Implementing a TLabel with TabStop and FocusRect? - delphi

I'm using Delphi7 and I'm trying to implement a LinkLabel like the ones you can find under the Control Panel on Windows Vista and above.
Changing the cursor/color on hover is really simple, the only thing I need to do is to make the TLabel receive tab stops and to draw a focus rectangle around it.
Any ideas on how to do this? I understand that the TLabel doesn't receive tabs because of its nature. There is also TStaticText which does receive tabs, but it also doesn't have a focus rectangle.

Here's a derived static that draws a focus rectangle when focused. 'TabStop' should be set, or code that checks should be added. Doesn't look quite nice (the control doesn't actually have room for lines at all edges), but anyway:
type
TStaticText = class(stdctrls.TStaticText)
private
FFocused: Boolean;
protected
procedure WMSetFocus(var Message: TWMSetFocus); message WM_SETFOCUS;
procedure WMKillFocus(var Message: TWMKillFocus); message WM_KILLFOCUS;
procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
end;
...
procedure TStaticText.WMSetFocus(var Message: TWMSetFocus);
begin
FFocused := True;
Invalidate;
inherited;
end;
procedure TStaticText.WMKillFocus(var Message: TWMKillFocus);
begin
FFocused := False;
Invalidate;
inherited;
end;
procedure TStaticText.WMPaint(var Message: TWMPaint);
var
DC: HDC;
R: TRect;
begin
inherited;
if FFocused then begin
DC := GetDC(Handle);
GetClipBox(DC, R);
DrawFocusRect(DC, R);
ReleaseDC(Handle, DC);
end;
end;

Related

How to stop TRadioButton reacting at arrow keys?

I have a panel with a few TRadioButtons placed horizontally. If the most left button is focused and I press Left Arrow, the focus jumps to the most right button. I want to stop this behavoir for all arrows when they reach the edge. Is it possible ?
I tried overriding the WM_KEYDOWN but the buttons never receive this message when a arrow key is pressed.
TRadioButton = class(StdCtrls.TRadioButton)
protected
procedure WMKeyDown(var Message: TWMKeyDown); message WM_KEYDOWN;
procedure WMKeyUp(var Message: TWMKeyUp); message WM_KEYUP;
public
BlockLeft, BlockRight: Boolean;
constructor Create(AOwner: TComponent); override;
end;
constructor TRadioButton.Create(AOwner: TComponent);
begin
inherited;
BlockLeft:= False;
BlockRight:= False;
end;
procedure TRadioButton.WMKeyDown(var Message: TWMKeyDown);
begin
if BlockLeft and (Message.CharCode = VK_LEFT) then Exit;
if BlockRight and (Message.CharCode = VK_RIGHT) then Exit;
inherited;
end;
procedure TRadioButton.WMKeyUp(var Message: TWMKeyUp);
begin
if BlockLeft and (Message.CharCode = VK_LEFT) then Exit;
if BlockRight and (Message.CharCode = VK_RIGHT) then Exit;
inherited;
end;
VCL offsets keyboard messages to become a control notification and sends it to the message's destined control. Hence you should be intercepting a CN_KEYDOWN message instead.
If this is for a one time design consideration, I would prefer to handle this behavior at the form level since IMO a control, itself, shouldn't care where it is placed on. For a form where all radio buttons are expected to behave similar, an example could be:
procedure TForm1.CMDialogKey(var Message: TCMDialogKey);
begin
if ActiveControl is TRadioButton then
case Message.CharCode of
VK_LEFT, VK_UP: begin
if ActiveControl.Parent.Controls[0] = ActiveControl then begin
Message.Result := 1;
Exit;
end;
end;
VK_RIGHT, VK_DOWN: begin
if ActiveControl.Parent.Controls[ActiveControl.Parent.ControlCount - 1]
= ActiveControl then begin
Message.Result := 1;
Exit;
end;
end;
end;
inherited;
end;
If this is not for a one time behavior, I'd go for writing a container control as Victoria mentioned in the comments to the question.

How can I avoid a form getting focus when dragged

I have a simple form that only contains a TTouchKeyboard. The forms BorderStyle is set to bsToolWindow. To avoid the form getting focus when clicking the touch keyboard I handle the WM_MOUSEACTIVATE message with this implementation:
procedure TKeyboardForm.WMMouseActivate(var Message: TWMMouseActivate);
begin
Message.Result := MA_NOACTIVATE;
end;
The BorderStyle setting allows the form to be dragged with the title bar, but in that case the form still gets the focus. Is there a way to avoid this?
Update: I tried adding WS_EX_NOACTIVATE to ExStyle in CreateParams, but unfortunately that doesn't hinder the form to receive focus when dragged.
procedure TKeyboardForm.CreateParams(var Params: TCreateParams);
begin
inherited;
Params.ExStyle := Params.ExStyle or WS_EX_NOACTIVATE;
end;
Because I was not very pleased with the approach that requires me to manually update the focused form variable in the keyboard form, I searched for a more transparent solution and came up with this approach.
Update: The previous approach had some issues with VCL styles. In addition not all of the message handlers were really necessary, though others turned out to be helpful, too. This version works well with VCL styles avoiding any flicker as far as possible:
type
TKeyboardForm = class(TForm)
TouchKeyboard1: TTouchKeyboard;
private
FLastFocusedForm: TCustomForm;
procedure SetLastFocusedForm(const Value: TCustomForm);
protected
procedure WMActivate(var Message: TWMActivate); message WM_ACTIVATE;
procedure WMMouseActivate(var Message: TWMMouseActivate); message WM_MOUSEACTIVATE;
procedure WMSetFocus(var Message: TWMSetFocus); message WM_SETFOCUS;
procedure Notification(AComponent: TComponent; Operation: TOperation); override;
property LastFocusedForm: TCustomForm read FLastFocusedForm write SetLastFocusedForm;
public
class constructor Create;
destructor Destroy; override;
function SetFocusedControl(Control: TWinControl): Boolean; override;
end;
type
TKeyboardFormStyleHook = class(TFormStyleHook)
protected
procedure WMNCActivate(var Message: TWMNCActivate); message WM_NCACTIVATE;
end;
procedure TKeyboardFormStyleHook.WMNCActivate(var Message: TWMNCActivate);
begin
{ avoids the title bar being drawn active for blink }
Message.Active := False;
inherited;
end;
class constructor TKeyboardForm.Create;
begin
TCustomStyleEngine.RegisterStyleHook(TKeyboardForm, TKeyboardFormStyleHook);
end;
destructor TKeyboardForm.Destroy;
begin
LastFocusedForm := nil;
inherited;
end;
procedure TKeyboardForm.Notification(AComponent: TComponent; Operation: TOperation);
begin
if (Operation = opRemove) and (AComponent = FLastFocusedForm) then begin
FLastFocusedForm := nil;
end;
inherited;
end;
function TKeyboardForm.SetFocusedControl(Control: TWinControl): Boolean;
begin
LastFocusedForm := Screen.FocusedForm;
result := inherited;
end;
procedure TKeyboardForm.SetLastFocusedForm(const Value: TCustomForm);
begin
if FLastFocusedForm <> Value then
begin
if FLastFocusedForm <> nil then begin
FLastFocusedForm.RemoveFreeNotification(Self);
end;
FLastFocusedForm := Value;
if FLastFocusedForm <> nil then begin
FLastFocusedForm.FreeNotification(Self);
end;
end;
end;
procedure TKeyboardForm.WMActivate(var Message: TWMActivate);
begin
Message.Active := WA_INACTIVE;
inherited;
end;
procedure TKeyboardForm.WMMouseActivate(var Message: TWMMouseActivate);
begin
inherited;
Message.Result := MA_NOACTIVATE;
end;
procedure TKeyboardForm.WMSetFocus(var Message: TWMSetFocus);
begin
inherited;
if (FLastFocusedForm <> nil) and (message.FocusedWnd <> FLastFocusedForm.Handle) then begin
SendMessage(FLastFocusedForm.Handle, WM_SETFOCUS, 0, 0);
Message.FocusedWnd := FLastFocusedForm.Handle;
end;
end;
The following combination of WMMouseActivate(), WMNCActivate() and reseting focus seems to fulfill your wishes:
The keyboard form (with BorderStyle = bsToolWindow) has message handlers for WM_MOUSEACTIVATE (as you already have) and WM_NCACTIVATE. The latter for having a point where to reset focus to the window with the edit control.
In addition the keyboardform will keep track of which form holds the edit (or other) control that has focus, and does that by introducing a new method for showing, which I called ShowUnfocused() and a field called FocusedForm: THandle.
procedure TKbdForm.ShowUnfocused(FocusedWindow: THandle);
begin
FocusedForm := FocusedWindow;
Show;
end;
procedure TKbdForm.FormShow(Sender: TObject);
begin
SetForegroundWindow(FocusedForm);
end;
procedure TKbdForm.WMMouseActivate(var Message: TWMMouseActivate);
begin
Message.Result := MA_NOACTIVATE;
end;
procedure TKbdForm.WMNCActivate(var Message: TWMNCActivate);
begin
Message.Result := 1; // important
SetForegroundWindow(FocusedForm);
end;
The keyboardform is invoked by the following common code of the edit controls:
procedure TForm17.EditClick(Sender: TObject);
begin
KbdForm.ShowUnfocused(self.Handle);
(Sender as TWinControl).SetFocus;
end;
An alternative to what is said above, could be to set the BorderStyle = bsNone and arrange the dragging of the form with the Mouse Down, Move, Up events directly from the forms surface (or maybe a panel to mimic a top frame), and adding a close button. The challenge would be to get it visually acceptable.

Delphi, How to show an overlayed control on mouse move

I use Delphi 7 and I have a TFrame (hosted by a TForm) with three panels that span over the whole surface, in a "upside down T" layout.
The panels should be resizeable, so I could use 2 splitters, but I want to give a better user experience: I'd like to have a single "size grip" in the T junction.
This "handle" should appear only when the user hovers the junction area.
So here is my question: what is the best way to have a control show on top of any other on mouse move?
TFrame.OnMouseMove don't get called (obviously) because there are the panels inside and possibly any sort of other controls inside them.
I also strongly want to keep all the code inside the frame.
I see 2 solutions:
Install a local Mouse Hook and go with it. But there could be some
performance issues (or not?)
Handle TApplication.OnMessage inside
the frame, but adding some other code in order to simulate a "chain"
of event handlers. This is because other parts of the application
could need to handle TApplication.OnMessage for their own purposes.
Any other idea?
Thank you
To make a mouse move event notifier for the whole frame, no matter which child control is hovered, you can write a handler for the WM_SETCURSOR message as I've learnt from TOndrej in this post. From such event handler you can then determine which control is hovered and bring it to front.
Please note, I have done quite commonly used mistake here. The GetMessagePos result must not be read this way. It's even explicitly mentioned in docs. I don't have Windows SDK to see the MAKEPOINTS macro, so I'll fix this later:
type
TFrame1 = class(TFrame)
// there are many controls here; just pretend :-)
private
procedure WMSetCursor(var Msg: TWMSetCursor); message WM_SETCURSOR;
end;
implementation
procedure TFrame1.WMSetCursor(var Msg: TWMSetCursor);
var
MsgPos: DWORD;
Control: TWinControl;
begin
inherited;
MsgPos := GetMessagePos;
Control := FindVCLWindow(Point(LoWord(MsgPos), HiWord(MsgPos)));
if Assigned(Control) then
Control.BringToFront;
end;
I'll post this self-answer just because it works and it could be useful in some cases, but I marked TLama's as the best answer.
This is the solution 2) of the question:
TMyFrame = class(TFrame)
// ...design time stuff...
private
FMouseHovering: Boolean;
FPreviousOnAppMessage: TMessageEvent;
procedure DoOnAppMessage(var Msg: TMsg; var Handled: Boolean);
protected
procedure CMMouseEnter(var Message: TMessage); message CM_MOUSEENTER;
procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
end;
implementation
constructor TMyFrame.Create(AOwner: TComponent);
begin
inherited;
FMouseHovering := False;
FPreviousOnAppMessage := Application.OnMessage;
Application.OnMessage := DoOnAppMessage;
end;
destructor TMyFrame.Destroy;
begin
Application.OnMessage := FPreviousOnAppMessage;
inherited;
end;
procedure TRiascoFrame.CMMouseEnter(var Message: TMessage);
begin
FMouseHovering := True;
end;
procedure TRiascoFrame.CMMouseLeave(var Message: TMessage);
begin
FMouseHovering := False;
end;
procedure TMyFrame.DoOnAppMessage(var Msg: TMsg; var Handled: Boolean);
begin
if (Msg.message = WM_MOUSEMOVE) and FMouseHovering then
DoHandleMouseMove(Msg.hwnd, Integer(LoWord(Msg.lParam)), Integer(HiWord(Msg.lParam)));
if Assigned(FPreviousOnAppMessage) then
FPreviousOnAppMessage(Msg, Handled);
end;
procedure TMyFrame.DoHandleMouseMove(hWnd: HWND; X, Y: Integer);
var
ClientPoint: TPoint;
begin
ClientPoint := Point(X, Y);
Windows.ClientToScreen(hwnd, ClientPoint);
Windows.ScreenToClient(Self.Handle, ClientPoint);
if PtInRect(ClientRect, ClientPoint) then
begin
// ...do something...
end;
end;

Highlight TPanel on mouse move

I'm trying to make app to show some information, It'll create Panels runtime and place info on it, each panel will be flat as on picture, also app will use runtime themes, so i'd not be able to change panel bg color on mouse move, I tried to place info on TSpeedButton :v O.o it has wonderfull highlight function when it's flat while app is using runtime theme, but the main problem is that images and labels aren't moving when i move speedbutton and i need this much, they just stay there..
I tried to edit TCustomPanel.Paint to see if panel will look like highlighted button, adding code at the end:
PaintRect := ClientRect;
Details := StyleServices.GetElementDetails(ttbButtonHot);
StyleServices.DrawElement(Canvas.Handle, Details, PaintRect);
but with no success..
also it's pretty hard to link some custom code OnClick event at runtime, e.g:
ShowMessage('custom message on each panel');
I have not got any idea on how to do this, hope some one will give me advice or show me some example..
btw, panel will be created this way:
var
P: TPanel;
begin
P := TPanel.Create(Self);
P.Left := 20;
P.Top := 100;
P.Width := 60;
P.Height := 20;
P.Visible := True;
P.Parent := Self;
#P.OnClick := #Showmessageproc; // somehow this way..
end;
App pic:
If i do so:
procedure TMyPanel.MouseMove(Shift: TShiftState; X, Y: Integer);
var
mEvnt: TTrackMouseEvent;
begin
inherited;
if not FMouseTracking then begin
mEvnt.cbSize := SizeOf(mEvnt);
mEvnt.dwFlags := TME_LEAVE;
mEvnt.hwndTrack := Handle;
TrackMouseEvent(mEvnt);
FMouseTracking := True;
showmessage('IN');
end;
end;
procedure TMyPanel.WMMouseLeave(var Msg: TMessage);
begin
if Msg.Msg = WM_MOUSELEAVE then showmessage('OUT');
Msg.Result := 0;
FMouseTracking := False;
if Assigned(FOnMouseLeave) then
FOnMouseLeave(Self);
end;
procedure G(Sender: TObject);
begin
showmessage('message');
end;
procedure TMainFrm.Button1Click(Sender: TObject);
var
P: TMyPanel;
begin
P := TMyPanel.Create(Self);
P.Left := 20;
I := I + 100;
P.Top := I;
P.Width := 200;
P.Height := 80;
P.Visible := True;
P.Parent := Self;
#P.OnClick := #g;
end;
when I move mouse on runtime created panel, 2 msgbox appears, IN and OUT, "mousemove" works fine but "mouse leave" bad, also the mainc question is still actual. the problem is that that I can't get canvas of created panel to draw on. the example above could be achieved more simple way:
#P.OnMouseLeave := #onmouseleaveproc;
#P.OnMouseMove := #onmousemoveproc;
but with Canvas, everything is more difficult, somewhere i've read that canvas is protected in TCustomPanel.
Also there's another question: Is it possible to handle panel wich called e.g OnMouseMove ? because there maybe will be 30 of them (runtime created panels)
I've tried this way: (and it does not works)
type
TMyPanel = class(TPanel)
public
constructor Create(AOwner: TComponent); override;
private
// FMouseTracking: Boolean;
// FOnMouseLeave: TNotifyEvent;
procedure CMMouseEnter(var msg: TMessage); message CM_MOUSEENTER;
procedure CMMouseLeave(var msg: TMessage); message CM_MOUSELEAVE;
protected
// procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
published
// property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
end;
constructor TMyPanel.Create(AOwner: TComponent);
begin
ControlStyle := ControlStyle - [csParentBackground] + [csOpaque];
inherited;
end;
procedure TMyPanel.CMMouseEnter(var msg: TMessage);
begin
inherited;
Color := clBlue;
{ Do Whatever }
end;
procedure TMyPanel.CMMouseLeave(var msg: TMessage);
begin
inherited;
Color := clRed;
{ Do Whatever }
end;
Simply, color does not changes. (color changes with themes OFF)
It's basically explained here for Delphi 6, but same concept I think. You want to define a custom windows message handler for your panel. This will give you basic mouse enter/exit capability. You can then play with setting TPanel properties from there to find something to your liking. For example, to mock a speed button, you might be able to just set the background color and change the border bevel accordingly. If that isn't adequate, you can write to the TPanel's Canvas directly (paint the behavior that you want to see) on mouse enter/exit to get the visual behavior you're after.
I created the following new component in Delphi and installed it. A new TColorPanel component showed up in a new MyComponents tab in the IDE. I then used this to put a TColorPanel on a new app and it responded properly to the mouse enter/leave events, changing the color as desired. I'm not sure how you made your app's panels as TMyPanel instead of standard TPanel. This is just how I tried it. I used your latest message handling code as-is.
unit ColorPanel;
interface
uses
WinTypes, WinProcs, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls;
type
TColorPanel = class(TPanel)
public
constructor Create(AOwner: TComponent); override;
private
procedure CMMouseEnter(var msg: TMessage); message CM_MOUSEENTER;
procedure CMMouseLeave(var msg: TMessage); message CM_MOUSELEAVE;
protected
// procedure MouseMove(Shift: TShiftState; X, Y: Integer); override;
published
// property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('MyComponents', [TColorPanel]);
end;
constructor TColorPanel.Create(AOwner: TComponent);
begin
ControlStyle := ControlStyle - [csParentBackground] + [csOpaque];
inherited;
end;
procedure TColorPanel.CMMouseEnter(var msg: TMessage);
begin
inherited;
Color := clBlue;
{ Do Whatever }
end;
procedure TColorPanel.CMMouseLeave(var msg: TMessage);
begin
inherited;
Color := clRed;
{ Do Whatever }
end;
end.
I'm not sure why yours isn't working, other than to determine how you declared your app's panels to be TMyPanel.

How to set background image for Edit (Delphi)

how can i have a image for Editbox background ?
This is very possible, indeed. In your form, define
private
{ Private declarations }
FBitmap: TBitmap;
FBrush: HBRUSH;
protected
procedure WndProc(var Message: TMessage); override;
and do
procedure TForm1.FormCreate(Sender: TObject);
begin
FBitmap := TBitmap.Create;
FBitmap.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\AS20Utv.bmp');
FBrush := 0;
FBrush := CreatePatternBrush(FBitmap.Handle);
end;
and
procedure TForm1.WndProc(var Message: TMessage);
begin
inherited;
case Message.Msg of
WM_CTLCOLOREDIT, WM_CTLCOLORSTATIC:
if (Message.LParam = Edit1.Handle) and (FBrush <> 0) then
begin
SetBkMode(Message.WParam, TRANSPARENT);
Message.Result := FBrush;
end;
end;
end;
Of course you can wrap this into a component of your own, say TEditEx. If I get time over, I might do this. (And, notice that there is no need to buy an expensive (and maybe not that high-quality) component pack from a third-party company.)

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