Is it possible to edit a DFM (Delphi's form script format) in such a way that a form closes itself when shown?
I don't code in Delphi, so I'm not familiar with how these forms work, but it seems I could put code (but not standard Delphi code as it seems) in the OnShow or OnCreate events of the form. However, after trying several statements like Close, Exit, FormNameExit, Destroy, etc. won't work (a log will be created, stating the error that the value of the OnShow property was invalid, etc.)
The normal way of closing the form is through a button, but the button doesn't have a OnClick event, just a property, "ModalResult = 1".
Is there a way to make the window close upon opening, some standard function I could put on the OnCreate or OnShow events of the form? Or maybe, creating a checkbox on the form itself, that gives ModalResult = 1? (don't know if this works)
Thanks for any suggestion!
=)
(Note: maybe it's obvious, but I don't have the source.)
Not in DFM. You would have to modify the source.
The OnShow and OnCreate lines you're seeing are only used to give the name of a method that's already defined in the source code. You can't add much functionality at all by modifying the DFM file.
Perhaps the form already has a matching event handler that closes it: the OnClick handler for a close button or menu item, maybe? If so, you could try setting it as the OnShow or OnCreate handler.
You might be able to add a TButton to the form and set its ModalResult -- I don't recall whether you actually need a field in the form class for each control in the DFM -- but that would only work if the form is shown modally, and you'd still have to click it to make the form close.
EDIT: Seeing some of your comments added while I typed my text-wall clarifies things a bit.
I'm guessing that you you're using a resource editor to edit the DFM and modify the behaviour of the app without actually touching the source code?
In this case, the best you could try is to set the Visible property to False. However, this will have no benefit if the developer 'actively displays the form in code'. (He could have done this by calling Show, ShowModal or even by explicitly setting the Visible property.)
Unfortunately, if this is the case, then there's nothing you can do without modifying the actual source code. This is because the DFM is processed when the form is loaded; i.e. before the developer's code that shows the form. Even looking for a place to set ModalResult is useless, because the current ModalResult is cleared when ShowModal is called.
I don't think I understand exactly what you're trying to do, because it doesn't make sense.
It seems to me that you want the form to be automatically closed as soon as it is shown; and that doesn't make sense. :S
So, if I have understood you correctly, please explain why you would want to do this; there may be a better solution for your actual problem.
However, some general concepts...
If you want a form to close, you should link it to some action that closes the form. Either put a button on the form, or a menu item.
Standard forms have a standard Windows mechanism to close them by default. (I.e. the X on the top-right.)
There are two ways of showing forms, and the way in which it is shown does have an effect on how it will be closed. It can be shown modally (which means it is the only form of the application which will interact with the user), or it can be shown normally (which allows the user to switch between other forms of the application).
The point of showing a form modally is that it blocks the flow of your code until the user has finished doing something that was required; it often involves the user providing some form of answer or confirmation.
When shown modally, the form should rather be closed with a ModalResult.
When shown normally, the ModalResult has no effect.
Whenever a form is 'closed', there are a few ways in which this can be done.
The form can simply be hidden; it's still there, but invisible. Next time you want to show the form, you just make it visible again.
The form can be destroyed; meaning that it no longer exists in memory. If this is done, then next time you want to use the form, you have to recreate it.
The attempt to close the form can be actively prevented (Not usually advisable; but may be necessary in specific cases - if for example some information on the form is incorrect).
The form may be simply minimised (this is often done with MDI child forms).
NOTE: There are also a number of attributes on forms (FormStyle being the most important) that have an effect on how it behaves, displays, and can be closed. (E.g. MDI Child forms will by default either minimise, or do nothing when closed.)
NB:If the main form of an application is properly closed, then the application will shut down.
Now, some of the technicalities...
As mentioned earlier a form can be displayed either modally, or normally; using either MyForm.Show; or ModalResult := MyForm.ShowModal;
NOTE: If the form was shown modally, you then need to check the ModalResult to find out the user's answer and act accordingly.
If you displayed the form modally, you should set the ModalResult and the form will close itself. An easy way to do this is to assign a ModalResult to the buttons on the form; then the button will automatically set the form's ModalResult when clicked.
If you displayed the form normally, then all you need to do is call MyForm.Close at the appropriate point in time. NB: Note their are other ways to 'close' a form, but it is better to use this method because it allows you to handle the OnCloseQuery event which is a mechanism to confirm whether the form is allowed to close.
NOTE: While closing the form, there are two events that Delphi can call which you can handle in order to modify how the closing of the form behaves:
OnCloseQuery is called to confirm whether the form is allowed to close.
OnClose is called to find out how the form should close (as explained previously).
Coming back to your question (which sounds like you want the form closed automatically). Rather than closing the form automatically; just don't bother showing it. This is very easy to do. All forms have a Visible property; if set to True, Delphi will automatically show the form normally when it is created. So all you need to do is ensure the property is False.
You really can't do much without the source but move files around or change existing properties. If you have a MAP file for the program and there are existing events in place (onCreate/OnShow) you could patch the executable to invoke different code for those events, but it won't be easy and you have to insure that you don't inject more code than was there previously or make any external calls to routines which don't exist.
Related
This is a strange one: This is the situation
The application builds an edit form at run-time from an XML document. The UI/UX design is such that there are three levels of nested TTabControls and for the final (lowest) level the TTabItem is created at run-time. This has a TVertScrollBox which itself contains a column-grid control of mine and that (at last!) contains the THtmlEditor.
The problem is that when the controls are built and the content loaded, the THtmlEdit initially ignores keydown. It will respond to mouse events, the caret can be positioned. Switching to a different top-level tab, or away from the whole application and back, then cures the issue and the editor responds to keydown messages.
I have tried putting a breakpoint in procedure THtmlEditor.KeyDown() ... and then tracing back up the call-chain. There doesn't seem to be anything behaving differently. I've paid particular attention to input focus, explicitly calling Editor.SetFocus even though that is apparently already called ...
I have tried putting a conditional breakpoint in function TPlatformWin.HandleMessage: Boolean; ... and my only observation is that when in non-working mode, the call to DispatchMessage(Msg) doesn't arrive at the editor, or its parent form.
I have tried to build a MDC for this, replicating the structure outlined above but ... that always works!
What can I try next?
Has anyone seen this behaviour (and fixed it)?
EDIT:
The detail I didn't mention -- didn't think about it -- is that for the error condition to show, the control focused before the THmtlEditor is a TWebBrowser. If I set focus on a TEdit after TWebBrowser and then to THtmlEditor it seems to work.
Grrr!
This is only half an answer, but for future reference, this is what I've done:
It's a bodge :-(
I've put a TEdit on the main form and set it invisible. I've then added a handler to the MainForm OnFocusChanged which sets a boolean trap-flag to track if TWebBrowser has previously been focused.
For the instances of THtmlEditor I've added an OnClick handler which checks the trap-flag and makes the TEdit visible, calls SetFocus on it, re-hide the TEdit and return True so that the THtmlEditor can re-set focus to itself. The trap-flag is to avoid unnecessarily losing focus if the user is just clicking in the THtmlEditor.
The next step -- which I may never get to -- would be to trace through the focus code for TEdit. My suspicion is that it all relates ITextInput which TEdit supports and THtmlEditor doesn't.
I have a main form and a secondary form both with some DBAware controls from a common database. Currently I am using ShowModal but I would like to be able to use Modal to go back to the main form and navigate the database.
In the secondary I can replace the TDBEdits with TEdits and stuff them with data when I Show the secondary form. There is no means of navigating the database in the secondary form, but, if the user can go back to the main form where they can navigate, I will need to reset the database cursor when they return to the secondary.
How can I tell that the secondary form has just lost focus? I can grab the database cursor position.
How can I tell when the secondary form gets focus again? So I can reset the database cursor if it was moved before returning.
Thanks
p.s. Please no questions on why and/or alternative suggestions. It is an existing application and I really do not want to have to fix miles of code. As crappy as it is, it has been working for years and the customer wants the change of possible. :)
Use the form's OnActivate and OnDeactivate events. OnActivate is called when the form gains focus, and OnDeactivate is called when it loses it.
Note that these events are only triggered when focus is transferred within your own application. If you need to know when your application itself loses or gains focus, use TApplication.OnActivate and TApplication.OnDeactivate instead.
You can take a look at the onActivate and onDeactivate events of the secondary form. I think they are what you need.
Note: OnDeactivate works only if focus is switched to another form of project. For example I have project1.exe which creates 2 forms Form1 and Form2 . So Form1 OnDeactivate event triggers if I ckick Form2. But it will not be trigger if I click Notepad window.
I am currently working on a Customer Management application made in SmartGWT 2.0.
The Add Customer form is a fairly big one with multiple tabs and each tab has lot of fields. This form is opened in a modal window which have a save and a close button at the bottom.
Since this is a huge form, sometimes the rep accidentally hits Close without noticing that there is some information in one of the tabs.
We want to add some kind of alert when user tries to close the form after he has made changes to it.
I saw that there is ChangeHandler on text items which can flag a change which can be evaluated before firing the close event. However currently doing this for so many fields is a little bit cumbersome. Is there a way of achieving this on a DynamicForm level or even better on the Window level?
I am looking for a SmartGWT equivalent of this jquery code:
$("input:text, select, input:checkbox, input:radio, input:password").change(function(){
unloadRoutineFlag = true;
});
Take a closer look at this handler at the dynamicForm level.
addItemChangedHandler(ItemChangedHandler handler)
Handler fired when there is a changed() event fired on a FormItem
within this form.
Typically, when a formItem fires the changed() event, the form gets notified. Let us know if this works.
I have found what appears to be a bug related to TTreeView.
Take a form containing a TTreeView with HideSelection set to True.
Make the tree view multi-select and select multiple items in the tree view.
Show another form so that your app has two forms.
Give the tree view the focus and then click in the other form.
The result looks like this:
But in fact there should be no items highlighted. Interestingly, the last item is selected and it is no longer highlighted, as indeed should all the other items. It appears that the most recently clicked item is the one that gets the special treatment.
If instead you click in the edit box (or indeed any other control that takes focus) then all items are correctly hidden. So it's fine for the focus to transfer to another control on the form—the problem seems to be limited to deactivating the form.
I have discovered by trial and error that I can fix this by calling Invalidate on the tree view whenever the form is deactivated and activated (need to prevent mirror image of the bug). However, I'm looking for a better understanding of what the bug is and how to fix it in a less invasive manner, i.e. at the tree view level rather than the containing form level.
So, to summarise, my questions are:
What exactly is causing the problem?
How can I fix it without writing code that hooks TForm events?
Submitted the issue as QC#94908.
The solution seems to be to respond to NM_SETFOCUS and NM_KILLFOCUS notifications by invalidating selected nodes. You can modify TCustomTreeView.CNNotify directly or you can write a new TCustomTreeView descendant. Here is a quick hack only to show the missing code:
type
TTreeView = class(ComCtrls.TTreeView)
private
procedure CNNotify(var Message: TWMNotifyTV); message CN_NOTIFY;
end;
procedure TTreeView.CNNotify(var Message: TWMNotifyTV);
begin
case Message.NMHdr^.code of
NM_KILLFOCUS, NM_SETFOCUS:
InvalidateSelectionsRects;
end;
inherited;
end;
Edit: David's QC report.
On my main form I have a TPanel containing buttons that act as a toolbar. I want to clone/copy this toolbar and the buttons and their functionality to a second form.
Cloning the menu was simple using newmenu.merge(mainmenu). That was an excellent shortcut to duplicating a Tmainmenu.
But I am at a loss on how to easily duplicate my toolbar without having to manually assign the events and keep a timer to compare and track which buttons are enabled and disabled in comparison to the real mainmenu on the main form. Depending on what the application is doing the main toolbar buttons will be enabled and disabled at various times.
Any ideas here? Thanks for any suggestions or tips to make this easier.
Duplicating the controls
In the Form Designer, select the panel and press Ctrl+C to copy it and all its children to the clipboard. Go to the second form and press Ctrl+V to paste.
If you're still working on the design and want to keep it consistent between both forms, then create a TFrame and design your toolbar layout there. Then put an instance of that frame on both your forms. Changes to the frame design will be reflected in the forms.
See Working with frames in the help.
Making sure both sets of buttons are enabled consistently
Create a data module. Put a TActionList on it. Add an action to it for each button on your main form. Assign event handlers to the actions' OnUpdate events. In them, set the actions' Enabled properties. Finally, assign each button's Action property to refer to the corresponding action object. The buttons will automatically get enabled and disabled with the actions. No timer required.
Furthermore, you can handle the actions' OnExecute events, too. Clear each button's OnClick property, and then move the button's OnClick code into the corresponding action's OnExecute handler. It will automatically get called when you click the button, even though the OnClick property is empty.
When you assign the Caption or Hint property of a TAction, the corresponding properties of any associated controls also change. Likewise for images, if the control supports them. Actions can be assigned to menu items, too.
See Using action lists in the help.
Acting like a toolbar
Just use TToolbar. That's what it's for.
Or, once you're used to actions, put a TActionManager in your project and use it with TActionToolbar and TActionMainMenuBar. See Organizing actions for toolbars and menus in the help.
Are the buttons attached to actions? If so, you can use the OnUpdate event of the TActionList to specify what should and should not be enabled. If not, it isn't too much work to convert to using actions.
If you go this route to convert to using a ActionList, consider putting the ActionList in a datamodule where different units and forms could reference it.
You can Use ClipBoard Object For Copy Your Panel.
Clipboard.SetComponent(Panel1);
Clipboard.GetComponent(Form2,GroupBox1);