動作環境

C++ Builder XE4
RAD Studio 10.2 Tokyo Update 2 (追記: 2018/01/05)

TPageControlのページを動的に変更してみる。

参考: https://stackoverflow.com/questions/21970127/delete-tabs-from-a-page-control-at-run-time

Unit1.h

//---------------------------------------------------------------------------

# ifndef Unit1H
# define Unit1H
//---------------------------------------------------------------------------
# include <System.Classes.hpp>
# include <Vcl.Controls.hpp>
# include <Vcl.StdCtrls.hpp>
# include <Vcl.Forms.hpp>
# include <Vcl.ComCtrls.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:	// IDE で管理されるコンポーネント
	TPageControl *PageControl1;
	TButton *B_add;
	TButton *B_delete;
	void __fastcall B_addClick(TObject *Sender);
	void __fastcall B_deleteClick(TObject *Sender);
private:	// ユーザー宣言
public:		// ユーザー宣言
	__fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
# endif

Unit1.cpp

//---------------------------------------------------------------------------

# include <vcl.h>
# pragma hdrstop

# include "Unit1.h"
//---------------------------------------------------------------------------
# pragma package(smart_init)
# pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::B_addClick(TObject *Sender)
{
	int count = PageControl1->PageCount;

	TTabSheet *pPage = new TTabSheet(PageControl1);
	pPage->PageControl = PageControl1;
	pPage->Caption = L"Page" + IntToStr(count);
	pPage->Name = L"ts" + IntToStr(count);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::B_deleteClick(TObject *Sender)
{
	int count = PageControl1->PageCount;

	if (count == 0) {
        return;
	}

	delete PageControl1->Pages[count - 1];
}
//---------------------------------------------------------------------------