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Questions tagged [vcl]

This tag is used for questions regarding the Visual Component Library used in Borland/CodeGear/Embarcadero Delphi and C++Builder products as well as Python GUI apps. Do not confuse this with the Varnish Configuration Language (VCL). Use the "varnish-vcl" tag for questions related to that product.

Visual Component Library is a visual component-based object-oriented framework tightly integrated with Delphi and C++Builder. It's also available for Python as a GUI framework.

VCL components cover visual and non-visual components like:

  • Windows common controls
  • Database access components
  • Internet connection components

The component approach allows programmers to extend easily the VCL.

Resources:

1590 questions
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5 answers

Datagrid export to pdf

how can I can export the data shown on a DBgrid to a pdf file?
Michael
6
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4 answers

DBLookupComboBox - How to clear the selected item?

What I tried to achieve is like setting ItemIndex to -1 as like in normal ComboBox, so that the selected item will be cleared. There is no ItemIndex for DBLookupComboBox, and the Text property is read only. So how do I clear the selected item?…
Kw Choy
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4 answers

how to dynamically create a component in delphi such as TLabel or TEdit ...etc

Using Delphi 2010 SQLQuery1.First; // move to the first record while(not SQLQuery1.EOF)do begin // do something with the current record // What's the code should i write in this part in order to create a TEdit // containing the user…
Rafik Bari
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6 answers

Can I make a TTreeNode invisible?

TTreeNode does not have a Visible property, so the obvious option does not exist. Is there any other way to make a TTreeNode and all its child nodes invisible? Of course I want to be able to make it visible again later. This is with Delphi…
dummzeuch
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6
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1 answer

Understanding TBitmap.Scanline in Delphi & C++ Builder

Delphi & C++ Builder have a TBitmap class with a Scanline property which returns the memory of pixels of the bitmap. This seems to be different when I look in a hex editor of the BMP file. I'm trying to port a C++ Builder app to Java, and would…
SRobertJames
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1 answer

How to fix Delphi component with TFont property that gets "cannot assign NIL to a TFont" at design time?

I have started building a new component in Delphi 6 Pro. Currently it just has a single TFont published property. However, when I drop the component on a Form at design time, and click on the edit button for the "textAttr_1" property (ellipsis), I…
Robert Oschler
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0 answers

Delphi properties based on sets of subrange types are not streamed correctly to DFM file

Consider the following code: type TColors = (Red, Blue, Green, Yellow, Orange); // base type TMyColors = Green..Orange; // subrange type TAllowedColors = set of TMyColors; // set based on the subrange above …
Alexandre M
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6 answers

How do I port code for Borland C++ builder to Linux?

I have source code for a Windows DLL that is written in C++ and uses Visual Component Library. Now my task is to port that to Linux, but I don't have source code for the VCL itself, or any kind of documentation (and I have never worked with Borland…
ajanicij
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1 answer

Delphi Controls for Editing Key/Value Pairs?

What Delphi visual control or combination of controls do you suggest for editing, adding and deleting key/value pairs (strings)?
jpfollenius
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7 answers

Is there a way to locate unused event handlers in Delphi?

Finding dead code in Delphi is usually real simple: just compile and then scan for routines missing their blue dots. The smart linker's very good about tracking them down, most of the time. Problem is, this doesn't work for event handlers because…
Mason Wheeler
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3 answers

How do I add support for actions in my component

What do I need to do for adding actions support to my component. It is a button component but I guess it is the same for whatever component type it is. Any information or how to will help.
Roy M Klever
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3 answers

Delphi extract key from TObjectDictionary

sharing the code on this question as reference: Delphi TPair Exception How can I retrieve the key and value from a TObjectDictionary concrete entry without using TPair and without extracting/remove/delete the pair from the list ? {$APPTYPE…
ferpega
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2 answers

Hiding items in TListBox while filtering by String

Short Version: Is there any way to control or modify LisBox items individually? for example set their Visible property to False separately. I found a TListBoxItem class in Fire Monkey when I was searching, but I don't want to use Fire Monkey and…
Armin Taghavizad
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1 answer

Custom drawing of TCustomListbox items

I'm rewriting a VCL component showing a customized TCustomListbox to Firemonkey in Delphi 10.2. The customization used an overridden DrawItem, basically adding some indentation and setting the text color depending on the item text and…
maaartinus
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6
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2 answers

How to make Delphi TButton control stay pressed?

I've seen How to make a Delphi TSpeedButton stay pressed ..., but I want it to be TButton because of the way it supports drawing glyph (I mean Images, ImageIndex, HotImageIndex, ...). I know that I can draw it all by code, but I thought there must…
saastn
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