Using C++Builder to list all available VCL styles in a ComboBox and apply a selected style using the ComboBoxChange event

The C++ Application User Interface

For the application user interface I have a TButton (has code to populate the ComboBox with selected application styles) and a TComboBox (to display and allow selection of a style).

 C++ code
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
#include <Vcl.Themes.hpp>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"

TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    // populate the ComboBox with VCL styles that are selected
    //    in Project | Options | Application | Appearance
    ComboBox1->Items->BeginUpdate();
    try
    {
        ComboBox1->Items->Clear();
        DynamicArray<String> styleNames = Vcl::Themes::TStyleManager::StyleNames;

        for(int i = 0; i < styleNames.Length; ++i) 
       {
            String styleName = styleNames[i];
            ComboBox1->Items->Add(styleName);
        }
    }
    __finally
    {
        ComboBox1->Items->EndUpdate();
    }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ComboBox1Change(TObject *Sender)
{
    // set the style for the selected combobox item
    Vcl::Themes::TStyleManager::TrySetStyle(ComboBox1->Items->Strings[ComboBox1->ItemIndex],false);
}
//--------------------------------------------------------------------------- 

The Application in Action

TComboBox populated with VCL styles selected Application Style Changed by TComboBox selection 

References

VCL Styles Overview

Project Options Application Appearance

VCL Styles Support for High-DPI Graphics

C++Builder Product Information

C Builder Product Page – Native Apps that Perform. Build Windows C++ Apps 10x Faster with Less Code
C Builder Product Editions – C++Builder is available in four editions – Professional, Enterprise, Architect and Community (free). C++Builder is also available as part of the RAD Studio development suite.