Develop Reference

Get current MessageBox

I have a large application with several forms, any of them could get a MessageBox (MessageBox.Show()) that is modal and locks the form.
On activation of another form I now need to find this MessageBox and bring the form that has this MessageBox to front. Is there any way to check this?
I know about the Application.OpenForms property, maybe there is something like this for MessageBox?
Edit1 : For example, say that we open Winform1, then a event in Winform1 will go to the mainController that opens Winform2. Lateron Winform1 is getting a MessageBox.Show, But its fully possible to bring Winform2 to front(above Winform1). So now I need to react to the Winform.Activated to check if there is any MessageBox.Show and if so, bring this form that holds the MessageBox to front.

You could find them by using Application.OpenForms like this:
foreach (Form f in Application.OpenForms)
{
if (f.Visible && ! f.CanFocus)
{
// whatever...
}
}
Or: use a different approach altogether:
Make all your forms handle Application.EnterThreadModal and Application.LeaveThreadModal, so that when the app goes modal while that form is current, you add that form onto a list so you can keep track of it, and remove it from the list when it leaves modal...
Then all you need to do is query that list to see if any forms have a modal dialog box open.

Try using one of the Show methods that takes an owner:
MessageBox.Show(this, "My Message");
I tested this on .NET 4 / Windows 7, and when the message box is opened it brings its owner to the front.

new form problem c#

I'm aware that this title doesn't say much but it's really hart to explain what I want in few words.
I have two forms (main & help). Once I press button on main form help form pop ups. What I would like to implement is function to block user from doing anything on main form till he close help form.
I would not like to play with visible controls but I would like to have an effect you might have seen on some program that when user tries to click on main form help form "blinks" along with error sound playing. Once user close help form program works as usual
Hope you understand what I meant

This is called a modal dialog, and luckily, the answer is simple; show the child Form with the ShowDialog method instead of using Show. This is a blocking call that will not return until the child form/dialog is closed, so it means that you can check the return value and any properties if needed right after that line of code (probably not useful for a help window, but in most circumstances it is useful to check the user's action).
using( var dlg = new MyHelpDialog() )
{
if( dlg.ShowDialog() == DialogResult.OK )
{
// user chose "OK", do something (?)
// you can also access properties of the form after the fact
string whatever = dlg.SomeStringProperty;
}
}

You're looking for modal forms:
How to: Display Modal and Modeless Windows Forms

The thing you're talking about is called a "Modal Window".
See
How to: Display Modal and Modeless Windows Forms

C#: Is there a winforms way to make C# MessageBox Buttons (YesNo) larger?

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

c# - create invisible user control

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;
}

C#: What is the proper way to show a form for "frmMainForm" settings and disposing?

Backdrop: There are two forms, the main application form and a form to edit various settings for the operations of main application.
What would be the proper way to show the frmSettings form and how to dispose it once clicked OK or Cancel in the actual frmSettings form?

Perhaps a Dialog would be better suited to your Settings "form." There are subtle differences between a dialog and a form that would make the dialog easier to handle. A return code indicating the button that was clicked makes dialogs useful.
Supposing that you used a dialog - a using statement could be used (off the top of my head):
using (DialogSettings dlgSettings = new DialogSettings)
{
if (dlgSettings.ShowDialog() == DialogResult.OK)
{
}
}
If you insist on using a form then you would have to
Instance the form
show the form
record whether ok or cancel was clicked to a form level variable (from within the forms ok/cancel button click code)
hide the form
save the recorded value from the form
dispose of the form
make use of the saved ok/cancel value

fyi, using "frm" is not a recommended part of the C# coding guidelines. Microsoft prefers you don't use hungarian notation in .NET at all.

using (frmSettings s = new frmSettings() )
{
if( s.ShowDialog() == DialogResult.OK )
{
//do work
}
}

In the main application declare an instance and show it.
using(frmSettings settingsInstance = new frmSettings())
{
settingsInstance.Show(); //or ShowDialog()
}
Then just close the form when done...