ChoiceListButton Control

Synopsis

I wanted to have a button that would display a selection of choices to the user. I could of course use an ownerdraw combo box. The problem with that solution, is that, when the dropdown is collapsed it will display the last chosen item always insted of some descriptive text.

That was why I opted for a custom solution.

ITCLib

Optionally, the control can use the freeware library 'ITCLib' from Interface technologies, Inc. This is a great library and I will suggest that every MFC developer takes a look at it - it is a real time saver.

ITCLib has only been used for painting the small arrow on the button, and is as such not an integreated part of the control. That is why all references to ITCLib is initially disabled via preprocessor statements, so the sample should compile fine on installations without the library.

To enable ITCLib:

• If you have ITCLib installed and you want to enable it, do the following:
• In Project Settings - C/C++ - Preprocessor - Preprocessor definitions, add _ITCDLL
• In Project Settings - C/C++ - Preprocessor - Additional include directories, add the folder with your ITCLib header files
• In Project Settings - Link - Input - Additional Library Path, add the folder with your ITCLib lib-files

That's it!

If you want to use you own button class for painting the arrow or what ever it is you want to paint on the button surface, you could enherit CChoiceWindowBtn from your own class instead of CButton or ITCImageButton.

Using the control

To use the control, create a project and add these files:

ChoiceWindow.h
ChoiceWindow.cpp
ChoiceWindowBtn.h
ChoiceWindowBtn.cpp
drop_arrow.bmp (or another bitmap)

Assign the bitmap the resource name "DROP_ARROW" - notice as  a string - not as an integer ID.

Next add a button to a dialog and use the member functions from you WM_INITDIALOG handler.

Add an object of type CChoiceWindowBtn to the dialog class. Make sure to add the header include too.

Example - notice the use of preprocessor definitions.

#ifdef _ITCDLL
	m_btnDropDown.SubclassControl(IDC_OPTIONS, this);
	m_btnDropDown.AddImage("DROP_ARROW", -1, RGB(255,0,255));
	m_btnDropDown.SetImageAlign(DT_RIGHT|DT_VCENTER);
#else
	m_btnDropDown.SubclassDlgItem(IDC_OPTIONS, this);
#endif

	m_btnDropDown.AddChoice("Name", TRUE);
	m_btnDropDown.AddChoice("Address", TRUE);
	m_btnDropDown.AddChoice("Notes", FALSE);
	m_btnDropDown.AddChoice("Telephone", TRUE);

The API

The control is accessed through the class CChoiceWindowButton. It has a few simple member functions:

CChoiceWindowButton::AddChoice

void AddChoice(LPCTSTR szText, BOOL bChecked=FALSE)

Return value
None
Parameters
szText: The text to display as a choice.
bChecked: Should the choice be iniitally checked or not.
Remarks
Adds a new choice to the list.

CChoiceWindowButton::Reset

void Reset()

Return value
None
Parameters
None
Remarks
Deletes all the items from the choice list.

CChoiceWindowButton::GetCheck

BOOL GetCheck(int iItem)

Return value
Boolean - the state of the choice specified by iItem
Parameters
nItem: Zero based index of the item to query the state for.
Remarks
Returns TRUE if the choice had a check mark, and FALSE if the choice was not checked by the user.

CChoiceWindowButton::SetCheck

void SetCheck(int iItem, BOOL bCheck=TRUE)

Return value
void
Parameters
iItem: Zero based index of the item to query the state for.
bCheck: Boolean value. If true, the item is checked otherwise it is unchecked.

CChoiceWindowButton::GetItemCount

int  GetItemCount()

Return value
The number of items in the list.
Parameters
none

CChoiceWindowButton::GetListCtrl

CListCtrl&  GetListCtrl()

Return value
A reference to the underlying CListCtrl object 
Parameters
none
Remarks
You access the list control like this:
CListCtrl& list = btnChoiceList.GetListCtrl();

CChoiceWindowButton::RemoveAt

void  RemoveAt(int iIndex)

Return value
None
Parameters
The index of the item to remove from the list.

CChoiceWindowButton::m_bDisableIfEmpty

BOOL m_bDisableIfEmpty

Remarks
Boolean value, that specifies if the button is disbaled if the choice list does not contain any items. The default value is TRUE.

CChoiceWindowButton::Reset

void Reset()

Return value
None
Parameters
None
Remarks
Removes all the items from the list.

CChoiceWindowButton::SetItemData

void SetItemData(int iIndex, DWORD dwData)

Return value
None
Parameters
iIndex - Index of the item to associate the data with,
dwData - A 32 bit value to associate with the item. This may be zero.
Remarks
Associates a 32 bit value with an item.

CChoiceWindowButton::GetItemData

DWORD SetItemData(int iIndex)

Return value
DWORD - The 32 bit value associated with the item.
Parameters
iIndex - Index of the  item to associate the data with,
Remarks
Retrieves the 32 bit value associated with an item.

History

July 1999
Version 1.0 was released at CodeGuru as "ChoiceListButton".

August 1999
Minor bugfix to the class was posted at CodeGuru.com.

15 Dec 1999
Posted at CodeProject.com.

February 2000
Version 1.0.2 posted at CodeProject.com. Added SetItemData() and GetItemData() member functions.