Timer control freezing the UI

Hello,

CF 3.5 VS 2008

I have a timer control that is being used to do some work. Code below. The timer interval is set for 1 second. However, when the timer is running the UI freezes for a short period.

I understand that the timer control is uses the UI thread, but I didn't think the amount of work was too much to make the UI freeze for short periods.

I couldn't see any server timers for the compact framework.

Any suggestions would be most helpful.

Code:

---

//Get the signal strength of the AP that the adapter is currently connected to
        private void GetSignalStrength()
        {
            try
            {
                //Loop through all the AP nearby and find the one that is currently being connected (Associated)
                if (currentAdapter.NearbyAccessPoints.Count > 0)
                {               
                    foreach (AccessPoint ap in currentAdapter.NearbyAccessPoints)
                    {
                        if (ap.Name == currentAdapter.AssociatedAccessPoint)
                        {
                          this.DisplaySignalStrength(ap.SignalStrength.ToString());
                          //Break out of for loop when the currently connected AP has been found.
                          break;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        //Display the signal strength by filling the bars depending on
        //the strength of the access point.
        private void DisplaySignalStrength(string strength)
        {
            this.pbExcellent.BackColor = Color.Transparent;
            this.pbVeryGood.BackColor = Color.Transparent;
            this.pbGood.BackColor = Color.Transparent;
            this.pbLow.BackColor = Color.Transparent;
            this.pbVeryLow.BackColor = Color.Transparent;

            switch (strength)
            {
                case "Excellent":
                    this.pbExcellent.BackColor = Color.Green;
                    this.pbVeryGood.BackColor = Color.Green;
                    this.pbGood.BackColor = Color.Green;
                    this.pbLow.BackColor = Color.Green;
                    this.pbVeryLow.BackColor = Color.Green;
                    break;
                case "Very Good":
                    this.pbVeryGood.BackColor = Color.Green;
                    this.pbGood.BackColor = Color.Green;
                    this.pbLow.BackColor = Color.Green;
                    this.pbVeryLow.BackColor = Color.Green;
                    break;
                case "Good":
                    this.pbGood.BackColor = Color.Green;
                    this.pbLow.BackColor = Color.Green;
                    this.pbVeryLow.BackColor = Color.Green;
                    break;
                case "Low":
                    this.pbLow.BackColor = Color.Green;
                    this.pbVeryLow.BackColor = Color.Green;
                    break;
                case "Very Low":
                    this.pbVeryLow.BackColor = Color.Green;
                    break;
                default:
                    break;
            }
        }

        //Check the signal strength every 1 second
        private void tmrPollAP_Tick(object sender, EventArgs e)
        {
            this.GetSignalStrength(); 
        }

---

Actually, I would suspect that the amount of time being taken by what you are doing may well be longer than you think. To me, checking signal strength seems like a time-intensive operation. You might write yourself a little profiler to test it. I have one in VB, but they are so easy to write that it's hardly worth passing it out. Just start a stopwatch object at the beginning of the tick event, stop it at the end, and look at the elapsed time. I think you will probably find that the timing is not what you had hoped for. If that is the case, I would say that you should seriously consider checking the signal strength in a background thread. This could either run periodically (you could start it on the timer tick), or run continuously (which might impact performance, too), only updating the display periodically.

Hello,

Visual Studio 2008 development edition comes with a profiler that measures the time it takes. I will investigate this.

I was thinking of using a background thread. However, as the picture boxes are on the UI thread then I would have to use the picture boxes to invoke a delegate to marshal the call to the UI thread. Just seems a lot of coding for something that seemed easy.

However, I will try the background thread and post back with the code.

Thanks,

I would do the profiling first. I suspect the signal strength takes a certain amount of time, but I'd want to confirm that it is the cause of the slowdown.