function dxMessageDlg(const AMessage: string; const ATitle: string; ADialogType: TMsgDlgType = TMsgDlgType.mtInformation; AButtons: TMsgDlgButtons = [mbOK]; AHelpContext: Longint = 0; ADefaultButton: TMsgDlgBtn = TMsgDlgBtn.FirstButton; const AHyperlinkClickProc: TdxMessageDialogHyperlinkClickDelegate = nil; const AShowHyperlinkHintProc: TdxMessageDialogShowHyperlinkHintDelegate = nil): Integer;

uses
  dxMessageDialog, // Declares the dxMessageDlg method
  Winapi.Windows; // Declares WinAPI constants
// ...

procedure TMyForm.DemonstrateDxMessageDlg3;
var
  ATitle, AMessage, AHelpURL: string;
  ADialogType: TMsgDlgType;
  AButtons: TMsgDlgButtons;
  ADefaultButton: TMsgDlgBtn;
  AHelpContext, ACloseAction: Integer;
begin
  // Define a formatted message with a hyperlink (using the BBCode-inspired markup)
  AHelpURL := 'https://docs.devexpress.com/VCL/dxMessageDialog.dxMessageDlg(80E4ACD7)';
  AMessage := '[URL=' + AHelpURL + ']dxMessageDlg[/URL] opens a message dialog box with ' +
    'a message ([B]AMessage[/B]) and a set of buttons ([B]AButtons[/B]).' +
    sLineBreak + sLineBreak +
    'This function overload allows you to set the message box title ([B]ATitle[/B]) ' +
    'and select the default button ([B]ADefaultButton[/B]).';

  ATitle := 'Message Box Example'; // Defines a message box title
  ADialogType := mtInformation; // Defines the "Information" dialog icon and sound
  AButtons := mbYesNoCancel; // Defines a button set (Yes, No, and Cancel)
  ADefaultButton := mbCancel; // Moves focus to the Cancel button
  AHelpContext := 0; // Retains the default help context

  // Display a message box
  ACloseAction :=
    dxMessageDlg(AMessage, ATitle, ADialogType, AButtons, AHelpContext, ADefaultButton);

  // Identify the action used to close the message box
  case ACloseAction of
    IDYES: Caption := 'Yes is clicked';
    IDNO: Caption := 'No is clicked';
    IDCANCEL: Caption := 'Cancel is clicked';
    0: Caption := 'Failed to create a message box';
  end;
end;

#include "dxMessageDialog.hpp" // Declares the dxMessageDlg method
#include <Winapi.Windows.hpp> // Declares WinAPI constants

// Add the following linker directive to the corresponding CPP source file:
#pragma link "dxMessageDialog" // Required to use dxMessageDialog.hpp declarations
// ...

void __fastcall TMyForm::DemonstrateDxMessageDlg3()
{
  UnicodeString ATitle, AMessage, AHelpURL;
  TMsgDlgType ADialogType;
  TMsgDlgButtons AButtons;
  TMsgDlgBtn ADefaultButton;
  int AHelpContext, ACloseAction;

  // Define a formatted message with a hyperlink (using the BBCode-inspired markup)
  AHelpURL = "https://docs.devexpress.com/VCL/dxMessageDialog.dxMessageDlg(80E4ACD7)";
  AMessage =
    "[URL=" + AHelpURL + "]dxMessageDlg[/URL] opens a message dialog box with "
    "a message ([B]AMessage[/B]) and a set of buttons ([B]AButtons[/B])." +
    sLineBreak + sLineBreak +
    "This function overload allows you to set the message box title ([B]ATitle[/B]) "
    "and select the default button ([B]ADefaultButton[/B]).";

  ATitle = "Message Box Example"; // Defines a message box title
  ADialogType = mtInformation; // Defines the "Information" dialog icon and sound
  AButtons = mbYesNoCancel; // Defines a button set (Yes, No, and Cancel)
  ADefaultButton = mbCancel; // Moves focus to the Cancel button
  AHelpContext = 0; // Retains the default help context

  // Display a message box
  ACloseAction = dxMessageDlg(
    AMessage, ATitle, ADialogType,
    AButtons, AHelpContext, ADefaultButton);

  // Identify the action used to close the message box
  switch (ACloseAction)
  {
    case IDYES: Caption = "Yes is clicked"; break;
    case IDNO: Caption = "No is clicked"; break;
    case IDCANCEL: Caption = "Cancel is clicked"; break;
    case 0: Caption = "Failed to create a message box"; break;
  }
}