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Background Worker and Timer in System Tray App C#

This is an incredibly simple task tray app - using ApplicationContext and a few guides I found online.
The purpose of the app is to query a small REST API and show a message box to the user on a given result. I need to essentially have the API query in a background loop, running every 10 seconds or something similar. This is to report on data that I've made accessible via another service.
I've done some reading and it seems a BackgroundWorker and Timer is an appropriate option, but I'm lost on where to go next. How exactly can I achieve this? I initially tried adding a while(true) loop to the TaskTrayApplicationContext but it just created an infinite loop whereby you couldn't do anything else with the app.
namespace TaskTrayApplication
{
public class TaskTrayApplicationContext : ApplicationContext
{
NotifyIcon notifyIcon = new NotifyIcon();
Configuration configWindow = new Configuration();
public TaskTrayApplicationContext()
{
MenuItem configMenuItem = new MenuItem("Configuration", new EventHandler(ShowConfig));
MenuItem exitMenuItem = new MenuItem("Exit", new EventHandler(Exit));
notifyIcon.Icon = TaskTrayApplication.Properties.Resources.AppIcon;
notifyIcon.DoubleClick += new EventHandler(ShowMessage);
notifyIcon.ContextMenu = new ContextMenu(new MenuItem[] { configMenuItem, exitMenuItem });
notifyIcon.Visible = true;
}
void ShowMessage(object sender, EventArgs e)
{
// Only show the message if the settings say we can.
if (TaskTrayApplication.Properties.Settings.Default.ShowMessage)
MessageBox.Show("This is the Serenity TaskTray Agent.");
}
void ShowConfig(object sender, EventArgs e)
{
// If we are already showing the window meerly focus it.
if (configWindow.Visible)
configWindow.Focus();
else
configWindow.ShowDialog();
}
void Exit(object sender, EventArgs e)
{
// We must manually tidy up and remove the icon before we exit.
// Otherwise it will be left behind until the user mouses over.
notifyIcon.Visible = false;
Application.Exit();
}
}
}
And the Program.cs
using System;
using System.Collections.Generic;
using System.Windows.Forms;
namespace TaskTrayApplication
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
// Instead of running a form, we run an ApplicationContext.
Application.Run(new TaskTrayApplicationContext());
}
}
}

Threading is hard, concurrency is hard. Background worker and System.Timers are both constructs that run in their own thread.
winforms won't allow for interaction between threads that own a control (read: that created a control) and threads that don't. This is a whole subject apart i wont get into now - theres good stuff to read out there why this is and how to go about it: https://visualstudiomagazine.com/articles/2010/11/18/multithreading-in-winforms.aspx
There are tools to help, one is the dispatchertimer:
https://learn.microsoft.com/en-us/dotnet/api/system.windows.threading.dispatchertimer?view=netcore-3.1
This is a special timer that instead of its own thread, schedules tasks on the main thread. The main thread in a winforms application handles the drawing of controls, showing of the different windows etc. e.g. this 'owns' all controls.
A sample can be seen on msdn, i adopted it here to show you what you could do:
public class TaskTrayApplicationContext : ApplicationContext
{
...
DispatcherTimer dispatcherTimer;
public TaskTrayApplicationContext()
{
...
dispatcherTimer = new System.Windows.Threading.DispatcherTimer();
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0,0,1);
dispatcherTimer.Start();
}
private void dispatcherTimer_Tick(object sender, EventArgs e)
{
// Fetch your data via a rest api
var myData = MyDataFunction();
// check and show dialog if the data is not okay
if(myData.Result.Value = 'NOT_OKAY!')
ShowMessage(this, myData.Result); // or something.
}
...
Now since this does not utilize a second thread, this means the main ui thread could be blocked from drawing the windows, reacting to user input etc. because its busy doing work in the timer_tick function. This would for example happen if your rest call takes a long time.
This will make your application freeze and irresponsive. This could be a problem but most likely wont, so lets burn that bridge when we get to it.

C# Threading still make UI unresponsive

Well , I have a form1 which has buttons and if you click one of its button
It would load the UserControl into panel in form1
That usercontrol1 contains a lot of data like Database,charts and picture boxes too. So it would definitely make the User Interface unresponsive while loading.
So I read some article and I found out that I need to run it through another thread so I tried it and it just increase the performance by a little bit.
The usercontrol1 still make the GUI unresponsive for about 3-5 sec and what if my data become larger.
I want to make it responsive and show to user that still loading by running the animated picturebox and stop if its finish loading
here is my code:
private void click_dashb_Click(object sender, EventArgs e)
{
ParameterizedThreadStart pts = new ParameterizedThreadStart(load_UserControl);
Thread t = new Thread(pts);
t.Start();
//Animated Picturebox to show user that UI is loading
pictureBox1.Enabled = true;
hover.Location = new Point(42, 130);
}
private void load_UserControl(object state)
{
Invoke(new Action(() =>
{
//load user control through another thread
while (panel1.Controls.Count > 0)
panel1.Controls[0].Dispose();
Home frm = new Home();
frm.AutoScroll = true;
panel1.Controls.Add(frm);
frm.Show();
}));
//Stop the animated GIF means the load is finish!
pictureBox1.Enabled = false;
}
If you help me about this problem. I might apply it to all of my works. because most of it contains large data.
Thanks stackoverflow community :)
EDIT:
After reading the comments suggesting to use Background worker . I tried to use it. but still getting a little bit unresponsiveness
Here's the new code:
private void click_dashb_Click(object sender, EventArgs e)
{
bgw.RunWorkerAsync();
}
private void bgw_DoWork(object sender, DoWorkEventArgs e)
{
try
{
BeginInvoke((MethodInvoker)delegate
{
while (panel1.Controls.Count > 0)
panel1.Controls[0].Dispose();
Home frm = new Home();
frm.AutoScroll = true;
panel1.Controls.Add(frm);
frm.Show();
});
}
catch (Exception x)
{
MessageBox.Show("An error occured while performing operation" + x);
}
}
private void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
}
private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
{
MessageBox.Show("Operation Cancelled");
}
else
{
MessageBox.Show("Operation Completed");
}
}
It's a little bit better but i still got a little unresponsiveness. Can you check out my code and what's wrong with this.?
thanks again

The problem with your code is that although you run the load_UserControl code in a new thread, that code calls Invoke which effectively makes al the code run on the UI thread again. I can image you did that because accessing Forms and PictureBoxes requires running on the UI thread.
The solution (in general) is to do non-UI work on a seperate thread and then switch back to the UI thread to update the visual controls.
To do this, you can conveniently use the BackgroundWorker class. In the DoWork event handler you do the heavy computation, in the RunWorkerCompleted event handler you update the controls. If you want, you can even update some controls (like a progressbar) during the work by means of the ProgressChanged event handler.

Well, just starting a new thread doesn't make the UI responsive by definition. You need to make the thread so that it actually does stuff in parallel.
Your thread does not, as it basically executes all code in this.Invoke.
That being said: Your code needs to be executed in this.Invoke, as almost everything you do needs to be done on the UI thread.
So in your case, there's really no point in parallelizing stuff, as there's no way to do what you want to do without blocking the UI thread and no technique I know of (Threads, Tasks, BackgroundWorker, etc.) will solve this problem.

Main thread locking up in C#

I am faced with a problem. I am clicking a button that is calling several methods, although the main thread is locking up, so I created an instance of my class (which is Form1) e.g. Form1Object and then the button called the methods as so: Form1Object.Check1 and so on.
Although the thread still locked up (i.e. the GUI became unresponsive for a period) Is there anyway of getting around this, any examples would be greatly appreciated.
The code in question is below:
private void StartChecks_Click(object sender, EventArgs e)
{
Form1 Form1Object = new Form1();
Form1Object.InitChecks();
}
public void InitChecks()
{
Check1();
Check2();
Check3();
Check4();
Check5();
Check6();
Check7();
}

Creating a new Form does not start a new Thread.
You will have to move those CheckN() methods to a BackgroundWorker.
private void StartChecks_Click(object sender, EventArgs e)
{
Form1 Form1Object = new Form1();
var worker = new BackgroundWorker();
worker.DoWork += (s, arg) =>
{
Form1Object.InitChecks();
};
// add progress, completed events
worker.RunWorkerAsync();
}
But note that this require that the checks are independent and do not interact with any Control.

What you need to do is start a parallel thread to do the check, so you won't lock up the main thread:
private void StartChecks_Click(object sender, EventArgs e)
{
Form1 Form1Object = new Form1();
Thread t = new Thread(
o =>
{
Form1Object.InitChecks();
});
t.Start();
}
Hopefully you don't need to actually retrieve anything from those calculations, so you can just fire and forget about it.

You have several options here, and use them depending of your skill/preference/requirement:
if you don't update anything on the form while you process, start another thread and call everything on that thread, and update UI when appropriate (when everything is finished)
if you need to update things on your form while processing, you have several options:
either use Application.DoEvents() from the processing loop of every method you use
start a new thread then update form controls with Invoke() - if you try to update them directly, you'll be in trouble
If you care to comment and decide for one of the options, I can provide more info on just that...

Program hangs after leaving screen saver or locking computer

Our program works fine, until someone locks the computer or the screen-saver pops up (but not ctrl+alt+delete). Once the computer is unlocked/the screen saver is closed, the application stops drawing everything except the title bar, and stops responding to input - it displays a mostly-white window which can't be moved or closed.
(Example of application freezing - the mountains are from my desktop background)
If we let it sit for about 5~10 minutes, it comes back to life, and doesn't hang again (even after locking the computer/screen saver popup) until the application is restarted.
It's difficult to debug, because it doesn't happen when the program is started from Visual Studio, only when the .exe is manually opened.
It only happens when the splash-screen is shown - if I remove the code to show the splash-screen, it stops happening. We need the splash-screen, however.
I've tried every suggestion on this page; the only one this doesn't happen with is using Microsoft.VisualBasic.WindowsFormsApplicationBase, but that causes all sorts of other problems.
Information about this on the Internet appears to be scarce - has anyone run into a similar problem before?
Here is the relevant code:
//Multiple programs use this login form, all have the same issue
public partial class LoginForm<TMainForm>
where TMainForm : Form, new()
{
private readonly Action _showLoadingForm;
public LoginForm(Action showLoadingForm)
{
...
_showLoadingForm = showLoadingForm;
}
private void btnLogin_Click(object sender, EventArgs e)
{
...
this.Hide();
ShowLoadingForm(); //Problem goes away when commenting-out this line
new TMainForm().ShowDialog();
this.Close();
}
private void ShowLoadingForm()
{
Thread loadingFormThread = new Thread(o => _showLoadingForm());
loadingFormThread.IsBackground = true;
loadingFormThread.SetApartmentState(ApartmentState.STA);
loadingFormThread.Start();
}
}
Here is an example of one of the _showLoadingForm actions used in one of the programs:
public static bool _showSplash = true;
public static void ShowSplashScreen()
{
//Ick, DoEvents! But we were having problems with CloseSplashScreen being called
//before ShowSplashScreen - this hack was found at
//https://stackoverflow.com/questions/48916/multi-threaded-splash-screen-in-c/48946#48946
using(SplashForm splashForm = new SplashForm())
{
splashForm.Show();
while(_showSplash)
Application.DoEvents();
splashForm.Close();
}
}
//Called in MainForm_Load()
public static void CloseSplashScreen()
{
_showSplash = false;
}

Splash Screen Issues
The DoEvents thing is very undesirable and doesn't necessarily accomplish what you think it does. DoEvents tell the CLR to attend to the windows message loop (for the splash screen), but doesn't necessarily offer up any processing time to other threads. Thread.Sleep() will offer other threads a chance to process, but won't necessarily allow the windows message loop for your splash screen to continue pumping messages. So you really need both if you must use a loop, but in a minute I'm going to recommend getting away from this loop altogether. In addition to that loop issue, I don't see any explicit way the splash thread is being cleaned up. You need some kind of Thread.Join() or Thread.Abort() happening somewhere.
Instead of using a Application.DoEvents() loop, I like to use a ManualResetEvent to synchronize the splash forms start up with the calling thread. That way the ShowSplash() method doesn't return until the splash is shown. Anytime after that we are obviously ok to close it down as we know it was finished being shown.
Here's a thread with a few good examples:.NET Multi-threaded Splash Screens in C#
Here's how I modified my favorite example, that #AdamNosfinger posted, to include a ManualResetEvent to synchronize the ShowSplash method with the splash screen thread:
public partial class FormSplash : Form
{
private static Thread _splashThread;
private static FormSplash _splashForm;
// This is used to make sure you can't call SplashScreenClose before the SplashScreenOpen has finished showing the splash initially.
static ManualResetEvent SplashScreenLoaded;
public FormSplash()
{
InitializeComponent();
// Signal out ManualResetEvent so we know the Splash form is good to go.
SplashScreenLoaded.Set();
}
/// <summary>
/// Show the Splash Screen (Loading...)
/// </summary>
public static void ShowSplash()
{
if (_splashThread == null)
{
// Setup our manual reset event to syncronize the splash screen thread and our main application thread.
SplashScreenLoaded = new ManualResetEvent(false);
// show the form in a new thread
_splashThread = new Thread(new ThreadStart(DoShowSplash));
_splashThread.IsBackground = true;
_splashThread.Start();
// Wait for the splash screen thread to let us know its ok for the app to keep going.
// This next line will not return until the SplashScreen is loaded.
SplashScreenLoaded.WaitOne();
SplashScreenLoaded.Close();
SplashScreenLoaded = null;
}
}
// called by the thread
private static void DoShowSplash()
{
if (_splashForm == null)
_splashForm = new FormSplash();
// create a new message pump on this thread (started from ShowSplash)
Application.Run(_splashForm);
}
/// <summary>
/// Close the splash (Loading...) screen
/// </summary>
public static void CloseSplash()
{
// need to call on the thread that launched this splash
if (_splashForm.InvokeRequired)
_splashForm.Invoke(new MethodInvoker(CloseSplash));
else
Application.ExitThread();
}
}
Main Form Issues
It looks as though you are launching your mainform from your login window using ShowDialog and then closing the login form. Have I understood correctly? This is not good if so. ShowDialog is intended for child windows of your application and wants to have an owner window, if you don't specify an owner form in the method arguments the currently active window is assumed to be the owner. See MSDN
So your main form is assuming the login form is its parent, but you close the login form shortly after showing the main form. So I'm not sure what state the application is left in at that point. You should consider using a standard Form.Show() method instead and simply adjusting the Form properties to appear like a dialog if this is the desired outcome (ex: BorderStyle, MaximizeBox, MinimizeBox, ControlBox, TopMost).
IMPORTANT EDIT: Ok I'm human, I messed up and forgot ShowDialog was a blocking method. While that does negate the owner handle issue, I still recommend not using ShowDialog for your main application form unless you can provide a significant justification for it that is not appearance or threading related (as those should be fixed with other techniques). The advice is still sound, despite the misstep on my part.
Possible Painting Issues
You did not specify which controls you were using or if you were doing any custom painting in your application. But you need to keep in mind some windows handles will be forcibly closed when you lock the computer. For example if you have some custom painted controls and are caching fonts, brushes or other GDI resources you need to have some try { ... } catch { ... } blocks in your code that dispose of and then rebuild the cached GDI resources when an exception is raised during painting. I've run into this before where I was custom painting a list box and caching some GDI objects. If you have any custom painting code anywhere in your app, including in the splash screen, please double check all GDI objects are nicely disposed/cleaned up.

After adding a few lines of code to the code snippets above, I could compile a working program. However, I could not reproduce the problem (Windows 7 Starter). I tried locking the computer, and starting the screen saver, too. I did this while the splash screen was active, and in other situations, but the main window always remained responsive. I think there must be something else going on here, probably during the initialization of the main window.
Here is the code, maybe it helps the others figure out the problem.
using System;
using System.Threading;
using System.Windows.Forms;
public class MainForm : Form
{
//Here is an example of one of the _showLoadingForm actions used in one of the programs:
public static bool _showSplash = true;
public static void ShowSplashScreen()
{
//Ick, DoEvents! But we were having problems with CloseSplashScreen being called
//before ShowSplashScreen - this hack was found at
//http://stackoverflow.com/questions/48916/multi-threaded-splash-screen-in-c/48946#48946
using(SplashForm splashForm = new SplashForm())
{
splashForm.Show();
while(_showSplash)
Application.DoEvents();
splashForm.Close();
}
}
//Called in MainForm_Load()
public static void CloseSplashScreen()
{
_showSplash = false;
}
public MainForm()
{
Text = "MainForm";
Load += delegate(object sender, EventArgs e)
{
Thread.Sleep(3000);
CloseSplashScreen();
};
}
}
//Multiple programs use this login form, all have the same issue
public class LoginForm<TMainForm> : Form where TMainForm : Form, new()
{
private readonly Action _showLoadingForm;
public LoginForm(Action showLoadingForm)
{
Text = "LoginForm";
Button btnLogin = new Button();
btnLogin.Text = "Login";
btnLogin.Click += btnLogin_Click;
Controls.Add(btnLogin);
//...
_showLoadingForm = showLoadingForm;
}
private void btnLogin_Click(object sender, EventArgs e)
{
//...
this.Hide();
ShowLoadingForm(); //Problem goes away when commenting-out this line
new TMainForm().ShowDialog();
this.Close();
}
private void ShowLoadingForm()
{
Thread loadingFormThread = new Thread(o => _showLoadingForm());
loadingFormThread.IsBackground = true;
loadingFormThread.SetApartmentState(ApartmentState.STA);
loadingFormThread.Start();
}
}
public class SplashForm : Form
{
public SplashForm()
{
Text = "SplashForm";
}
}
public class Program
{
public static void Main()
{
var loginForm = new LoginForm<MainForm>(MainForm.ShowSplashScreen);
loginForm.Visible = true;
Application.Run(loginForm);
}
}

Several years later (with the code no longer in front of me), I'll add an answer for anyone else who experiences this problem.
The issue turned out to be exactly as Hans Passant had guessed. The problem was that, due to some incredibly obscure and innocuous bugs in the .Net framework, InvokeRequired can sometimes return false when it should return true, causing code that should run on the GUI thread to run in the background (which, due to some more obscure and innocuous bugs, causes the behavior I was seeing).
The solution is to not rely on InvokeRequired, using a hack similar to this:
void Main()
{
Thread.Current.Name = "GuiThread";
...
}
bool IsGuiThread()
{
return Thread.Current.Name == "GuiThread";
}
//Later, call IsGuiThread() to determine if GUI code is being run on GUI thread
This solution, as well as an extremely in-depth look at the causes of the issue, was found here.

since there is no working example
can you try removing Application.DoEvents(); and inserting a thread.sleep?
Application.DoEvents(); let say can be very evil.

From the quick scan I did of your code, it looks like the key to your problem might be using
Application.Run(_splashForm);
Ideally you would use that inside a thread, but maybe it would work in conjunction with your DoEvents too. Sorry if you are doing that and I just missed it...

In our application we had some similar problems with the splash screen. We wanted to have a splash screen with an animated gif (don't blame on me, it was a management decision). That only works correctly, when the splashScreen has its own message loop. Because I think the DoEvents is the key to your problem, I show you, how we solved it. Hopefully it will help you to solve your problem!
We're going to show the splash screen in that way:
// AnimatedClockSplashScreen is a special form from us, it can be any other!
// Our form is set to be TopMost
splashScreen = new AnimatedClockSplashScreen();
Task.Factory.StartNew(() => Application.Run(splashScreen));
The splash screen is a simple containing the animated gif of a clock. It doesn't have any loop, so it doesn't steel any time.
When the splash needs to be closed, we do it in that way:
if (splashScreen != null)
{
if (splashScreen.IsHandleCreated)
{
try
{
splashScreen.Invoke(new MethodInvoker(() => splashScreen.Close()));
}
catch (InvalidOperationException)
{
}
}
splashScreen.Dispose();
splashScreen = null;
}

remove this line, you don't need it, You are forcing it to a single thread when the default is mta. Take the default.
loadingFormThread.SetApartmentState(ApartmentState.STA);
change the following:
using(SplashForm splashForm = new SplashForm())
{
splashForm.Show();
while(_showSplash)
Application.DoEvents();
splashForm.Close();
}
to:
SplashForm splashForm = new SplashForm())
splashForm.Show();
Change this:
public static void CloseSplashScreen()
{
_showSplash = false;
}
to this:
public static void CloseSplashScreen()
{
splashForm.Close();
}

Here's a shot in the dark: when we idle, we also ask the thread to go to sleep. I'm not sure that this will help, but it's worth a shot:
while(_showSplash) {
System.Threading.Thread.Sleep(500);
Application.DoEvents();
}

Have you tried using a WaitHandle for showing the form in the thread?
Something like:
EventWaitHandle _waitHandle = new AutoResetEvent(false);
public static void ShowSplashScreen()
{
using(SplashForm splashForm = new SplashForm())
{
splashForm.Show();
_waitHandle.WaitOne();
splashForm.Close();
}
}
//Called in MainForm_Load()
public static void CloseSplashScreen()
{
_waitHandle.Set();
}

I think your problem is because you are using Form.ShowDialog, not Application.Run. ShowDialog runs a restricted message loop that runs on top of the main message loop and ignores some windows messages.
Something like this should work:
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault( false );
Application.Run( new MainForm() );
}
}
public partial class MainForm: Form
{
FormSplash dlg = null;
void ShowSplashScreen()
{
var t = new Thread( () =>
{
using ( dlg = new FormSplash() ) dlg.ShowDialog();
}
);
t.SetApartmentState( ApartmentState.STA );
t.IsBackground = true;
t.Start();
}
void CloseSplashScreen()
{
dlg.Invoke( ( MethodInvoker ) ( () => dlg.Close() ) );
}
public MainForm()
{
ShowSplashScreen();
InitializeComponent();
Thread.Sleep( 3000 ); // simulate big form
CloseSplashScreen();
}
}

progressBar while MainFrom initialize

I have a windows form application that needs to load a bunch of things before loading the Main window. I thought this would justify a ProgressBar, so I thought I display another form that contains the ProgressBar Control using the constructor of my main form.
It all works fine but if I try to put the text in a Label on the intro form its content won't show until the main form is loaded. Is here a way to avoid this other than loading the intro window first?

Warning: this post contains elements of self promotion ;o)
I would probably use a splash form in this case. I wrote a blog post a while ago (triggered by this SO Q&A) about a thread-safe splash form that could be used together will long-running main form initializations.
In short the approach is to using ShowDialog, but to create and display the form on a separate thread so it doesn't block the main thread. The form contains a status message label (could of course be extended with a progressbar as well). Then there is a static class that provides thread-safe methods for displaying, updating and closing the splash form.
Condensed code samples (for commented code samples, check the blog post):
using System;
using System.Windows.Forms;
public interface ISplashForm
{
IAsyncResult BeginInvoke(Delegate method);
DialogResult ShowDialog();
void Close();
void SetStatusText(string text);
}
using System.Windows.Forms;
public partial class SplashForm : Form, ISplashForm
{
public SplashForm()
{
InitializeComponent();
}
public void SetStatusText(string text)
{
_statusText.Text = text;
}
}
using System;
using System.Windows.Forms;
using System.Threading;
public static class SplashUtility<T> where T : ISplashForm
{
private static T _splash = default(T);
public static void Show()
{
ThreadPool.QueueUserWorkItem((WaitCallback)delegate
{
_splash = Activator.CreateInstance<T>();
_splash.ShowDialog();
});
}
public static void Close()
{
if (_splash != null)
{
_splash.BeginInvoke((MethodInvoker)delegate { _splash.Close(); });
}
}
public static void SetStatusText(string text)
{
if (_splash != null)
{
_splash.BeginInvoke((MethodInvoker)delegate { _splash.SetStatusText(text); });
}
}
}
Example of usage:
SplashUtility<SplashForm>.Show();
SplashUtility<SplashForm>.SetStatusText("Working really hard...");
SplashUtility<SplashForm>.Close();

There sure is. It's called a BackgroundWorker.
Here is a code snippet from Figo Fei with slight modification for explanation purposes:
private void button1_Click(object sender, EventArgs e)
{
progressBar1.Maximum = 100;
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
backgroundWorker1.RunWorkerAsync();
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// This would be the load process, where you put your Load methods into.
// You would report progress as something loads.
for (int i = 0; i < 100; i++)
{
Thread.Sleep(100);
backgroundWorker1.ReportProgress(i); //run in back thread
}
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) //call back method
{
progressBar1.Value = e.ProgressPercentage;
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) //call back method
{
progressBar1.Value = progressBar1.Maximum;
}
Hope this helps you.

You can show your SplashForm from either the main program or the MainForm constructor, that doesn't really matter. What you are seeing is that as long as your Loading process isn't completed, no messages are processed and hence no Screen updates are happening. The ProgressBar is an exception, it runs it's own thread for precisely this reason.
The short solution is to do a SplashForm.Update() after changing the Label. A little more involved would be to start a separate Thread with a MessagePump (Application.Run). Here is a SO question with some more leads.

The problem is most likely because there is not a running message loop at the time you are attempting to display the progress bar form. There should be a line of code that looks something like the following in the entry point of your application.
Application.Run(new Form1());
The call to Application.Run will start the message loop, but do you see how the Form1 constructor is executed before the message loop is running? And since your progress bar logic is in that constructor then there is no mechanism running that can dispatch the form's painting messages.
I think the best approach is to load a splash screen first and kick off a worker thread (you could use BackgroundWorker for that) that does the time consuming work. The progress bar will live on the splash screen form and you will update that periodically. Once the work is complete then you can close the splash screen and load the main form.