C / C++ / MFC

class CMyView : public CView
{
public:
//------- Blah Blah (usual stuff) -------//

protected:
int selectedimage;
}

CMyView::CMyView()
{
   selectedimage = -1;
}

void CMyView::OnPicture1()
{
   selectedimage = 1;
   Invalidate();
}

void CMyView::OnDraw(CDC *dc)
{
   switch(selectedimage)
   {
   case 1:
      DrawImage1();
      break;
   case 2:
      etc...
      break;
   }
}

#if !defined(AFX_STDAFX_H__48A33CB4_51D8_45C7_8B74_162AA2953797__INCLUDED_)
#define AFX_STDAFX_H__48A33CB4_51D8_45C7_8B74_162AA2953797__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#define VC_EXTRALEAN		// Exclude rarely-used stuff from Windows headers

#include <afxwin.h>         // MFC core and standard components
#include <afxext.h>         // MFC extensions
#include <afxadv.h>
#include <afxdisp.h>        // MFC Automation classes
#include <afxdtctl.h>		// MFC support for Internet Explorer 4 Common Controls
#ifndef _AFX_NO_AFXCMN_SUPPORT
#include <afxcmn.h>			// MFC support for Windows Common Controls
#endif // _AFX_NO_AFXCMN_SUPPORT

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_STDAFX_H__48A33CB4_51D8_45C7_8B74_162AA2953797__INCLUDED_)

...
case WM_PRINT:
case WM_PAINT:
{
    HDC hdc;
    PAINTSTRUCT ps;
    //Test if the wPAram already contains the HDC
    if (NULL != wParam)
    {
    // This is the DC that you should use to paint with.
        hdc = (HDC)wParam;
    }
    else
    {
    // OTherwise call begin paint like normal.
       hdc = ::BeginPaint(hWnd, &ps);
    }

    // Your paint code goes here.

    if (NULL == wParam)
    {
    // If you called beginpaint, hten you will need to call endpaint.
        ::EndPaint(hWnd, &ps);
    }
}
break;
...