Smart Alarm Using OpenNetCF and C# for SmartPhone (Windows Mobile 2003)

Introduction

I got myself a SmartPhone Sagem myS-7 for my b'day this year. Having used a lot of other phones I was a bit disappointed by the Alarm option within SmartPhone. It's very very basic. You can only select the time. (Under Settings / More / Date and Time. The Snooze option sleeps for 10 minutes and you don't have an option to change that. So I got myself to writing an alarm which did most of the things I wanted.)

I started with the Timer object and it was firing the event at the right time. The only problem I was having was that it just wouldn't take the phone out of Standby mode. I Googled around a bit and I realized that I was supposed to set system notification in order for the phone to come out of standby. I looked around to executing native code but I found OpenNetCF. It's got a good set of classes and it had the notification functionality as well.

Using the code

The code is pretty straightforward. Set a Timer object to do an hourly check for upcoming Alarm events. If an alarm is found within the next hour it sets another Timer object to execute and set a Notify.RunAppAtTime from OpenNETCF.Win32.Notify. The application actually playing the alarm (rooster at its best) is a standalone SmartPhone app and plays the Wav file using the SoundPlayer control from OpenNETCF.Windows.Forms.

For persisting alarm data, I used DataSet's ReadXml and WriteXml.

private void GetNextNotificationInfo()
{
    this.nextAlarmUp = 0;
    DataSet dsAlarms = new DataSet();
    if(File.Exists(ConfigFile) == true)
    {
        dsAlarms.ReadXml(ConfigFile);
        if(dsAlarms.Tables.Count != 0 && dsAlarms.Tables[0].Rows.Count != 0)
        {
            DateTime dtCurrent = DateTime.Now;
            long CurrentTimeInTicks = dtCurrent.TimeOfDay.Ticks;
            int currentDayOfWeek = (int)dtCurrent.DayOfWeek;
            string filterExpression = "Enabled = true AND TimeInTicks >= " 
                + CurrentTimeInTicks + " AND Days LIKE '%" + 
                Convert.ToString(currentDayOfWeek) + "%'";
            string sortExpression = "TimeInTicks DESC";
            DataRow[] drActiveAlarms = 
              dsAlarms.Tables[0].Select(filterExpression, 
              sortExpression);

            if(drActiveAlarms.Length > 0)
            {
                DataRow drSelectedAlarm = drActiveAlarms[0];
                long SelectedTimeInTicks = 
                  Convert.ToInt64(drSelectedAlarm["TimeInTicks"]);

                if(SelectedTimeInTicks > CurrentTimeInTicks)
                {
                    TimeSpan tsSelectedTime = new TimeSpan(SelectedTimeInTicks);
                    TimeSpan tsCurrentTime = dtCurrent.TimeOfDay;

                    TimeSpan tsDifference = tsSelectedTime - tsCurrentTime;

                    if(tsDifference.TotalSeconds < 3600)
                    {
                        // set timerNotify to fire 1 minute before alarm time
                        // and set the AlarmExec to run after a minute

                        this.nextAlarmUp = Convert.ToInt32(drSelectedAlarm["ID"]);
                        this.timerNotify.Interval = 
                         Convert.ToInt32(tsDifference.TotalMilliseconds - 60*1000);
                        this.timerNotify.Enabled = true;
                    }
                    else
                    {
                        this.nextAlarmUp = 0;
                        this.timerNotify.Enabled = false;
                    }
                }
            }
        }
    }
}

private void timerNotify_Tick(object sender, System.EventArgs e)
{
    this.timerNotify.Enabled = false;
    Notify.RunAppAtTime(this.AppPath + "SDAlarmExec.exe", 
                             DateTime.Now.AddMinutes(1));
    this.ExecuteDisable();
    GetNextNotificationInfo();
}

Points of Interest

By default when you save data as XML, the file is created in the root directory. To get the application's path, you need to use Assembly.GetExecutingAssembly().GetModules()[0].FullyQualifiedName. This returns /Storage Card/Program Files/SmartAlarm.exe. Fetch the assembly name using Assembly.GetExecutingAssembly().GetModules()[0].Name and replace it with "" and you have the path.

I noticed the following points which might help when creating SmartPhone apps:

The Build Cab option fails. But it does create a Build.bat file under the Obj/Release folder (if you are doing a release build package).
Update the batch file for Cab generation to use C:\Program Files\Windows CE Tools\wce420\SMARTPHONE 2003\Tools\CabwizSP.exe instead of C:\Program Files\Microsoft Visual Studio .NET 2003\CompactFrameworkSDK\v1.0.5000\bin\cabwiz.exe.
Copy vsd_setup.dll from C:\Program Files\Microsoft Visual Studio .NET 2003\CompactFrameworkSDK\v1.0.5000\Windows CE\wce400\armv4 to C:\Program Files\Microsoft Visual Studio .NET 2003\CompactFrameworkSDK\v1.0.5000\Windows CE\Smartphone\wce400\armv4.
Copy vsd_setup.dll from C:\Program Files\Microsoft Visual Studio .NET 2003\CompactFrameworkSDK\v1.0.5000\Windows CE\wce400\x86 to C:\Program Files\Microsoft Visual Studio .NET 2003\CompactFrameworkSDK\v1.0.5000\Windows CE\Smartphone\wce400\x86.
For OpenNetCF, manually install OpenNETCF.SDF.smp.armv4.cab in the phone.
If you are using OpenNetCF, the emulator doesn't work any more by default. If you would like to use the emulator add the OpenNetCF referenced assemblies as content in the Project.
Lastly when the DateTime control receives control, it doesn't allow any other elements to have focus that easily. That is the reason why I have set its receive focus at the very end. It's a limitation of the control.