Today I receive a question about how disable the vcl styles in the non client area of a vcl form. Well that can be done using a Style hook.
Tipically a VCL form with a vcl style look like this
To remove the vcl style in the non client are we need create a style hook which descend of the TMouseTrackControlStyleHook and then override the PaintBackground and Create methods.
Check this sample code
TFormStyleHookNC= class(TMouseTrackControlStyleHook) protected procedure PaintBackground(Canvas: TCanvas); override; constructor Create(AControl: TWinControl); override; end; constructor TFormStyleHookNC.Create(AControl: TWinControl); begin inherited; OverrideEraseBkgnd := True; end; procedure TFormStyleHookNC.PaintBackground(Canvas: TCanvas); var Details: TThemedElementDetails; R: TRect; begin if StyleServices.Available then begin Details.Element := teWindow; Details.Part := 0; R := Rect(0, 0, Control.ClientWidth, Control.ClientHeight); StyleServices.DrawElement(Canvas.Handle, Details, R); end; end;
And apply in this way
After of that this is the result
February 7, 2012 at 7:10 pm
February 11, 2012 at 7:23 am
when I try to apply this stylehook in initialization section:
I get an error immediately after program start:
Debugger Exception Notification
Project Project1.exe raised exception class $C0000005 with message ‘access violation at 0x0057019a: read of address 0x00000000’.
Break Continue Help
if I try to apply this stylehook in TForm1.OnCreate method, I don’t get any errors but this stylehook doesn’t apply (non-client areas are skinned)
here is the priject:
help me, please
February 12, 2012 at 6:18 pm
This issue is caused because the vcl styles must be initializated before to call the RegisterStyleHook method, so you must include the Vcl.Styles unit in the implementation part of your main unit or reorder the unit declaration of your project to something like this
February 13, 2012 at 11:10 am
Great tips on vcl styles, they have helped me tons lately on my project. And a little bit off topic question.. I have some minor issues with VirtualStringTree component, using your tips to do following: TStyleManager.Engine.RegisterStyleHook(TBaseVirtualTree, TListBoxStyleHook);
(listbox, because TTreeViewStyleHook bugs with the scrollbars a bit), Anyway idea is to apply vcl style to the 3rd party component, it works great for the scrollbars which is what i want, but when vcl styles are enabled the VirtualTreeView flickers alot when the form is resized.. any hidden magic to prevent that or ideas ? it has to do with the repainting the control and the hook..but ? :) ..
March 12, 2012 at 8:20 am
He had problems using the VCL component TRibbon with Styles. The top edge of the screen was all wrong. Take the test yourself.
But with this solution you have implemented solve the problem.
I created a unit for class “TFormStyleHookNC” and made the call “TStyleManager.Engine.RegisterStyleHook (TForm1, TFormStyleHookNC)” in the project file (. dpr) after the begin. It worked perfectly.
March 21, 2012 at 2:04 pm
Thank you Rodrigo for this hook !
I have a question : how to apply this hook to “MessageDlg” and “ShowMessage” (…) ?
March 21, 2012 at 5:58 pm
If you are using a update minor than 4 you can use this code
If you are using the update 4, is more difficult because the StyleHook inheritance not work correctly (check this QC http://qc.embarcadero.com/wc/qcmain.aspx?d=104035), So the only alternative is use a code like this.
And before to call the ShowMessage or MessageDlg functions set the value of the UseLatestCommonDialogs variable to false
March 21, 2012 at 8:31 pm
I’m in update 2, so it works perfectly ;)
Thank you again !
September 5, 2012 at 1:29 pm
well, how to enable vclstyles only for some control(controls) ?
September 5, 2012 at 1:36 pm
Hi, try the answer to this question http://stackoverflow.com/questions/8598728/how-to-disable-vcl-styles-in-delphi
November 1, 2012 at 8:32 am
hi. if i use this hook i have problem with TMainMenu. how can i use TMainMenu with this hook?
November 1, 2012 at 12:26 pm
The TMainMenu is outside of the scope of this hook, so you have two workarounds , 1) implement the TMainMenu Style hook inside of the TFormStyleHookNC class just how is made in the TFormStyleHook style hook, 2) or replace the TMainMenu for the TActionMainMenuBar component.