I am trying to create a windows form that gets displayed for 2 seconds when triggerd by an event, and then closes automatically.
I have tried several options. This is my current code:
this.aletPopup.StartPosition = FormStartPosition.CenterScreen;
this.aletPopup.Show();
Thread.Sleep(2000);
this.aletPopup.Close();
This preforms the actions that I desire, however, when the form loads it does not load the label or image which is on the form. Instead, the area where the image and label are become transparent. My desired output is this:
I have also tried using this.aletPopup.ShowDialog();, which does display the graphics. However, the form will not close automatically when using this method.
EDIT: I am attempting to use
Michael Perrenoud's solution. However, I cannot get the form to close. I have a timer set at a 2000ms interval which is initally disabled. Am I overriding the OnShown correctly?
public AlertPopForm()
{
InitializeComponent();
}
private void closingTimer_Tick(object sender, EventArgs e)
{
closingTimer.Enabled = false;
this.Close();
}
private void AlertPopForm_OnShown(object sender, System.EventArgs e)
{
closingTimer.Enabled = true;
closingTimer.Start();
}
Instead, how about leveraging ShowDialog, and then using a Timer on the dialog form. In the Tick event of the Timer, close the form.
this.aletPopup.StartPosition = FormStartPosition.CenterScreen;
this.aletPopup.ShowDialog();
You could even pass the interval into the .ctor of the dialog form if you wanted some flexibility.
It's very important to note here that you'd need to leverage the OnShown override to actually Start the Timer so the form is in fact shown to the user.
The reason can be in Message Loop. When you block your thread by Thread.Sleep, it also blocks Message loop.
You can make like this:
this.aletPopup.StartPosition = FormStartPosition.CenterScreen;
this.aletPopup.Show();
for(var i = 0; i<= 200; i++)
{
Thread.Sleep(10);
Application.DoEvents();
}
this.aletPopup.Close();
DoEvents will process messages from message queue during that time.
When calling Thread.Sleep you're blocking the UI thread, thus preventing it from processing UI events.
You need to ensure that Close is called after 2 seconds without actually blocking the main thread. There are a number of ways of doing this, such as using a Timer, or something like Task.Delay:
aletPopup.StartPosition = FormStartPosition.CenterScreen;
aletPopup.Show();
Task.Delay(TimeSpan.FromSeconds(2))
.ContinueWith(t => aletPopup.Close(),
TaskScheduler.FromCurrentSynchronizationContext());
The reason this is happening, is that you are halting the thread that draws the form. So the form has time to display, but as it's being drawn, the thread is being stopped.
Easy enough to fix....
Add an event handler to the popup for the Load event with the following handler:
private async void handleLoad(Object sender, EventArgs args)
{
await Task.Delay(2000);
Close();
}
Remark
Because you used Show(), the user could always click around this popup. If this is undesirable, then use ShowDialog() instead.
Did you try a refresh to redraw the form?
this.aletPopup.StartPosition = FormStartPosition.CenterScreen;
this.aletPopup.Show();
this.alertPopup.Refresh();
Thread.Sleep(2000);
this.aletPopup.Close();
Related
I'd like to have a welcoming form, named the StartForm. This closes, then opens my MenuForm.
Current problem is: First one stays open, doesn't close to show the second one.
I tried several things, like simply showing and hiding them. I now try Application.run and then hide it. Unfortunately it stays open. And doesnt Application.run the second form.
static void Main()
{
Form StartForm = new Main();
MForm MenuForm = new MForm();
Application.Run(StartForm);
//
Task.Delay(500).ContinueWith((t) =>
{
StartForm.Hide();
Application.Run(MenuForm);
});
}
I expected this to Close the first form after waiting the delay, but it stays open.
Calling Application.Run() causes a new application message loop to begin running on the current thread. If a subsequent call to Application.Run() is made while the first application is running an InvalidOperationException is thrown according to the docs. However, this is not actually possible in your case as your call to Application.Run() is being invoked on the UI thread, which blocks the execution of any following code until it exits.
Instead, what we need is to bootstrap the application by using Application.Run(new Main()) and then inside of the Main form we will handle the displaying and hiding behaviour.
Here is how I would suggest achieving this:
Firstly, in your Main method, replace everything with Application.Run(new Main());.
Then inside of your Main form create a method like the following:
private void Main_Shown(Object sender, EventArgs e)
{
Task.WaitAll(Task.Delay(500));
this.Hide();
var menuForm = new MForm();
menuForm.Closed += (obj, args) => { this.Show(); };
menuForm.Show();
}
And lastly, go into your Main.Designer.cs file and make sure you subscribe the Shown event to Main_Shown method you just created in the InitializeComponent method like so:
this.Shown += new System.EventHandler(this.Main_Shown);
Explanation of what is going on here:
According to the docs the Form.Shown Event gets fired the first time a form is shown to the user. This is perfect for this use case, so we 'hook' into it and respond to it by awaiting a delay of 500 milliseconds.
Afterwards we hide the current (Main) form, create the new (MForm) form and show it. But the more important detail is that we subscribe to that form's Closed event so that when it is closed by the user, the Main form shows itself again.
use timer to Open Second form in Firstform
and Hide Firstform after show Secondform.
like this.
Main
static void Main()
{
Form StartForm = new Main();
Application.Run(StartForm);
}
FirstForm
set timer with interval 5000 and Enable it.
private void timer1_Tick(object sender, EventArgs e)
{
MForm MenuForm = new MForm();
this.Hide();
MenuForm.Show();
timer1.Stop();
}
Hi I have been trying to add a button into my program that when you click the button it displays text in a label, waits so the user can read it, then exits the program. but if I run it and try it it only waits then exits without displaying text. sorry if that was a bad explanation I just got into coding. This is what I have.
private void button3_Click(object sender, EventArgs e)
{
label1.Text = "Text Here";
Thread.Sleep(500);
this.Close();
}
Call label1.Invalidate() to force the control to be redrawn. When you call Thread.Sleep, the UI thread will be blocked and not update.
If this doesn't work, try label1.Refresh() or Application.DoEvents();
private void button3_Click(object sender, EventArgs e)
{
label1.Text = "Text Here";
label1.Invalidate();
Thread.Sleep(500);
this.Close();
}
A more ideal solution would be to use a timer, another thread, or some kind of async event to run the code separately from your UI:
timer = new Timer();
timer.Interval = 500;
timer.Tick += (sender, e) => Close();
timer.Start();
or
new Thread(delegate() {
Thread.Sleep(500);
this.Close();
}).Start();
Also note that 500 milliseconds is a pretty short time, did you mean 5000 milliseconds, which is equivalent to 5 seconds? You may want to also take a look at Winforms: Application.Exit vs Enviroment.Exit vs Form.Close, as Close() closes the current window.
Instead of using Thread.Sleep which blocks the UI thread (and keeps it from updating with your text), its better to keep the UI responsive. This will keep the UI working and delay then close the application.
private void button3_Click(object sender, EventArgs e)
{
label1.Text = "Text Here";
Task.Delay(5000).ContinueWith((arg) => Application.Exit());
}
The Task is run in another thread, delays for the specified milliseconds (5000 or 5 seconds in this case) then continues with a call to close the application.
By the way, this.Close() works to close the application only if the form you are running it from is the "initial" form of the application. If you ran the same code from another child form, it would only close the form. The better thing to do if you want to actually close the application is to use the Application.Close() method. This gracefully closes the application. If you want to down-right terminate, you can use Environment.Exit(int).
I have a Console app that displays a WinForms Form.
In the Form, the user clicks button 1 and it runs a long subroutine. I want to have a button 2 that can kill the subroutine at any point. However, the UI freezes when I click button 1 until the subroutine has finished. How can I get the UI to not freeze?
Your long-running code is blocking the UI thread, so you can no longer click the second button, nor interact with the UI in any way until the code is finished executing.
You'll need to move your long-running code to a separate thread. There are various (and newer) ways of doing this, but one way is the BackgroundWorker. It's pretty easy to learn, and wraps some nice functionality, like cancelling the thread.
Here's a short WinForms app to demonstrate. You have to explicitly enable the ability for the thread to be cancelled. In this example, the while loop continues indefinitely, but checks every 100ms to see if there's a request for it to be cancelled. When you click the second button, the cancellation request is sent, and the thread ends.
public partial class Form1 : Form
{
private BackgroundWorker bg;
public Form1()
{
InitializeComponent();
bg = new BackgroundWorker
{
WorkerSupportsCancellation = true
};
bg.DoWork += (sender, args) =>
{
while (true)
{
Thread.Sleep(100);
if (bg.CancellationPending)
break;
}
MessageBox.Show("Done!");
};
}
private void button1_Click(object sender, EventArgs e)
{
bg.RunWorkerAsync();
}
private void button2_Click(object sender, EventArgs e)
{
bg.CancelAsync();
}
}
Following up on chouaib's comment, another nice thing about using the BackgroundWorker in a WinForms environment is that you can drop and drop it onto your designer, similar to a Menu, Timer, etc. You can then access its members in the "properties" panel, setting "WorkerSupportsCancellation" to true, subscribing to events, etc.
From your comment:
"is there a way to run this background process and be able to update the main userform? I keep getting the "cross-thread operation not valid control accessed from a thread other than the..." I want to run the long-running background operation, and have it update the main UI with text in a label (like a percentage of its progress)"
If you want to update the UI while the thread is running, you should do that from the ProgressChanged event. First, enable that option and subscribe to the event:
bg.WorkerReportsProgress = true;
bg.ProgressChanged += bg_ProgressChanged;
Then call ReportProgress() when you want to update the UI. You could pass back a percentage complete and some text, for instance:
bg.ReportProgress(50, "Almost there...");
Finally, update the UI from inside the event:
void bg_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
var message = e.UserState.ToString();
var percent = e.ProgressPercentage;
lblStatus.Text = message + " " + percent;
}
You need to make it multithreaded as suggested in the comments. The older way of doing this was manage your own thread. Then along came the background worker (cheap and easy). Now a days you have other options such as the Task Library.
Remember - anything the runs on the UI thread prevents the UI from sending and receiving events until that operation is finished.
Look into the BackgroundWorker component
Below is my coding:
Form2 msgForm;
private void button3_Click_1(object sender, EventArgs e)
{
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
msgForm = new Form2();
try
{
bw.RunWorkerAsync();
msgForm.ShowDialog();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
void bw_DoWork(object sender, DoWorkEventArgs e)
{
// Coding that transmit protocol and will last around 2 minutes.
}
void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
msgForm.Close();
}
I use the background worker method everytime I click a button to transmit protocols that last around 2 minutes. During transmission, the From2 will show 'Please wait'.
But I have some problem using this coding. The problem is like, when I click the button the first time, it will transmit the protocol once. After that I click again which is the second time, it transmit the protocol twice. After that I click again which is the third time, it transmit the protocol 3 times.... And so on. The times of protocol of transmit increase each time I click the button.
Aren't that it will only run once the coding in void bw_DoWork everytime I click the button?
Is there something wrong with my coding?
You're appending an additional handler every time you click, and then it's run along with everything you added before, which stays where it is (because the object is still there, you're re-using it).
To solve this, you need to either:
Move the declaration of the background worker inside the method (so it's new every time, with only one DoWork handler
Like this:
private void button3_Click_1(object sender, EventArgs e)
{
BackgroundWorker bw = new BackgroundWorker();
// rest of your code
}
Move the .DoWork += ... which appends the handler in the constructor of the class
It mostly depends on if you use that worker somewhere else.
It looks like a new worker starts on every click.
To avoid this behaviour, check if the worker is busy before starting it again.
try
{
if (!bw.IsBusy)
bw.RunWorkerAsync();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
And you can disable the button while the backgroundworker does its job, by button3.Enabled = false; and re-enable it in the bw_RunWorkerCompleted method, letting the user understand he has to wait and cannot click again until the process is finished.
First make sure that your lists/Collections are clear before transmit codes.
Then Use BreakPoint in your source code and remember that your BackgroundWorker can't run twice or more because you use ShowDialog.
Check if the worker is busy:
if (!bw.IsBusy)
bw.RunWorkerAsync();
I would also disable the button and change the text to for example 'Running' while the process is being excecuted.
Use the bw_RunWorkerCompleted method event call to then re-enable the button and change the text. This method runs on the same thread as the UI so there are no cross thread issues.
On your design, why are you showing another form for the 'Please wait' notification? I would suggest updating a label on your existing form either before the async process starts (so not cross thread UI issues) or if you need to update after then you can use the following:
lblNotify.Invoke(new Action(() => lblNotify.Text = #"Please wait"));
The above will then allow you to run your request on the main thread.
I'm running a data import, using a Windows form to kick off the import and show progress.
I've got this whole thing so nice and user friendly, with major and minor progress bars and everything... but just one problem... the form refresh keeps going AWOL.
I have a call to Form.Refresh() every time I update my labels/progress bars, and it usually starts off working. But if ever I need to break into debug mode, just to hand-hold the import a bit, the Refresh() call stops working, and sometimes even if I'm running without Debug mode, at some unpredictable point the same thing happens: the labels and progress bars do not get updated, and if you hide the form and reopen it, the form does not repaint at all - it just shows up entirely white.
Why, oh why, does Form.Refresh() stop working, and how can I fix this?
It sounds as if the import runs on the UI thread, which means that this thread is blocked, preventing the form from repainting itself. A better approach would be to use a BackgroundWorker component, do the import in the DoWork event handler and use the ProgressChanged to update the UI.
Example:
private void StartImport()
{
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.RunWorkerAsync();
}
private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
// do some work simulating a lenghy process which occasionally
// reports progress with data back to the caller
for (int i = 0; i < 100; i++)
{
Thread.Sleep(200);
backgroundWorker.ReportProgress(i, "Item No " + i.ToString());
}
}
private void BackgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
listBox.Items.Add(e.UserState.ToString());
}
Using this approach you will typically not need to call Refresh to force a repaint of the form.
You may want to change your code into using BeginUpdate and EndUpdate, like so:
Control.BeginUpdate();
// Do something to the control, e.g. add items or whatnot
Control.EndUpdate();
This way Refresh shouldn't be necessary.
AFAIK constantly calling Refresh is really a hack and should be avoiding, as it stresses the CPU quite a bit (it has to refresh everything instead of just the things which are changed).
Edit: If the form starts being white, it seems the drawing code is not been called at all, which indicates it's somewhat not responding.
I'd check the code for anything that can deadlock or otherwisely hang.
You could use observer pattern..in short if anything changes in model observer pattern will make sure that change is visible on form..
google it for some examples..
Depending on what .NET framework you're using, you can use the Task.Run approach:
private void btnShowProgress_Click(object sender, EventArgs e)
{
progressBar1.Value = 0;
Task.Run(() =>
{
for (int i = 0; i <= 100; i++)
{
Thread.Sleep(100);
progressBar1.Invoke(new MethodInvoker(delegate { progressBar1.Value = i; }));
}
});
}
Task.Run info
Using invoke with controls
The solution may not be the best practice but it definitely works for small applications.
In Form1 create a bool to check to see if the form is closed.
public bool formclosed = false
Then in Form2 on the Form Closing Event Handler add
formclosed = true
also in the Form2 after
InitializeComponent();
add
formclosed = false;
In Form1 create a timer.
In the timer1.Tick event handler say
private void timer1_Tick(object sender, EventArgs e)
{
if(formclosed == true)
{
Application.Restart();
}
}
This will restart the application and refresh everything ... I also had my text saved to the Properties.Settings.Default so everytime the application started the default settings would show.
I created an initial version of a Progress control using a BackgroundWorker. The Progress control computed and displayed nice things like Estimated Duration, Estimated Time to Completion. Each statistic was displayed by custom control based on a Label control. The Progress control worked in my production code.
Then I made some changes to the Progress control. I switched from basing my custom statistics controls from Label to Panel. I successfully ran all my tests (using NUnit). Then, I created a Test Windows Forms app. The Progress control successfully worked in the Test Windows Forms app.
When I ran my production Windows app with the updated Progress control it didn't display the statistics.
I tried Thread.Sleep(N), Form.Refresh(). None of those worked to update the statistics.
I eventually called Control.Invalidate() on each Statistic control. The Invalidate caused OnPaint to be called and the control happily updated the display with its specific statistic.
For Each Stat_Obj As Control in Statistics_Controls
Stat_Obj.Invalidate()
Next
You might need to give the window time to redraw itself. I understand you're doing the import in a loop and the loop is running on the main UI thread? Try adding this line to the loop:
Application.DoEvents();