I've built a Windows form application which contains some forms. I would like to create a button on a certain form which saves its state.
For example, if I have a textbox in which a user typed "Hello" and pressed the save button, when he goes back to this form, the textbox would still say "Hello". I want it to happen only in the same execution of the program, which means when the program closes and reopens, the textbox wouldn't say "Hello" anymore (which is why Settings don't fit my need I believe, because they keep the changes between executions).
Since you only want the form to retain its state while the application is running, the solution is very simple: never close the form, just hide it. When you're ready to display it again, show it. It will re-appear on the screen, everything exactly as it was left. (Unless, of course, you loop through the controls and reset their properties.)
In the simplest case, you accomplish this by substituting calls to this.Close with this.Hide. But it is likely more complicated than that, since the user can close your form with the big red X. To ensure all attempts to close the form are stealthily rerouted as requests to hide the form requires some minor finesse:
private void MyForm_FormClosing(object sender, FormClosingEventArgs e)
{
if (e.CloseReason == CloseReason.UserClosing)
{
e.Cancel = true; // cancel the request to close
this.Hide(); // hide the form instead
}
}
Note that this code checks the close reason and ensures that it's a user-initiated close request. This is very important. If you omit this part, you can't close the form programmatically, either!
Store your data in static variables and they will live until you close your program.
static string textboxText = textbox1.text;
Related
I'm encountering strange behaviour from my WinForms app in VS 2010. I launch a new form using straight-forward code:
MainDisplayForm.cs:
using (MyForm myForm = new MyForm())
{
var result = myForm.ShowDialog();
if (result == DialogResult.OK)
{
// do stuff
}
}
I added a Cancel button to MyForm that displayed a confirmation MessageBox to the user and then called this.Close(). I later removed the this.Close() line because I added a dedicated Close button. However, whenever I press Cancel the instance of MyForm still closes!
MyForm.cs:
private void cmdCancel_Click(object sender, EventArgs e)
{
DialogResult result = MessageBox.Show( ... )
// clear the form if user really wants to quit
// this.Close()
// even after removing the above line, program still jumps to FormClosing
}
When I debug line-by-line after clicking on the Cancel button, the program flow just jumps to MyForm_FormClosing after it hits the end of cmdCancel_Click. I created a new button and set its click event to cmdCancel_Click and it did not close the form - so the problem is solved, but I am still wondering if this is just a bug, or something else? I also made sure to reset the DialogResult property of my Cancel button back to None (after changing it to Cancel before I introduced the dedicated Close button).
When exiting the scope of 'using' statement, it calls 'myForm.Dispose()' (that's the whole point of 'using' - to make sure Dispose()is called). This in turn destroys 'myForm' instance, including closing the window.
I have a form, wherein I prohibit the user from closing it when the user clicks the Close (X) button. Is it possible to show a tooltip on the Close (X) button whenever it is clicked? I want to do it to notify the user why the form would not close.
I thought of a messagebox but then I thought it would be too annoying to close the messagebox every time you click the Close (X) button.
Is there a better way to notify the user, than what I'm trying to do?
EDIT:
This is my code for the FormClosing event
private void InputForm_FormClosing(object sender, FormClosingEventArgs e)
{
if (e.CloseReason == CloseReason.UserClosing)
{
e.Cancel = true;
if (!mCloseReason)
{
e.Cancel = false;
}
}
}
I have a method that will save the inputs in the form. Once that method is finished, I need to automatically close the form. The if-statement will be true once I call this.Close(), this means I can't close the form. That's why I used a variable called mCloseReason to be able to close the form automatically. Now, that's why I was asking if I can notify the user through a tooltip once the Close (X) button is clicked.
I believe the default tooltip for the close(X) button is not editable without some hacking (and it is not practical).
Maybe what you could do is have a status field below your form, so when the user clicks the close button, it says in the status field "cannot close form (...)"
Or another idea is to have a message pop up somewhere on the form and go away after a little, indicating the form cannot be closed.
Another good idea was mentioned by Roger... just have a Close button somewhere on the form with a tooltip coded to it, and hide the forms' title bar?
Within the application I am writing for testing/learning C#, I use the hidden/visible property to open and close windows.
It is a WPF application.
In the main window, I have a "close" button that triggers this method:
public void buttonQuit_Click(object sender, RoutedEventArgs e)
{
var message = exitmessage;
var title = exitTitle;
var result = MessageBox.Show(
message, // the message to show
title, // the title for the dialog box
MessageBoxButton.YesNo, // show two buttons: Yes and No
MessageBoxImage.Question); // show a question mark icon
// lets see what has been pressed
switch (result)
{
case System.Windows.MessageBoxResult.Yes: // Yes button pressed
CloseAllWindows();
break;
case System.Windows.MessageBoxResult.No: // No button pressed
break;
default: // Neither Yes nor No pressed (just in case)
MessageBox.Show("Oh noes! What did you press?!?!");
break;
}
}
This way I make sure that all windows get closed, including the hidden ones.
But now is the catch; when the user presses (in the main window) the top right red X in toolbar to close, only that main window gets closed, but in the background the hidden ones are still there.
So in fact it is 2 questions:
Is CloseAllWindows(); really sufficient to get the app 100% closed down?
How do I "catch" the event when the user presses that red X in the toolbar, and make this also trigger the right closing event?
You should be handling either the Closing or Closed event for your window(s). The former allows you to cancel the close, while the latter just allows you to perform necessary cleanup in response to the window being closed.
So, in this case, you should place the code from your buttonQuit_Click method into a handler method attached to the Closing event so that it gets triggered regardless of how the window is closed.
Then, your buttonQuit_Click method can simply call the window's Close method. That will close the window, in turn raising the Closing event, and running your code in the attached handler method.
As far as your other question, CloseAllWindows will do exactly what it says: it will close all of the windows that your application has opened. In most cases, that should be sufficient to close the application, but it might not be, especially if you've created non-background threads or depending on the ShutdownMode setting.
App.Current.Shutdown will work unconditionally.
You could use the Closing event of the window for that.
Some more info
http://msdn.microsoft.com/en-us/library/system.windows.window.closing.aspx
I'm using c# to make a mobile 6 application. I created another windows form in the project. This is the form that I would like to load first. This is what have tried:
MainMenu gameMenu = new MainMenu();
private void MainForm_Load(object sender, EventArgs e)
{
this.Hide();
gameMenu.ShowDialog();
.....
}
When I run this the emulator comes up but it just stays as the default windows screen. And I don't get any of my forms.
GameMenu's parent is MainForm, which is now hidden, so the Dialog isn't going to be visible. You need to adjust your logic to do one of the following:
show the GameMenu first (i.e. Application.Run(new GameMenu))
Don't hide MainForm
Use gameMenu.Show() instead of ShowDialog()
You may need to get rid of this.Hide() or use gameMenu.Show() instead of gameMenu.ShowDialog() or you may need to do both.
If you have to use gameMenu.Show() instead of gameMenu.ShowDialog(), you may also want to do the following:
Subscribe to MainForm's GotFocus event and call gameMenu.Show() again whenever the other form gains focus unintentionally. Set MainForm's Enabled property to false while the gameMenu is shown if you want to prevent any accidental interaction with the MainForm while the gameMenu is supposed to be shown.
I have a problem with modality of the forms under C#.NET. Let's say I have main form #0 (see the image below). This form represents main application form, where user can perform various operations. However, from time to time, there is a need to open additional non-modal form to perform additional main application functionality supporting tasks. Let's say this is form #1 in the image. On this #1 form there might be opened few additional modal forms on top of each other (#2 form in the image), and at the end, there is a progress dialog showing a long operation progress and status, which might take from few minutes up to few hours. The problem is that the main form #0 is not responsive until you close all modal forms (#2 in the image). I need that the main form #0 would be operational in this situation. However, if you open a non-modal form in form #2, you can operate with both modal #2 form and newly created non modal form. I need the same behavior between the main form #0 and form #1 with all its child forms. Is it possible? Or am I doing something wrong? Maybe there is some kind of workaround, I really would not like to change all ShowDialog calls to Show...
Image http://img225.imageshack.us/img225/1075/modalnonmodalproblem.png
Modal forms do exactly what "modal" means, they disable all other windows in the app. That's rather important, your program is in a somewhat perilous state. You've got a chunk of code that is waiting for the dialog to close. Really Bad Things could happen if those other windows were not disabled. Like the user could start the modal dialog again, now your code is nested twice. Or she could close the owner window of the dialog, now it suddenly disappears.
These are the exact kind of problems you'd run into if you call Application.DoEvents() inside a loop. Which is one way to get a form to behave modal without disabling other windows. For example:
Form2 mDialog;
private void button1_Click(object sender, EventArgs e) {
mDialog = new Form2();
mDialog.FormClosed += (o, ea) => mDialog = null;
mDialog.Show(this);
while (mDialog != null) Application.DoEvents();
}
This is dangerous.
It is certainly best to use modal forms the way they were designed to stay out of trouble. If you don't want a modal form then simply don't make it modal, use the Show() method. Subscribe to its FormClosing event to know that it is about to close:
private void button1_Click(object sender, EventArgs e) {
var frm = new Form2();
frm.FormClosing += new FormClosingEventHandler(frm_FormClosing);
frm.Show();
}
void frm_FormClosing(object sender, FormClosingEventArgs e) {
var frm = sender as Form2;
// Do something with <frm>
//...
}
The first thing that comes to mind would be something like this. You could disable form 1 when you launch form 2 and then have form 1 handle the closed event of the second form to re-enable itself. You would NOT open modal 2 using show dialog.
Now keep in mind, from a user perspective this is going to be quite cumbersome, you might look at doing a MDI application to get all windows inside of a single container.
Your main form will not be responsive until any modal dialogs that are in the same process space are closed. There is not work around for that.
It looks to me like you could use an MDI application setting the Form #0 IsMdiContainer property to true.
Then, you could do something alike:
public partial class Form0 {
public Form0 {
InitializeComponent();
this.IsMdiContainer = true; // This will allow the Form #0 to be responsive while other forms are opened.
}
private void button1_Click(object sender, EventArgs e) {
Form1 newForm1 = new Form1();
newForm1.Parent = this;
newForm1.Show();
}
}
Using the ShowDialog() as you stated in your question will make all of the forms Modal = true.
By definition, a modal form is:
When a form is displayed modally, no input (keyboard or mouse click) can occur except to objects on the modal form. The program must hide or close a modal form (usually in response to some user action) before input to another form can occur. Forms that are displayed modally are typically used as dialog boxes in an application.
You can use this property [(Modal)] to determine whether a form that you have obtained from a method or property has been displayed modally.
So, a modal form shall be used only when you require immediate assistance/interaction from the user. Using modal forms otherwise makes believe that you're perhaps running into a wrong direction.
If you do not want your main form to be an MDI container, then perhaps using multithreading is one solution through a simple BackgroundWorker class is the key to what you want to achieve. Thus, it looks to me like a design smell...
What is it you want to do, apart of making your main form responsive, etc.
What is it you have to do?
Explaining what you have to do, we might be able to guide you altogether into the right, or at least perhaps better, direction.
Actually the answer is very simple. Try
newForm.showDialog();
This will open a new form, while the parent one is inaccessible.