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Closed 10 years ago.
Iam a noobi
i have this problem , i need to make a timer for my program ,which starts when the user clicks a specific button. and then to output the countdown in to a label
Thanks in advance
The DispatcherTimer is located in the System.Windows.Threading Namespace.
Something like this should work:
public partial class MainWindow : Window
{
int count = 0;
System.Windows.Threading.DispatcherTimer tmr = new System.Windows.Threading.DispatcherTimer();
public MainWindow()
{
InitializeComponent();
tmr.Interval = new TimeSpan(0, 0, 2);
tmr.Tick += new EventHandler(tmr_Tick);
}
private void button1_Click(object sender, RoutedEventArgs e)
{
tmr.Start();
}
void tmr_Tick(object sender, EventArgs e)
{
label1.Content = count += 1;
}
private void button2_Click(object sender, RoutedEventArgs e)
{
tmr.Stop();
}
}
This was pulled from production so I'm sure it works:
...
_Timer = new DispatcherTimer();
_Timer.Interval = TimeSpan.FromMilliseconds(125);
_Timer.Tick += new EventHandler(_Timer_Tick);
_Timer.IsEnabled = true;
_Timer.Start();
...
void _Timer_Tick(object sender, EventArgs e)
{
try {
...Do your thing here
} catch (Exception x){
Debug.WriteLine("Error: "+x);
}
}
Related
I can't update my WinForm label properties.
Details: I am trying to check my database and get some values posted, but I can't even update a mere label it seems. I'm using SharpDevelop.
The code:
//this is my form
public partial class MainForm : Form
{
//Declaring timer
public static System.Timers.Timer aTimer = new System.Timers.Timer();
public MainForm()
{
InitializeComponent();
//Timer
aTimer.Elapsed +=new ElapsedEventHandler(OnTimedEvent);
aTimer.Interval = 2000; //milisecunde
aTimer.Enabled = true;
label1.Text="some_text";
}
private static void OnTimedEvent(object source, ElapsedEventArgs e) {Check();}
public static void Check()
{
//Database checks here..
try{label1.Text="new_text";}catch(Exception e) {MessageBox.Show(e.ToString());}
MessageBox.Show("BAAAA");
}
void Button1Click(object sender, EventArgs e)
{
label1.Text = "mergeeeeee?!";
}
}
EDIT: I've removed all static modifiers. Also updated the post with the new code (try catch is added and the messagebox after it + a button that changes the label).
The try catches the following error:
. Really could use some help, been researching answers for more than 6 hours.
Try this (use a System.Windows.Forms.Timer instead of System.Timers.Timer):
//Declaring timer
public System.Windows.Forms.Timer aTimer = new System.Windows.Forms.Timer();
public Form1()
{
InitializeComponent();
//Timer
aTimer.Tick += aTimer_Tick;
aTimer.Interval = 2000; //milisecunde
aTimer.Enabled = true;
label1.Text = "some_text";
}
void aTimer_Tick(object sender, EventArgs e)
{
Check();
}
public void Check()
{
try
{
//Database checks here..
label1.Text = string.Format("new_text {0}", DateTime.Now.ToLongTimeString());
}
catch (Exception ex)
{
throw ex;
}
MessageBox.Show("BAAAA");
}
The Elapsed event of the System.Timers.Timer is fired on a non-UI thread (change your original code to not swallow exceptions and you should see the cross-thread exception).
I used the following code for my project and it worked.
It has a button to activate the timer and the timer raises an event when 500 milliseconds passed.
private void ActiveTimer_Click(object sender, EventArgs e)
{
EnableTimer();
}
private void EnableTimer()
{
System.Timers.Timer raiseTimer = new System.Timers.Timer();
raiseTimer.Interval = 500;
raiseTimer.Elapsed += RaiseTimerEvent;
raiseTimer.AutoReset = true;
raiseTimer.Enabled = true;
}
private void RaiseTimerEvent(object sender, System.Timers.ElapsedEventArgs e)
{
this.Invoke(new Action(() =>
{
label1.Text += "500 ms passed\n";
}));
}
I have a BackgroundWorker on my WPF UserControl.
private readonly BackgroundWorker worker = new BackgroundWorker();
public ucCustomer()
{
InitializeComponent();
worker.DoWork += worker_DoWork;
worker.RunWorkerCompleted += worker_RunWorkerCompleted;
}
private void worker_DoWork(object sender, DoWorkEventArgs e)
{
// run all background tasks here
System.Threading.Thread.Sleep(10000);
}
private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
//update ui once worker complete his work
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
worker.RunWorkerAsync();
}
Above code is work, the UI is response when the task is working, but if i change the worker_DoWork() to
private void worker_DoWork(object sender, DoWorkEventArgs e)
{
// run all background tasks here
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background,
new Action(() => {
gridDataBind(); //A long data-mining task,using Dispatcher.Invoke() to access UI.
}));
}
private void gridDataBind()
{
SnEntities sn = new SnEntities();
var customers = from c in sn.Customer select c;
dgCustomer.ItemsSource = customers.ToList();
}
The UI is freeze until the task is end.
Is it any solution?
Thanks you.
Try setting the ItemsSource like below code:
private void worker_DoWork(object sender, DoWorkEventArgs e)
{
// run all background tasks here
e.Result = gridDataBind(); //A long data-mining task.
}
private IList<Customer> gridDataBind()
{
SnEntities sn = new SnEntities();
var customers = from c in sn.Customer select c;
return customers.ToList();
}
private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
var customers = e.Result as IList<Customer>;
ObservableCollection<Customer> gridItemsSource = new ObservableCollection<Customer>();
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background,
new Action(() =>
{
dgCustomer.ItemsSource = gridItemsSource;
}));
foreach(var customer in customers)
{
Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Background,
new Action(() =>
{
gridItemsSource.Add(customer);
}));
}
}
Store your data in e.result at worker_DoWork and update UI at the worker_RunWorkerCompleted.
in that case UI will be free when data will coming from database.
Try this, it should help you
Application.Current.Dispatcher.BeginInvoke(
DispatcherPriority.Background,
new Action(() => gridDataBind();));
It is possible to detect a touch press and hold gesture with the MouseRightButtonDown event. Unfortunately it fires not until I release my finger from the screen. This is to late!
Does anyone have ideas? Thanks in advance.
It is possible to do that in an awaitable fashion. Create a timer with specific interval. Start it when user tapped and return the method when timer elapsed. If user release the hand, return the method with false flag.
public static Task<bool> TouchHold(this FrameworkElement element, TimeSpan duration)
{
DispatcherTimer timer = new DispatcherTimer();
TaskCompletionSource<bool> task = new TaskCompletionSource<bool>();
timer.Interval = duration;
MouseButtonEventHandler touchUpHandler = delegate
{
timer.Stop();
if (task.Task.Status == TaskStatus.Running)
{
task.SetResult(false);
}
};
element.PreviewMouseUp += touchUpHandler;
timer.Tick += delegate
{
element.PreviewMouseUp -= touchUpHandler;
timer.Stop();
task.SetResult(true);
};
timer.Start();
return task.Task;
}
For more information, read this post.
Great piece of code. I add just an example usage for completeness:
private async void btn_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
if (await TouchHold(btn, TimeSpan.FromSeconds(2)))
{
// todo: long press code goes here
}
}
And from XAML:
<Button Name="btn" PreviewMouseDown="btn_PreviewMouseDown">Press long</Button>
Use the Hold gesture provided by Blake.NUI toolkit
Either a button or label or image, we can use the MouseDown and MouseUp for starting the delay and Stopping the delay.
For MouseDown,
// Declaration of timer and timercount
int timerCount = 0;
DispatcherTimer dt = new DispatcherTimer();
public myConstructor()
{
dt.Interval = new TimeSpan(0, 0, 1);
}
// Mouse Down Event
private void EnterHoldState(object sender, TouchEventArgs e)
{
timerStarted();
}
//Mouse Up event
private void ExitHoldState(object sender, RoutedEventArgs e)
{
timerStopped();
}
// Stops the timer and resets the timer count to 0
private void timerStopped()
{
dt.Stop();
timerCount = 0;
}
// Starts the timer and sets delayCounter function for counting the delay seconds and acts on it
private void timerStarted()
{
dt.Tick += delayCounter;
dt.Start();
}
//Once delay timer reaches 2 seconds, the button navigates to nextpage.
private void delayCounter(object sender, EventArgs e)
{
timerCount++;
if (timerCount == 2)
{
this.NavigationService.Navigate(new nextPage());
}
}
I recently had to implement a Button where I needed to it to trigger after being pressed for five seconds.
To do this I created an attached behavior. I have the five seconds backed into the behavior as I did not need this configurable but easily done with a Dependency Property and it is hooked up to be used with a Command in an MVVM way but it could easily be changed to trigger Click.
<Button Command="{Binding Path=ButtonCommand}">
<i:Interaction.Behaviors>
<behaviors:PressAndHoldBehavior />
</i:Interaction.Behaviors>
</Button>
public sealed class PressAndHoldBehavior : Behavior<Button>
{
private DispatcherTimer dispatcherTimer;
protected override void OnAttached()
{
dispatcherTimer = new DispatcherTimer {Interval = TimeSpan.FromSeconds(5)};
dispatcherTimer.Tick += OnDispatcherTimerTick;
AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObjectPreviewMouseLeftButtonDown;
AssociatedObject.PreviewMouseLeftButtonUp += AssociatedObjectPreviewMouseLeftButtonUp;
}
protected override void OnDetaching()
{
dispatcherTimer.Stop();
dispatcherTimer.Tick -= OnDispatcherTimerTick;
dispatcherTimer = null;
AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObjectPreviewMouseLeftButtonDown;
AssociatedObject.PreviewMouseLeftButtonUp -= AssociatedObjectPreviewMouseLeftButtonUp;
}
private void AssociatedObjectPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
dispatcherTimer.Start();
e.Handled = true;
}
private void AssociatedObjectPreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
dispatcherTimer.Stop();
e.Handled = true;
}
private void OnDispatcherTimerTick(object sender, EventArgs e)
{
AssociatedObject.Command.Execute(null);
}
}
I'm hoping someone can help me with what I thought would be a relatively straight forward problem.
I am setting a fadeout animation in code using a DoubleAnimation object. It fades out an image, and then fires off the Completed event when it's done.
I would like to get the name of the control that the fadeout animation was applied to from within the event handler, but I can't find a way.
Any help appreciated. Thanks.
DispatcherTimer timer = new DispatcherTimer();
public MainWindow()
{
InitializeComponent();
image1.Visibility = System.Windows.Visibility.Visible;
image2.Visibility = System.Windows.Visibility.Collapsed;
timer.Interval = TimeSpan.FromSeconds(2);
timer.Tick += new EventHandler(timer_Tick);
timer.Start();
}
void FadeOut(UIElement element)
{
DoubleAnimation FadeOut = new DoubleAnimation(1, 0, new Duration(TimeSpan.FromSeconds(0.5)));
FadeOut.Completed += new EventHandler(FadeOut_Completed);
element.BeginAnimation(OpacityProperty, FadeOut);
}
void FadeOut_Completed(object sender, EventArgs e)
{
// How to find out which control was targeted?
}
void timer_Tick(object sender, EventArgs e)
{
if (image1.Visibility == System.Windows.Visibility.Visible)
{
FadeOut(image1);
//image1.Visibility = System.Windows.Visibility.Collapsed;
//image2.Visibility = System.Windows.Visibility.Visible;
}
}
The following code gives you the target of completed animation. Place it in FadeOut_Completed() handler:
DependencyObject target = Storyboard.GetTarget(((sender as AnimationClock).Timeline as AnimationTimeline))
However this will only work if animation target object is specified. To do it add the following to FadeOut() method:
Storyboard.SetTarget(FadeOut, element);
I have a MediaElement, but how can I call a function when the property "position" of MediaElement changes?
Position is not a DependencyProperty.
You can use a DispatchTimer. This article provides some good insight on how to get this working. MediaElement and More with WPF.
Here is some sample code that I took from a project I'm working on. It shows the position of the video using a slider control and allows the user to change the position.
I'm a bit of a newbie too, so it is possible that some of it is wrong (feel free to comment on problems in the comments section :).
private DispatcherTimer mTimer;
private bool mIsDragging = false;
private bool mTick = false;
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
medPlayer.Play();
medPlayer.Stop();
mTimer = new DispatcherTimer();
mTimer.Interval = TimeSpan.FromMilliseconds(100);
mTimer.Tick += new EventHandler(mTimer_Tick);
mTimer.Start();
}
void mTimer_Tick(object sender, EventArgs e)
{
if (!mIsDragging)
{
try
{
mTick = true;
sldPosition.Value = medPlayer.Position.TotalMilliseconds;
}
finally
{
mTick = false;
}
}
}
private void sldPosition_DragStarted(object sender, System.Windows.Controls.Primitives.DragStartedEventArgs e)
{
mIsDragging = true;
medPlayer.Pause();
}
private void sldPosition_DragCompleted(object sender, System.Windows.Controls.Primitives.DragCompletedEventArgs e)
{
mIsDragging = false;
if (chkPlay.IsChecked.Value)
medPlayer.Play();
}
private void sldPosition_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
var pos = TimeSpan.FromMilliseconds(e.NewValue);
lblPosition.Content = string.Format("{0:00}:{1:00}", pos.Minutes, pos.Seconds);
if (!mTick)
{
medPlayer.Position = TimeSpan.FromMilliseconds(sldPosition.Value);
if (medPlayer.Position == medPlayer.NaturalDuration.TimeSpan)
{
chkPlay.IsChecked = false;
medPlayer.Stop();
}
}
}