BitBlt() in Child Wnd's OnPoint() failed.

BitBlt() in Child Wnd's OnPoint() failed.

• ShaneShowers

  Thank you viorel.
  
  But I am not yet clear.
  Is it simply enough to pass parent window as parameter and specify WS_CHILD style to a class derived from CWnd/CDialog
  Will this embed my CWnd/CDialog derived class's object into another window
  
  Can u show me a small example (pseudo)code snippet
  
  Sorry for asking more.
  Because I already tried, could not get desired result, displayed as a seperate window.
  
  :)
  Purusothaman A
  
  

• Chandrakanttt

  Use SetParent(HWND hChild, HWND hParent). You have to be careful because the new parent window have to send all the necessary messages to the child window in order for this to work properly. Additionally, your child window will disappear from the task bar because it behaves now as a child control.
  
  

• neotom

  I think you should create your window with WS_CHILD style, but without styles specific to separate windows. When you create it with CreateWindow function, specify the parent window as a parameter. The proper place for creating child controls is the handler for WM_CREATE or WM_INITDIALOG notifications.

   

  I hope this helps.

  
  

• Dan_Brownlow

  I would try without parent "CWnd::OnPaint();". I hope this helps.

  
  

• droujav

  Thanks Viorel.
  
  It works!
  
  :)
  Purusothaman A
  
  

• sandyJ

  child CWnd, got shown in dialog box as a child control.
  
  myCWnd.h file:
  ============
  #pragma once
  
  
  // myCWnd
  
  class myCWnd : public CWnd
  {
  HBITMAP hBmp;
  CBitmap ObjBmp;
  DECLARE_DYNAMIC(myCWnd)
  
  public:
  myCWnd();
  virtual ~myCWnd();
  afx_msg void OnPaint();
  
  protected:
  DECLARE_MESSAGE_MAP()
  };
  
  myCWnd.cpp file
  ==============
  // myCWnd.cpp : implementation file
  //
  
  #include "stdafx.h"
  #include "myCWnd.h"
  
  
  // myCWnd
  
  IMPLEMENT_DYNAMIC(myCWnd, CWnd)
  
  myCWnd::myCWnd()
  {
  CString sBmpImgPath = "D:\\temp\\sujith_1.bmp";
  hBmp = (HBITMAP)::LoadImage(NULL, sBmpImgPath, IMAGE_BITMAP, 100, 100, LR_LOADFROMFILE | LR_CREATEDIBSECTION);
  
  if(!hBmp)
  MessageBox("Img Loading Failed.");
  else
  ObjBmp.Attach(hBmp);
  }
  
  myCWnd::~myCWnd()
  {
  }
  
  
  BEGIN_MESSAGE_MAP(myCWnd, CWnd)
  ON_WM_PAINT()
  END_MESSAGE_MAP()
  
  
  
  // myCWnd message handlers
  afx_msg void myCWnd::OnPaint()
  {
  CWnd::OnPaint();
  
  if(hBmp)
  {
  CPaintDC dc(this);
  CDC memDC;
  
  memDC.CreateCompatibleDC(&dc);
  memDC.SelectObject(&ObjBmp);
  
  dc.BitBlt(10, 10, 100, 100, &memDC, 0, 0, SRCCOPY);
  }
  }
  
  Declaration in Dialog's header file:
  ==========================
  myCWnd obj;
  
  from Dialog's OnInitDialog()
  ======================
  obj.Create(NULL, "Sample", WS_VISIBLE|WS_VSCROLL|WS_CHILD|WS_BORDER, CRect(100,100,200,200), this, 132422);
  
  myCWnd's OnPaint gets called.
  BitBlt() returned 1.
  but no out put.
  I verified that image loading is always successfull.
  And MessageBox() in myCWnd's constructor never displayed.
  
  I am using Visual Studio 2005.
  Pls point out me where I am wrong.
  
  Waiting for valuable suggestions.
  
  Thankyou.
  
  :)
  Purusothaman A
  
  
  
• BitBlt() in Child Wnd's OnPoint() failed.