public class Terminator : INotifyPropertyChanged
{
    private bool terminate;
    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    public bool Terminate
    {
        get
        {
            return this.terminate;
        }
        set
        {
            if (value != this.terminate)
            {
                this.terminate = value;
                NotifyPropertyChanged();
            }
        }
    }

    public PlayerThreadNotify(bool terminate = false)
    {
        this.terminate = terminate;
    }
}

public class SomeClass {

    public SomeClass(Terminator t) {
        t.PropertyChanged += Teminator_PropertyChanged;
    }

    public void LongRunningMethod(Terminator t) {
        /// .. do work
    }

    private void Teminator_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e) {
        /// .. handle that LongRunningMethod should stop
    }


}

public static void ThreadFunc(Terminator t) {
    var obj = new SomeClass(t);
    obj.LongRunningMethod(t);
}