ATL / WTL / STL

18-Nov-03 17:17

Hi All,

I seem to be having the most stupid problem (well I am the stupid one) with retrieving the selected value out of a ComboBox.

Background info:
All my development is within an ATL Com based DLL. I have extended its functionality by including the WTL libraries in the stdafx.h header.

The DLL is a set of tools and dlgs that are loaded into the calling application.

I have read Michael Dunns intro to WTL articles and found them encouraging... hence trying to use them in my project. However I seem to be having trouble implementing the msg maps and ddx maps etc in the dialogs as they seem to crash the calling application. For the calling application and DLL to work, the dialogs must be of type CAxDialogImpl.

I have one Dialog that I have managed to use WTL message maps in and it works ok. However other time it doesn't. I cannot get the DDX map to map the values from my ComboBox to my class members:

<br />
class CTargetDialog : public CAxDialogImpl<CTargetDialog>,//public CUpdateUI<CTargetDialog>,<br />
                      //public CMessageFilter, public CIdleHandler,<br />
                      public CWinDataExchange<CTargetDialog>,<br />
                      public CComObjectRootEx<CComSingleThreadModel>,<br />
                      public CComCoClass<CTargetDialog><br />
{<br />
public:<br />
	CTargetDialog(IApplicationPtr pApp);<br />
	~CTargetDialog();<br />
<br />
	enum { IDD = IDD_TARGETDIALOG };<br />
<br />
BEGIN_MSG_MAP(CTargetDialog)<br />
   MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)<br />
   COMMAND_ID_HANDLER(IDOK, OnOK)<br />
   COMMAND_ID_HANDLER(IDCANCEL, OnCancel)<br />
   COMMAND_HANDLER(IDC_COMBO_TARGET, CBN_SELCHANGE, OnSelchangeCombo_target)<br />
   COMMAND_HANDLER(IDC_COMBO_TARGET, CBN_DROPDOWN, OnDropdownCombo_target)<br />
END_MSG_MAP()<br />
<br />
BEGIN_DDX_MAP(CTargetDialog)<br />
   DDX_CONTROL(IDC_COMBO_TARGET, m_pComboBox)<br />
   DDX_TEXT(IDC_COMBO_TARGET, m_szTargetLayer)<br />
END_DDX_MAP()<br />
// Handler prototypes:<br />
//  LRESULT MessageHandler(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);<br />
//  LRESULT CommandHandler(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
//  LRESULT NotifyHandler(int idCtrl, LPNMHDR pnmh, BOOL& bHandled);<br />
<br />
   LRESULT OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);<br />
   LRESULT OnOK(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
   LRESULT OnCancel(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
   LRESULT OnSelchangeCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
   LRESULT OnDropdownCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
   HWND GetPicHandle();<br />
<br />
private:<br />
   CComboBoxImpl m_pComboBox;<br />
   CString m_szTargetLayer;<br />
   IApplicationPtr m_ipApp;<br />
   IMxApplicationPtr m_ipMxApp;<br />
   IDocumentPtr m_ipDoc;<br />
   IMxDocumentPtr m_ipMxDoc;<br />
   IEditorPtr m_ipEditor;<br />
   IMapPtr m_ipMap;<br />
};<br />

I have defined the CComboBoxImpl in my stdafx.h like

<br />
class CComboBoxImpl : public CWindowImpl<CComboBoxImpl, CComboBox><br />
    { DECLARE_EMPTY_MSG_MAP(); };<br />

So I have pretty much given up on trying to change the message_maps and the DDX stuff, as compiler gives error when I request

<br />
DoDataExhange(true);<br />

That being said and done, how do you get the value from a combo box?
I have tried the following but the itellisense definition of the object is different to what the compiler accepts. Instead of using DDX I have:

<br />
LRESULT CTargetDialog::OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)<br />
{<br />
   //DoDataExhange(true);<br />
   m_pComboBox.Attach(GetDlgItem(IDC_COMBO_TARGET));<br />
   ATLASSERT(m_pComboBox.m_hWnd != NULL);<br />
<br />
   return 1;  // Let the system set the focus<br />
}<br />

<br />
LRESULT CTargetDialog::OnSelchangeCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)<br />
{<br />
   CString pValueString; <br />
   BSTR pBSTR<br />
   int i = this->m_pComboBox.GetDlgItemText(IDC_COMBO_TARGET, pBSTR); //Only works with BSTR<br />
   this->m_pComboBox.GetLBText(0, pValueString); //Works, but not the selected item.<br />
<br />
   AtlMessageBox(NULL, pValueString.AllocSysString(), _T("Selection"), MB_OK);<br />
	return 0;<br />
}

Are the Dialogs meant to work in DLL the same message map way as in EXE? I know they are not in terms of the greater picture, but in terms of there own object entity.

your guidance would be greatly appreciated.

cheers
Bryce

Michael Dunn18-Nov-03 17:26

18-Nov-03 17:26

It looks OK at first glance. What are the compiler errors?

--Mike--
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"That probably would've sounded more commanding if I wasn't wearing my yummy sushi pajamas."
-- Buffy

bryces18-Nov-03 17:39

18-Nov-03 17:39

Thanks for your help,

The compiler errors are:

For fetching the selected item in the combo box

<br />
CString pValueString;<br />
int i = this->m_pComboBox.GetDlgItemText(IDC_COMBO_TARGET, pValueString);<br />

error C2664: 'int __thiscall ATL::CWindow::GetDlgItemTextW(int,unsigned short *& ) const' : cannot convert parameter 2 from 'class WTL::CString' to 'unsigned short *& '
A reference that is not to 'const' cannot be bound to a non-lvalue

And for OnInit....

<br />
DoDataExhange(true);<br />

Michael Dunn22-Nov-03 16:30

22-Nov-03 16:30

The first error looks like the compiler is trying to generate a call to the GetDlgItemText() that takes a BSTR&. You probably need to add #define _WTL_USE_CSTRING before your WTL includes.
The second one is you probably forgot to inherit from CWinDataExchange<>

--Mike--
Ericahist | CP SearchBar v2.0.2 | Homepage | RightClick-Encrypt | 1ClickPicGrabber
Laugh it up, fuzzball.

bryces23-Nov-03 11:47

23-Nov-03 11:47

Hi Mike,

Thanks fro the reply.

Here is my inheritance list for my dialog:

class CTargetDialog : public CAxDialogImpl<CTargetDialog>,<br />
                      public CWinDataExchange<CTargetDialog>,<br />
                      public CComObjectRootEx<CComSingleThreadModel>,<br />
                      public CComCoClass<CTargetDialog><br />

And here is is my listing for stdafx.h

<br />
#if !defined(AFX_STDAFX_H__63977A7A_D850_4BDE_A636_B409D3974963__INCLUDED_)<br />
#define AFX_STDAFX_H__63977A7A_D850_4BDE_A636_B409D3974963__INCLUDED_<br />
<br />
#if _MSC_VER > 1000<br />
#pragma once<br />
#endif // _MSC_VER > 1000<br />
<br />
#define STRICT<br />
#ifndef _WIN32_WINNT<br />
#define _WIN32_WINNT 0x0400<br />
#endif<br />
<br />
#define _WTL_USE_CSTRING<br />
#define _ATL_APARTMENT_THREADED<br />
<br />
#include <atlbase.h><br />
#include <atlapp.h><br />
extern CAppModule _Module;<br />
#include <atlcom.h><br />
#include <atlhost.h><br />
#include <atlwin.h><br />
#include <atlctl.h><br />
<br />
#include <atlframe.h><br />
#include <atlcrack.h><br />
#include <atlmisc.h><br />
#include <atlctrls.h><br />
#include <atlctrlx.h><br />
#include <atlddx.h><br />
<br />
#include <exdisp.h><br />
#include <exdispid.h><br />
<br />
#pragma warning(push)<br />
#pragma warning(disable : 4146)<br />
#pragma warning(disable : 4192)<br />
#import "C:\arcgis\arcexe83\bin\esriCore.olb" \<br />
		raw_interfaces_only, \<br />
		raw_native_types, \<br />
		no_namespace, \<br />
		named_guids, \<br />
		exclude("OLE_COLOR", "OLE_HANDLE")<br />
#pragma warning(pop)<br />
<br />
#include "C:\arcgis\arcexe83\ArcObjects Developer Kit\Kits\CATIDs\arccatids.h"<br />
<br />
<br />
#if _ATL_VER < 0x0700<br />
#undef BEGIN_MSG_MAP<br />
#define BEGIN_MSG_MAP(x) BEGIN_MSG_MAP_EX(x)<br />
#endif<br />
<br />
class CStaticImpl : public CWindowImpl<CStaticImpl, CStatic><br />
    { DECLARE_EMPTY_MSG_MAP() };<br />
<br />
class CComboBoxImpl : public CWindowImpl<CComboBoxImpl, CComboBox><br />
    { DECLARE_EMPTY_MSG_MAP(); };<br />

I have had to reorganize my header files list in the Tools>Options>Directories otherwise I get a redefinition of ISegment error. I have placed the path of the widowsSDK at the bottom of the list and the path to the WTL libraries at the top of the list.

I doubt this is the source of my problems though.

cheers
Bryce

bryces23-Nov-03 11:53

23-Nov-03 11:53

The inheritance list for the dialogs is like the following... the <CTargetDialog>, were all removed

class CTargetDialog : public CAxDialogImpl<CTargetDialog>,
public CWinDataExchange<CTargetDialog>,
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<CTargetDialog>,

bryces23-Nov-03 12:29

23-Nov-03 12:29

Ahhhh found out something interesting.

if you try to change the About dialog in a WTL wizard created application, which is dialog based.... the compiler bombs as well. so if you do the following: Add a combo box to the about dialog and label it IDC_COMBO_TARGET

aboutdlg.h

<br />
// aboutdlg.h : interface of the CAboutDlg class<br />
//<br />
/////////////////////////////////////////////////////////////////////////////<br />
<br />
#if !defined(AFX_ABOUTDLG_H__A290BA10_FE73_4A12_8FCA_FEBA7A47586B__INCLUDED_)<br />
#define AFX_ABOUTDLG_H__A290BA10_FE73_4A12_8FCA_FEBA7A47586B__INCLUDED_<br />
<br />
class CAboutDlg : public CAxDialogImpl<CAboutDlg>,<br />
                  public CWinDataExchange<CAboutDlg>,<br />
                  public CComObjectRootEx<<CComSingleThreadModel>,<br />
                  public CComCoClass<CAboutDlg><br />
{<br />
public:<br />
	enum { IDD = IDD_ABOUTBOX };<br />
<br />
	BEGIN_MSG_MAP(CAboutDlg)<br />
		MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)<br />
		COMMAND_ID_HANDLER(IDOK, OnCloseCmd)<br />
		COMMAND_ID_HANDLER(IDCANCEL, OnCloseCmd)<br />
      COMMAND_HANDLER(IDC_COMBO_TARGET, CBN_SELCHANGE, OnSelchangeCombo_target)<br />
      COMMAND_HANDLER(IDC_COMBO_TARGET, CBN_DROPDOWN, OnDropdownCombo_target)<br />
	END_MSG_MAP()<br />
<br />
// Handler prototypes (uncomment arguments if needed):<br />
//	LRESULT MessageHandler(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)<br />
//	LRESULT CommandHandler(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/)<br />
//	LRESULT NotifyHandler(int /*idCtrl*/, LPNMHDR /*pnmh*/, BOOL& /*bHandled*/)<br />
<br />
	LRESULT OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/);<br />
	LRESULT OnCloseCmd(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/);<br />
   LRESULT OnSelchangeCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
   LRESULT OnDropdownCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);<br />
<br />
private:<br />
   CComboBoxImpl m_pComboBox;<br />
   CString m_szTargetLayer;<br />
};<br />
<br />
#endif // !defined(AFX_ABOUTDLG_H__A290BA10_FE73_4A12_8FCA_FEBA7A47586B__INCLUDED_)<br />

aboutdlg.cpp

<br />
// aboutdlg.cpp : implementation of the CAboutDlg class<br />
//<br />
/////////////////////////////////////////////////////////////////////////////<br />
<br />
#include "stdafx.h"<br />
#include "resource.h"<br />
<br />
#include "aboutdlg.h"<br />
<br />
LRESULT CAboutDlg::OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)<br />
{<br />
	CenterWindow(GetParent());<br />
	return TRUE;<br />
}<br />
<br />
LRESULT CAboutDlg::OnCloseCmd(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/)<br />
{<br />
	EndDialog(wID);<br />
	return 0;<br />
}<br />
<br />
LRESULT CAboutDlg::OnSelchangeCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)<br />
{<br />
   //DoDataExhange(true);<br />
   //UpdateData();<br />
	// TODO : Add Code for control notification handler.<br />
   CString pValueString;<br />
   //BSTR pValueString;<br />
   int i = this->m_pComboBox.GetDlgItemText(IDC_COMBO_TARGET, &pValueString);<br />
   //this->m_pComboBox.GetLBText(wNotifyCode, pValueString);<br />
<br />
   //AtlMessageBox(NULL, pValueString.AllocSysString(), _T("Selection"), MB_OK);<br />
	return 0;<br />
}<br />
LRESULT CAboutDlg::OnDropdownCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)<br />
{<br />
   HRESULT hr;<br />
   return 0;<br />
}<br />

Then in your stdafx.h define the following

<br />
#define _WTL_USE_CSTRING<br />
#define _ATL_APARTMENT_THREADED<br />
<br />
//.... other stuff..<br />
<br />
#include <atlcom.h><br />
#include <atlhost.h><br />
#include <atlwin.h><br />
#include <atlctl.h><br />
<br />
#include <atlframe.h><br />
#include <atlcrack.h><br />
#include <atlmisc.h><br />
#include <atlctrls.h><br />
#include <atlctrlx.h><br />
#include <atldlgs.h><br />
//#include <atlctrlw.h><br />
#include <atlddx.h><br />
<br />
//.. other stuff..<br />
<br />
class CComboBoxImpl : public CWindowImpl<CComboBoxImpl, CComboBox><br />
    { DECLARE_EMPTY_MSG_MAP(); };<br />

Anyone got thoughts on why this would happen?

cheers
Bryce

Michael Dunn23-Nov-03 14:57

23-Nov-03 14:57

You need to add the BEGIN_DDX_MAP/END_DDX_MAP map to the class for DoDataExchange() to work.

--Mike--
Ericahist | CP SearchBar v2.0.2 | Homepage | RightClick-Encrypt | 1ClickPicGrabber
Laugh it up, fuzzball.

bryces23-Nov-03 15:17

23-Nov-03 15:17

I left it out deliberatly to test if I could use the GetDialogText(...) call. Which still fails.

<br />
LRESULT CAboutDlg::OnSelchangeCombo_target(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)<br />
{<br />
   DoDataExhange(true); //gives>error C2065: 'DoDataExhange' : undeclared identifier<br />
   CString pValueString;<br />
   //error C2664: 'int __thiscall ATL::CWindow::GetDlgItemTextA(int,unsigned short *& ) const' : cannot<br />
   //convert parameter 2 from 'class WTL::CString *' to 'unsigned short *& ' <br />
   //A reference that is not to 'const' cannot be bound to a non-lvalue<br />
   int i = this->m_pComboBox.GetDlgItemText(IDC_COMBO_TARGET, &pValueString);<br />
<br />
   //works, but how can you find out which was selected<br />
   //this->m_pComboBox.GetLBText(wNotifyCode, pValueString);<br />
<br />
   //AtlMessageBox(NULL, pValueString.AllocSysString(), _T("Selection"), MB_OK);<br />
   return 0;<br />
}<br />
</code<br />
<br />
The message map to test dataexchange is defined as<br />
<br />
<code><br />
BEGIN_DDX_MAP(CAboutDlg)<br />
   //DDX_CONTROL(IDC_STATIC_PIC, m_pPic)<br />
   DDX_CONTROL(IDC_COMBO_TARGET, m_pComboBox)<br />
   DDX_TEXT(IDC_COMBO_TARGET, m_szTargetLayer)<br />
END_DDX_MAP()<br />

I was wondering if you had tested what I described in another post about changing the aboutdlg setting?

cheers
Bryce

Michael Dunn23-Nov-03 17:37

23-Nov-03 17:37

Well, you misspelled the function - DoDataExchange. Wink | ;)

I checked again and GetDlgItemText() is a CWindow function, so there is no overload that takes a CString obviously. Look at the code for DDX_Text in atlddx.h to see how to use it with a BSTR.

--Mike--
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"Linux is good. It can do no wrong. It is open source so must be right. It has penguins. I want to eat your brain."
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bryces23-Nov-03 17:57