plumothy

In my Delphi project, the availability of some features depends on the user's licence. So, a Basic licence will not allow access to Advanced features. However, I want Basic licence users to see what they are missing by placing a "No Entry" form over the restricted part of the application. I have a form with a No Entry sign and a couple of TLabels. The No Entry form has an AlphaBlendValue = 100 so that it is translucent - the user can see what's behind it and the two TLabels tell them what they are missing and what to do about it. This is working nicely except for one thing: the AlphaBlendValue is having no effect so the form displays completely opaque (the user cannot see what is underneath). I cannot upload my project because it is confidential and simply way too big. I have tried for many hours to reproduce this issue in various test projects but have been unable to do so - they all work perfectly!! So, I can only conclude that there is some aspect of my project that is causing the No Entry form to display 100% opaque. I have wasted many hours changing things (pure trial and error), but nothing helped. My only hope is that someone here has experienced the same (or similar) issue and managed to discover the cause. Or, perhaps I am going about this the wrong way and there is a better solution? Delphi 12.2 Enterprise Windows 11 Professional Here is the unit for the No Entry form: unit NoEntryForm; interface uses System.SysUtils, Vcl.Controls, Vcl.Forms, SVGIconImage, Vcl.ExtCtrls, System.Classes, Vcl.StdCtrls; type INoEntryForm = interface ['{085FB8DC-3E21-4A50-B4CC-006E9872BF62}'] procedure ShowMe; end; /// <summary> /// A "no entry" panel to be displayed when a user attempts to access a feature to which their application licence does not permit access. /// It is intended to encourage the user to upgrade by showing them a glimpse of what they are missing. /// </summary> TfrmNoEntry = class(TForm, INoEntryForm) imgNoEntry: TSVGIconImage; pnlTop: TPanel; lblNoEntry: TLabel; lblPleaseUpgrade: TLabel; procedure ShowMe; public { Public declarations } end; procedure ShowNoEntry(const strMessage: string; const ctlParent: TWinControl; const strCaption: string); implementation {$R *.dfm} /// <summary> /// Displays a "No Entry" form over the given control (ctlParent) /// </summary> /// <param name="strMessage">Message to the user (typically something about having to upgrade to access the inaccessible feature)</param> /// <param name="ctlParent">The TWinControl descendant on which the No Entry form should be displayed (eg a TPanel for example)</param> /// <param name="strCaption">The No Entry form's caption (typically "No Entry")</param> procedure ShowNoEntry(const strMessage: string; const ctlParent: TWinControl; const strCaption: string); begin for var i := 0 to ctlParent.ControlCount - 1 do begin if ctlParent.Controls[i] is TfrmNoEntry then exit; // ctlParent already has a TfrmNoEntry so we can stop here end; var frmNoEntry := TfrmNoEntry.Create(nil); var FormInterface: INoEntryForm := frmNoEntry; frmNoEntry.Parent := ctlParent; frmNoEntry.TransparentColor := false; frmNoEntry.AlphaBlend := True; frmNoEntry.AlphaBlendValue := 100; frmNoEntry.Align := alNone; frmNoEntry.BoundsRect := ctlParent.BoundsRect; frmNoEntry.Anchors := [akLeft,akTop,akRight,akBottom]; frmNoEntry.lblNoEntry.Caption := strCaption; frmNoEntry.lblPleaseUpgrade.Caption := strMessage; frmNoEntry.ShowMe; end; procedure TfrmNoEntry.ShowMe; begin Show; end; end. So, in my project if I need to display a No Entry form on top of Panel1 I just call ShowNoEntry; ShowNoEntry('Text explaining why access is denied', Panel1, 'No Entry!');

Thank you to everyone who has responded in this listing - you inspired me to look in the right place to solve the issue. As is usually the case, it was my own fault! I had a Custom Manifest file specified in the Project Options. The problem with that was the manifest file was missing (which must have happened after I specified it). Delphi does not tell you this when you build (perhaps it should - I'll suggest it to Embarcadero). This explains why my forms were being painted fully opaque. After I corrected the manifest problem, MDI forms were not being painted correctly when maximized (large areas not painted at all). Again, my own fault! My MDI forms descend from a common ancestor (to ensure they all have a consistent appearance and behaviour). I discovered today that the ancestor form had AlphaBlend = True (and AlphaBlendValue = 255). I wouldn't have knowingly done that, so must have had a "senior moment" at some point (no-one else works on this project!). So with AlphaBlend = False, everything works the way I want it to. All that explains why I could not reproduce the issue in a new test project. Once again, thanks for your input guys.

Just tried it. Does not work (form remains opaque) unless I have a manifest. If I have a manifest then maximising MDI forms just produces a mess.

This looks interesting - I'll give it a go tomorrow.

My joy was short lived. With a manifest, my application does not maximize MDI windows properly. Large portions remain unpainted and menus are not merging correctly. Back to the drawing board!

Uwe Raabe - brilliant, thank you!!! If only the Delphi documentation had mentioned that

In the Object Inspector, if you double-click the OnHint event of a TAction then you get a procedure like this: procedure TForm1.Action1Hint(var HintStr: string; var CanShow: Boolean); There is no Sender parameter (like most other events have) so how can I tell which TAction made the call if several TActions share this event?

Anders, Thanks for clarifying. Yes you’re right, it’s a hack - but that is exactly what makes it interesting to me. (Although I think a single line of comments would be enough to explain it - “hack to get at sending Action in OnHint event”.) I really enjoy discovering how things work and what is “under the hood” (whether it’s how to build a Delphi application or how to build a house). I now have 3 possible answers to my original question and I will try them all (not just the hack) and then decide which to deploy in my project.

Anders, I don't understand. Please explain what you mean by that.

Remy - thank you. That looks interesting - I will try it.

Thanks Remy - I suspected as much. I wonder why they did it that way? Just about every other event I have ever used has a Sender parameter. I actually want to use OnHint for my Dataset Actions so I can customise the Hints depending on which dataset the Action is working on. Then the Hint can be more meaningful - eg "Delete order item" rather than a generic "Delete record". Your suggestion will work of course, but I might investigate creating my own descendant Dataset Action.

I have Delphi 11.2, Patch 1 running on Windows 11. This is my first post here so I hope someone can help. I want to create a new component that is a descendant of another component that is already installed. But I keep getting errors. As an example, here is what happens when I try to create a descendant of TButton... I did this: - Component | New Component - VCL for Delphi Win32 - select 'TButton' in list - Class Name = 'TMyButton' - Palette Page = 'Samples' - Unit Name = 'E:\MyButton.pas' - Selected 'Install to New Package' - Package Name = 'e:\MyOwnButton.dpk' - Click Finish. Got this error: --------------------------- Error --------------------------- Registration procedure, Mybutton.Register in package C:\Users\Public\Documents\Embarcadero\Studio\22.0\Bpl\MyOwnButton.bpl raised exception class EAccessViolation: Access violation at address 67127F63 in module 'rtl280.bpl'. Read of address 00000008. --------------------------- OK --------------------------- So, then I tried this: - Component | Install Packages - Add... - Browsed to select C:\Users\Public\Documents\Embarcadero\Studio\22.0\Bpl\MyOwnButton.bpl Got this error: --------------------------- MyOwnButton - Delphi 11 - MyButton [Built] --------------------------- Registration procedure, Mybutton.Register in package C:\Users\Public\Documents\Embarcadero\Studio\22.0\Bpl\MyOwnButton.bpl raised exception class EAccessViolation: Access violation at address 67127F63 in module 'rtl280.bpl'. Read of address 00000008. --------------------------- OK --------------------------- I am able to create TMyButton on Delphi 10.4 running on Windows 10 - so is there a bug in Delphi 11.2, am I doing something wrong or is there some other explanation?

Hi, I'm pleased to hear that I am not the only one! Thanks for the link to RSP-39519 - from there I saw someone else with similar issues was able to solve them by changing the project's resource compiler from Borland (BRCC32) to the Windows SDK one. So I did the same and it has fixed my particular issue but Embarcadero still need to investigate what is going on.

Here is the code generated by Delphi in my TButton example: package MyOwnButton; {$R *.res} {$IFDEF IMPLICITBUILDING This IFDEF should not be used by users} {$ALIGN 8} {$ASSERTIONS ON} {$BOOLEVAL OFF} {$DEBUGINFO OFF} {$EXTENDEDSYNTAX ON} {$IMPORTEDDATA ON} {$IOCHECKS ON} {$LOCALSYMBOLS ON} {$LONGSTRINGS ON} {$OPENSTRINGS ON} {$OPTIMIZATION OFF} {$OVERFLOWCHECKS ON} {$RANGECHECKS ON} {$REFERENCEINFO ON} {$SAFEDIVIDE OFF} {$STACKFRAMES ON} {$TYPEDADDRESS OFF} {$VARSTRINGCHECKS ON} {$WRITEABLECONST OFF} {$MINENUMSIZE 1} {$IMAGEBASE $400000} {$DEFINE DEBUG} {$ENDIF IMPLICITBUILDING} {$IMPLICITBUILD ON} requires rtl, vcl; contains MyButton in 'MyButton.pas'; end. unit MyButton; interface uses System.SysUtils, System.Classes, Vcl.Controls, Vcl.StdCtrls; type TMyButton = class(TButton) private { Private declarations } protected { Protected declarations } public { Public declarations } published { Published declarations } end; procedure Register; implementation procedure Register; begin RegisterComponents('Samples', [TMyButton]); end; end.