Can this function be improved? - visual-c++

Question

I have come up with the following function which works as it should:
bool CChristianLifeMinistryStudentMaterialDlg::EncodeText(HWND hWnd, CString strCode)
{
bool bHandled = false;
map<HWND, CComboBox*> mapControls;
map<HWND, CString*> mapControlsText;
mapControls.emplace(m_cbMaterialAssignment1.GetSafeHwnd(), &m_cbMaterialAssignment1);
mapControls.emplace(m_cbMaterialAssignment2.GetSafeHwnd(), &m_cbMaterialAssignment2);
mapControls.emplace(m_cbMaterialAssignment3.GetSafeHwnd(), &m_cbMaterialAssignment3);
mapControls.emplace(m_cbMaterialAssignment4.GetSafeHwnd(), &m_cbMaterialAssignment4);
mapControlsText.emplace(m_cbMaterialAssignment1.GetSafeHwnd(), &m_strMaterialAssignment1);
mapControlsText.emplace(m_cbMaterialAssignment2.GetSafeHwnd(), &m_strMaterialAssignment2);
mapControlsText.emplace(m_cbMaterialAssignment3.GetSafeHwnd(), &m_strMaterialAssignment3);
mapControlsText.emplace(m_cbMaterialAssignment4.GetSafeHwnd(), &m_strMaterialAssignment4);
if (mapControls.find(::GetParent(hWnd)) != mapControls.end())
{
UpdateData(TRUE);
DWORD dwSel = mapControls[::GetParent(hWnd)]->GetEditSel();
CMeetingScheduleAssistantApp::EncodeText(*mapControlsText[::GetParent(hWnd)],
strCode, LOWORD(dwSel), HIWORD(dwSel));
UpdateData(FALSE);
bHandled = true;
}
else
{
map<HWND, CEdit*> mapControls;
map<HWND, CString*> mapControlsText;
mapControls.emplace(m_editBibleReading.GetSafeHwnd(), &m_editBibleReading);
mapControls.emplace(m_editDiscussionVideoTheme.GetSafeHwnd(), &m_editDiscussionVideoTheme);
mapControls.emplace(m_editDiscussionVideoMaterial.GetSafeHwnd(), &m_editDiscussionVideoMaterial);
mapControlsText.emplace(m_editBibleReading.GetSafeHwnd(), &m_strBibleReading);
mapControlsText.emplace(m_editDiscussionVideoTheme.GetSafeHwnd(), &m_strDiscussionVideoTheme);
mapControlsText.emplace(m_editDiscussionVideoMaterial.GetSafeHwnd(), &m_strDiscussionVideoMaterial);
if (mapControls.find(hWnd) != mapControls.end())
{
UpdateData(TRUE);
DWORD dwSel = mapControls[hWnd]->GetSel();
CMeetingScheduleAssistantApp::EncodeText(*mapControlsText[hWnd],
strCode, LOWORD(dwSel), HIWORD(dwSel));
UpdateData(FALSE);
bHandled = true;
}
}
return bHandled;
}
The code is straight forward to follow. But as you can see I have to potentially deal with either a comb box edit control or regular edit control. As a result, I have two sets of similar code.
Is it possible to consolidate some of this code without overcomplicating it too much? My project is set to the ISO C++ 17 Standard if that helps.
Update
Initially I thought I would try a single map of CWnd* pointers. But then I had the two problems of CComboBox verses CEdit.
CComboBox uses:
::GetParent(hWnd)
GetEditSel()
CEdit uses:
hWnd
GetSel()
By using a single list of CWnd* I no longer know which is a combo or a edit control.
—-
Update
The core problem I would like to solve is to have a single loop rather than the two.

Answer 1

One possibility would be to define an interface to the functionality you need, then a couple of implementations of that functionality. Add in a map to get from an HWND to the object you need, and you're off to the races:
class Writer {
virtual DWORD getSel() = 0;
CString* data;
public:
Writer(CString *data) : data(data) {}
void write(CString text) {
UpdateData(true);
DWORD selection = getSel();
CMeetingScheduleAssistantApp::EncodeText(*data, text, LOWORD(dwSel), HIWORD(dwSel));
UpdateData(false);
}
virtual ~Writer() = default;
};
class ComboBoxWriter : public writer {
CWnd *parent;
DWORD getSel() override { return parent->GetEditSel(); }
public:
ComboBoxWriter(CComboBox &dest, CString &data) : Writer(&data), parent(dest.GetParent()) {}
};
class EditCtrlWriter : public Writer {
CEdit *ctrl;
DWORD getSel() override { return ctrl->GetSel(); }
public:
EditCtrlWriter(CEdit &ctrl, CString &data) : Writer(&data), ctrl(&ctrl) {}
};
bool CChristianLifeMinistryStudentMaterialDlg::EncodeText(HWND hWnd, CString strCode) {
static std::map<HWND, Writer*> controls {
{ m_cbMaterialAssignment1.GetSafeHwnd(), new ComboBoxWriter(&m_cbMaterialAssignment1, &m_strMaterialAssignment1) },
{ m_cbMaterialAssignment2.GetSafeHwnd(), new ComboBoxWriter(&m_cbMaterialAssignment2, &m_strMaterialAssignment2) },
{ m_cbMaterialAssignment3.GetSafeHwnd(), new ComboBoxWriter(&m_cbMaterialAssignment3, &m_strMaterialAssignment3) },
{ m_cbMaterialAssignment4.GetSafeHwnd(), new ComboBoxWriter(&m_cbMaterialAssignment4, &m_strMaterialAssignment4) },
{ m_editBibleReading.GetSafeHwnd(), new EditCtrlWriter(&m_editBibleReading, &m_strBibleReading) },
{ m_editDiscussionVideoTheme.GetSafeHwnd(), new EditCtrlWriter(&m_editDiscussionVideoTheme, &m_strDiscussionVideoTheme) },
{ m_editDiscussionVideoMaterial.GetSafeHwnd(), new EditCtrlWriter(&m_editDiscussionVideoMaterial, &m_strDiscussionVideoMaterial) }
};
auto ctrl = controls.find(hwnd);
if (ctrl == controls.end())
return false;
ctrl->second->write(strCode);
return true;
}
This isn't a lot shorter overall (in fact, it's almost the same length), but quite a bit more of that length is boilerplate that's pretty easy to ignore.

Answer 2

Your building maps of HWND to MFC controls looks very strange.
Surely MFC already has that map. See if this helps: https://learn.microsoft.com/en-us/cpp/mfc/accessing-run-time-class-information?view=msvc-160

Answer 3

Based on the comments to one of the answers (#vlad-feinstein):
all HWND handles are unique system-wide
I decided that I could take a much simpler approach to simplifying my code:
bool CChristianLifeMinistryStudentMaterialDlg::EncodeText(HWND hWnd, CString strCode)
{
map<HWND, CWnd*> mapControls; // Use generic CWnd pointers
map<HWND, CString*> mapControlsText;
// Lookup map of controls
mapControls.emplace(m_cbMaterialAssignment1.GetSafeHwnd(), &m_cbMaterialAssignment1);
mapControls.emplace(m_cbMaterialAssignment2.GetSafeHwnd(), &m_cbMaterialAssignment2);
mapControls.emplace(m_cbMaterialAssignment3.GetSafeHwnd(), &m_cbMaterialAssignment3);
mapControls.emplace(m_cbMaterialAssignment4.GetSafeHwnd(), &m_cbMaterialAssignment4);
mapControls.emplace(m_editBibleReading.GetSafeHwnd(), &m_editBibleReading);
mapControls.emplace(m_editDiscussionVideoTheme.GetSafeHwnd(), &m_editDiscussionVideoTheme);
mapControls.emplace(m_editDiscussionVideoMaterial.GetSafeHwnd(), &m_editDiscussionVideoMaterial);
// Lookup map of text values
mapControlsText.emplace(m_cbMaterialAssignment1.GetSafeHwnd(), &m_strMaterialAssignment1);
mapControlsText.emplace(m_cbMaterialAssignment2.GetSafeHwnd(), &m_strMaterialAssignment2);
mapControlsText.emplace(m_cbMaterialAssignment3.GetSafeHwnd(), &m_strMaterialAssignment3);
mapControlsText.emplace(m_cbMaterialAssignment4.GetSafeHwnd(), &m_strMaterialAssignment4);
mapControlsText.emplace(m_editBibleReading.GetSafeHwnd(), &m_strBibleReading);
mapControlsText.emplace(m_editDiscussionVideoTheme.GetSafeHwnd(), &m_strDiscussionVideoTheme);
mapControlsText.emplace(m_editDiscussionVideoMaterial.GetSafeHwnd(), &m_strDiscussionVideoMaterial);
// Determine if the use clicked on a combo or edit control
bool bIsComboControl = false;
HWND hWndToUse = nullptr;
if (mapControls.find(::GetParent(hWnd)) != mapControls.end())
{
bIsComboControl = true;
hWndToUse = ::GetParent(hWnd);
}
else if (mapControls.find(hWnd) != mapControls.end())
hWndToUse = hWnd;
if (hWndToUse == nullptr)
return false;
// Process
UpdateData(TRUE);
// Get the correct selection from the control
DWORD dwSel = (bIsComboControl) ?
((CComboBox*)mapControls[hWndToUse])->GetEditSel() :
((CEdit*)mapControls[hWndToUse])->GetSel();
// Encode the text
CMeetingScheduleAssistantApp::EncodeText(*mapControlsText[hWndToUse],
strCode, LOWORD(dwSel), HIWORD(dwSel));
UpdateData(FALSE);
return true;
}