What i am trying to accomplish is to create new touchkeyboard.
First i created buttons which i derive from speed buttons.
That done, now i need to create multiple buttons and layout them somewhere. This is were i get stuck.
I created a new component which i derive from TGraphicControl (this should be my new touchkeyboard), but i don't know how to add components to canvas. I actually don't know whether i'm supposed to add them to canvas or to some other component (eg. panel)!?!
Is my approach OK?
Thanks in advance.
If you're creating a custom visual control, you need to create the buttons and position them manually. For example:
TOnScreenKeyboard = class(TWinControl)
public
constructor Create(AOwner: TComponent);
end;
[...]
constructor TOnScreenKeyboard.Create(AOwner : TComponent)
var
TempButton : TSpeedButton;
begin
inherited;
TempButton := TSpeedButton.Create(self);
TempButton.Parent := self;
TempButton.Top := 10;
TempButton.Left := 15;
TempButton.Caption := 'A';
end;
You can put the button creation into a loop and position each one according to where it should be.
(I wrote this off the top of my head, and I don't write a lot of Pascal anymore, so there may be some minor mistakes! But it should get you started.)
Because of your wording and confusion between Panel, Canvas and custom controls in general, I assume you're a Delphi beginner. You need to learn about frames: embarcadero docwiki link on frames
Frames allow you to create re-usable portions of GUI. You use the IDE to "draw" the frame, you can then place that composite control (the frame) onto forms or other frames. It's a very powerful feature and it's conceptually very close to what other languages call "custom controls" (very close to what asp.net or WPF consider a custom control to be).
In the Delphi world, when you say "custom control", people would normally expect you to want to create an reusable control that's placed in a package and it's installed in the IDE. It's an fairly advanced subject. If that's what you want then I misunderstood the question, sorry.
Related
I use this code: How to make a combo box with fulltext search autocomplete support? to create custom TComboBox control with searching.
Everything was working fine but I decided to add bitmaps (pictures) into it using this method: ComboBox Simple with Bitmap
But when I added the second code I lost the searching functionality. To enable Owner drawing I added csOwnerDrawFixed style to control in constructor
constructor TComboBox.Create(AOwner: TComponent);
begin
...
Style := csOwnerDrawFixed; ; << Added to enable owner draw
end;
How can I combine these two codes? The strange thing is when I run the project I can see the control redrawing correctly first time but then all data are lost and no drawing is done.
#Rohit Gupta: Actually it is pretty easy to merge that 2 codes: simply place 2nd code into 1st one and rename class :)
I did this but the code is not working - painting the control causes freezing of software and I could not solve this issue that is why I asked for help.
#Warren P: you are right, the better is to create custom control which handles everything.
I created my own control which is basically TEdit with owner draw and TListBox with owner draw and TSpeedButton which works fine:
I need to do some tweaking now and finished control will be available on my blog.
If someone is interested then grab it later on http://unsigned.sk/blog/ (I will post comment here once finished).
Thanks to all for ideas!
I have a project with multiple TcxGrids on. The class hierarchy structure of the grids in my project are as follows:
TForm->TPanel->TcxPageControl->TcxTabSheet(subclassed)->TcxGrid->TcxGridLevel->TcxGridDBBandedTableView
In my subclassed TcxTabSheet I have added a new property "ReadOnly" that when set loops over the tabsheets controls and sets them to enabled/disabled respectively.
When a TcxGrid controls enabled property is set to true, the user can no longer interact with the grid at all (including navigating).
It seems I need to set the OptionsData.Editing property on the TcxGridDBBandedTableView to achieve a readonly but still navigable grid control.
Simple enough until you factor in that I want to do this in a loose coupled manner which I think leaves me the option of RTTI.
I have written the following code that loops over the forms controls (looping over the tabs controls or components doesn't give me access to the TcxGridDBBandedTableView). Once the control is found I can set its editing property via RTTI. I just don't seem to able to determine if that TcxGridDBBandedTableView belongs to the TabSheet it sits on.
var
compIdx: Integer;
begin
for compIdx := 0 to Pred(ComponentCount) do
if (Components[compIdx].ClassNameIs('TcxGridDBBandedTableView')) then
SetOrdProp(GetObjectProp(Components[compIdx], 'OptionsData'), 'Editing', Ord(not FReadOnly));
end;
TL;DR
How can I determine what pagectrl tab a cxgrid is on and set its TableView.OptionsData.Editable property without adding any devexpress units to the uses clause of the unit.
You are iterating over the components owned by the form. I think that's the wrong approach. You should be looking at the parent/child relationship rather than ownership. Not least because it's perfectly possible for a form to contain controls that it does not own. So, your approach can fail to find controls, particularly dynamically created controls.
So, if you have a tabsheet (or indeed any windowed control), you can iterate over its children like this:
for i := 0 to TabSheet.ControlCount-1 do
DoSomething(TabSheet.Controls[i]);
If your target grid control is a direct descendent of the tabsheet then this will be enough. If it is more than one level deep in the hierarchy then you will need a recursive solution. I will leave that recursive solution as an exercise for you.
Suppose that you have a control and want to find the tabsheet that it sits inside, then you need to walk up the parent chain. Like this:
function GetParentOfClass(Control: TControl; AClass: TWinControlClass): TWinControl;
var
Control: TWinControl;
begin
while Assigned(Control) and not (Control is AClass) do
Control := Control.Parent;
Result := TWinControl(Control);
end;
Please help me with my question.
I have TreeView and Frames, how can I shift them if I click on an item of TreeView?
Is it better to use PageControl (PageControl1.Pages[i].TabVisible := false;) instead of Frames or Frames fit better?
Thank you very much!
To answer your first question "how to ... using a TreeView?" : Implement the OnChange event of the TreeView. The node parameter refers to the newly selected item.
About your second question "Should I use Frames or a PageControl?" : Well, one does not exclude the other and you perfectly can use both. Indeed, I advice to do so when you use the contents of such a TabPage multiple times. In those cases, place the Frame with Align = alClient on your TabPage.
Frames are usefull to design an arbitrary reusable container. For instance: you could set the same FrameType on every Page of the PageControl, assuming they all look the same but each working with different data.
Another possible minor advantage of using frames is not to get confused about all the controls on the TabPages.
But if every TabPage is unique in terms of visual style or control layout, then it's perfectly ok to not use frames and design the pages on the PageControl directly.
And about the shifting part: I don't exactly understand what you want to accomplish by setting the visibility of a tab, but shifting to another page (depending entirely on your implementation) based on the node could be as simple as:
procedure TForm1.TreeView1Change(Sender: TObject; Node: TTreeNode);
begin
PageControl1.ActivePageIndex := Node.Index;
end;
I was wondering why Delphi (2007) provides three widgets that seem to do the same thing, and what the advantages/disadvantages are for each.
On the same topic, if I want to display different sets of controls, why should I favor eg. PageControl + TabSheets + Frames, instead of just displaying different frames directly on the parent form?
Thank you.
From the helpfile on TTabSet:
Tab set controls are commonly used to
display tabbed pages within a dialog
box. TTabSet is provided for backward
compatibility. Use TTabControl
component in 32-bit Windows
applications.
So the real question is, what's the difference between TTabControl and TPageControl? The difference is that TTabControl only has one "page", whereas TPageControl has one page for each tab. This makes them useful in different situations.
TPageControl is useful for dialogs where you want to fit more UI on the screen than you have screen space to fit it in. Organize your UI into categories and put each category on one page. You see this pattern a lot in Options dialogs, for example.
TTabControl, on the other hand, works well for working on an array/list of objects. Create a UI to display and edit the properties of a single object, and place it on a TTabControl, then create one tab for each object and set up the event handlers so it'll load a new object from the array into the controls whenever you change tabs.
As for the frames question, the main reason to use a TPageControl in conjunction with frames is because it provides a prebuilt way to decide which frame to display. That way you don't have to reinvent a mechanism for it.
One method that I have used with great success is to use frames with a TPageControl and late bind my frames to the tPageControl the first time the page is selected. This keeps the form load time down, by not creating frames which are never viewed, but yet allows the flexibility of being created, the state is maintained when changing between tabs. Recently I switched to using forms and embedding them instead of frames...but the concept is the same.
The same can be done using a single "mount point" on a TTabControl and switching it out as the tab is changed, but then the issue of how to deal with the tab state as tabs are switched back too comes up.
[EDIT] The question comes up how do I handle communication between the frame and the parent form. This actually is very easy to do using interfaces. Just create a new unit that will be shared by the form AND the frame and add two interfaces:
type
IFormInterface = interface
[guid]
procedure FormProc;
end;
IFrameInterface = interface
[guid]
procedure SetFormController(Intf:IFormInterface);
end;
Have the form implement the IFormInterface, and the frame implement the IFrameInterface. When you click on a tab and show a frame, then run code like the following:
var
FrameIntf : IFrameInterface;
begin
if Supports(FrameObj,IFrameINterface,FrameIntf) then
FrameIntf.SetFormController(Self);
end;
your frame implementation of the SetFormController method would then hold onto the reference passed, which would allow it to call upwards into the form.
procedure TFrame1.SetFormController(Intf:IFormInterface);
begin
fFormController := Intf;
end;
Procedure TFrame1.Destroy; override;
begin
fFormController := nil; // release the reference
inherited;
end;
Procedure TFrame1.Button1Click(Sender:tObject);
begin
if fFormController <> nil then
fFormController.FormProc
else
Raise Exception.Create('Form controller not set');
end;
I don't know whether this question can be answered here, but I hope it will.
I wrote a simple text editor in Delphi 7 that serves as my primary IDE for writing C code under Windows. I run Windows in a VM and I needed something light.
In any case, it uses a TpageControl that gets a new tab whenever you open or create a new file. Pretty standard.
Now, the TPageControl under Delphi has no flat property.
NO I don't mean setting the tab style to tsButtons or tsFlatButtons
the borders cannot be set to "none" and it looks pretty bad when you add a text editor into the tab control.
Is there any way to make a TpageControl flat?
EDIT:
On an open source PageControl that supports flat here's what I found:
procedure TCustomTabExtControl.WndProc(var Message: TMessage);
begin
if(Message.Msg=TCM_ADJUSTRECT) and (FFlat) then
begin
Inherited WndProc(Message);
Case TAbPosition of
tpTop : begin
PRect(Message.LParam)^.Left:=0;
PRect(Message.LParam)^.Right:=ClientWidth;
PRect(Message.LParam)^.Top:=PRect(Message.LParam)^.Top-4;
PRect(Message.LParam)^.Bottom:=ClientHeight;
end;
tpLeft : begin
PRect(Message.LParam)^.Top:=0;
PRect(Message.LParam)^.Right:=ClientWidth;
PRect(Message.LParam)^.Left:=PRect(Message.LParam)^.Left-4;
PRect(Message.LParam)^.Bottom:=ClientHeight;
end;
tpBottom : begin
PRect(Message.LParam)^.Left:=0;
PRect(Message.LParam)^.Right:=ClientWidth;
PRect(Message.LParam)^.Bottom:=PRect(Message.LParam)^.Bottom-4;
PRect(Message.LParam)^.Top:=0;
end;
tpRight : begin
PRect(Message.LParam)^.Top:=0;
PRect(Message.LParam)^.Left:=0;
PRect(Message.LParam)^.Right:=PRect(Message.LParam)^.Right-4;
PRect(Message.LParam)^.Bottom:=ClientHeight;
end;
end;
end else Inherited WndProc(Message);
end;
The thing is when I tried something similar on the main application it won't work. It won't even compile.
When the tabs are drawn as buttons, no border is drawn around the display area, so set the Style property to tsButtons or tsFlatButtons. (For non-VCL programmers, this is equivalent to including the tcs_Buttons window style on the tab control.)
An alternative is to use a TNotebook. It holds pages, but it doesn't do any painting at all. You'd have to provide the tabs yourself, such as by setting the tab control's height equal to the height of the tabs, or by using a TTabSet. (TTabSet is available in Delphi 2005; I'm not sure about Delphi 7.)
Regarding the code you found, it would be helpful if you indicated why it doesn't compile, or if you gave a link to where you found it, since I suppose the compilation error was because it refers to fields or properties of the custom class rather than the stock one. Here's what you can try to put it in your own code, without having to write a custom control.
Make two new declarations in your form like this:
FOldTabProc: TWndMethod;
procedure TabWndProc(var Msg: TMessage);
In the form's OnCreate event handler, assign that method to the page control's WindowProc property:
FOldTabProc := PageControl1.WindowProc;
PageControl1.WindowProc := TabWndProc;
Now implement that method and handle the tcm_AdjustRect messsage:
procedure TForm1.TabWndProc(var Msg: TMessage);
begin
FOldTabProc(Msg);
if Msg.Msg = tcm_AdjustRect then begin
case PageControl1.TabPosition of
tpTop: begin
PRect(Msg.LParam)^.Left := 0;
PRect(Msg.LParam)^.Right := PageControl1.ClientWidth;
Dec(PRect(Msg.LParam)^.Top, 4);
PRect(Msg.LParam)^.Bottom := PageControl1.ClientHeight;
end;
end;
end;
end;
You can fill in the other three cases if you need them. Tcm_AdjustRect is a message identifier declared in the CommCtrl unit. If you don't have that message in that unit, declare it yourself; its value is 4904.
I suspect this doesn't stop the control from drawing its borders. Rather, it causes the contained TTabSheet to grow a little bigger and cover up the borders.
I'm using Delphi XE8 and the following seems to do the trick:
ATabControl.Tabs.Clear;
ATabControl.Style := TTabStyle.tsFlatButtons;
ATabControl.Brush.Color := clWhite;
You could always use a commercial solution. I would strongly recommend Raize components, which support flat TPageControls with tabs. The component set is very easy to work with, and supports numerous visual enhancements which in my opinion give a better feel to any application.
(source: raize.com)
Drop two TPageControls, one with tabs as Tabs, with a global height equal to the tabs, and one with flatbuttons and Tabvisible properties set to false, which would be aligned under the first one. Then make sure the tab change on the first TPagecontrol makes the tabs also change in the second one.