There are some program tools such as WinSpy++ which will allow you to hover over the Handle of any Control/Component and return the Class Name of that Handle. So for example, if I dropped a TMemo on a Delphi Form and compiled the Application, if I used WinSpy++ and hovered over the Application (above the Memo), it will reveal the Class Name of the Editor as TMemo.
Now, suppose I dont want anybody using such a program to determine the Components I am using in my Application, how would I prevent Class Names from showing up in a tool, such as WinSpy++?
I ask because I dont want anyone to easily create clones of any Applications I may create and release, if the Class Names of the Components I am using are discovered it would make their task easier because then they know what to use.
Simply put, how can I hide the Class Names of the VCL I use in my Delphi Application from external viewer tools like WinSpy++.
WinSpy++ can be found here: http://www.catch22.net/software/winspy
To add, I know I can custom derive these components to change the Class Names to my own, but their must be an easier way.
You could override CreateParams and put your own class name into Params.WinClassName. The default behaviour is implemented in TWinControl.CreateParams:
with Params do
...
StrPCopy(WinClassName, ClassName);
Related
I would like to add "MyProperty" to TTabSheet and work with it at design time. However if I subclass it I fear I will need to also subclass TPageControl, since it internally creates/manages the TTabSheets.
I believe this would require duplicating the TTabSheet management code to reference TMyTabSheet instead of TTabSheet, since it will need to invoke TMyTabSheet.create. This feels like something I will regret when a new version of Delphi updates TPageControl and I forget to update TMyPageControl.
I am also researching "class helpers" as another option.
Does anyone have advice on how to best accomplish this?
Thanks!
Type Helpers are merely compile-time sugar, they would cause no effect over the already compiled code, that stock VCL is together with TPageControl and TForm. That is a dead-end.
However you have a slight misconception here that TPageControl... internally creates... the TTabSheets. Indeed, when you create the sheets by the means of TPageControl itself, like right-clicking it and selecting "New Tab" that si what happens. But when you create the living form object out of DFM file (or DFM resource in your compiled EXE) that is TForm itself that creates ALL the components, including both page control and its tabsheets.
Just see my answer at How to efficiently let a `ParentFont = False` child control to use same font name as parent? - that would show you how far it is about the owner - TForm, not about TPageControl or other parent components when it comes about selecting specific classes for the actual tabs or other elements..
So you are free to pursue subclassing tabsheets only.
Create the TMyTabsheet = class(TTabSheet) component
Create and install into IDE the design-time package that would introduce new subclassed tab sheet to Delphi Form Editor
In your form put the stock TPageControl and create all the needed tabs regular way
in IDE form Editor right-click over the form free space and in the menu do the "View As Text Alt-F12" command - you would see the text content of your form's DFM file
in those DFM sources find your tab sheets and change their stock TTabSheet class to be your derived sub-class
right-click the text editor and choose "View As Form Alt-F12" command
If all was done correct then Delphi would recreate the form with your new-class sheets now. Find your new properties in Object Inspector and change them.
Now switch to .Pas sources of your form and find the declarations of those tab sheets and change their type too. That is only required if you would have to access your new properties from the Delphi sources. If not you can leave their declaration as TTabSheet in pas-file as your class is direct descendant from it. You may leave those declarations as they were - but then you would have to add RegisterClass(TMyTabSheet); call into the very initialization section at the bottom of your unit, so when the form would construct itself out of the DFM it would be able to find the class implementation by the name. If you would change the declaration (at least one of those) then your form would automagically call all needed RegisterClass before streaming out of DFM. Choose any option you like.
Optionally and later, extend your design-time package to find and hijack IDE Form Editor's right-click menu for TPageControl and add "New My Subclassed Tab" command there. Just to avoid manual post-factum DFM editing. if you would do it often
This feels like something I will regret when a new version of Delphi updates TPageControl
After you created and tuned the form and saved it into DFM - it would be TForm that creates all the components out of the saved DFM-data, and that includes your tabs too. Unless very improbable event EMBT would kill the whole VCL streaming (made back in Delphi 1 in 1995) and redesign it from scratch (killing all the compatibility with existing Delphi sources at once), there should be no problem with forward compatibility with specifying your class in DFM. It is just the standard way VCL is designed - to get specific component types from the DFM.
I've had this long time problem that I can't view as text the main form for a project I inherited. Even if no other forms are open.
How can I debug the cause of this error message? What options do I have to fix it?
I found one related newsgroup post http://embarcadero.newsgroups.archived.at/public.delphi.ide/200906/0906193960.html but this only addresses the form inheritance cause, and doesn't explain anything about linked modules. I don't believe I'm using form inheritance.
I do have a DM (data module) for the project, and the form does load a couple of images from the dm through properties of a TTreeView on the form--does having a data module automatically mean I can never view as text a form in Delphi (aside from viewing the form as text in notepad)? It doesn't seem to matter whether my DM is open or closed in the IDE.
I also found one SO question with a related title (Module %s has open descendants or linked modules. can not reload) but the question itself and it's answer is not particularly relevant.
This is sometimes caused by a form that inherits from another form in your project (or the gallery) (known as Visual Form Inheritance in the documentation, IIRC). The IDE doesn't know how to find the base class for the form; it needs that opened before the descendant form. For instance, this can cause the same error if the unit containing TMyBaseForm isn't opened first in the IDE, particularly if the base (ancestor) unit is not included in the project first:
unit SpecialForm;
interface
uses
Forms, { all the other usual stuff }, BaseForm;
type
TMySpecialForm = class(TMyBaseForm)
private
public
end;
You can tell if this is the case by looking at your form's class declaration - if it descends from anything other than TForm, this is probably the cause of the error.
(Another instance of it happening is often when using a datamodule, because the base TDataModule .DFM isn't available. Attempting to view the datamodule .DFM as text will cause this error every time; the solution is to close your project and use an external editor such as Notepad or Notepad++ to edit the .dfm for your datamodule.)
I've had this issue occasionally, perhaps when I've used Frames, but my latest instance didn't involve Frames nor Data Modules nor inherited forms.
After an enormous amount of work creating a copy of the form (which copy didn't have the problem) and renaming the original unit and the form itself (which initially seemed to solve the problem), it turned out to be a live binding between forms.
Specifically, in my FMX application Form A has an options page with a TSpinBox that allows the user to set the minimum value for a TTrackBar on Form B (which was the form giving me grief). So the TSpinBox.Value was set to update the TTrackBar.Min field by means of a live binding. Closing Form A, or removing that live binding (and replacing it with an event handler to do the same thing) solved the problem.
I'd like to call upon the answer of Phillip J. Rayment and ADD that you don't have to have live binding to have this problem occur. It's sufficient to have custom control (class) of which you have an instance in another form. Then the RLink32 problem can appear and won't be solved until you close the form where you have the instance. The problem I experienced gave the following messages:
-RLink32 (during building)
-Access violation in module designide160.bpl` (if I made a modification to the problematic form)
-The module has open descendants or linked modules” error (if I tried to 'View as Form')
Hi I'm developing a TControl descendant, lets name it THTMLBaseControl, at runtime that control only generates and output HTML code based on the settings of that control, so all the additional properties of the base TControl class and methods, including Windows Messaging system is really not used at runtime and causes memory overhead.
I need that control to be inherited from TControl so at design time I can use all the IDE designer stuff.
But at runtime almost all of those properties that at desingtime are needed i dont need them.
I also have all my controls inherited from that THTMLBaseControl, so creating a wrapper class per control class is not an option because it will duplicate the code a lot.
So what i need is something that at runtime, before the class is instantiated I can change the parent class so it will be instantiated based on another TControl-like class, maybe named TmyBaseControl inherited from "TComponent" as TControl Does, but that will not have all that TControl memory overhead and will only have the properties and methods needed by my THTMLBaseControl.
I really dont have a GUI at rutime is a web server that will serve only HTML, is some thing that intraweb and Raudus do, but always the issue is that all are based on TControl, so they have to be created at run time and generate a lot memory and process overhead that is not used. and maybe there could a solution so any THTMlBaseControl descendant instantiated at runtime will inherit the all properties and methods from TmyBaseControl and not from TControl.
I have seen there are ways to hack the VMT but maybe there are other solution and have not seen it. I already done changing the NewInstance, ClassParent and TnstanceSize class methods but i have to specify from which class and obviously i have to do the same steps per each inherited THTMLBaseControl class
And for the sake of all:
This is just a doubt, I need the components to be controls like TEdit, TPanel, visible and editable by the designer IDE I even could create my own TControl class but I was just thinking if I can reuse the code already existing.
Regards
You cannot change the class a run time. Once an object is instantiated, its class is fixed. You could hack the object to change its VMT pointer, making it refer to a different class, but that would still not address your main concern, which is memory usage — even if you change the VMT pointer, all the memory for the object has already been allocated; changing the VMT pointer doesn't magically make the object occupy less memory.
The first thing you could do is stop descending from TControl. As you've noted, you don't need any of the things it provides. All you want is something you can drop on a form at design time to set its properties. For that, all you need is TComponent, so make that your base class instead of TControl. Then you'll get something more like TTimer, which has no GUI. Once you've done that, you no longer need TForm, either. Instead, you can put your component on a TDataModule, which is specifically designed for managing non-visual components at design time.
I've had this problem for years but maybe it is now possible to easilty solve it. I need to lay out a panel with several TEdit controls, each should show, and allow editing of, a published property of a class. Traditionally I would use TEdit (or a numeric derivative from the Raize or Developer Express libraries) and 'wire up' the OnKeyPress and OnExit events, convert between the edit text and the property type etc etc. All as per Delphi 1 (whose big birthday is soon!).
These days we have RTTI and Live Bindings, so ideally I'd like a way of telling a TEdit (or another similar control) about a single published property and the necessary 2-way link would then be established without all the wiring up and conversions. An object inspector does this job of course, but I'd like a more formal custom layout using labelled edit controls. It would be fine to simply cope with integer, float and string, and something like a TDBEdit where the field name was my property name would be great.
I've taken a look at the 'Bind Visually' designer (I have XE3) but I'm on to uncertain ground. Can anyone suggest a means of doing this? Thanks.
The comments above by Ken White and Sir Rufo are good pointers to the use of Live Bindings for wiring up components between each other, but I need to wire up controls to my own object and which is created at runtime. Further digging led me to this excellent article which pretty much does what I want. Jarrod's TBoundObject is intended to be the ancestor for your own objects, but by including an FObject field passed in the constructor and replacing his use of 'Self' by FObject, you can instantiate a standalone 'TObjectBinder' that easily connects various standard controls to published properties.
1- Why is it necessary to name the methods of a class in a dwsunit this way?
dwsUnitClasses'ClassName''MethodName'Eval(Info: TProgramInfo;
var ExtObject: TObject)
2- Is there a link that must be done between the method defined in a dwsunit and its code?
coz it is not working with me. I took the demo attached with the DWscript (Custom Classes) and made something that looks like it but it is just not functioning.
No it's not necessary, that's just the format the IDE uses for auto-generated event names.
Usually you define script classes, their methods in the structure view, then you double-click their OnEval (or other) event in the properties editor, the IDE will create a method with a name like the above and you can implement there.
If you declare the methods manually, then you also have to attach their events manually, but it's not different than what you end up doing for a button click event (and where you end up with a Button1Click method).
Apart from the implementation code itself, most of the declarations in DWScript can happen at design-time, and are stored in the DFM. The Structure View is convenient for that, but you can also use the property editor only (it was even more convenient in older Delphi versions, when the structure view was sticking to design-time structures, rather than being reused for source structure).