I have timer that starts counting when a certain event (someEvent) occurs for one second, if the event is fired again within this second I want the first timer to stop and starts counting again from 0 I tried this :
void someEvent (object sender, TextChangedEventArgs e )
{
aTimer = new System.Timers.Timer();
aTimer.Change(5000, 0);
aTimer.Elapsed += OnTimedEvent;
aTimer.AutoReset = true;
aTimer.Enabled = true;
}
timer definition in the MainWindow:
private System.Timers.Timer aTimer;
According to this C# Timer.Change Method
But I get an error over aTimer.Change saying: "timer doesn't contain a definition of 'Change'."
This was implemented using WPF.
Namespaces Matter
.NET has quite a few timers classes, each of which have their own specific functionality and exposed methods, so it can be easy to get confused between the namespaces (as most of the classes are just called Timer).
You are currently using the System.Timers.Timer class, which primarily consists of the Start() and Stop() methods. If you want the Change() method, you would need to instead use an instance of the System.Threading.Timer class :
// Declare the timer as the other type of timer
aTimer = new System.Threading.Timer();
Yours is a System.Timers.Timer. This timer does not have a Change Method
The Timer.Change() event is used in System.Threading.Timer Timer.Change
Related
I'm trying to get more familiar with eventhanlders, but my current even only updates once, I want it to update until I close the application.
This is my code:
private static event EventHandler Updater;
Updater += Program_updater;
Updater.Invoke(null, EventArgs.Empty);
Application.Run();
private static void Program_updater(object sender, EventArgs e)
{
KeyUtils.Update();
Framework.Update();
}
But like I said, it will only update once, I want it to update until I close my application. I know I can just do a While(true) but I rather not.
I think you want a Timer here:
Timer aTimer = new System.Timers.Timer(2000);
// Hook up the Elapsed event for the timer.
aTimer.Elapsed += Program_updater;
// Have the timer fire repeated events (true is the default)
aTimer.AutoReset = true;
// Start the timer
aTimer.Enabled = true;
Specify callback:
private void Program_updater(Object source, System.Timers.ElapsedEventArgs e)
{
KeyUtils.Update();
Framework.Update();
}
Now every 2 seconds (or specify any other interval) callback OnTimedEvent will be called.
It is absolutely normal that your event is fired only once because the application starts only once.
What you acctualy need is to set up a timer and do some work on its tick.
Please have a look on example in answer for that question Simple example of the use of System. Timers. Timer in C#
Well it only updates once since you only invoke it once (I don't really get the context where your code runs since you both declare a static variable and invokes it on the same scope which is impossible).
If you want something to occur periodically you should use Timer, or in some cases AutoResetEvent/ManualResetEvent.
EventHandlers should be used only when you work as event driven which mean you want your handler to invoke When something happens
Here an example for [System.Timers.Timer][2] with your handler:
//Invoke every 5 seconds.
Timer timer = new Timer(5000);
//Add your handler to the timer invocation list.
timer.Elapsed += Program_updater;
//Start the timer.
timer.Start();
Also you need Program_update's signature to look like that:
private void Program_updater(object source, ElapsedEventArgs e)
This question already has answers here:
System.Timers.Timer timer1_Elapsed not firing! Help!
(5 answers)
Closed 7 years ago.
I had created new Timer variable on my Window Form Application:
intervalTime = new System.Timers.Timer();
intervalTime.Interval = 5000;
intervalTime.Enabled = true;
Console.WriteLine(intervalTime.Enabled.ToString());
intervalTime.Elapsed += new ElapsedEventHandler(intervalTime_Elapsed);
Console.WriteLine(intervalTime.Enabled.ToString());
and my Timer would execute every 5 seconds with ElapsedEvent:
void intervalTime_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
//Do something....
}
but ElapsedEvent not firing at all. How should I do to make it fired? I check that intervalTime.Enabled is true.
I had found this question before but it not solve my problem
You need to set the event handler before to start the timer. That is before you call intervalTime.Enabled = true;
using System;
using System.Timers;
namespace ConsoleApplication4
{
class Program
{
static void Main(string[] args)
{
var intervalTime = new System.Timers.Timer();
//Do IT HERE
intervalTime.Elapsed += new ElapsedEventHandler(intervalTime_Elapsed);
intervalTime.Interval = 5000;
intervalTime.Enabled = true;
Console.WriteLine(intervalTime.Enabled.ToString());
Console.WriteLine(intervalTime.Enabled.ToString());
Console.ReadLine();
}
static void intervalTime_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
//Do something....
Console.WriteLine("New event fired");
}
}
}
You probably want to use System.Windows.Forms.Timer and not System.Timers.Timer here. System.Windows.Forms.Timer has a Tick event that automatically fires every N milliseconds (that you can set using Interval property just like System.Windows.Forms.Timer). This is unlike System.Timers.Timer which fires Elapsed event only once and acts more like a time-bomb than a "scheduled ticker".
If you must use System.Windows.Forms.Timer, you should set AutoReset property to True for the event to occur repeatedly.
EDIT
It seems like at some point they have changed the AutoReset property's default value to true; meaning that System.Timers.Timer now fires Elapsed event repeatedly by default, just like System.Windows.Forms.Timer. However, note that Microsoft explicitly recommends using System.Windows.Forms.Timer in WinForms applications, just like I did above.
I'm not sure if we have to start this timer after we defined it.
Maybe we should do it like this:
intervalTime.Start();
So i created UserControl with dataGridView, actually how I will this object is less important, but let's say i have alredy DataSource and I want to refresh dataGridView with these values.
on example i have function fillDataGridView() and I want it to call every 2 minutes
I think that I could do this with Thread class, but w/o any success yet
How do you deal with UI refresh?
I know that this looks like "yet another guy with UI update problem", but from what I saw I really can't the easiest way to do it
public partial class Alertbox : UserControl
{
private static System.Timers.Timer aTimer;
public Alertbox()
{
InitializeComponent();
aTimer = new System.Timers.Timer(10000);
aTimer.Elapsed += new ElapsedEventHandler(Update);
aTimer.Interval = 2000;
aTimer.Enabled = true;
}
public void Update(object source, ElapsedEventArgs e)
{
BT_AddTrigger.Text += "test"; // append to button text
}
}
It shout's that
An exception of type 'System.InvalidOperationException' occurred in
System.Windows.Forms.dll but was not handled in user code Additional
information: Cross-thread operation not valid: Control 'BT_AddTrigger'
accessed from a thread other than the thread it was created on.
Use a System.Windows.Forms.Timer instead of System.Timer.Timer.
You're getting the Cross Thread Operation Not Valid error because System.Timer.Timer runs on a different thread, and you can't invoke an operation on a Winforms thread from another thread without calling Control.Invoke().
System.Windows.Forms.Timer will use the same thread as the UI, and you'll avoid these problems.
You can use one of the handy Timer classes in .Net to trigger every 2 min.
Here is an example
http://msdn.microsoft.com/en-us/library/system.windows.forms.timer(v=vs.110).aspx
You can use System.Windows.Forms:
using System.Windows.Forms;
public Alertbox()
{
InitializeComponent();
var timer = new Timer {Interval = 2*60*1000};
timer.Tick += Timer_Tick;
timer.Start();
}
void Timer_Tick(object sender, EventArgs e)
{
BT_AddTrigger.Text += "test";
}
You should use timer class in this way
System.Timers.Timer testTimer = new System.Timers.Timer();
testTimer.Enabled = true;
//testTimer.Interval = 3600000; //1 hour timer
testTimer.Interval = 100000;// Execute timer every // five seconds
testTimer.Elapsed += new System.Timers.ElapsedEventHandler(FillGrid);
This question already has answers here:
How do you add a timer to a C# console application
(12 answers)
Closed 3 years ago.
What is the best way to implement a timer? A code sample would be great! For this question, "best" is defined as most reliable (least number of misfires) and precise. If I specify an interval of 15 seconds, I want the target method invoked every 15 seconds, not every 10 - 20 seconds. On the other hand, I don't need nanosecond accuracy. In this example, it would be acceptable for the method to fire every 14.51 - 15.49 seconds.
Use the Timer class.
public static void Main()
{
System.Timers.Timer aTimer = new System.Timers.Timer();
aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
aTimer.Interval = 5000;
aTimer.Enabled = true;
Console.WriteLine("Press \'q\' to quit the sample.");
while(Console.Read() != 'q');
}
// Specify what you want to happen when the Elapsed event is raised.
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
Console.WriteLine("Hello World!");
}
The Elapsed event will be raised every X amount of milliseconds, specified by the Interval property on the Timer object. It will call the Event Handler method you specify. In the example above, it is OnTimedEvent.
By using System.Windows.Forms.Timer class you can achieve what you need.
System.Windows.Forms.Timer t = new System.Windows.Forms.Timer();
t.Interval = 15000; // specify interval time as you want
t.Tick += new EventHandler(timer_Tick);
t.Start();
void timer_Tick(object sender, EventArgs e)
{
//Call method
}
By using stop() method you can stop timer.
t.Stop();
It's not clear what type of application you're going to develop (desktop, web, console...)
The general answer, if you're developing Windows.Forms application, is use of
System.Windows.Forms.Timer class. The benefit of this is that it runs on UI thread, so it's simple just define it, subscribe to its Tick event and run your code on every 15 second.
If you do something else then windows forms (it's not clear from the question), you can choose System.Timers.Timer, but this one runs on other thread, so if you are going to act on some UI elements from the its Elapsed event, you have to manage it with "invoking" access.
Reference ServiceBase to your class and put the below code in the OnStartevent:
Constants.TimeIntervalValue = 1 (hour)..Ideally you should set this value in config file.
StartSendingMails = function name you want to run in the application.
protected override void OnStart(string[] args)
{
// It tells in what interval the service will run each time.
Int32 timeInterval = Int32.Parse(Constants.TimeIntervalValue) * 60 * 60 * 1000;
base.OnStart(args);
TimerCallback timerDelegate = new TimerCallback(StartSendingMails);
serviceTimer = new Timer(timerDelegate, null, 0, Convert.ToInt32(timeInterval));
}
So I have this awesome pictureBox1 in my C# program. Every 5 second I call an time method like this:
public Form1()
{
InitializeComponent();
aTimer = new System.Timers.Timer(10000);
aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
aTimer.Interval = 2000;
aTimer.Enabled = true;
}
private static void OnTimedEvent(object source, ElapsedEventArgs e)
{
}
I am trying to change a property of a pictureBox object I got. But I get this error when trying to do so:
Error 1 An object reference is required for the non-static field, method, or property 'Simma.Form1.pictureBox1' C:\Users\John\Desktop\Simma\Simma\Form1.cs 39 13 Simma
The pictureBox1 is set to Public though.
The problem must be in the code you haven't shown us... presumably in OnTimedEvent.
The simplest fix is to make OnTimedEvent an instance method instead. This isn't a matter of accessibility (and the field shouldn't be public - make it private!) it's a matter of trying to use an instance field from a static method.
Note, however, that you also shouldn't try to access a UI element from a non-UI thread. Currently your timer will fire its event in a different thread, causing cross-thread issues.
The simplest fix for this is to use a System.Windows.Forms.Timer instead of a System.Timers.Timer.