给你一个例子:新建一个工程,在窗体上放一个Image控件,以下是.h,.cpp文件代码:
//*.h
#ifndef Unit1H
#define Unit1H
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <ExtCtrls.hpp>
#include <jpeg.hpp>
//---------------------------------------------------------------------------
class TForm1 : public TForm
{
__published:    // IDE-managed Components
  TImage *Image1;
  void __fastcall Image1MouseDown(TObject *Sender, TMouseButton Button,
          TShiftState Shift, int X, int Y);
  void __fastcall Image1MouseMove(TObject *Sender, TShiftState Shift,
          int X, int Y);
private:    // User declarations
  int m_iOldX, m_iOldY;
public:        // User declarations
  __fastcall TForm1(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm1 *Form1;
//---------------------------------------------------------------------------
#endif

//*.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)
{
  DoubleBuffered = true;
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Image1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
  m_iOldX = X;
  m_iOldY = Y;
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Image1MouseMove(TObject *Sender, TShiftState Shift,
      int X, int Y)
{
  if(Shift.Contains(ssLeft))
  {
    Image1->Left += X - m_iOldX;
    Image1->Top  += Y - m_iOldY;
  }
}
//---------------------------------------------------------------------------