Programming Windows with MFC

1
Programming Windows with MFC
2
Chapter 5

• The MFC Collection Classes

3
The Standard Template Library

• Convenient implementations of arrays, linked
  lists, maps, and other containers
• A container in the language of STL
• An object that stores collections of data

4
The MFC Collection Classes

• MFC collection classes
• own implementations of arrays, linked lists, and
  maps in a family of classes
• Never have to write a linked list

5
Arrays
6
Arrays

• Access violation

int array10 for (int i0 ilt10 i)
arrayi i 1

• What happened when i 10?

7
Arrays

• Get and Set functions

class CArray int Get (int nIndex)
assert (nIndex gt 0 nIndex lt m_nSize)
return m_pDatanIndex void Set (int
nIndex, int nVal) assert (nIndex gt 0
nIndex lt m_nSize) m_pDatanIndex nVal

CArray array (10) for (int i0 ilt10 i)
array.Set (i, i 1) // Asserts when i 10.
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The MFC Array Classes

• CArray class
• A template class
• Create type-safe arrays
• Defined in the header file Afxtempl.h
• Nontemplatized array classes
• Designed to hold a particular type of data
• defined in Afxcoll.h

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Type-Specific MFC Array Classes
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Usages

• SetSize
• InsertAt
• RemoveAt
• RemoveAll

• CUIntArray array
• array.SetSize (10)
• for (int i0 ilt10 i)
• arrayi i 1

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Dynamic Array Sizing

• SetSize
• SetAtGrow
• Add
• InsertAt
• Append
• Copy

12
CMemoryExceptions

• try
• CUIntArray array
• // Might throw a CMemoryException.
• array.SetSize (1000)
• catch (CMemoryException e)
• AfxMessageBox (_T ("Error
• Insufficient memory"))
• // Delete the exception object.
• e-gtDelete ()

13
Creating Type-Safe Array Classes with CArray

• Your own MFCs CArray class

CArrayltCPoint, CPointgt array // Populate the
array, growing it as needed. for (int i0 ilt10
i) array.SetAtGrow (i, CPoint (i10, 0))
// Enumerate the items in the array. int
nCount array.GetSize () for (i0 iltnCount
i) CPoint point arrayi TRACE (_T
("xd, yd\n"), point.x, point.y)
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Lists
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Linked list

• Support fast item insertion and removal
• A collection of items that contain pointers to
  other items

item pItem GetHead () while (pItem ! NULL)
pItem pItem-gtpNextItem item pItem
GetTail () while (pItem ! NULL) pItem
pItem-gtpPrevItem
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Type-Specific MFC List Classes
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Lists

• AddHead
• RemoveHead/RemoveTail/RemoveAll
• GetNex/GetPrev
• GetHeadPosition/GetTailPosition
• Find

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Creating Type-Safe List Classes with CList

• CListltCPoint, CPointgt list
• // Populate the list.
• for (int i0 ilt10 i)
• list.AddTail (CPoint (i10, 0))
• // Enumerate the items in the list.
• POSITION pos list.GetHeadPosition ()
• while (pos ! NULL)
• CPoint point list.GetNext (pos)
• TRACE (_T ("xd, yd\n"), point.x, point.y)

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Maps

• Look-up table

20
Type-Specific MFC Map Classes
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CMapStringToString

• CMapStringToString map
• map_T("Sunday") _T("Dimanche")
• map_T("Monday") _T("Lundi")
• map_T("Tuesday") _T("Mardi")
• map_T("Wednesday") _T("Mercredi")
• map_T("Thursday") _T("Jeudi")
• map_T("Friday") _T("Vendredi")
• map_T("Saturday") _T("Samedi")
• CString string
• if (map.Lookup (_T ("Thursday"), string))
• TRACE (_T ("Thursday in English s in
  French\n"), string)

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The Typed Pointer Classes

• A set of three template classes designed to
  handle collections of pointers in a type-safe
  manner

23
Collection Classes for Pointers
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CObList

• CTypedPtrListltCObList, CLinegt list
• // Populate the list.
• for (int i0 ilt10 i)
• int x i 10
• CLine pLine new CLine (x, 0, x, 100)
• list.AddTail (pLine)
• // Enumerate the items in the list.
• POSITION pos list.GetHeadPosition ()
• while (pos ! NULL)
• CLine pLine list.GetNext (pos) // No
  casting!