I've seen others do something similar using Func<Task> but I have no idea how they implemented that.

Is this something that is possible to do and if so how should I go about doing it?

Thank you in advance!!

public static List<ConsumableBase> Instances = new List<ConsumableBase>();
public static async void Manage()
{
    IEnumerable<Type> _classes = GetChildrenOfType(typeof(ConsumableBase));
    foreach (Type _class in _classes)
    {
        ConsumableBase _obj = (ConsumableBase) InstantiateType(_class);
        Instances.Add(_obj);
    }
}
private static IEnumerable<Type> GetChildrenOfType(Type _type)
{
    var _classes = AppDomain.CurrentDomain.GetAssemblies()
        .SelectMany(s => s.GetTypes())
        .Where(p => _type.IsAssignableFrom(p));

    return _classes;
}

private static object InstantiateType(Type _type)
{
    var _ctors = _type.GetConstructors(BindingFlags.Public);
    var _inst = _ctors[0].Invoke(new object[] { });

    return _inst;
}

 

[jmcilhinney]

The first thing that comes to mind is this sort of thing:

private Task currentTask;

public void StartNewTask()
{
    if (currentTask?.IsCompleted == true)
    {
        currentTask = Task.Run(DoSomething);
    }
}

public void DoSomething()
{
    // ...
}

You can then call StartNewTask wherever and whenever you want, e.g. from the event handler for a Timer that is invoked every second.

 

[fakeNoose]

Why I didn't think of such a simple way of doing it, I really don't know, but thank you!

 

[jmcilhinney]

Actually, I just realised that my code isn't quite right. That should be:

if (currentTask?.IsCompleted != false)

The first time around, currentTask will be null and thus currentTask?.IsCompleted will be also be null. If that expression is null or true then you want to start a new task.