Multi-threading issue in c# - c#

I am trying to graph data with Interval timing in my Windows Forms Application.
I need the graphing elements to be ran on a separate thread, but I have three different functions being called and cant simply use thread.start();
I tried running just the controls in it's own thread but it tells me that another thread owns the controls.
When I run the program as is, the chart lags horribly, meaning it needs to be in an independent thread
This all needs to be ran on a seperate thread because my form lags when updating this
public void GraphData()
{
var mapper = Mappers.Xy<MeasureModel>()
.X(model => model.DateTime.Ticks) //use DateTime.Ticks as X
.Y(model => model.Value); //use the value property as Y
Charting.For<MeasureModel>(mapper);
//the ChartValues property will store our values array
ChartValues = new ChartValues<MeasureModel>();
cartesianChart1.Series = new SeriesCollection
{
new LineSeries
{
Values = ChartValues,
PointGeometrySize = 1,
StrokeThickness = 2
}
};
cartesianChart1.AxisX.Add(new Axis
{
DisableAnimations = true,
LabelFormatter = value => new System.DateTime((long)value).ToString("hh:mm:ss"),
Separator = new Separator
{
Step = TimeSpan.FromSeconds(1).Ticks
}
});
var thread = new Thread(() =>
{
SetAxisLimits(System.DateTime.Now);
Timer = new System.Windows.Forms.Timer
{
Interval = 20
};
Timer.Tick += TimerOnTick;
Timer.Tick += timerdata_event;
Timer.Start();
});
thread.Start();
}
public ChartValues<MeasureModel> ChartValues { get; set; }
public System.Windows.Forms.Timer Timer { get; set; }
private void SetAxisLimits(System.DateTime now)
{
cartesianChart1.AxisX[0].MaxValue = now.Ticks + TimeSpan.FromMilliseconds(1000).Ticks; // force the axis to be 100ms ahead
cartesianChart1.AxisX[0].MinValue = now.Ticks - TimeSpan.FromSeconds(4).Ticks; // only care about the last 8 seconds
}
private void TimerOnTick(object sender, EventArgs eventArgs)
{
var now = DateTime.Now;
var queue = new Queue(tempStore);
var b = queue.Dequeue();
ChartValues.Add(new MeasureModel
{
DateTime = now,
Value = double.Parse(b.ToString())
});
SetAxisLimits(now);
if (ChartValues.Count > 100) ChartValues.RemoveAt(0);
}

Take a look at BackgroundWorker. It's a system component that allows a threaded procedure to do its work asynchronously and provides two callback events (ProgressChanged, RunWorkerCompleted) that are run on the UI thread.

there are two things ...
1. windows form use queue not threading, and it's build on STA (Single Thread Architect) event though when we look at it, it look like MTA...
So first thing, if you run in separate thread, you should synchronize with windows queue... it sometime even cause errors if you don't do that when you work with controls
calling: this (which this mean this form instance)
this.Invoke(new Action(delegate(){ /* your Synchronized code comes here */}))
or (Action)delegate() {} as i saw in internet
Second put calculation on background, perform something such as dual buffering... mean you don't neither apply, nor synchronize with your form, while you are performing calculation or drawings...
once you are done, you just apply does are drawn in the back....
So your end code will be like this:
{ //New thread function
// Calculates
// Draw arts
// Synchronize
this.Invoke((Action)delegate() {
//Perform Synchronizing Code
// Apply your drawn image and graphics to your image viewer, aka picture box
}
// End of thread, or if you need something extra to be performed afterward...
}
But if you do not have access to that component drawer.... try see how the performance look like, if you pass it parameters in the background, then add it to your form? if the processing of initializing the component is lower than changing graphic while running, if that looked good, go with that way, cause when you draw in some component, every change cause the form to redraw, and it comes with performance penalty.

Related

How to keep cancelling the task until a condition is met (TaskCanceledException)

I want to call a method after some delay when an event is raised, but any subsequent events should "restart" this delay. Quick example to illustrate, the view should be updated when scrollbar position changes, but only 1 second after the user has finished scrolling.
Now I can see many ways of implementing that, but the most intuitive would be to use Task.Delay + ContinueWith + cancellation token. However, I am experiencing some issues, more precisely subsequent calls to my function cause the TaskCanceledException exception and I started to wonder how I could get rid of that. Here is my code:
private CancellationTokenSource? _cts;
private async void Update()
{
_cts?.Cancel();
_cts = new();
await Task.Delay(TimeSpan.FromSeconds(1), _cts.Token)
.ContinueWith(o => Debug.WriteLine("Update now!"),
TaskContinuationOptions.OnlyOnRanToCompletion);
}
I have found a workaround that works pretty nicely, but I would like to make the first idea work.
private CancellationTokenSource? _cts;
private CancellationTokenRegistration? _cancellationTokenRegistration;
private void Update()
{
_cancellationTokenRegistration?.Unregister();
_cts = new();
_cancellationTokenRegistration = _cts.Token.Register(() => Debug.WriteLine("Update now!"));
_cts.CancelAfter(1000);
}
You should consider using Microsoft's Reactive Framework (aka Rx) - NuGet System.Reactive and add using System.Reactive.Linq;.
You didn't say hat UI you're using, so for Windows Forms also add System.Reactive.Windows.Forms and for WPF System.Reactive.Windows.Threading.
Then you can do this:
Panel panel = new Panel(); // assuming this is a scrollable control
IObservable<EventPattern<ScrollEventArgs>> query =
Observable
.FromEventPattern<ScrollEventHandler, ScrollEventArgs>(
h => panel.Scroll += h,
h => panel.Scroll -= h)
.Select(sea => Observable.Timer(TimeSpan.FromSeconds(1.0)).Select(_ => sea))
.Switch();
IDisposable subscription = query.Subscribe(sea => Console.WriteLine("Hello"));
The query is firing for every Scroll event and starts a one second timer. The Switch operator watches for every Timer produces and only connects to the latest one produced, thus ignoring the previous Scroll events.
And that's it.
After scrolling has a 1 second pause the word "Hello" is written to the console. If you begin scrolling again then after every further 1 second pause it fires again.
In my own experience I've dealt with lots of scenarios just like the one you describe, e.g. update something one second after the mouse stops moving etc.
For a long time I would do timer restarts just the way you describe, by cancelling an old task and starting a new one. But I never really liked how messy that was, so I came up with an alternative that I use in production code. Long-term it has proven quite reliable. It takes advantage of the captured context associated with a task. Multiple instances of TaskCanceledException no longer occur.
class WatchDogTimer
{
int _wdtCount = 0;
public TimeSpan Interval { get; set; } = TimeSpan.FromSeconds(1);
public void Restart(Action onRanToCompletion)
{
_wdtCount++;
var capturedCount = _wdtCount;
Task
.Delay(Interval)
.GetAwaiter()
.OnCompleted(() =>
{
// If the 'captured' localCount has not changed after awaiting the Interval,
// it indicates that no new 'bones' have been thrown during that interval.
if (capturedCount.Equals(_wdtCount))
{
onRanToCompletion();
}
});
}
}
Another nice perk is that it doesn't rely on platform timers and works just as well in iOS/Android as it does in WinForms/WPF.
For purposes of demonstration, this can be exercised in a quick console demo where the MockUpdateView() action is sent to the WDT 10 times at 500 ms intervals. It will only execute one time, 500 ms after the last restart is received.
static void Main(string[] args)
{
Console.Title = "Test WDT";
var wdt = new WatchDogTimer { Interval = TimeSpan.FromMilliseconds(500) };
Console.WriteLine(DateTime.Now.ToLongTimeString());
// "Update view 500 ms after the last restart."
for (int i = 0; i < 10; i++)
{
wdt.Restart(onRanToCompletion: ()=>MockUpdateView());
Thread.Sleep(TimeSpan.FromMilliseconds(500));
}
Console.ReadKey();
}
static void MockUpdateView()
{
Console.WriteLine($"Update now! WDT expired {DateTime.Now.ToLongTimeString()}");
}
}
So, with 500 ms times 10 restarts this verifies one event at 5 seconds from the start.
You can combine a state variable and a delay to avoid messing with timers or task cancelation. This is far simpler IMO.
Add this state variable to your class/form:
private DateTime _nextRefresh = DateTime.MaxValue;
And here's how you refresh:
private async void Update()
{
await RefreshInOneSecond();
}
private async Task RefreshInOneSecond()
{
_nextRefresh = DateTime.Now.AddSeconds(1);
await Task.Delay(1000);
if (_nextRefresh <= DateTime.Now)
{
_nextRefresh = DateTime.MaxValue;
Refresh();
}
}
If you call RefreshInOneSecond repeatedly, it pushes out the _nextRefresh timestamp until later, so any refreshes already in flight will do nothing.
Demo on DotNetFiddle
One approach is to create a timer and reset this whenever the user does something. For example using System.Timers.Timer
timer = new Timer(1000);
timer.SynchronizingObject = myControl; // Needs a winforms object for synchronization
timer.Elapsed += OnElapsed;
timer.Start(); // Don't forget to stop the timer whenever you are done
...
private void OnUserUpdate(){
timer.Interval = 1000; // Setting the interval will reset the timer
}
There are multiple timers to chose from, I believe the same pattern is possible with the other timers. DispatchTimer might be most suitable if you use WPF.
Note that both System.Timers.Timer and Task.Delay uses System.Threading.Timer in the background. It is possible to use this directly, just call the .Change method to reset it. But be aware that this raises the event on a taskpool thread, so you need to provide your own synchronization.
I implemented the same scenario in a JavaScript application using Timer. I believe it's the same in the .NET world. Anyway handling this use-case when the user calls a method repeatedly with Task.Delay() will put more pressure on GC & thread pool
var timer = new Timer()
{
Enabled = true,
Interval = TimeSpan.FromSeconds(5).TotalMilliseconds,
};
timer.Elapsed += (sender, eventArgs) =>
{
timer.Stop();
// do stuff
}
void OnKeyUp()
{
timer.Stop();
timer.Start();
}

How to improve performance on wpf GUI main thread that is done in two windows

I have a wpf application, It has mainWindow that creates _otherWindow that displays on a secondary monitor. Both windows have elements that need to change along with time. (mainWindow updates an Image and also plots a graph, finally _otherWindow updates a shape position depending on some computations).
What is my problem? well, I am reading a video frame by frame within a Thread (however I would like to allow this with stream taken with a camera). And as I update GUI every frame in a certain time, Application is getting a heavy load and is getting slow...
I realized that commenting either mainWindow updating Image, or commenting _otherWindow updating shape position codes make the application run nice, but the issue is when they run together.
Here is a detailed description
First I compute some things inside _otherWindow and compute position of a shape.
Then I compute some stuff related to image and the update frame adding some stuff to bitmap
Then I update position of shape inside _otherWindow
Finally I plot results (the plot needs data gotten from mainWindow and _otherWindow)
For this, I use tasks and wait for them.
I have this:
private Thread _camera;
private void CaptureVideo()
{
_camera = new Thread(CaptureVideoCallback)
{
Priority = ThreadPriority.Highest
};
_camera.Start();
}
private VideoCapture _capture;
private void CaptureVideoCallback()
{
//some computing here read from a video file...
_capture = new VideoCapture("someVideo.mp4");
for (var i = 0; i < _capture.FrameCount; i++)
{
_capture.Read(_frame);
if (_frame.Empty()) return;
//*************task that does heavy computation in other class
var heavyTaskOutput1 = Task.Factory.StartNew(() =>
{
_otherWindow.Dispatcher.Invoke(() =>
{
ResultFromHeavyComputationMethod1 = _otherWindow.HeavyComputationMethod1();
});
}
);
////*************task that does heavy computation in current class
var heavyTaskOutput2 = Task.Factory.StartNew(() =>
{
ResultFromHeavyComputationMethod2 = HeavyComputationMethod2(ref _frame);
var bitmap = getBitmapFromHeavyComputationMethod2();
bitmap.Freeze();
//update GUI in main thread
Dispatcher.CurrentDispatcher.Invoke(() => ImageSource = bitmap);
});
////*************wait both task to complete
Task.WaitAll(heavyTaskOutput1, heavyTaskOutput2 );
//update _otherWindow GUI
var outputGui = Task.Factory.StartNew(() =>
{
_otherWindow.Dispatcher.Invoke(() =>
{
_otherWindow.UpdateGui();
});
}
);
outputGui.Wait();
////*************plot in a char using gotten results, UPDATE GUI
Task.Run(() =>
{
PlotHorizontal();
});
}
}
What would be a good way to speed this up?
I mean I know that GUI stuff need to be done on main thread, but this is slowing down things.
Edit
Have changed code as Clemens suggested:
//*************task that does heavy computation in other class
var heavyTaskOutput1 = Task.Run(() =>
{
ResultFromHeavyComputationMethod1 = _otherWindow.HeavyComputationMethod1();
}
);
////*************task that does heavy computation in current class
var heavyTaskOutput2 = Task.Run(() =>
{
ResultFromHeavyComputationMethod2 = HeavyComputationMethod2(ref _frame);
var bitmap = getBitmapFromHeavyComputationMethod2();
bitmap.Freeze();
//update GUI in main thread
Dispatcher.CurrentDispatcher.Invoke(() => ImageSource = bitmap);
});
////*************wait both task to complete
Task.WaitAll(heavyTaskOutput1, heavyTaskOutput2);
//update _otherWindow GUI
var outputGui = Task.Run(() =>
{
_otherWindow.Dispatcher.Invoke(() =>
{
_otherWindow.UpdateGui();
});
}
);
outputGui.Wait();
It's a bit hard to guess. Do you have Visual Studio? I think even the Community edition has some profiling capabilities (menu: Analyze/Performance Profiler...). That may point out some non-obvious bottlenecks.
My thoughts:
getBitmapFromHeavyComputationMethod2 appears to return a new bitmap every time through. I can't infer the actual type it's returning, but it likely involves a semi-large un-managed memory allocation and implements IDisposable. You might check on whether you're disposing that appropriately.
Rather than create a new bitmap for every frame, can you use a WriteableBitmap? Be sure to lock and unlock it if you do. Perhaps ping-pong (alternate) between two bitmaps if you need to.
It appears you may be serializing your "heavy computation" with your I/O read (first one, then the other). Perhaps launch the read as an async as well, and wait on it in your WaitAll so that the computation and I/O can happen concurrently. Something in this shape:
var readResult = _capture.Read(_frame);
for (...) {
// check read result
// ...
// launch heavy computation
readResult = Task.Run(() => _capture.Read(nextFrame);
Task.WaitAll(pupilOutput, outputTest, readResult);
_frame = nextFrame;
}
Note this would read N+1 times for N frames--maybe your Read method is okay with that.

C# WinForms Trying to Update UI with Timer but without slowing the performance down

so currently I've got an application that has 2 processes. One process is pining, while pinging the process is writing down the results into an array.
Another process is for updating the UI every second with a timer. Whats being update is an mschart to be more exact.
That's how I have set up the timer:
readonly System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
myTimer.Interval = 1000;
myTimer.Tick += WriteFunction;
Now this is the method that I'm calling every second for refreshing the UI / actually Graph:
private void WriteFunction(object objectInfo, EventArgs e)
{
foreach (NetPinger.source.AddGraph b in graphList)
{
b.fileRead();
}
}
The method, for updating the chart is inside another class, and looks like this:
public void fileRead()
{
double unixTimestamp = (Int32)(DateTime.UtcNow.Subtract(new DateTime(1970, 1, 1))).TotalSeconds;
chart_holder.Series[0].Points.Clear();
for (double i = unixTimestamp; unixTimestamp - graphSizing < i; i--)
{
bool exists;
try
{
exists = Array.Exists(file, element => element.XValue == i);
exists = true;
}
catch
{
exists = false;
}
try
{
if (exists == false)
{
DataPoint point = new DataPoint(i, 0);
chart_holder.Series[0].Points.Add(point);
}
else
{
DataPoint point = Array.Find(file, element => element.XValue == i);
chart_holder.Series[0].Points.Add(point);
}
}
catch(Exception ex)
{
MessageBox.Show(Convert.ToString(ex));
}
}
}
Now what I noticed was that if the graphSizing (number that I'm looping through) is kept low, the performance is kinda fine and everything is sync (multiple graphs from UI are updated at same time etc.) like it should be. But as soon as i rise it let's say to like 50 or even 250 (what the goal should be) the UI and Graph updating are being very very slow. It's only updating like every 3s and the UI is in general very laggy and slow.
Does anyone has any advice how I can maintain good performance or where I messed up that the UI is so slow? For further questions or more details feel free to ask.
Thanks a lot for your time and helping.
Greetings C.User
Your code always runs in the UI thread, since System.Windows.Forms.Timer calls the delegate on the UI thread. Even if that where not the case (and you used System.Timer instead), you delegate everything back to the UI with your Invoke call. You need to make sure you prepare the data on another thread first and do as little as possible in the UI thread itself.

Dedicated C# class to update progressbar

I would like to make a dedicated class to update the progress bar in my apps (in this case a WPF progressbar). I did something like this :
public class ProgressBarUpdate : IDisposable
{
private readonly double _delta;
private int _current;
private int _total;
private readonly ProgressBar _pb;
public ProgressBarUpdate(ProgressBar pb, int total)
{
_pb = pb;
_total = total;
// the pb.Maximum is a double so it doesn`t get truncated
_delta = _pb.Maximum / total;
_current = 0;
_pb.Visibility = Visibility.Visible;
}
public void Dispose()
{
_pb.Visibility = Visibility.Collapsed;
_current = 0;
}
public void UpdateProgress()
{
_pb.Value =(int)_delta * (++_current);
}
That i use like this (in the UI thread) :
using (var pu = new ProgressBarUpdate(pb, totalCount)
{
for (x=0; x<totalCount; x++)
{
// operations here
pu.UpdateProgress()
}
}
But the UI, probably blocked, is not updating correctly. What is the best way to display all the progress?
Winforms/WPF program is an Eventing system. There is a single thread which continuously processes events from an event queue. That is its main job and ideally that is the only thing which it should do. Any sort of UI activity generates events in the event queue - like you move your mouse over the window or click something or some other window overlaps your window and then again when it goes away from the overlapped position. All these events are processed by the UI thread and that keeps the UI updated all the time.
Further, Winforms/WPF make it necessary to access and/or update controls and their properties in a thread safe manner by allowing it only on the UI thread.
If you block this UI thread or do some other CPU bound calculation on it, then your UI responsiveness and updated behavior will suffer. Worst case UI will freeze.
Hence the correct answer for you is to do your calculation loop on another worker thread and only update the progress bar UI by marshaling the call to UI thread using the Dispatcher.
However, to answer your question and satisfy your inquisition, here is something that is possible - but it is bad practice and your should never do the following...:
To make it simple, when you update the Value property of the progress bar, it invalidates the progress bar UI - so, UI must update. Hence lets say an event is generated in the event queue which will cause some code to run which will update the UI. However, you are running in a loop over the UI thread - so, the thread has no chance to process this event unless your loop is over. Hence you don't see any UI update. The trick is to make the UI thread process that event before you make the next update on the Value of progress bar. You can do this by forcefully invoking a lower priority item into the event queue - so that normal and higher priority items are processed before going to the next iteration.
using (var pu = new ProgressBarUpdate(pb, totalCount))
{
for (int x = 0; x < totalCount ; x++)
{
// operations here
pu.UpdateProgress();
Dispatcher.Invoke(DispatcherPriority.Background, new Action(()=>{}));
}
}
If you're doing your work, and calling UpdateProgress, on the UI thread then it won't update until you finish the work and the UI thread can do other work (like refresh the UI). So this will never work.
If you're doing your work on a background thread, then you need to use a Dispatcher to marshal the setting the value to the UI thread.
Here's an example from http://tech.pro/tutorial/800/working-with-the-wpf-dispatcher
if (!myCheckBox.Dispatcher.CheckAccess())
{
myCheckBox.Dispatcher.Invoke(
System.Windows.Threading.DispatcherPriority.Normal,
new Action(
delegate()
{
myCheckBox.IsChecked = true;
}
));
}
else
{
myCheckBox.IsChecked = true;
}
Try this:
public ProgressBarUpdate(ProgressBar pb, int total)
{
_pb = pb;
_total = total;
_delta = _pb.MaxValue/((double)total); /make sure you do not truncate delta
_current = 0;
_pb.Visibility = Visibility.Visible;
}
public void Dispose()
{
_pb.Visibility = Visibility.Collapsed;
_current = 0;
}
public void UpdateProgress()
{
_pb.Value = (int)( _delta * (++_current)); //update after the increment
}
I suggest also using float instead of double.
You've been saying you want to avoid using threads, I assume because you don't want unnecessary complication, but it's really not a big deal. It's a very simple matter to make an operation multi-threaded. Even for very short and simple tasks, this is the most straightforward way to achieve what you want. Using TPL, it would look something like this:
using System.Threading.Tasks;
...
Task.Factory.StartNew(() => {
for (...) {
// operation...
progressBar.Dispatcher.BeginInvoke(() => progressBar.Value = ...);
}
});

Pause execution of a method without locking GUI. C#

I'm working on a card game in C# for a project on my Intro to OOP paper and have got the game working now but am adding "flair" to the GUI.
Currently cards are dealt and appear on the UI instantaneously. I want to have to program pause for a moment after dealing a card before it deals the next.
When a game is started the following code runs to populate the PictureBoxes that represent them (will be a loop eventually):
cardImage1.Image = playDeck.deal().show();
cardImage2.Image = playDeck.deal().show();
cardImage3.Image = playDeck.deal().show();
cardImage4.Image = playDeck.deal().show();
cardImage5.Image = playDeck.deal().show();
...
I have tries using System.Threading.Thread.Sleep(100); between each deal().show() and also inside each of those methods but all it achieves is locking up my GUI until all of the sleeps have processed then display all of the cards at once.
I have also tried using a combination of a timer and while loop but it resulted in the same effect.
What would be the best way of achieving the desired result?
The problem is that any code that you run on the UI will block the UI and freeze the program. When your code is running (even if it's running Thread.Sleep), messages (such as Paint or Click) sent to the UI will not be processed (until control returns to the message loop when you exit your event handler), causing it to freeze.
The best way to do this is to run on a background thread, and then Invoke to the UI thread between sleeps, like this:
//From the UI thread,
ThreadPool.QueueUserWorkItem(delegate {
//This code runs on a backround thread.
//It will not block the UI.
//However, you can't manipulate the UI from here.
//Instead, call Invoke.
Invoke(new Action(delegate { cardImage1.Image = playDeck.deal().show(); }));
Thread.Sleep(100);
Invoke(new Action(delegate { cardImage2.Image = playDeck.deal().show(); }));
Thread.Sleep(100);
Invoke(new Action(delegate { cardImage3.Image = playDeck.deal().show(); }));
Thread.Sleep(100);
//etc...
});
//The UI thread will continue while the delegate runs in the background.
Alternatively, you could make a timer and show each image in the next timer tick. If you use a timer, all you should do at the beginning is start the timer; don't wait for it or you'll introduce the same problem.
Normally I'd simply recommend a function like this to perform a pause while allowing the UI to be interactive.
private void InteractivePause(TimeSpan length)
{
DateTime start = DateTime.Now;
TimeSpan restTime = new TimeSpan(200000); // 20 milliseconds
while(true)
{
System.Windows.Forms.Application.DoEvents();
TimeSpan remainingTime = start.Add(length).Subtract(DateTime.Now);
if (remainingTime > restTime)
{
System.Diagnostics.Debug.WriteLine(string.Format("1: {0}", remainingTime));
// Wait an insignificant amount of time so that the
// CPU usage doesn't hit the roof while we wait.
System.Threading.Thread.Sleep(restTime);
}
else
{
System.Diagnostics.Debug.WriteLine(string.Format("2: {0}", remainingTime));
if (remainingTime.Ticks > 0)
System.Threading.Thread.Sleep(remainingTime);
break;
}
}
}
But there seems to be some complication in using such a solution when it is called from within an event handler such as a button click. I think the system wants the button click event handler to return before it will continue processing other events because if I try to click again while the event handler is still running, the button depresses again even though I'm trying to drag the form and not click on the button.
So here's my alternative. Add a timer to the form and create a dealer class to handle dealing with cards by interacting with that timer. Set the Interval property of the timer to match the interval at which you want cards to be dealt. Here's my sample code.
public partial class Form1 : Form
{
CardDealer dealer;
public Form1()
{
InitializeComponent();
dealer = new CardDealer(timer1);
}
private void button1_Click(object sender, EventArgs e)
{
dealer.QueueCard(img1, cardImage1);
dealer.QueueCard(img2, cardImage2);
dealer.QueueCard(img3, cardImage1);
}
}
class CardDealer
{
// A queue of pairs in which the first value represents
// the slot where the card will go, and the second is
// a reference to the image that will appear there.
Queue<KeyValuePair<Label, Image>> cardsToDeal;
System.Windows.Forms.Timer dealTimer;
public CardDealer(System.Windows.Forms.Timer dealTimer)
{
cardsToDeal = new Queue<KeyValuePair<Label, Image>>();
dealTimer.Tick += new EventHandler(dealTimer_Tick);
this.dealTimer = dealTimer;
}
void dealTimer_Tick(object sender, EventArgs e)
{
KeyValuePair<Label, Image> cardInfo = cardInfo = cardsToDeal.Dequeue();
cardInfo.Key.Image = cardInfo.Value;
if (cardsToDeal.Count <= 0)
dealTimer.Enabled = false;
}
public void QueueCard(Label slot, Image card)
{
cardsToDeal.Enqueue(new KeyValuePair<Label, Image>(slot, card));
dealTimer.Enabled = true;
}
}
The cheap way out would be to loop with calls to Application.DoEvents() but a better alternative would be to set a System.Windows.Forms.Timer which you would stop after the first time it elapses. In either case you'll need some indicator to tell your UI event handlers to ignore input. You could even just use the timer.Enabled property for this purpose if it's simple enough.
I would try puting the code that deals the deck ( and calls Thread.Sleep) in another thread.

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