Preventing multiple View clicks in Android (MonoDroid) using C# lock() - c#

I'm trying to prevent multiple clicks from taking affect, and would like to know if the following logic will cover all possibilities?
Currently, each successive "click" (touch) fires off an additional download.
private object CLICK_LOCK = new System.Object();
public void ViewClickHandler(object o, System.EventArgs a)
{
View clickedView = (View)o;
lock (CLICK_LOCK)
{
if (clickedView.Clickable == false)
{
return;
}
clickedView.Clickable = false;
}
// sets clickedView.Clickable = true when finished
(new DownloadAsyncTask()).Execute();
}

To prevent multiple View clicks in a short time, a better solution is set a limit time for the Button. If the time interval between the two clicks does not exceed the MIN_CLICK_DELAY_TIME, the event will not trigger.
//Prevent multiple clicks in 1 second.
public static int MIN_CLICK_DELAY_TIME = 1000;
private long lastClickTime = 0;
bt.Click += ViewClickHandler;
public void ViewClickHandler(object o, System.EventArgs a)
{
long currentTime = Calendar.Instance.TimeInMillis;
if (currentTime - lastClickTime > MIN_CLICK_DELAY_TIME)
{
lastClickTime = currentTime;
OnNoDoubleClick();
}
}
protected void OnNoDoubleClick()
{
(new DownloadAsyncTask()).Execute();
}

Related

C#.net, raising events while processing a long task, show a form which can have "Pause" and "Continue" to continue processing

I process a file line by line reading various events that have a time stamp and data associated with them. I want to be able to show a form while doing processing which I need to interact with and intercept some events by having a button saying interrupt EventX and if it is pressed it will show the event data in a rich text box field when this event is reached sometime in the future. I can then change some of that event data (let's say I simulate some conditions) and when I press "Resume" it should resume processing by raising an event to the intended subscriber for further processing.
So I need an interceptor that will be pass-trough mechanism when a certain form element is pressed and pass that data to the intended subscriber.
I am ok to wait synchronously for modifying data and pressing "Resume"
Thanks
If you want to have a Responsive GUI while doing a long running operation, you need some form of Multitasking. Wich means either async/await or any of the many Multithreading (Thread and BackgroundWorker, mostly) approaches
While pause and resume could be added, doing so usually more work then it is worth. At the very least you run into issues like still held filehandles or race conditions. Often a "cancel" action is way enough/better then a full stop/resume mechanic.
As a Beginner I would advice you to use the BackgroundWorker. It is about as easy as getting into Multitasking via Multithreading can be. I even wrote a example for it a few years back:
#region Primenumbers
private void btnPrimStart_Click(object sender, EventArgs e)
{
if (!bgwPrim.IsBusy)
{
//Prepare ProgressBar and Textbox
int temp = (int)nudPrim.Value;
pgbPrim.Maximum = temp;
tbPrim.Text = "";
//Start processing
bgwPrim.RunWorkerAsync(temp);
}
}
private void btnPrimCancel_Click(object sender, EventArgs e)
{
if (bgwPrim.IsBusy)
{
bgwPrim.CancelAsync();
}
}
private void bgwPrim_DoWork(object sender, DoWorkEventArgs e)
{
int highestToCheck = (int)e.Argument;
//Get a reference to the BackgroundWorker running this code
//for Progress Updates and Cancelation checking
BackgroundWorker thisWorker = (BackgroundWorker)sender;
//Create the list that stores the results and is returned by DoWork
List<int> Primes = new List<int>();
//Check all uneven numbers between 1 and whatever the user choose as upper limit
for(int PrimeCandidate=1; PrimeCandidate < highestToCheck; PrimeCandidate+=2)
{
//Report progress
thisWorker.ReportProgress(PrimeCandidate);
bool isNoPrime = false;
//Check if the Cancelation was requested during the last loop
if (thisWorker.CancellationPending)
{
//Tell the Backgroundworker you are canceling and exit the for-loop
e.Cancel = true;
break;
}
//Determin if this is a Prime Number
for (int j = 3; j < PrimeCandidate && !isNoPrime; j += 2)
{
if (PrimeCandidate % j == 0)
isNoPrime = true;
}
if (!isNoPrime)
Primes.Add(PrimeCandidate);
}
//Tell the progress bar you are finished
thisWorker.ReportProgress(highestToCheck);
//Save Return Value
e.Result = Primes.ToArray();
}
private void bgwPrim_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
pgbPrim.Value = e.ProgressPercentage;
}
private void bgwPrim_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
pgbPrim.Value = pgbPrim.Maximum;
this.Refresh();
if (!e.Cancelled && e.Error == null)
{
//Show the Result
int[] Primes = (int[])e.Result;
StringBuilder sbOutput = new StringBuilder();
foreach (int Prim in Primes)
{
sbOutput.Append(Prim.ToString() + Environment.NewLine);
}
tbPrim.Text = sbOutput.ToString();
}
else
{
tbPrim.Text = "Operation canceled by user or Exception";
}
}
#endregion
Thank you Christofer,
I accepted you answer as you gave me some suggestions how to solve my problem.
You can see bellow how I solved this problem
Rad
//class variable
private SimulatorRunner simulatorRunner;
//Code behind DevicesSimulatorForm form
private void RunSimulator()
{
btnRerun.BackColor = Color.BurlyWood;
ParameterizedThreadStart start = new ParameterizedThreadStart(RunSimulator);
Thread simulatorProcessingThread = new Thread(start);
simulatorProcessingThread.Start(this);
}
//This will run in a separate thread so when accessing controls Invoke is being used.
public void RunSimulator(object form)
{
DevicesSimulatorForm devicesSimulatorForm = (DevicesSimulatorForm) form;
simulatorRunner.Run(devicesSimulatorForm);
devicesSimulatorForm.InvokeEx(formInner =>
{
formInner.btnRerun.BackColor = Color.LightGray;
InitializeFields();
InitializeTextBackBorder();
InitializeButtonControls();
running = false;
});
}
public class SimulatorRunner
{
public void Run(DevicesSimulator form)
{
string buffer = "Some content read from file in a loop that needs to be passed
to a rich text box when a boolean Intercept check box is true
and FormStatusIntercept will return true and with Thread.Sleep(1)
we will have a chance to update the buffer to the new value and by
unchecking Intercept check box we will exit while loop and continue
processing"
while (true)
{
if (FormStatusIntercept(form, ref buffer))
{
Thread.Sleep(1);
}
else
{
publishEventArgs.Buffer = buffer;
break;
}
}
PublishEvent?.Invoke(this, publishEventArgs);
}
}
private bool FormStatusIntercept(DevicesSimulator simulatorForm, ref string buffer)
{
string modifiedBuffer = buffer;
//When btnFormStatus button is pressed it changes FormStatusContinued = true
//which allows continuation of the processing by exiting while loop
if (simulatorForm.FormStatusContinued == true)
{
simulatorForm.InvokeEx(form =>
{
if (form.rtbFormStatus.Text != modifiedBuffer)
{
modifiedBuffer = form.rtbFormStatus.Text;
}
form.FormStatusContinued = false;
form.FormStatusInterceptPending = false;
});
buffer = modifiedBuffer;
return false;
}
else if (simulatorForm.FormStatusIntercept == true)
{
if (simulatorForm.FormStatusInterceptPending == false)
{
//Whith check box pressed (true) we request a stop
//and we enter a while loop with Thread.Sleep(1)
simulatorForm.InvokeEx(form =>
{
form.btnFormStatus.Text = "Continue";
form.rtbFormStatus.Text = modifiedBuffer;
form.FormStatusInterceptPending = true;
});
}
return true;
}
return false;
}

Time based event in C#

what I want to do is the following:
I got several variables e.g. and when one variable changes in value (from 0 to 1) i want to start a 'time based event'.
public int a = 0;
public int b = 0;
if (a == 1)
{
//"check for two seconds if int b becomes 1 otherwise go back to usual loop"
}
//basically a second if-statement would follow:
if ( b == 1 within 5 seconds)
{
//"go to next step"
}
I realize this is extremely generic, but hopefully you get what I want to do.
If not, I can elaborate.
Thank you for help.
Capsule your variables and start a timer if the variables get changed:
//initialising
Timer T = new System.Timers.Timer(2000); //Timer with two second interval
aTimer.Elapsed += TimerElapsed;
private int a = 0;
public int A
{
get
{
return a;
}
set
{
if (value == 1)
{
T.Start();
}
a = value;
}
}
private void TimerElapsed(Object source, System.Timers.ElapsedEventArgs e)
{
//timer elapsed code
T.Stop();
}
if you change the value of your variable A, the timer gets startet if the new values is 1. After the Timer is elapsed it stops.

How to loop asynchronously?

I get List of websites I need to loop through and to spend on each certain amount of time. Looping needs to be asynchronous, because on each website music will be played, and that's the main point - to hear the music in that amount of time, and then to load another page and to listen to its music and so on. Also, form need to be available for user actions.
Code I've got so far is this:
public void playSound(List<String> websites)
{
webBrowser.Navigate(Uri.EscapeDataString(websites[0]));
foreach (String website in websites.Skip(1))
{
StartAsyncTimedWork(website);
// problem when calling more times
}
}
private System.Windows.Forms.Timer myTimer = new System.Windows.Forms.Timer();
private void StartAsyncTimedWork(String website)
{
myTimer.Interval = 7000;
myTimer.Tick += new EventHandler(myTimer_Tick);
myTimer.Start();
}
private void myTimer_Tick(object sender, EventArgs e)
{
if (this.InvokeRequired)
{
this.BeginInvoke(new EventHandler(myTimer_Tick), sender, e);
}
else
{
lock (myTimer)
{
if (this.myTimer.Enabled)
{
this.myTimer.Stop();
// here I should get my website which I need to search
// don't know how to pass that argument from StartAsyncTimedWork
}
}
}
}
One way to do this is as below.
Make websites a class field (if it isn't already), so the timer event handler can access this collection.
Add a field to keep track of the current index.
Add a field to prevent re-entrant calls to PlaySounds.
You're using a WinForms timer, which executes on the same thread as the form, so there's no need for InvokeRequired etc.
Some pseudo-code (warning, this is untested):
private bool isPlayingSounds;
private int index;
private List<String> websites;
private Timer myTimer;
private void Form1_Load()
{
myTimer = new System.Windows.Forms.Timer();
myTimer.Interval = 7000;
myTimer.Tick += new EventHandler(myTimer_Tick);
}
public void PlaySounds(List<String> websites)
{
if (isPlayingSounds)
{
// Already playing.
// Throw exception here, or stop and play new website collection.
}
else
{
isPlayingSounds = true;
this.websites = websites;
PlayNextSound();
}
}
private void PlayNextSound()
{
if (index < websites.Count)
{
webBrowser.Navigate(Uri.EscapeDataString(websites[index]));
myTimer.Start();
// Prepare for next website, if any.
index++;
}
else
{
// Remove reference to object supplied by caller
websites = null;
/ Reset index for next call to PlaySounds.
index = 0;
// Reset flag to indicate not playing.
isPlayingSounds = false;
}
}
private void myTimer_Tick(object sender, EventArgs e)
{
myTimer.Stop();
PlayNextSound();
}

How do I subscribe to raised events and printing together?

I have been working on a program that has 3 classes of which 2 of the classes have timers that repeat at different intervals and once one "cycle" of the timer is done it raises an event with a string as return. The 3rd class subscribes to the events from the other two timer classes and prints them to screen. it works great!
But my issue is that it is printing them separately. Lets say that the first timer class runs and then raises "hello" every 2 minutes and the other class "dog" every second and every time an event is raised it prints the raised event to console. I would want it to instead print "hellodog" every second and store the value of the first timer(hello) in a private field or something so it still prints to screen even if the timer(the slower 2 minute timer) hasn't been fired. and when the 2 minute timer fires it updates the value to whatever the new one is and that new value get printed to screen until it fires again.
If it is confusing I will gladly clarify. its kind of hard to explain.
namespace Final
{
public class Output
{
public static void Main()
{
var timer1 = new FormWithTimer();
var timer2 = new FormWithTimer2();
timer1.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
timer2.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer2_NewStringAvailable);
Console.ReadLine();
}
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString = e.Value;
//To something with 'theString' that came from timer 1
Console.WriteLine(theString);
}
static void timer2_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString2 = e.Value;
//To something with 'theString2' that came from timer 2
Console.WriteLine(theString2);
}
}
public abstract class BaseClassThatCanRaiseEvent
{
public class StringEventArgs : EventArgs
{
public StringEventArgs(string value)
{
Value = value;
}
public string Value { get; private set; }
}
//The event itself that people can subscribe to
public event EventHandler<StringEventArgs> NewStringAvailable;
protected void RaiseEvent(string value)
{
var e = NewStringAvailable;
if (e != null)
e(this, new StringEventArgs(value));
}
}
public partial class FormWithTimer : BaseClassThatCanRaiseEvent
{
Timer timer = new Timer();
public FormWithTimer()
{
timer = new System.Timers.Timer(200000);
timer.Elapsed += new ElapsedEventHandler(timer_Tick); // Everytime timer ticks, timer_Tick will be called
timer.Interval = (200000); // Timer will tick evert 10 seconds
timer.Enabled = true; // Enable the timer
timer.Start(); // Start the timer
}
void timer_Tick(object sender, EventArgs e)
{
...
RaiseEvent(gml.ToString());
}
}
public partial class FormWithTimer2 : BaseClassThatCanRaiseEvent
{
Timer timer = new Timer();
public FormWithTimer2()
{
timer = new System.Timers.Timer(1000);
timer.Elapsed += new ElapsedEventHandler(timer_Tick2); // Everytime timer ticks, timer_Tick will be called
timer.Interval = (1000); // Timer will tick evert 10 seconds
timer.Enabled = true; // Enable the timer
timer.Start(); // Start the timer
}
void timer_Tick2(object sender, EventArgs e)
{
...
RaiseEvent(aida.ToString());
}
}
}
You can use the same event handler for both timers. And construct the output by identifying the senders. (Didn't test the code for syntax errors.)
private static string timer1Value = string.Empty;
private static string timer2Value = string.Empty;
private static FormWithTimer timer1;
private static FormWithTimer2 timer2;
public static void Main()
{
timer1 = new FormWithTimer();
timer2 = new FormWithTimer2();
timer1.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
timer2.NewStringAvailable += new EventHandler<BaseClassThatCanRaiseEvent.StringEventArgs>(timer1_NewStringAvailable);
Console.ReadLine();
}
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
if (sender == timer1)
{
timer1Value = e.Value.ToString();
}
else if (sender == timer2)
{
timer2Value = e.Value.ToString();
}
if (timer1Value != String.Empty && timer2Value != String.Empty)
{
Console.WriteLine(timer1Value + timer2Value);
// Do the string concatenation as you want.
}
Correct me if I misunderstand the question, but it sounds like you want to coordinate your response to the two timer events (print "hellodog").
It seems to me that the easiest way to do this is to just use a single timer, and have the timer's event handler count the number of times the handler has been invoked to decide whether to take the once-per-second action, or also take the once-per-two-minutes action.
Since the slow timer is an exact multiple of your fast timer, you would set just one timer that triggers every second, and also do the 2-minute action every 120 invocations of the 1 second timer (120 seconds = 2 minutes).
I think I understand what you want and that is to synchronize the output of both timers. I am afraid there is no way to do it other than to slog through it. Set up a bunch of Boolean variables that track whether each event fired and whether the synchronized message was sent to the output.
This should do what you want.
public static void Main()
{
var timer1 = new FormWithTimer();
var timer2 = new FormWithTimer2();
var value1 = "";
var value2 = "";
Action writeValues = () => Console.WriteLine(value1 + value2);
timer1.NewStringAvailable += (s, e) =>
{
value1 = e.Value;
writeValues();
};
timer2.NewStringAvailable += (s, e) =>
{
value2 = e.Value;
writeValues();
};
Console.ReadLine();
}
Let me know if this is right. Cheers.
The second (quicker) timer should be the only one to print.
The first (slower) timer should only update a string which the second timer will use.
In the 'Output' class (you can put it before Main):
string string1;
and then:
static void timer1_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
string1 = e.Value;
}
static void timer2_NewStringAvailable(object sender, BaseClassThatCanRaiseEvent.StringEventArgs e)
{
var theString2 = e.Value;
//To something with 'theString2' that came from timer 2
Console.WriteLine(string1 + theString2);
}

C# how to loop while mouse button is held down

Can you point me in the right direction? I'm trying to get a loop to trigger while the form button is depressed.
//pseudocode
While (button1 is pressed)
value1 += 1
And then of course stop looping when the button is released
To avoid using threads you can add a Timer component on your form/control and simply enable it on mouse down and disable it on mouse up. Then put the code you would normally put inside the loop in the Timer_Tick event. If you want to use System.Timers.Timer you can use the Timer.Elapsed event instead.
Example (using System.Timers.Timer):
using Timer = System.Timers.Timer;
using System.Timers;
using System.Windows.Forms;//WinForms example
private static Timer loopTimer;
private Button formButton;
public YourForm()
{
//loop timer
loopTimer = new Timer();
loopTimer.Interval = 500;/interval in milliseconds
loopTimer.Enabled = false;
loopTimer.Elapsed += loopTimerEvent;
loopTimer.AutoReset = true;
//form button
formButton.MouseDown += mouseDownEvent;
formButton.MouseUp += mouseUpEvent;
}
private static void loopTimerEvent(Object source, ElapsedEventArgs e)
{
//this does whatever you want to happen while clicking on the button
}
private static void mouseDownEvent(object sender, MouseEventArgs e)
{
loopTimer.Enabled = true;
}
private static void mouseUpEvent(object sender, MouseEventArgs e)
{
loopTimer.Enabled = false;
}
You could use a thread to do the counting, and stop the thread when the mouse is released. The following has worked nicely for me:
var b = new Button { Text = "Press me" };
int counter = 0;
Thread countThread = null;
bool stop = false;
b.MouseDown += (s, e) =>
{
stop = false;
counter = 0;
countThread = new Thread(() =>
{
while (!stop)
{
counter++;
Thread.Sleep(100);
}
});
countThread.Start();
};
b.MouseUp += (s, e) =>
{
stop = true;
countThread.Join();
MessageBox.Show(counter.ToString());
};
Of course, if you want the event handlers to be methods rather than lambdas, you will have to turn all the variables into fields.
private void button1_MouseDown(object sender, MouseEventArgs e)
{
timer1.Enabled = true;
timer1.Start();
}
private void button1_MouseUp(object sender, MouseEventArgs e)
{
timer1.Stop();
}
private void timer1_Tick(object sender, EventArgs e)
{
numericUpDown1.Value++;
}
I was inspired by what I read here and decided to write my own button class called a RepeatingButton. On first click it waits for 500ms, then repeats ever 300ms until 2s, then repeats every 100ms (i.e. it uses acceleration).
Here is the code;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
/// <summary>
/// A repeating button class.
/// When the mouse is held down on the button it will first wait for FirstDelay milliseconds,
/// then press the button every LoSpeedWait milliseconds until LoHiChangeTime milliseconds,
/// then press the button every HiSpeedWait milliseconds
/// </summary>
public class RepeatingButton : Button
{
/// <summary>
/// Initializes a new instance of the <see cref="RepeatingButton"/> class.
/// </summary>
public RepeatingButton()
{
internalTimer = new Timer();
internalTimer.Interval = FirstDelay;
internalTimer.Tick += new EventHandler(internalTimer_Tick);
this.MouseDown += new MouseEventHandler(RepeatingButton_MouseDown);
this.MouseUp += new MouseEventHandler(RepeatingButton_MouseUp);
}
/// <summary>
/// The delay before first repeat in milliseconds
/// </summary>
public int FirstDelay = 500;
/// <summary>
/// The delay in milliseconds between repeats before LoHiChangeTime
/// </summary>
public int LoSpeedWait = 300;
/// <summary>
/// The delay in milliseconds between repeats after LoHiChangeTime
/// </summary>
public int HiSpeedWait = 100;
/// <summary>
/// The changeover time between slow repeats and fast repeats in milliseconds
/// </summary>
public int LoHiChangeTime = 2000;
private void RepeatingButton_MouseDown(object sender, MouseEventArgs e)
{
internalTimer.Tag = DateTime.Now;
internalTimer.Start();
}
private void RepeatingButton_MouseUp(object sender, MouseEventArgs e)
{
internalTimer.Stop();
internalTimer.Interval = FirstDelay;
}
private void internalTimer_Tick(object sender, EventArgs e)
{
this.OnClick(e);
TimeSpan elapsed = DateTime.Now - ((DateTime)internalTimer.Tag);
if (elapsed.TotalMilliseconds < LoHiChangeTime)
{
internalTimer.Interval = LoSpeedWait;
}
else
{
internalTimer.Interval = HiSpeedWait;
}
}
private Timer internalTimer;
}
Anywhere you have a button, you can just replace it with a repeating button and it will just have all the new functionality built in.
Enjoy!
Sterren
A recent article from Fabulous Adventures in Coding provides this narrative, which might help answer your question:
A surprising number of people have magical beliefs about how exactly applications respond to user inputs in Windows. I assure you that it is not magic. The way that interactive user interfaces are built in Windows is quite straightforward. When something happens, say, a mouse click on a button, the operating system makes a note of it. At some point, a process asks the operating system "did anything interesting happen recently?" and the operating system says "why yes, someone clicked this thing." The process then does whatever action is appropriate for that. What happens is up to the process; it can choose to ignore the click, handle it in its own special way, or tell the operating system "go ahead and do whatever the default is for that kind of event." All this is typically driven by some of the simplest code you'll ever see:
while(GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
That's it. Somewhere in the heart of every process that has a UI thread is a loop that looks remarkably like this one. One call gets the next message. That message might be at too low a level for you; for example, it might say that a key with a particular keyboard code number was pressed. You might want that translated into "the numlock key was pressed". TranslateMessage does that. There might be some more specific procedure that deals with this message. DispatchMessage passes the message along to the appropriate procedure.
I want to emphasize that this is not magic. It's a while loop. It runs like any other while loop in C that you've ever seen. The loop repeatedly calls three methods, each of which reads or writes a buffer and takes some action before returning. If one of those methods takes a long time to return (typically DispatchMessage is the long-running one of course since it is the one actually doing the work associated with the message) then guess what? The UI doesn't fetch, translate or dispatch notifications from the operating system until such a time as it does return.
Override the OnMouseDown() method in your form and then if the button you want is pressed, that would equal your loop. Example:
protected override void OnMouseDown(MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
// this is your loop
}
}
It's not a loop in the traditional sense, but should work for what you need.
You will need to handle the MouseDown() event for your form, using the MouseEventArgs argument to figure out which button was pressed.
RepeatButton is perfect for that:
<RepeatButton Delay="1000" Interval="500" HorizontalAlignment="Left" Content="+" Click="IncreaseButton_Click"/>
private void IncreaseButton_Click(object sender, RoutedEventArgs e)
{
value1++;
}
It's been several years since I posted this but someone upvoted it so it popped up in my notifications. Now that I have a lot more experience lol, I thought I'd see if this simple problem is as simple as it sounds, and it was:
public partial class Form1 : Form
{
private bool _isRunning;
public Form1()
{
InitializeComponent();
txtValue.Text = #"0";
btnTest.MouseDown += (sender, args) =>
{
_isRunning = true;
Run();
};
btnTest.MouseUp += (sender, args) => _isRunning = false;
}
private void Run()
{
Task.Run(() =>
{
while (_isRunning)
{
var currentValue = long.Parse(txtValue.Text);
currentValue++;
txtValue.Invoke((MethodInvoker) delegate
{
txtValue.Text = currentValue.ToString();
});
}
});
}
}
Based on Steztric's answer, an extension method with a few bug fixes and different options for the rate of increase.
/// <summary>
/// An extension method to add a repeat click feature to a button. Clicking and holding on a button will cause it
/// to repeatedly fire. This is useful for up-down spinner buttons. Typically the longer the mouse is held, the
/// more quickly the click events are fired. There are different options when it comes to increasing the rate of
/// clicks:
/// 1) Exponential - this is the mode used in the NumericUpDown buttons. The first delay starts off around 650 ms
/// and each successive delay is multiplied by 75% of the current delay.
/// 2) Linear - the delay more slowly reaches the fastest repeat speed. Each successive delay subtracts a fixed
/// amount from the current delay. Decreases in delays occur half a second apart.
/// 3) Two Speed - this delay starts off at a slow speed, and then increases to a faster speed after a specified delay.
/// 4) Three Speed - the repeat speed can increase from slow, to medium, to fastest after a specified delay.
///
/// If repeating is added to a button that already has it, then it will be replaced with the new values.
/// </summary>
public static class RepeatingButtonEx {
private static Hashtable ht = new Hashtable();
private class Data {
private static readonly System.Reflection.MethodInfo methodOnClick = null;
static Data() {
methodOnClick = typeof(Button).GetMethod("OnClick", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
}
public Button Button = null;
private Timer Timer = new Timer();
public double? GradientRate;
public int? LinearGradient = null;
public int FirstDelayMillis;
public int FastestRepeatMillis;
public int[] SwitchesMillis;
public int[] SpeedsMillis;
private DateTime lastEvent = DateTime.MinValue;
private int millisCount = 0;
private int currentSpeed = 0;
private int waitSum = 0;
public Data(Button button, double? gradientRate, int? linearGradient, int firstDelayMillis, int fastestRepeatMillis, int[] switchesMillis, int[] speedsMillis) {
Button = button;
GradientRate = gradientRate;
LinearGradient = linearGradient;
FirstDelayMillis = firstDelayMillis;
FastestRepeatMillis = fastestRepeatMillis;
SwitchesMillis = switchesMillis;
SpeedsMillis = speedsMillis;
Timer.Interval = firstDelayMillis;
Timer.Tick += Timer_Tick;
Button.MouseDown += Button_MouseDown;
Button.MouseUp += Button_MouseUp;
Button.MouseLeave += Button_MouseLeave;
}
void Button_MouseDown(object sender, MouseEventArgs e) {
if (!Button.Enabled)
return;
lastEvent = DateTime.UtcNow;
Timer.Start();
}
void Button_MouseUp(object sender, MouseEventArgs e) {
Reset();
}
void Button_MouseLeave(object sender, EventArgs e) {
Reset();
}
private void Reset() {
Timer.Stop();
Timer.Interval = FirstDelayMillis;
millisCount = 0;
currentSpeed = 0;
waitSum = 0;
}
void Timer_Tick(object sender, EventArgs e) {
if (!Button.Enabled) {
Reset();
return;
}
methodOnClick.Invoke(Button, new Object[] { EventArgs.Empty });
//Button.PerformClick(); // if Button uses SetStyle(Selectable, false); then CanSelect is false, which prevents PerformClick from working.
if (GradientRate.HasValue || LinearGradient.HasValue) {
int millis = Timer.Interval;
if (GradientRate.HasValue)
millis = (int) Math.Round(GradientRate.Value * millis);
else if (LinearGradient.HasValue) {
DateTime now = DateTime.UtcNow;
var ts = now - lastEvent;
int ms = (int) ts.TotalMilliseconds;
millisCount += ms;
// only increase the rate every 500 milliseconds
// otherwise it appears too get to the maximum rate too quickly
if (millisCount >= 500) {
millis -= LinearGradient.Value;
millisCount -= 500;
lastEvent = now;
}
}
if (millis < FastestRepeatMillis)
millis = FastestRepeatMillis;
Timer.Interval = millis;
}
else {
if (currentSpeed < SpeedsMillis.Length) {
TimeSpan elapsed = DateTime.UtcNow - lastEvent;
if (elapsed.TotalMilliseconds >= waitSum) {
waitSum += SwitchesMillis[currentSpeed];
Timer.Interval = SpeedsMillis[currentSpeed];
currentSpeed++;
}
}
}
}
public void Dispose() {
Timer.Stop();
Timer.Dispose();
Button.MouseDown -= Button_MouseDown;
Button.MouseUp -= Button_MouseUp;
Button.MouseLeave -= Button_MouseLeave;
}
}
///<summary>The repeating speed becomes exponentially faster. This is the default behavior of the NumericUpDown control.</summary>
///<param name="button">The button to add the behavior.<param>
///<param name="firstDelayMillis">The delay before first repeat in milliseconds.</param>
///<param name="fastestRepeatMillis">The smallest delay allowed. Note: Masharling between the timer and the UI thread has an unavoidable limit of about 10 milliseconds.</param>
///<param name="gradientRate">The new interval is the current interval multiplied by the gradient rate.</param>
public static void AddRepeatingExponential(this Button button, int firstDelayMillis = 500, int fastestRepeatMillis = 15, double gradientRate = 0.75) {
AddRepeating(button, firstDelayMillis, fastestRepeatMillis, gradientRate, null, null, null);
}
///<summary>The repeating speed becomes linearily faster.</param>
///<param name="button">The button to add the behavior.<param>
///<param name="firstDelayMillis">The delay before first repeat in milliseconds.</param>
///<param name="fastestRepeatMillis">The smallest delay allowed. Note: Masharling between the timer and the UI thread has an unavoidable limit of about 10 milliseconds.</param>
///<param name="linearGradient">If specified, the repeats gradually happen more quickly. The new interval is the current interval minus the linear gradient.</param>
public static void AddRepeatingLinear(this Button button, int firstDelayMillis = 500, int fastestRepeatMillis = 50, int linearGradient = 25) {
AddRepeating(button, firstDelayMillis, fastestRepeatMillis, null, linearGradient, null, null);
}
///<summary>The repeating speed switches from the slow speed to the fastest speed after the specified amount of milliseconds.</summary>
///<param name="button">The button to add the behavior.<param>
///<param name="firstDelayMillis">The delay before first repeat in milliseconds.</param>
///<param name="fastestRepeatMillis">The smallest delay allowed. Note: Masharling between the timer and the UI thread has an unavoidable limit of about 10 milliseconds.</param>
///<param name="slowRepeatMillis">The delay in milliseconds between repeats when in the slow repeat state.</param>
///<param name="slowToFastestSwitchMillis">The delay in milliseconds before switching from the slow repeat speed to the fastest repeat speed.</param>
public static void AddRepeatingTwoSpeed(this Button button, int firstDelayMillis = 500, int fastestRepeatMillis = 100, int slowRepeatMillis = 300, int slowToFastestSwitchMillis = 2000) {
AddRepeating(button, firstDelayMillis, fastestRepeatMillis, null, null, new[] { slowRepeatMillis, fastestRepeatMillis }, new [] { slowToFastestSwitchMillis, 0 });
}
///<summary>The repeating speed switches from the slow to medium to fastest at speed switch interval specified.</summary>
///<param name="button">The button to add the behavior.<param>
///<param name="firstDelayMillis">The delay before first repeat in milliseconds.</param>
///<param name="fastestRepeatMillis">The smallest delay allowed. Note: Masharling between the timer and the UI thread has an unavoidable limit of about 10 milliseconds.</param>
///<param name="slowRepeatMillis">The delay in milliseconds between repeats when in the slow repeat state.</param>
///<param name="mediumRepeatMillis">The delay in milliseconds between repeats when in the medium repeat state.</param>
///<param name="speedSwitchMillis">The delay in milliseconds before switching from one speed state to the next speed state.</param>
public static void AddRepeatingThreeSpeed(this Button button, int firstDelayMillis = 500, int fastestRepeatMillis = 75, int slowRepeatMillis = 300, int mediumRepeatMillis = 150, int speedSwitchMillis = 2000) {
AddRepeating(button, firstDelayMillis, fastestRepeatMillis, null, null, new[] { slowRepeatMillis, mediumRepeatMillis, fastestRepeatMillis }, new [] { speedSwitchMillis, speedSwitchMillis, 0 });
}
private static void AddRepeating(this Button button, int firstDelayMillis, int fastestRepeatMillis, double? gradientRate, int? linearGradient, int[] speedsMillis, int[] switchesMillis) {
Data d = (Data) ht[button];
if (d != null)
RemoveRepeating(button);
d = new Data(button, gradientRate, linearGradient, firstDelayMillis, fastestRepeatMillis, switchesMillis, speedsMillis);
ht[button] = d;
button.Disposed += delegate {
RemoveRepeating(button);
};
}
///<summary>Removes the repeating behavior from the button.</summary>
public static void RemoveRepeating(this Button button) {
Data d = (Data) ht[button];
if (d == null)
return;
ht.Remove(button);
d.Dispose();
}
}
you could use the mouseMove Event and check if the mousebutton is held down like:
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if(e.Button==MouseButtons.Left)
{
//your code here
}
}
Similar to Timwi's solution above except using async/await for asynchronous IO and lock for synchronization for some state...
using System;
using System.Windows.Forms;
using System.Threading.Tasks;
namespace Foo {
partial class Form1: Form {
private static readonly object mousePressLock = new object();
private bool mousePressed;
private Task task;
private async Task MouseAction(Action action) {
while (true) {
lock (mousePressLock) {
if (mousePressed)
action();
else
break;
}
await Task.Delay(100).ConfigureAwait(false);
}
}
private void PnlTranslate_Paint(object sender, PaintEventArgs e) {
}
private void Up_MouseUp(object sender, MouseEventArgs e) {
lock (mousePressLock) { mousePressed = false; }
task.Wait();
}
private void Up_MouseDown(object sender, MouseEventArgs e) {
lock (mousePressLock) { mousePressed = true; }
int cnt = 0;
task = MouseAction(() => {
Console.WriteLine($"mouse up action {++cnt}");
});
}
public Form1() {
InitializeComponent();
mousePressed = false;
task = null;
}
}
}
Also, note the ConfigureAwait(false) call. I ran into deadlock without that b.c. tasks were fighting to be on the same thread. It was so annoying.

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