It is possible that when I use:
MessageBox.Show("hello");
..to still use the form but the MessageBox is open like a second window?
because currently, when I show the MessageBox, I need to first click yes or no then I can use my form again.
Yes, you can!
If you simply want to display a MessageBox, don't care what happens with it, and don't want to wait until it's closed, you may launch it on a separate thread. The easiest way to do that would be using Task.Run().
Here's an example:
private void button1_Click(object sender, EventArgs e)
{
Task.Run(() => MessageBox.Show("hello"));
// The remaining code will run without waiting for the MessageBox to be closed.
}
A couple of notes worth mentioning:
Only use this for simple message boxes where you don't care about the result. If you want to act based on the result and execute something (on the main thread), things get a little bit trickier.
You won't be able to keep the MessageBox on top of the form. Once you interact with the form, it will come on top. If you need to keep the MessageBox on top and still have the ability to interact with the form, a custom MessageBox (i.e., form) would be better in that case because you can set the Owner property to keep it on top.
No. The application focus remains on the Message Box until it is dismissed. According to the documentation:
It is a modal window, blocking other actions in the application until the user closes it.
What you can do is create your own form, style it to look like a standard Message Box, and show that form using the .Show() functionality on an instance of it:
var messageBox = new MyCustomMessageBox("hello");
messageBox.Show();
If you want the functionality to be identical in usage, you could even add a static method to your custom form which encapsulates it:
public static void Show(string message)
{
new MyCustomMessageBox(message).Show();
}
Though what I wouldn't recommend doing is calling your custom form MessageBox, that would just be asking for confusion.
Related
In my .NET application I am showing a form with a "Please wait" message if some task takes a while to tell the user that the program still works. This form has to run in it's own thread since the main thread is the one doing work and therefore busy. I read that one can use Form.Owner for this task, but I don't think that works if the forms run on different threads.
The problem is that the wait form can be hidden behind the main form in which case the user couldn't see it and can't bring it to the front, since it has no task bar button (an it musn't have one).
My question is if it is possible to let the wait form stay above the main form without making it an AlwaysOnTop form (which would stay above ALL windows)?
Your main thread should not be doing work. It should be handling UI and nothing else.
The right way to do this is to perform any and all time-consuming work in an asynchronous manner (e.g. in a separate thread), and keeping all of your user interface in the main thread. Then you can simply show the "Please wait" message form by calling the Form.ShowDialog() method. This will force focus to that dialog and keep it on top of its parent form (don't forget to pass the parent form reference to the ShowDialog() method).
Without a code example, I can't say exactly how this would look in your specific scenario. But the general idea looks something like this:
private void button1_Click(object sender, EventArgs e)
{
using (Form form = MyWaitMessageForm())
{
form.Shown += async (sender1, e1) =>
{
await Task.Run(() => MyLongRunningWork());
form.Close();
}
form.ShowDialog(this);
}
}
You can use the Form.TopMost property for this.
You can also use the following code:
protected void SetZOrder(IntPtr bottom, IntPtr top) {
const int flags = 0x0002 | 0x0001;
NativeMethods.SetWindowPos(bottom, top, 0, 0, 0, 0, flags);
}
bottom - the pointer of the main form, top - the pointer of the wait form. To get a pointer, use Form.Handle property. And call the SetZOrder via the BeginInvoke method of the parent form.
You could use the Form.ShowDialog(IWin32Window)
Form1 testDialog = new Form1();
testDialog.ShowDialog(this)
I'm trying to make a new form appear when I click on a label. I'm using Windows Application Forms.
Here's the code:
private void label1_Click(object sender, EventArgs e)
{
Form parpokeru = new Form();
parpokeru.Show();
parpokeru.ShowDialog();
}
When I click on the label, a error appears (Unhandled exception has occurred in your application...). Can anyone tell me how to fix it?
Call .Show() or .ShowDialog(). Not both.
Show() will display your second form, while still allowing the user to access the first form.
ShowDialog() will display your second form as "modal". Execution of code in the first form stops while the second form is open (at least on the main thread.. for example, timers will continue to run), and the user will not be able to access your first form while the second is open.
When you call the Show method your form is shown on video like another window and the code returns immediately from the call. So your code continues and all the forms of your application are available for the user interaction. It is calledd a modeless dialog
On the contrary, ShowDialog is a blocking call. The code doesn't return from this call until something happen inside the called form that terminates the visualization of the form. As an example comes to ming a call to the methid Hide or a click on a button with its DialogResult property set to something different from DialogResult.None. At this point the code from ShowDialog returns and the normal processing continue. While the code is blocked inside the ShowDialog the application is blocked and the user cannot interact with other forms or menus or whatever is displayed on video. It is called modal dialog
Another difference is ShowDialog returns value (a DialogResult enum value) that can can be used to determine how the user closed the form (DialogResult.Cancel, DialogResult.OK), also ShowDialog does not call the Dispose method at closing time. This will allow to retrieve property from the Modal Dialog like user inputs for further processing.
I cannot imagine what happen in the internal processing of your form if, after a modeless call to Show you call immediately a ShowDialog on the same form instance. However, an exception is really the minimum to expect from this code.
General description of application:
Main form as MDI Container. On application start, if there is no xml file for database configuration (it is checked in Main form) Main form i call another form as showdialog() to fill all database info to build connection string. Then i close form and open another for login, then i get back to Main form, which has Split Container (2 panels: 1-menu on top, 2-content from child forms).
I open forms with:
private void PlanButton_Click(object sender, EventArgs e)
{
plan.TopLevel = false;
KontenerMenu.Panel2.Controls.Add(plan);
plan.Dock = DockStyle.Fill;
plan.Show();
}
and close form with:
private void Plan_FormClosing(object sender, FormClosingEventArgs e)
{
e.Cancel = false;
this.Hide();
}
Problems i have with app:
1. When i hit Cancel button when i open ShowDialog() form for database app crashes. Cancel button is simply:
private void cancelButton_Click(object sender, EventArgs e)
{
Application.Exit();
}
2. I have problem with clicking button to open/close/open again child forms. When i hit 'X' and want o open, app crashes with exception that it cannot refer to non-existing object
3. I have several buttons when i hit one and then another one it is always below the first one and not on the top
4. For example my form is 200x200 and in right down corner i have button (so location let's say 190x190) and i hit maximize button. My button is still on 190x190 and i would like to have it on down right corner. I couldn't find any property for that. Is there any or i have to write some code for that.
I'm not sure I understood your questions. Please make them clear.
But as an answer to question #4, there's an anchor property that does what you want.
Instead of trying to exit the application from within the dialog form itself you should return a DialogResult value and test that in the main form. The cancel button on the dialog doesn't need any code, just set its DialogResult property to 'Cancel' and if you have an Ok button set its DialogResult to 'OK'.
DialogForm f = new DialogForm();
DialogResult r = f.ShowDialog();
if (r == DialogResult.Cancel)
{
Close();
}
I can immediately see a number of problems with you code, including:
If you're going to add controls dynamically using Controls.Add, you should make sure the controls you're adding are dynamically created using new(). I get a sense that you don't have a clear understanding of object lifetimes and the WindowForms control life cycle.
The Application.Exit method should be used only in unusual cases. It's purpose is to achieve exactly the result you're observing - to immediately "crash" the application. The easiest way to have a button close a modal dialog is the set the DialogResult property of the button.
Winforms has a very elegant system for placement of control on a variable sized window. In order to use this system, you should familiarize yourself with the Anchor and Dock properties that are available on all controls.
It looks like what you're doing is attempting to learn WinForms by trial and error. You can do this, but it will take much longer and be much more painful that getting a hold of a good tutorial, book, or perhaps even attending a class if you can manage it. That will allow you to take these issues one at a time and have a much more enjoyable learning experience.
I am displaying dialog on the main form, now one for loop is working behind but when that dialog will displayed code execution will be stopped, but I don't want to let stop the execution of the code, is any other any way to do that ?
EDIT: I am using now thread to do that and my code is like
Thread t;
private void StartParsingByLoop()
{
t = new Thread(new ThreadStart(RunProgress));
t.Start();
for (int i = 0; i < dialog.FileNames.Length; i++)
{
cNoteToParsed.AllContrctNotesFilePath.Add(dialog.FileNames[i].ToString());
}
cNoteToParsed.ParseContractNote();
if (cNoteToParsed.NOfContrctNoteParsed > 0)
LoadTransactionsInDataGridView();
t.Abort();
}
private void RunProgress()
{
frmProgress progressForImportingTran = new frmProgress("Importing Transactions", "ok");
progressForImportingTran.ShowDialog();
}
Now I have problem is that the dialog that shows the progress does not behave like dialog and gives access of the main form and if we try to access the main form then dialog goes to hide. And I dont want to make the dialog be hide.
You can let a different thread handle the loop.
Response to edit: Can you provide more details, perhaps some code? what is the loop doing? what form do you display?
(this answer is based on the assumption that we are taking about a winforms app)
Show the form using the Show method, rather than ShowDialog. By passing a reference to the main form, the dialog will stay on top of the main form even if it is not modal:
TheDialog dialog = new TheDialog();
dialog.Show(this);
Note though that the user can still interact with the controls on the main form, so you might want to disable some controls, depending on your scenario.
You state in your question that there are requirements that prevent you from using threading for this. This kind of requirement strikes me as odd, and it is a pity because this is one of the typical scenarios when you would want to use some sort of asynchronous construct. By performing heavy work on the UI thread, you get some drawbacks, including:
The UI will not be responsive - if you want to allow the user to cancel the work by clicking a button, that will be tricky to achieve in a robust manner.
The UI will not redraw properly since the UI thread is busy performing other work.
Do not use ShowDialog() but Show() to display the dialog windows. Show() will immediately return to the caller whereas ShowDialog() will hold the execution. Note that when using Show() your dialogs won't be modal anymore.
OK, so you don't need modal dialog, you need a mechanism for your user not to be able to select your main form while processing is enabled.
Modal dialog doesn't mean that execution is stopped - it just happens somewhere else.
There are several methods to do this, and you ruled out new thread creation (don't know why, it would solve it elegantly). If don't use thread, you'll have another problem - your processing should be done in CHUNKS and every little while you'll have to do something like Application.DoEvents() to enable your application to process messages and not be frozen to the user.
So, if you can create a method in the main form that shows your 'please wait' dialog which will perform some work and later do some more until is finished, you can do this:
create a new form (wait dialog)
start a timer inside of it and wire timer to the PARENT form
timer interval should be 1
ShowDialog() the form
on timer event do small amount of work (don't allow it to go more then 1/10 of seconds)
Can you do that?
Anyway:
task can't be split into small workable pieces
you can't use threads
you want your UI to be responsive
PICK 2. You can't have all 3 in Winforms.
I have a C# windows forms application. The way I currently have it set up, when Form1_Load() runs it checks for recovered unsaved data and if it finds some it prompts the user if they want to open that data. When the program runs it works alright but the message box is shown right away and the main program form (Form1) does not show until after the user clicks yes or no. I would like the Form1 to pop up first and then the message box prompt.
Now to get around this problem before I have created a timer in my Form, started the timer in the Form1_Load() method, and then performed the check and user prompt in the first Timer Tick Event. This technique solves the problem but is seems like there might be a better way.
Do you guys have any better ideas?
Edit: I think I have also used a background worker to do something similar. It just seems kinda goofy to go through all the trouble of invoking the method to back to the form thread and all that crap just to have it delayed a couple milliseconds!
I would use Form1_Shown()
Use the Shown event. It seems to suit what you need, and will only display the first time the form is shown.
Form f1 = new Form();
f1.Shown += new EventHandler(f1_Shown);
public void f1_Shown(object sender, EventArgs e)
{
// Show dialog in here
}
Try the "Shown" event:
Form.Show Event
Using a Windows.Forms.Timer is a good, stable, well-known, and easily understood technique for doing what you want. I would avoid any other timer objects.
The form's Shown event works well.
Overload / override the Show method. (My preferred technique for greater control.) In this method, I would do the checking needed. When ready, I would call the base.Show method, then do any other processing, such as message boxes, prompts, logging, or whatever.