parallel port event handler?

Question

I was able to salvage an ldr sensor from somewhere and now I'm playing around with it. was able to attach it to the parallel port along with an led so I can practice both input and ouput.

I was able to build a small program where if the ldr gets tripped the led will turn on

private void button1_Click(object sender, EventArgs e)
{
do
{
x= PortAccess.Input(889);
if(x==127)
PortAccess.Output(888,1);
if(x==111)
PortAccess.Output(888,0);
}while(x!=127)
}

I had to end it when it gets tripped otherwise its going to be an infinite loop. Now, what if I wanted to have it running the entire time the form is open, without having to press a button, and while other stuff are going on. what should I do?
I thought maybe I can make an event listener and handler for it, but how? or do I even need one and there is a simpler solution? Any ideas? thanks in advance

Sam Hobbs · Answer

If I understand what you need to do then you can use a timer. Note that there are at least three timer classes but for a form you you will likely want to use the Timer class in the Forms namespace. You can drag a Timer from the Toolbox and drop it on the form; the Timer does not show on the form but can be used in the code. Look in the All Windows Forms node of the Toolbox for the Timer component. Or you can create a timer as in: Timer timer1 = new Timer(); If you create the timer from the toolbox then you can add a Tick event for it using it's properties. If you create the timer in code as above you can adda a tick event as in: timer1.Tick += new EventHandler(TimerEventProcessor); You can set the interval either in the properties or in code then you need to start it. Please look at the documentation for details and ample samples. The tick event would be something such as: private static void TimerEventProcessor(Object myObject EventArgs myEventArgs) { . . . } Note that th tick event is static so if it needs to access the form's class you can use the timer's Tag property to pass something to the event handler. I forget what we do to get the object passed using the Tag property but if you need it we can find it. See my Scrolling Text Marquee Control for a simple sample of using a timer.

Sam Hobbs · Answer

Sounds like you are having fun making lights flash and timers go off.

wsdfg · Answer

thanks for the help guys. the timer works perfectly for this. cant believe I have never used it before.

Mike Gold · Answer

its fairly easy to use. from MSDN: private System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer(); myTimer.Tick += new EventHandler(TimerEventProcessor); // Sets the timer interval to 5 seconds. myTimer.Interval = 5000; myTimer.Start(); private static void TimerEventProcessor(Object myObject EventArgs myEventArgs) { // your parallel port code here }

wsdfg · Answer

thanks I'll try that. but first I need to read up on how to use timers. I guess I need to know how to use that 1st..