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C# WinForms ShowDialog() call arbitrary method

I'm working on a console application that creates a form to alert users of some given state - at a later stage, the code base will become a class library.
For now, however, I need to show the form (ShowDialog would be the best method here, I guess) THEN call an arbitrary method before the form closes.
As an example, I need to show the form, set the text value of a label control, wait for n number of seconds, then change the value of the label, then close the form. I know that this sounds a little trivial, but I'm trying to proof-of-concept the design.
I've taken a look around and it doesn't look like this is possible, as ShowDialog() requires me to close the form before I can continue through code listing in the calling method/class.
Here's what I have so far:
PopUpForm myForm = new PopUpForm(string messageToDisplay);
myForm.ShowDialog();
//call myForm.someMethod() here, before the form closes
//dispose of the form, now that we've no use for it
myform.Dispose();
//target method in PopUpform class
public void someMethod()
{
lblText.Text = "Waiting for some reason";
//wait n number of seconds
lblText.Text = "Finished waiting. Form will now close";
//it doesn't matter if the form closes before the user can see this.
}
It looks like ShowDialog() doesn't support this sort of behaviour. I'm looking into BackgroundWorker threads, but was wondering if anyone has any advice on this, or have encountered this before.

If you want to show the form, then continue working, then close it - you can do so via Form.Show() instead of Form.ShowDialog():
using (var myForm = new PopUpForm(messageToDisplay))
{
myForm.Show(); // Show the form
DoWork(); // Do your work...
myForm.Close(); // Close it when you're done...
}
However, if this is purely a console application (and doesn't have a message pump), then this will likely not work properly.
Other options would be to provide a timer within your Form to have it close, or pass a delegate into the Form to run your method on Show, after which it could close itself.
at a later stage, the code base will become a class library.
When you do this, you'll likely want to come up with a different mechanism to provide notifications. Coupling your library to a specific UI technology is a bad idea. It would likely be better to have your library just provide events or other notification, and allow the user to provide the UI/notification to the user.

If this code ie destiend to end up in a code library, I recommend against having it display any forms, ever, of its own volition. The library should generate events, or in some cases exceptions, that can be caught by the invoking application to allow it to display the form. If certain details requiring presentation to the user are internal to the library, expose a DisplayEventData() method from the library.

The ShowDialog-method creates a "modal" window, and usually blocks the UI until you close it (either by clicking OK or Cancel). You would need to create a WinForm yourself, can be a simple one though and create a message-pump for it. You can run your own form by calling
Application.Run(YourForm);
You would need to hold your console-thread with a mutex for example, to keep it from continuing, while the form is open.
The form offers all the methods you know from WinForms like Close, where you could tell your console-thread to continue.
See this on MSDN.

Get Data from Windows Form into C# program

I want my C# program to collect data. Then, when the OK button is clicked, I want this data to be loaded into my program -- such as into variables in Main(), or into data members of a class I have constructed, and I want the form to then go away -- not be hidden, but actually closed. Alas, read as I might in the book I have, the data collected by the form stays in the form, execution proceeds within the form, and the same form is used to display the result of the program's computations. Sheesh. All I want is to capture the form's information, close the form and proceed with my program. I would appreciate some tips on geting data from a form into Main() or into a class's data members.
Thanks,
Lucky

What you want to do is perfectly acceptable, it just isn't typical.
When you use Visual Studio to generate a WinForms project, it creates one form for you and
generates a call to Application.Run(new Form1()). For this version of the Run() method, your application will exit when the "main form" (the one passed to Run(), in this case Form1) closes.
There are three overloads (versions) of Application.Run(). For your purposes, you need to use a different overload:
Application.Run(ApplicationContext)
When you use this overload of Run(), you get to control when the application exits. In a nutshell, here's one way you could do it:
Create a class which inherits
ApplicationContext.
In its constructor:
Create your form.
Subscribe to its Closing and Closed events.
Show your form.
In your FormClosing event handler,
get the data from the form.
In your FormClosed event handler, do
whatever you want to do with the
data, and then exit the thread (or do something else).
Here's a crude example, but I will leave out the code for the form itself. Assume the form simply has one TextBox which has its Modifiers property set to Public. (This is NOT an elegant way to get data from a form, but that part is up to you).
namespace Me.MyDemo
{
static class Program
{
[STAThread]
static void Main()
{
MyApplicationContext ac = new MyApplicationContext();
Application.Run(ac);
}
class MyApplicationContext : ApplicationContext
{
string _text = "";
public MyApplicationContext()
{
Form1 f1 = new Form1();
f1.FormClosing += new FormClosingEventHandler(f1_FormClosing);
f1.FormClosed += new FormClosedEventHandler(f1_FormClosed);
Console.WriteLine("I am here. Showing form in 1 second...");
Thread.Sleep(1000);
f1.Show();
}
void f1_FormClosing(object sender, FormClosingEventArgs e)
{
_text = (sender as Form1).textBox1.Text;
}
void f1_FormClosed(object sender, FormClosedEventArgs e)
{
Console.WriteLine("You wrote: " + _text);
Console.WriteLine("I will go away in 2 seconds...");
Thread.Sleep(2000);
ExitThread();
}
}
}
}
Of course, you don't have to exit the thread. You can leave it running if there are other things for your program to do. It will just run as a windowless process. Just remember that you're responsible for eventually ending it.
For more help, look at the documentation for the System.Windows.Forms.Application class, and the ApplicationContext class.
For getting the data from your form, there are many ways to approach this. The simple way is to just give your form some public properties. A more sophisticated way would be to create a data class and use data-bound controls on your form.

You're writing in WinForms? As far as I know a Windows application has to have a window, even if it's one pixel by one pixel.
Have you seen any other Windows applications that work the way that you want yours to work? Opens a window, the window closes, but the program keeps on running? This is generally considered undesired behavior, similar to viruses and trojans.
You can create a console application or a Windows service with no GUI, of course.
What is the application doing behind the scenes after the data is entered? If it's just doing some calculations and saving to disk, uploading, or printing, leave the window open for that and then exit when it's done. Possibly include a progress bar.

Splash screen display method best practice C#

I am showing a splash form by starting a new thread immediately before running my main form.
In the method that is run by this thread, I am using Application.Run as shown in Option 1 below. Is this a correct way of doing this, or are there problems waiting for me becaue I have called Application.Run twice? An alternative is Option 2, also shown below where I call .ShowDialog() to display the form.
The splash form itself closes after a specified time, controlled within the form itself, and both options appear to work well.
So my question is: Which is preferred - Option 1 or Option 2? If you could give specific reasons for one or the other that would be great.
Thanks.
Snippet of Main:
// Run splash screen thread.
Thread splash = new Thread(new ThreadStart(ShowSplash));
splash.Start();
// Run main application.
Application.Run(new MainForm());
Show splash form option 1:
static void ShowSplash()
{
Application.Run(new SplashForm());
}
Show splash form option 2:
static void ShowSplash()
{
using (SplashForm splash = new SplashForm())
{
splash.ShowDialog();
}
}

Option 2 will probably run into trouble because then you are using the same Mesageloop as the MainForm but from another thread.
Option 1 is fine.

I realize that this may be an unusual viewpoint but have you considered not using a Splash screen and instead showing the information on the 'welcome page' or 'help > about' screen instead?
There are a handful of reasons to do this:
Unless you get into multi-threading, a Splash Screen may not repaint properly if some alert/msgbox pops up over the top of it, negating the benefit of the splash screen entirely.
Splash screens that show 'you have plugins x, y and z' installed can't really tell this until that information has been loaded up. By the time this info is loaded, your app is ready to go, so you'll either close the splash screen or it'll be in the way of the user.
If I look away and miss the splash screen, I'll miss whatever information you're telling me. If 'License expires in 3 days' is part of that information, and today is Friday, that means I won't realise that on Monday, I can't use the app. Obscure, but I've seen it.

Manage muliple windows forms in c# app

Any thoughts,recommendations, patterns on a good way to manage an app with multiple forms.
First page is login, that loads a "main form", from there a user could launch a number of other "sub forms" (could grow over time). User should be able to cancel out of whole app at any point.
I know the way I do it right now is not always elegant.
Cody

Consider using the DockPanel Suite. It allows you to create multiple form, and have a complete docking panel solution for you application.

I like an Explorer-style interface: Use a splitter in the main form. Use a list control or tree control in the left side, and add a reference to each sub-form as a tag on an item. When the user clicks on the item, push the sub-form from the tag to the right side of the splitter.
You can monitor the select changed event on the list/tree to do form-level validation.

There's nothing fundamentally wrong with how you've set things up, but I would change the relationship between your login form and your main form so that your main form isn't loaded by your login form.
In the Main method in your Program.cs file, replace this (presumed) line:
Application.Run(new LoginForm());
with something like this:
LoginForm login = new LoginForm();
DialogResult result = login.ShowDialog();
login.Dispose();
if (result != DialogResult.Cancel)
{
Application.Run(new MainForm());
}
Rewrite your LoginForm so that it just returns DialogResult.OK if the login is successful (this.DialogResult = DialogResult.OK), instead of loading and showing an instance of MainForm.
From that point on, there's nothing wrong with loading and showing additional forms from MainForm, provided that a user interface like that makes sense for your program (like, for example, a graphics editing program that incorporates various other floating tool windows as needed).
The user can "cancel out" of your entire application by just closing the main form, which is quite normal behavior for a Windows program.

"to manage an app with multiple forms."
Hi Cody,
Tip : do keep in mind that you have access to a very handy way to know, at all times (in any context where you are using the System.Windows.Forms library) the number of open forms in the Application via :
Application.OpenForms.Count
I think a lot depends on what exactly you mean by "manage" your multiple forms, and by what you mean by the term "sub-forms." I'm assuming you're already familiar with the built-in MDI multiple window facility in .NET, and looking for an alternative to that, or you wouldn't be asking this question. Please correct me if my assumptions are wrong.
If you mean by "sub-forms" : forms created within the scope of your "Main Form," then they will, of course, be disposed when the Main Form is closed.
I personally like the "multiple independent window" model in WinForms sometimes referred to as SDI+ (I think it was Chris Sells that coined this acronym).
I like to start by "hi-jacking" the standard Program.cs file so the Main procedure looks like this :
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Initializer.Initialize();
// it's now your responsibility to shut down the application !
Application.Run();
}
Where 'Intializer is a public static class with one public static method 'Intialize; it might look something like this :
public static class Initializer
{
public static StartFormTemplate StartForm;
public static MainFormTemplate MainForm;
public static void Initialize()
{
MainForm = new MainFormTemplate();
MainForm.FormClosing += new FormClosingEventHandler(FormClosing);
// StartForm will display MainForm in this case
// MainForm.Show();
StartForm = new StartFormTemplate();
StartForm.FormClosing += new FormClosingEventHandler(FormClosing);
StartForm.Show();
}
}
Every form created within the scope of the Initializer class is going to be an "indepedent window" (effectively with : Parent == null).
The interesting "business" in this model is the logic in the FormClosing event (not shown here) which, in this example, both StartForm and MainForm share. You can easily test for the Mainform closing by taking the 'sender parameter of the FormClosing call and comparing to MainForm :
MainForm == sender
And you can use Application.OpenForms.Count to detect when there is only one "independent" window left to close. The tricky part is making sure you detect the cases where you want to keep the MainWindow open and handle those first, cancelling the FormClose event as necessary.
I think that's enough for starters : this may be a "primrose path" you don't really wish to go down :)
best, Bill

I would recommend the Smart Client UI Application Block.
The Block is designed to help you build complex, WinForm–based solutions. It provides a proven architecture and implementation that helps you to build applications using the common patterns found in line-of-business front-end applications.
It allows your application to be
based on the concept of modules or
plug-ins.
Maintainable, reusable code through UI composition.
It facilitates development using
patterns for loose coupling between
modules.
Separation of Model (business logic and data access) from Presentation.
The Model-View-Presenter pattern.

You can use MDI. To do this, set the IsMdiContainer property of the parent from to true, and set the MdiParent property of each child from to the parent from before the child form is shown. You can then use an MdiList menu to automatically list all of the child forms.
Alternatively, you can use tabs; this is easiest to do with a third-party framework.
Finally, you could do it normally by calling the Show method of each child form with the parent form as a parameter.
For a more detailed and specific answer, please provide more details.

I use a navigation-style UI for that sort of thing. Check out this article on MSDN which describes a WinForms framework for "inductive UI" applications.

Load a form without showing it

Short version: I want to trigger the Form_Load() event without making the form visible. This doesn't work because Show() ignores the current value of the Visible property:
tasksForm.Visible = false;
tasksForm.Show();
Long version: I have a WinForms application with two forms: main and tasks. The main form is always displayed. The user can either click a button to open the tasks form, or click some buttons that just run a task directly without opening the tasks form.
When a user asks to run a task directly, I'd like to just call some public methods on the tasks form without showing it. Unfortunately, the task logic depends on stuff that happens in the Form_Load() event. The only way I can find to trigger Form_Load() is to call Show(). The best I've been able to do is to show the form in the minimized state:
tasksForm.WindowState = FormWindowState.Minimized;
tasksForm.Show();
I suppose the cleanest solution would be to pull the tasks logic out of the tasks form and into a controller class. Then I can use that class from the main form and from the tasks form, and only load the tasks form when I need it visible for the user. However, if it's an easy thing to load the form without displaying it, that would be a smaller change.

Perhaps it should be noted here that you can cause the form's window to be created without showing the form. I think there could be legitimate situations for wanting to do this.
Anyway, good design or not, you can do that like this:
MyForm f = new MyForm();
IntPtr dummy = f.Handle; // forces the form Control to be created
I don't think this will cause Form_Load() to be called, but you will be able to call f.Invoke() at this point (which is what I was trying to do when I stumbled upon this SO question).

It sounds to me like you need to sit down and re-think your approach here. I cannot imagine a single reason your public methods need to be in a form if you are not going to show it. Just make a new class.

I totally agree with Rich B, you need to look at where you are placing your application logic rather than trying to cludge the WinForms mechanisms. All of those operations and data that your Tasks form is exposing should really be in a separate class say some kind of Application Controller or something held by your main form and then used by your tasks form to read and display data when needed but doesn't need a form to be instantiated to exist.
It probably seems a pain to rework it, but you'll be improving the structure of the app and making it more maintainable etc.

From MSDN:
Form.Load
Occurs before a form is displayed for the first time.
Meaning the only thing that would cause the form to load, is when it is displayed.
Form.Show(); and Form.Visible = true; are the exact same thing. Basically, behind the scenes, Show checks for various conditions, then sets Visible to true. So obviously, setting visible to false (which it already is) before showing the form is meaningless.
But let's forget the technicalities. I completely agree with Rich B and Shaun Austin - the logic shouldn't be in that form anyway.

Sometimes this would be useful without it being bad design. Sometimes it could be the start of a migration from native to managed.
If you were migrating a c++ app to .NET for example, you may simply make yourwhole app a child window of the .NET form or panel, and gradually migrate over to the .NET by getting rid of your c++ app menu, status bar, toolbar and mapping teh .NEt ones to your app using platform invoke etc...
Your C++ app may take a while to load, but the .NET form doesn't..in which you may like to hide the .NEt form until your c++ app has initialised itself.
I'd set opacity=0 and visible=false to false after calling show, then when your c++ app loads, then reverse.

If you make the method public, then you could access it directly.... however, there could be some unexpected side effects when you call it. But making it public and calling it directly will not draw the screen or open the form.

Move mandatory initialization code for the form class out of the Load event handler into the constructor. For a Form class, instantiation of an instance (via the constructor), form loading and form visibility are three different things, and don't need to happen at the same time (although they do obviously need to happen in that order).

None of the answers solved the original question, so, add the below, call .Show() to load the form without showing it, then call .ShowForm() to allow it to be visible if you want to after:
private volatile bool _formVisible;
protected override void SetVisibleCore(bool value)
{
base.SetVisibleCore(_formVisible);
}
public void ShowForm()
{
_formVisible = true;
if (InvokeRequired)
{
Invoke((Action) Show);
}
else
{
Show();
}
}