Is there any way for detect MessageBox closing. Some workarounds can be possible maybe I can write my own custom MessageBox, but I want the operating system's MessageBox.
Maybe something like MessageBox.Closing += new EventHandler, any suggestions?
There is no "normal" way of doing that, if not using some not very riliable API calls and sniffing. But according to yuor comment, you need may be something like:
var flag = true;
MessageBox.Show(...);
flag = false;
This is a correct way of doing that. MessageBox.Show(...); is a blocking call.
If you need more control, define your own form, and it wil become your message box.
So you can have full control over it, and have also Closing event handler possibility.
You can use the MessageBox found int Extended WPF Toolkit™ Community Edition.
In its documentation there are two events called
CloseButtonClicked
Closed
But as explained in the Tigran answer, the MessageBox.Show call is modal and block the thread in which you make the call, so there is no need to catch the close event unless you are running another thread that should react immediately in some way to the closing of the messagebox.
In my case I just wanted to see if the MessageBox was clicked and then do something, hope it helps.
DialogResult result = MessageBox.Show("Your message");
if (result == DialogResult.OK)
{
Application.Exit(); //whatever you want
}
Related
It would be nice to have larger MessageBox Buttons since the target for this application is a tablet.
DialogResult dialogResult = MessageBox.Show(
message, caption,
MessageBoxButtons.YesNo,
MessageBoxIcon.Question,
MessageBoxDefaultButton.Button2);
switch (dialogResult)
{
case DialogResult.Yes:
// ...
It is a system setting. Tablet PCs are normally already configured to make it easy to tap buttons like this so that it works well in any program, not just yours. To configure your tablet, in Win7, use Control Panel + Display, Personalization, Window Color. Click Advanced appearance settings, select "Message Box" in the Item combo. Increase the font size. Don't be fooled by the poor preview, the button will actually grow. There are additional settings in this dialog you might want to tweak to make it easier to manipulate the UI.
A messagebox is just a simple modal form. You can make one yourself and use ShowDialog()
I'm not sure if it's possible or not, but you could use a simple form instead of a dialog box then you can get the design exactly as you wish.
Winforms way? Do you mean, an "automagically via a property change" way? If so, none that I know of.
You can spin up your own custom dialog/form that is bigger and use it instead. While this is not as automagic as the one line MessageBox.Show(), it is not very difficult.
That's not possible with MessageBox which wraps the native system dialog.
You'll need to produce your own dialog or even better see if there is a way to configure the system to give your app (and all others) bigger buttons.
The downside of rolling your own is that you lose all the functionality that the native one provides.
Yeah, going along with what MattP said, you'll need to create a custom form and then use the ShowDialog() method to display the second form as a modal dialog.
private void button2_Click(object sender, System.EventArgs e) {
using (Form2 xForm = new Form2()) {
if (xForm.ShowDialog(this) == DialogResult.OK) {
// Take some action
}
}
}
You can make a 2nd form, then you can make the buttons as big as you want
Is it possible to set the OpenFileDialog's cancel button enable = false? If so, How?
I'm using winforms
Edit
OpenFileDialog file_open_dialog = new OpenFileDialog();
I don't believe so, and with good reason! Are you sure that you want to disable the Cancel button? Being that this is a modal dialog this would prevent the user from continuing (and hence making your application unusable) until they selected a file - there are almost certainly going to be scenarios where this simply isn't possible, or the user doesn't want to be forced into saving a file.
Of course I could be wrong and there could be a completely legit scenario that I'm not aware of - however I'm afraid that Microsoft were also unaware of this scenario and so the OpenFileDialog doesn't support disabling the cancel button.
I'm afraid that if you really don't want a cancel button you will need to create your own clone of the dialog.
handle the cancel in a loop if you want? might frustrate users ;)
do
{}
while (openFileDialog1.ShowDialog() != DialogResult.OK);
I need to create a user control in C#.Net, which can be added to the application without being visible - just like the FolderBrowserDialog. It's a new window which I'll be using often so I think this is the right way. The window will be opened by envoking the showDialog-Method as known from the other dialog.
Any Idea?
Thanks and regards,
Daniel
Since all these "invisible" controls derive from Component class, you should start by reading the MSDN article on it: http://msdn.microsoft.com/en-us/library/system.componentmodel.component.aspx.
simply set Visible to false or isn't this what you're asking for ?
A UserControl is by definition not a Form; I think what you really want is a Component. That said, couldn't you really just create a new Form class that has the functionality you want? Whenever you want to display it, create a new instance and call ShowDialog. Or, if you want to preserve state, add an instance as a class member to your parent form, call its Show method whenever you want to display it, and add an event handler to its FormClosing event to check:
if (e.CloseReason == CloseReason.UserClosing)
and, if so,
e.Cancel = true;
Hide();
(This last part is to prevent errors if the user closes the form and then tries to display again after it's been disposed.)
I think more information may be needed, but if your crating a custom user control, the control should have a .Visible property. The follow is an example of how a button can be located on the form but hidden from a user.
button.Visible = true; // shows the button
button.Show(); // Shows the button
button.Visible = false; // hides the button
button.Hide(); // Hides the button
While the button may still be on the form/control, it will not be interactible by the user. You can still perform programmatic control on the button, but essentially it is not a user control while it is 'hidden'. If you want there to be a sort of hidden button that the user can click you will need to do other things to obtain this but It doesn't should like that is what you want.
This show/hide thought process sounds a lot like pains and confusion leftover from classic VB. The old form methods of show and hide, etc., were confusing and often left me as a developer in a position to not know whether an object existed or if was merely invisible. And checking was only trivial if you used On Error Goto to prevent a null reference. So right off I would advise not to think in terms of visibility unless you are doing something with a web page and need to maintain space and state.
First, create a Windows form and add it to your project, assuming that is the type of project that you are describing. Decorate the form with the proper controls, and where applicable, create properties to allow public access to the control values. Also set the DialogResult property of the buttons that either "OK" or "Cancel" the form. Give it an appropriate border style of either Fixed3D or FixedDialog. Maybe also set the property for where you want the form to appear on startup -- center parent, center screen, Windows default, etc. The event handlers for both "OK" and "Cancel" should invoke this.Close(); to close the window.
From the calling point in the code, here's some hypothetical code to get you going in the right direction. Write something like this in the place where you want to invoke your Dialog.
int intResult = 0;
string strResult = null;
MyDialogForm frm = new MyDialogForm();
frm.Title = "Select an Item";
frm.SomeProperty = 0;
frm.SomeOtherProperty = true;
if (frm.ShowDialog() == DialogResult.OK)
{
intResult = frm.Result;
strResult = frm.StringResult;
}
else if (frm.ShowDialog() == DialogResult.Cancel)
{
// User clicked the cancel button. Nothing to do except maybe display a message.
MessageBox.Show("Canceled Task");
}
...
// Somewhere further on down, but within scope, simply repeat
// what you just did, but without having to reinstantiate the
// form Window. But if you make it that far within the same
// scope, this method might be too busy and may need to be
// factored down.
So in short:
Scrap show/hide -- its not a good
practice.
Save the form data without
using an invisible form to save it;
that's the class's job.
If the UI requires a lot of flipping back and
forth between windows, check your
design for other alternatives for
solving the original problem. Maybe a design pattern such as MVC is for you, depending upon the size and complexity of your application.
Sound good?
You can put that control in a Panel. Set the panel height = 0 visible = false when you dont want to show the control.
And do the vice versa when you want to show it.
Derive from Control, not UserControl, and in the constructor set Visible = false.
Also create an event handler in the constructor.
VisibleChanged += new EventHandler(SetVisibleFalse);
Create a method named SetVisibleFalse.
private void SetVisibleFalse(object sender, EventArgs e)
{
if (Visible) Visible = false;
}
I am using Windows Form application. I want to open a small textbox on a window to enter user's name or Email in Starting for the program.
How can I achieve this?
Write one, 'tis almost trivial (creating the form and adding label, textbox and buttons) and using the VB one is perputating something that was only put in to appease the baying mob.
Key method is ShowDialog() which is a method on a Form.
On the form make sure you set the flags for the Ok and Cancel buttons correctly and provide a property (ideally) to allow you to read (and write if necessary) the text box
You can then do something along the lines of the following:
using(MyInputForm mif = new MyInputForm)
{
if (mif.ShowDialog() == DialogResult.OK)
{
dataFromDialog = mif.InputData;
}
else
{
// logic to deal with cancel
}
}
You can do something similar in WPF, don't have an example to hand though.
Maybe the answer to this question will help:
What is the C# version of VB.net’s InputDialog?
I have a very strange behavior that only seems to happen on one form.
Basically I am creating an instance of a Form, and calling Show() to display the form non-blocking. In that form's Load event handler, I have some logic that may call this.Close() under certain circumstances. This closes the form, but then the form Show() method in the client code throws an ObjectDisposedException.
The stack trace from the ObjectDisposedException is as follows:
at System.Windows.Forms.Control.CreateHandle()
at System.Windows.Forms.Form.CreateHandle()
at System.Windows.Forms.Control.get_Handle()
at System.Windows.Forms.ContainerControl.FocusActiveControlInternal()
at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.Show()
...etc.
This is what I'm seeing happen:
Control.Show() is called
my form is launched
the OnFormLoad method is called
the FormLoad event handler is called, inside of which I call this.Close()
the OnFormClosing method is called
the FormClosing event handler is called
Dispose is called on my form and all it's user controls
and then somewhere toward the end of the Control.Show() method, it tries to get a handle to the form, which freaks out and throws an exception because the object is marked disposed.
My real question is, why can I do this exact same thing on every other form I have without exceptions? Is it a GC issue? I've tried putting a GC.Collect() call right after the this.Close() and it makes no difference. Like I said, it happens 100% of the time on this form, and never anywhere else, regardless of child user controls, scope of the form variable, etc.
Any ideas?
The best way to do so :
this.BeginInvoke(new MethodInvoker(this.Close));
this is the most simple way you wont get ObjectDisposedException
I know this is an old issue but no one seemed to have posted the obvoius answer.
You say you call Control.Show() and then Form.Close() and then the form is Disposed of. Well, unless you use MDI or use ShowDialog that's just as documented. Though, the short version of the Close() documentation is "Closes the form", it actually also disposes it implicitly under certain conditions.
See the remarks section:
http://msdn.microsoft.com/en-us/library/system.windows.forms.form.close.aspx
If you want to show a form again. Use the Hide() method instead of Close().
Hope that helps other searching souls.
And guys, don't stop searching at "I don't know why it works sometimes". That becomes buggy software with lots of defensive "I'll call this method again just in case" stuff. Not good.
Ok, hate to answer my own question, but this was driving me nuts, and it was one of the hardest bugs to reproduce I've ever seen.
On my form I'm overriding the OnFormLoad and OnFormClose methods, where I save/restore the form's Size, Location, and WindowState to/from the registry. I took this code out and it fixed the problem. The weird thing is, I put it back and the problem didn't come back.
I finally reproduced the problem: you have to let the form open fully, maximize it, and then close it so that the Maximized state is saved to the registry. Then when you open it again, it will set it to Maximized, and if it closes in the Load handler, it tries to access the Size/Location as it's closing. Apparently accessing these values in the OnFormClosing method causes the form to try to focus IF AND ONLY IF the form is maximized, which is illegal, since the form has been disposed.
So basically, you can't access Form display properties in the OnFormClosing method of a form, if that form is going to call Close from it's Load event.(Unless you check the Disposed prop first)
pretty specific piece of Winforms wisdom I know, but I'm writing it down anyway.
If you want to close a form as if the user pressed the cross in the upper right corner (usually means cancel), just add the following code.
this.DialogResult = System.Windows.Forms.DialogResult.Cancel;
this.Close();
This also works in the form load function:
private void MyForm_Load (object sender, EventArgs e)
{
// do some initializations
if (!ContinueLoadingForm())
{
this.DialogResult = System.Windows.Forms.DialogResult.Cancel;
this.Close();
return;
}
// continue loading the form
}
If you don't want the form to be visible for a short while, set the Visible property false (for example in the designer or constructor), and set it back to true when you are certain the program can continue loading.
In load event is not realy good idea close the form. Do it after the Activated event.
protected override void CreateHandle()
{
base.CreateHandle();
if (FormMustClose) //FormMustClose is a variable in the loadevent.
{
Close();
}
}
One possibility:
They may have a timer on this form, that is being initialized and enabled in their FormLoad event. The timer would need to be disabled and stopped as well, before the form was closed, if the timer is trying to access the form when it's fired.
I've seen forms before that do this...
It seems to me, without looking closely at it, that the cleanest way to accomplish what you want might be to make a custom form class deriving from Form, and override OnFormLoad(...) and/or Show() to check for your condition and cancel out early.
That said, I don't know why it would work sometimes and not other times.
Have you tried stepping into the .net code to see what line of code is being called when the exception is occuring? If you have VS 2008 you can do so by going to Tools --> Options --> Debugging and select the Enable .NET Framework Source Stepping. Be warned, this may take a while to download all of the necessary files, but this way you can step into the form.Show() and see exactly what is going on.
Ok, it turns out it's a little simpler and more generic than I thought, but still weird and obscure.
If you're saving/loading the form Size/Location/WindowState when the form loads/closes like we do, you have to make sure that the OnLoad method calls base.OnLoad first so that the Form Load event handler fires, and THEN set the properties. Not doing so will only cause a problem if the form calls Close from inside the Load method. You'll get an ObjectDisposedException on the Show call after the form closing event is done.
My head hurts.
Form.Shown() Is the trick too.
As I understand it, setting the DialogResult of the form will close the form - may have to be other than DialogResult.None. (i.e. you don't need to then call the Form.Close() method).
The issue is also in part that if elsewhere in code, you are accessing a property of the form or control within it, that may prevent the form from closing.
It may also be best if as has been suggested, you have a property e.g.
private bool _loadedOk = false;
in your form which you set in your initialisation code. In one of the later events after Form_Loaded, you then interrogate this and close the form if it's false.
Perhaps someone can suggest the best event to do this in??
If you want to close the form without flicker, the best way I found was override SetVisibleCore Method:
public partial class MyForm : Form
{
...
protected override void SetVisibleCore(bool value)
{
if (value && !IsHandleCreated && !ContinueLoadingForm())
{
base.SetVisibleCore(false);
this.Close();
return;
}
base.SetVisibleCore(value);
}
}
Then you can simply do:
...
var myForm = new MyForm();
myForm.Show();
...
The Form only will appear if ContinueLoadingForm() be true, this works with ShowDialog() and Application.Run() as well.
Expanding on RCMAN's answer in this thread (which got me 99% of the way to the finish line) ...
Here is the code I ended up using which also avoids the screen flicker:
Me.FormBorderStyle = FormBorderStyle.None
Me.Opacity = 0.01
Me.MinimumSize = New Size(1, 1)
Me.Size = Me.MinimumSize
Me.Location = New Point(1, 1)
BeginInvoke(New MethodInvoker(AddressOf Me.Close))
Additionally, to avoid the message "This program might not have run correctly" I applied a manifest change as described by mik here:
How to prevent "This program might not have installed correctly" messages on Vista