Develop Reference

One dispatcher timer, move multiple elements C# wpf

I am trying to use DispatcherTimer for multiple elements (visual, moving stackpanel)
It is possible to call the same DispatcherTimer_Tick for multiple elements? and all of them to move at the same time, but using a loop? And also how should I delay the dispatcher timer to create a new troop after a period of time?
for the moment I've dont something like this
for (int i = 1; i < 3; i++)
{
dispatcherTimer = new DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0, 0, 0, 0, 1);
index = i;
FirstTroop(i);
dispatcherTimer.Start();
}

It is possible to call the same DispatcherTimer_Tick for multiple elements?
Yes you can call dispatcherTimer_Tick(null, null) anywhere in your code. But it is recommended to leave the event handler for only handling tick events and instead call a more meaningful method for this purpose. like a SpawnTroop:
dispatcherTimer_Tick(object sender, EventArgs e)
{
SpawnFirstTroop();
}
and all of them to move at the same time, but using a loop?
So you need to call dispatcherTimer_Tick inside a loop.
void Start()
{
dispatcherTimer = new DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = TimeSpan.FromMilliseconds(1000);
dispatcherTimer.Start();
}
dispatcherTimer_Tick(object sender, EventArgs e)
{
for (int i = 1; i < 3; i++)
{
SpawnTroop(i);
}
}
And also how should I delay the dispatcher timer to create a new troop after a period of time?
According to MSDN:
If a System.Timers.Timer is used in a WPF application, it is worth noting that the System.Timers.Timer runs on a different thread then the user interface (UI) thread. In order to access objects on the user interface (UI) thread, it is necessary to post the operation onto the Dispatcher of the user interface (UI) thread using Invoke or BeginInvoke. Reasons for using a DispatcherTimer opposed to a System.Timers.Timer are that the DispatcherTimer runs on the same thread as the Dispatcher and a DispatcherPriority can be set on the DispatcherTimer.
There are multiple solutions for this:
You can't use a Thread.Sleep with dispatcherTimer_Tick. But you can use Thread.Sleep with a Timer to delay inside timer's tick event handler.
You can write more code for your dispatcherTimer to enable two intervals (like a simple integer counter withing the event handler). this approach is not recommended.
You can use two dispatcher timers, one for queuing/requesting new objects, one for creating/showing them.

How do I trigger an event X seconds after a button has been clicked in a Xamarian iOS application?

I am teaching myself C# and, as part of this, am trying to develop an iOS countdown timer app that is to play a .wav sound file X seconds after a timer initiating button has been clicked as the timer value has gone from X to 0.
In an attempt to do this I have tried using the System.Timers namespace but have been unable to figure out how to program the countdown timer described above. Below is my incomplete code (code that obviously does not fulfill the above described function but might be a part of the full code that would fulfill that function):
partial void UIButton1416_TouchUpInside(UIButton sender)
{
url = NSUrl.FromFilename("Sounds/bell.wav");
bell = new SystemSound(url);
int RoundedTimerValue = Convert.ToInt32(Math.Round(TimerSlider.Value, 0));
System.Timers.Timer timer = new System.Timers.Timer();
timer.Interval = 60000;
timer.Enabled = true;
}
Does anyone know how to create the described countdown timer / Trigger an event X seconds after a button has been clicked?

Example Code.
Timer timer = new Timer();
timer.Interval = 60000;
timer.Elapsed += new ElapsedEventHandler((x,y) => {
//Do whatever you want
timer.Stop();
});
Put the below code in the Button Click Handler and make the timer variable global.
timer.Start();
Or you can leave everything in the Button's click handler, not a big deal.
Explanation:
The timer class has an event called Elapsed which is called when the specified number of milliseconds in the timer's Interval gets over. with the line
timer.Elapsed += new ElapsedEventHandler((x,y) => {...
we are assigning a Delegate(Virtual function) to be called when the timer is up. therefore any code within the braces{} will be called at every Timer.Interval milliseconds. we stop the timer at that time as we don't want it to keep running and generate a lot of events.
Update 2:
Normally , EventHandlers are Defined using
return_type functionName(object sender, EventArgs e);
But since the delegate is virtual, so is the parameter. x corresponds to sender and y corresponds to e.
that event handler code can also be written as below
void someFunction(object sender, ElapsedEventArgs e)
{
timer.Stop();
}
and then,
timer.Elapsed += new ElapsedEventHandler(someFunction);
As for the '=>' you can read about Lambda Expressions Here

Timer won't start after stop

In my application I'm using two Timer, each Timer use a BackgroundWorker. Here the declaration:
DispatcherTimer timer1 = new DispatcherTimer();
DispatcherTimer timer2 = new DispatcherTimer();
BackgroundWorker worker1 = new BackgroundWorker();
BackgroundWorker worker2= new BackgroundWorker();
I using timer1 for perform an heavy method with a BackgroundWorker and timer2 for execute another BackgroundWorker that check the content of a file.
In this way I assign the event to BackgroundWorkers:
worker1.DoWork += worker_DoWork;
worker1.RunWorkerCompleted += worker_RunWorkerCompleted;
worker1.WorkerSupportsCancellation = true;
worker2.DoWork += worker_DoWork2;
worker2.RunWorkerCompleted += worker_RunWorkerCompleted2;
worker2.WorkerSupportsCancellation = true;
Now timer1 have a range of 15 minutes so the BackgroundWorker execute the heavy method each 15 minutes. And timer2 have a range of 1 second. With the timer1 all working good, but the problems are coming when I've added the timer2.
As I said before this timer allow me to start a method that read a file through the worker2, this file have a property, if this property change I need to perform some special activity. Until here no problem.
What I did is the following:
//This method is called by MainWindow
public ReadFile()
{
//before this I already assigned to timer1 the tick event and start
timer2.Tick -= new EventHandler(Event_Tick);
timer2.Tick += new EventHandler(Event_Tick);
timer2.Interval = new TimeSpan(0, 0, 1);
timer2.Start();
}
This is the Tick event associated to timer2
private void Event_Tick(object sender, EventArgs e)
{
if (!worker1.IsBusy) //I skip the reading, worker1 is busy
{
timer1.Stop(); //stop the first timer
worker2.RunWorkerAsync();
}
else
{
Console.WriteLine("worker1 is busy!");
}
}
I don't need to add here the DoWork, is just a parsing of a file, very useless for the question. When worker2 complete the task I did this:
private void worker_RunWorkerCompleted2(object sender, RunWorkerCompletedEventArgs e)
{
timer1.Start();
ReadFile();
}
How you can see I start the timer1 again, and execute again the ReadFile method. Now if timer1 has reached the interval, so 15 minutes has passed, should execute the timer1.Tick += new EventHandler(Heavy_Tick); that execute the DoWork to worker1. But the timer1 never start.
I can't figure out to this, what am I doing wrong?

Now I get it!
You want to execute worker1 every 15 minutes and worker2 every second but only when worker1 is not busy. Your problem is this here:
if (!worker1.IsBusy) //I skip the reading, worker1 is busy
{
timer1.Stop(); //stop the first timer
worker2.RunWorkerAsync();
}
and this:
public ReadFile()
{
//before this I already assigned to timer1 the tick event and start
timer2.Tick -= new EventHandler(Event_Tick);
timer2.Tick += new EventHandler(Event_Tick);
timer2.Interval = new TimeSpan(0, 0, 1);
timer2.Start();
}
Set both timer intervals and tick event handlers during startup, e.g. Form_Load()or at the beginning of Main(). Start them there too. You should not have to stop any timer at all!
By setting the interval, all you have to do is handle the Tick() event. Remove your .Start() and Stop() calls from your WorkerCompletedand Tick methods and you should do fine.

So a lot could be going on here but you should make sure that:
You timer isn't storing it's old progress and you are checking for a certain length of time before stopping. This will automatically cause the timer to stop when restarting.
The timer.stop() function is not disposing your object to an un-restart-able state.
You aren't accessing the timer variable through some pointer that is maintain a stopped value. (Unlikely but annoying when it happens)
I'd personally consider just pausing the timer and resetting the progress, instead of fully stopping it since this is causing issues.

Timer C# Stop() doesn't really stop

I have a form which includes a textbox showing the time passing with an interval of 1 second up till 2 minutes. It is working ok. However I need the timer to stop when a round of game is over and start again when a button from another form is clicked. So I have _timer.Stop() in the timer_tick event handler and _timer.Start() in the button click event handler of Form 2.
My problem is that the timer then starts from how much time passes until I press the button on the other form and not from 0:00 again. Any Ideas?
This is the code regarding the timer:
private DateTime _myDateTime;
private System.Windows.Forms.Timer _timer;
private DateTime newDate;
public Tournament()
{
_timer = new System.Windows.Forms.Timer();
_timer.Interval = 1000;
_timer.Tick += Timer_Tick;
_myDateTime = DateTime.Now;
newDate = new DateTime();
newDate = newDate.AddMinutes(2.00);
_timer.Start();
InitializeComponent();
}
void Timer_Tick(object sender, EventArgs e)
{
var diff = DateTime.Now.Subtract(_myDateTime);
this.textBox1.Text = diff.ToString(#"mm\:ss");
DateTime dt = Convert.ToDateTime(diff.ToString());
if (newDate.Minute == dt.Minute)
{
_timer.Stop();
_myDateTime = DateTime.Now;
displayPointsOrResults();
this.textBox1.Text = diff.ToString(#"mm\:ss");
}
}
In displayPointsOrResults() I am creating instance of another form Points() so in Points form I have button 1 and I have this in its event handler apart other things which does not concern the timer: tournament.Timer1.Start();
Where I am getting the timer from the tournament class and starting it again.
What am I doing wrong?

My problem is that the timer then starts from how much time passes until I press the button on the other form and not from 0:00 again.
Well yes, it would - you're resetting _myDateTime when you stop the timer:
_timer.Stop();
_myDateTime = DateTime.Now;
You should move that second line to the point where you restart it.
Note that your title is incorrect - the timer really is stopping, in that it's not ticking any more. The timer isn't actually performing the timing, if you see what I mean - it's just a way of invoking an event handler regularly. The problem is within the event handler itself.

Ah the global vars, blessing and curse together.
Do you have resetted the _myDateTime to DateTime.Now, when you press the button?

When you stop the timer and restart it, should set the datetime to now.
_myDateTime = DateTime.Now;

Changing Time On MaskedTextbox

I want to design changing time on maskedtextbox in my application like windows where time changes on every second. I have set maskedtexbox1 as below:
maskedTextBox1.Text = DateTime.Now.ToShortTimeString();
which is showing current system short time but it’s not changing on every second like windows. How to do?
I'm on Visual Studio 2005, and .NET is below 3.5.

I'd use the timer and fire an event every second to update the time.
Create a timer (an instance of class Timer in the package System.Windows.Forms).
Set its frequency to 1 second (i.e. 1000 milliseconds).
Tell it what method to call when it goes off (the event handler Kaboom).
Somewhere in your executable code you do that by typing the following.
Timer ticker= new Timer();
ticker.Interval = 1000;
ticker.Tick += new EventHandler(Kaboom);
In the same class (or, if you're confident how to do it, somewhere where you can reach the code) you also create the handler for the fired event of ticking, so that the promise you made about a method to be called when the timer goes off is kept.
private void Kaboom(Object sender, EventArgs eventArgs)
{
// Execute the tickability code
MaskedTextBox1.Text = DateTime.Now.ToShortTimeString();
}
Also, don't forget to actually start your ticker when you feel that you're ready.
MyTimer.Start();
Tada!
EDIT:
For the sake of completeness, I'm also going to paste in a part of the reply of #CuaonLe (a higher threshold of competence and requirement for .NET 3.5 or newer).
Timer timer = new Timer { Interval = 1000 };
timer.Tick += (obj, args)
=> MaskedTextBox1.Text = DateTime.Now.ToLongTimeString();
timer.Start();

I guess you'll need to setup a Timer which updates your maskedTextBox1 every second.
For how to do that, please see: Add timer to a Windows Forms application
Cheers. Keith.

You can use System.Windows.Forms.Timer to update textbox value every second for example:
var timer = new Timer();
timer.Interval = 1000;
timer.Tick += delegate
{
textBox1.Text = DateTime.Now.ToLongTimeString();
};
timer.Start();