Binding a Windows Phone 7 button's action to a method in Expression Blend 4

I'm trying out Windows Phone 7 dev for the first time. I decided to try and port a Silverlight Timer example from the default examples in Expression Blend 4. The timer example for full-blown silverlight binds a TimerModel class to the timer, the start/stop toggle switch, etc. I've figured out how to create the datasource/datacontext and bind the properties to things on the screen. However, the Reset() method, which is a void doesn't show up in the bindable options for the Windows Phone 7 app. It's the exact same class in both, but for some reason the void method isn't bindable. Is there something I need to enable that was in the full Silverlight app that's not in Windows Phone 7? Is there something in particular that makes a class' properties or methods bindable when it's a data source? Is this just one of the limitations of Windows Phone 7's subset of Silverlight's features?

Below is the class, which is the same in both applications. I want to bind a button's click to the Reset() method.

namespace Time
{
    using System;
    using System.ComponentModel;
    using System.Windows.Threading;
    using System.Windows.Data;

    public class TimerModel : INotifyPropertyChanged
    {
        private bool isRunning;
        private DispatcherTimer timer;
        private TimeSpan time;
        private DateTime lastTick;

        public string FormattedTime
        {
            get 
            {
                return string.Format("{0:#0}:{1:00}:{2:00.00}", this.time.Hours, this.time.Minutes, (this.time.Seconds + (this.time.Milliseconds / 1000.0d)));
            }
        }

        private void UpdateTimes()
        {
            this.NotifyPropertyChanged("FormattedTime");
            this.NotifyPropertyChanged("Hours");
            this.NotifyPropertyChanged("Minutes");
            this.NotifyPropertyChanged开发者_如何学Python("Seconds");
        }

        public bool Increment
        {
            get;
            set;
        }

        public int Hours
        {
            get
            {
                return this.time.Hours;
            }
            set
            {
                this.time = this.time.Add(TimeSpan.FromHours(value - this.time.Hours));
                this.UpdateTimes();
            }
        }

        public int Minutes
        {
            get
            {
                return this.time.Minutes;
            }
            set
            {
                this.time = this.time.Add(TimeSpan.FromMinutes(value - this.time.Minutes));
                this.UpdateTimes();
            }
        }

        public int Seconds
        {
            get
            {
                return this.time.Seconds;
            }
            set
            {
                this.time = this.time.Add(TimeSpan.FromSeconds(value - this.time.Seconds));
                this.UpdateTimes();
            }
        }

        public bool IsRunning
        {
            get { return this.isRunning; }
            set
            {
                if (this.isRunning != value)
                {
                    this.isRunning = value;
                    if (this.isRunning)
                    {
                        this.StartTimer();
                    }
                    else
                    {
                        this.StopTimer();
                    }
                    this.NotifyPropertyChanged("IsRunning");
                }
            }
        }

        private void StartTimer()
        {
            if (this.timer != null)
            {
                this.StopTimer();
            }
            this.timer = new DispatcherTimer();
            this.timer.Interval = TimeSpan.FromMilliseconds(1);
            this.timer.Tick += this.OnTimerTick;
            this.lastTick = DateTime.Now;
            this.timer.Start();
        }

        private void StopTimer()
        {
            if (this.timer != null)
            {
                this.timer.Stop();
                this.timer = null;
            }
        }

        private void OnTimerTick(object sender, EventArgs e)
        {
            DateTime now = DateTime.Now;
            TimeSpan diff = now - this.lastTick;
            this.lastTick = now;

            if (this.Increment)
            {
                this.time = this.time.Add(diff);
            }
            else
            {
                this.time = this.time.Subtract(diff);
            }
            if (this.time.TotalMilliseconds <= 0)
            {
                this.time = TimeSpan.FromMilliseconds(0);
                this.IsRunning = false;
            }
            this.UpdateTimes();
        }

        public void Reset()
        {
            this.time = new TimeSpan();
            this.UpdateTimes();
        }

        public TimerModel()
        {
        }

        public event PropertyChangedEventHandler PropertyChanged;

        private void NotifyPropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }

}

I use the Caliburn Micro MVVM framework. It allows binding by convention so if you call your button RefreshButton and you have a method in your view model called RefreshButton it will get bound to the Click event automatically. Very powerful and easy.

I found out that Silverlight is using the stock CallMethodAction action, which is not available in Windows Phone 7. It seems that I have two options:

1. Use the onClick event like traditional forms, and just use the codebehind to call the method programmatically.
2. Create my own custom Action to recreate CallMethodAction. There is also an open source project which contains a port of the method from full-blown Silverlight, which you can find on Codeplex.