I need to stick a panel to dxSpreadSheet's particular cell, anyways to achieves this ?
I remembering doing grouping on components in MS-Word, same thing I needed in my Delphi 2010 application.
Related
Is there an option to use same components (check boxes, TEdits, etc.) on different tabs on TPageControl component?
Not directly, no because each page is a separate object. If you want to use the same controls on every page, use TTabControl instead.
If you need to use TPageControl, there are ways to dynamically move controls between pages but usually it is simpler to just copy and paste.
I need a very fast treeview able to list and scroll hundreds of thousands of items also with nesting of subitems etc. The standard Windows tree view control (wrapped with Delphi's TTreeView) is not up to the task. It's too slow.
Now I have checked TVirtualTreeView which is as fast as I need, but there is a problem, it does not work at all like the standard treeview but in a completely different way.
I am wondering if some expert using this component can tell me whether it is feasible to encapsulate it in a new component so that it will have properties and methods of a normal treeview but keeping the speed advantage?
If my question is not clear, I will try to elaborate it further.
My solutions for you is:
Add a new frame to your project
Drop a VirtualTreeView on it and align it as alClient
Add methods and properties in order to make the frame to mimic the TTreeView interface
Implement those methods and properties to deal with the internal TVirtualTreeView
Implement TVirtualTreeView events to mimic the TListView behavior
Replace your current TTreeView by the new frame
I guess this will get you close to what you want, balancing complexity and functionality.
I implemented two menu items for my component in Delphi IDE with TComponentEditor descendant. They're both supposed to be used with "right-clicking" a component on the form. But can I do this for component that is currently hidden (concealed) by other components? So I select a component with other tools (for example object inspector) and would like to activate one of my context menu items.
Shift-F10 doesn't work (at least in D5).
Bringing the component to top for this task is not an option.
Right-click the component in the Object TreeView (Shift-Alt-F11).
D7: Menu > View > Object TreeView
XE2: Menu > View > Structure
Or make a property editor with paDialog in the attributes and forward the Edit method to your component editor. Then double clicking that property or clicking the ellipsis will bring up the component editor, just like the Colums property for TDBEdit does.
If you feel like writing a something mimicking Delphi IDE's Object TreeView, I suggests you the following resources:
Populating all controls of a container object using recursion (Blog post). Using TVirtualTreeView like the Delphi IDE is better than the stock TTreeView to my opinion.
Study the commercial TLMDComponentTree
of the LMD IDE-Tools (Excerpt: This powerful control allows to use a Delphi IDE like Object TreeView. Collections, child controls etc. are automatically handled).
How can I merge two VCL components together so I can access both of their properties?
For example, I want to merge a TImage and a TPanel into one, I require that the TPanel is the base component, so the TImage will be child to the TPanel.
Is it possible to do this?
I've been trying to do this in Delphi 2010 via Component > New VCL Component but it creates non-visual components when I require a visual component.
What can I do to change this?
If I understand correctly I think you want to merge two components together and expose the properties for both?
If this is what you are looking for, I asked a similar question for joining a TImage and TScrollBox together which can be found here:
Component Creation - Joining Components Together?
SetSubComponent was the key to achieving this, it may be worth while reading the comments and answers from the link above to understand more.
The Delphi language does not support multiple inheritance of implementation, only multiple inheritance of interface. Thus you cannot simply merge together two classes in the way you hope.
What you are proposing sounds a bit odd anyway. Both TPanel and TImage have their own visual surfaces. The only plausible thing I can imagine is that you could make the TImage a child of the TPanel. Derive a new component from TPanel. That component would create and own a TImage. Make the parent of the TImage sub control be the panel. Any properties and events of the TImage control that you want to surface in your control would have to be done manually. This is composition rather than inheritance.
You might use a TFrame to create a component that exists of other visual components at design time, e.g. a TPanel with a TImage upon it. This is probably not exactly what you want: the properties are not 'merged' together, you must design your own properties and methods to make this newly created component behave as you want it to. The functionality you desire (changing visual features depending on the spot of the mouse) needs to be built only once into the frame.
My aim is to update the look of the GUI in my app. Currently my GUI contains a lot of listboxes which are used to edit some objects in an old fashioned way, that is, user double-clicks an item and a dialog is shown to modify the corresponding object.
I think a good modern approach is how Firefox displays the extensions installed (a snapshot below).
My question is about how to build such a GUI in Delphi(win32) easily? Are there any components you use mimicing such behaviour or will I just need to code this from stratch using panels? (IMO a very cumbersome job I'd like to avoid - the selection logic, resizings, etc...)
You can do something similar (not exactly) with standard components; TDBCtrlGrid, TSpeedButton,...
alt text http://img8.imageshack.us/img8/9585/imagen29ox3.png
If you're using Delphi 2007 or Delphi 2009, you might be able to do something similar using TCategoryButtons (from the 'Additional' component palette page). Drop it on a form and right click to display the popup menu, and then click "Categories Editor...". Add a category with the resulting dialog, set it's caption, and optionally set up Items it contains. Not exactly the same, but it might do what you need.
You could also use a dialog with a TTreeView (if you have categories of objects) or TListView to emulate the Delphi 2007 Projects->Options dialog. Clicking an item in the TreeView or ListView displays the proper page of a TPageControl to configure the object.
I mostly agree with Lars, but I would use a frame for each item instead of a panel. That would separate into its own file, and you would get easy designtime support for it.
Using a TFrame for each list item and put them all Aligned Top on a TScrollBox might work. Also see TDBCtrlGrid which does something like that in combination with datasets.
It can be done with existing Delphi controls.
For instance in the TCustomListBox control you can create your own OnDrawItem event to draw your own list item. You also need to create your own OnMeasureItem to change the item height.
In some cases it is very limited, so if you want more freedom you will need to do it from scratch.