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Weitere Steuerelemente

Zu den Steuerelementen (alte Standardelemente in blauer Farbe) gehören nun insgesamt folgende Typen:

Die neueren Win32 common controls senden ihre Nachrichten an das Elternfenster typischerweise als WM_NOTIFY.
Die bereits aus 16-bit Windows bekannten Windows Standard-Steuerelemente senden Nachrichten als WM_COMMAND.

Listenelement (List View)

Dies ist ein Listenelement, das in den MFC durch CListCtrl gesteuert wird. Erstellen Sie eine Dialog-Anwendung und platzieren Sie ein Listenelement in die Dialog-Ressource, wie oben abgebildet. Nach dem Kompilieren und Ausführen der Anwendung ergibt sich folgendes Bild:

In der Ressourcen-Datei stellt sich dieses Listenelement wie folgt dar:

BEGIN
    DEFPUSHBUTTON   "OK",IDOK,260,7,50,14
    PUSHBUTTON      "Abbrechen",IDCANCEL,260,23,50,14
    CONTROL         "List1", IDC_LIST1, "SysListView32", WS_BORDER | WS_TABSTOP, 16, 16, 229, 168
END

Zunächst noch eine Klärung, damit die klassische List Box nicht verwechselt wird mit dem hier besprochenen List View Control:

Unser IDC_LIST1 hat also bisher die beiden Eigenschaften WS_BORDER (Rand wie oben sichtbar) und WS_TABSTOP (kann den Tastatur-Focus erhalten, wenn die TAB Taste gedrückt wird. Mit jedem TAB wechselt der Tastatur-Focus zum nächten Steuerelement mit dem WS_TABSTOP Style). Will man weitere Eigenschaften, so muss man dies unter Eigenschaften einstellen. Dort sind bisher folgende Eigenschaften "angeklickt": Sichtbar, Rand und Tabstopp.

Wir beschaffen uns nun mittels Assistent (Strg+W) eine Membervariable m_List1 und fügen in OnInitDialog(...) zunächst Spalten in das Listenelement ein:

Danach folgen zur Demonstration vier Elemente in unserem Listenelement:

int i;
i = m_List1.InsertItem(LVIF_TEXT, 0, "Eins Eins", 0, 0, 0, NULL);
    m_List1.SetItem(i, 1, LVIF_TEXT, "Eins Zwei", 0, 0, 0, NULL);
i = m_List1.InsertItem(LVIF_TEXT, 1, "Zwei Eins", 0, 0, 0, NULL);
    m_List1.SetItem(i, 1, LVIF_TEXT, "Zwei Zwei", 0, 0, 0, NULL);

Damit unsere Spalten nach dem Einfügen automatisch auf die richtige Breite gesetzt werden, folgt ein "Autosize":

m_List1.SetColumnWidth(0, LVSCW_AUTOSIZE);
m_List1.SetColumnWidth(1, LVSCW_AUTOSIZE);

Damit wir unsere in InsertColumn(...) festgelegten Spaltenüberschriften sehen, müssen wir vorher unser Listenelement unter Eigenschaften - Formate von Symbol auf Bericht (LVS_REPORT) umstellen. Es gibt als weitere Auswahl noch Minisymbol und Liste.

In der Dialog-Ressource sieht das wie folgt aus:

CONTROL "List1", IDC_LIST1, "SysListView32", LVS_REPORT | WS_BORDER | WS_TABSTOP, 16, 16, 229, 168

Nehmen wir doch gleich die erste Nachricht NM_CLICK und fügen eine Behandlungsroutine ein:

BEGIN_MESSAGE_MAP(CTest001Dlg, CDialog)
    //{{AFX_MSG_MAP(CTest001Dlg)
    ON_WM_SYSCOMMAND()
    ON_WM_PAINT()
    ON_NOTIFY(NM_CLICK, IDC_LIST1, OnClickList1)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

void CTest001Dlg::OnClickList1(NMHDR* pNMHDR, LRESULT* pResult)
{
    MessageBox("Auf Listenelement geklickt.");    
    *pResult = 0;
}

typedef struct tagNMHDR 
{ 
    HWND hwndFrom; 
    UINT idFrom; 
    UINT code; 
} NMHDR; 

MFC liefert uns freundlicherweise in unserer Funktion bereits den Parameter pNMHDR, ein Zeiger auf diese Struktur NMHDR. Wir können damit weitere Informationen aus unserer Nachricht erhalten:

void CTest001Dlg::OnClickList1(NMHDR* pNMHDR, LRESULT* pResult)
{
    CString str;
    str.Format("Code: %i  IdFrom: %i  FensterFrom: %i",
        pNMHDR->code, pNMHDR->idFrom, pNMHDR->hwndFrom);
   
    MessageBox(str);
   
    *pResult = 0;
}

Damit erhalten wir beim Linksklick z.B.:



In resource.h finden wir die Zahl 1000 als Windows-interne ID für unser IDC_LIST1:

#define IDM_ABOUTBOX                    0x0010
#define IDD_ABOUTBOX                    100
#define IDS_ABOUTBOX                    101
#define IDD_TEST001_DIALOG              102
#define IDR_MAINFRAME                   128
#define IDC_LIST1                       1000

WM_NOTIFY 

    idCtrl = (int)    wParam; 
   pNMHDR = (NMHDR*) lParam; 

Neugierig, wie wir hoffentlich noch sind, testen wir das sofort:

BOOL CTest001Dlg::OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult) 
{
	if ( ((NMHDR*)lParam)->code == NM_CLICK)
	{
		CString str;
		str.Format( "idCtrl: %i", (int) wParam );
		MessageBox("NMCLICK\n" + str);
	}
	
	return CDialog::OnNotify(wParam, lParam, pResult);
}

Die Ausgabe ist interessant:



Jetzt erkennen wir auch ganz klar, warum erst ab dem zweiten Klick die Nachricht NM_CLICK (-2) erscheint, denn beim ersten Klick wird lediglich der Focus (

typedef struct tagNMLISTVIEW 
{
    NMHDR hdr;
    int iItem;
    int iSubItem;
    UINT uNewState;
    UINT uOldState;
    UINT uChanged;
    POINT ptAction;
    LPARAM lParam;
} NMLISTVIEW, *LPNMLISTVIEW;

hdr

NMHDR structure that contains information about this notification message.

iItem

Identifies the list-view item, or -1 if not used.

iSubItem

Identifies the subitem, or zero if none.

uNewState

New item state. This member is zero for notification messages that do not use it.

uOldState

Old item state. This member is zero for notification messages that do not use it.

uChanged

Set of flags that indicate the item attributes that have changed. This member is zero for notifications that do not use it.

Otherwise, it can have the same values as the mask member of the LVITEM structure.

ptAction

POINT structure that indicates the location at which the event occurred.

This member is undefined for notification messages that do not use it.

lParam

Application-defined value of the item. This member is undefined for notification messages that do not use it.

typedef struct _LVITEM 
{ 
    UINT    mask; 
    int     iItem; 
    int     iSubItem; 
    UINT    state; 
    UINT    stateMask; 
    LPTSTR  pszText; 
    int     cchTextMax; 
    int     iImage; 
    LPARAM  lParam;
#if (_WIN32_IE >= 0x0300)
    int     iIndent;
#endif
#if (_WIN32_WINNT >= 0x560)
    int     iGroupId;
    UINT    cColumns; // tile view columns
    PUINT   puColumns;
#endif
#if (_WIN32_WINNT >= 0x0600)
    int*    piColFmt
    int     iGroup
#endif
} LVITEM, *LPLVITEM; 

mask

Hier wird festgelegt, welche Datenelemente wirklich verwendet werden:

LVIF_COLUMNS	cColumns
LVIF_DI_SETITEM	The operating system should store the requested list item information and not ask for it again. This flag is used only with the LVN_GETDISPINFO notification message.
LVIF_GROUPID	iGroupId
LVIF_IMAGE	iImage
LVIF_INDENT	iIndent
LVIF_NORECOMPUTE	The control will not generate LVN_GETDISPINFO to retrieve text information if it receives an LVM_GETITEM message. Instead, the pszText member will contain LPSTR_TEXTCALLBACK.
LVIF_PARAM	lParam
LVIF_STATE	state
LVIF_TEXT	pszText

     

iItem

Mit null beginnender Index des Items

iSubItem

Mit 1 beginnder Index des SubItems,  0: kein SubItem 

state

Indicates the item's state, state image, and overlay image. The stateMask member indicates the valid bits of this member. Bits 0 through 7 of this member contain the item state flags. This can be one or more of the item state values.Bits 8 through 11 of this member specify the one-based overlay image index. Both the full-sized icon image list and the small icon image list can have overlay images. The overlay image is superimposed over the item's icon image. If these bits are zero, the item has no overlay image. To isolate these bits, use the LVIS_OVERLAYMASK mask. To set the overlay image index in this member, you should use the INDEXTOOVERLAYMASK macro. The image list's overlay images are set with the ImageList_SetOverlayImage function.Bits 12 through 15 of this member specify the state image index. The state image is displayed next to an item's icon to indicate an application-defined state. If these bits are zero, the item has no state image. To isolate these bits, use the LVIS_STATEIMAGEMASK mask. To set the state image index, use the INDEXTOSTATEIMAGEMASK macro. The state image index specifies the index of the image in the state image list that should be drawn. The state image list is specified with the LVM_SETIMAGELIST message.

stateMask

Value specifying which bits of the state member will be retrieved or modified. For example, setting this member to LVIS_SELECTED will cause only the item's selection state to be retrieved. This member allows you to modify one or more item states without having to retrieve all of the item states first. For example, setting this member to LVIS_SELECTED and state to zero will cause the item's selection state to be cleared, but none of the other states will be affected. To retrieve or modify all of the states, set this member to (UINT)-1.You can use the macro ListView_SetItemState both to set and to clear bits.

pszText

If the structure specifies item attributes, pszText is a pointer to a null-terminated string containing the item text. If the structure receives item attributes, pszText is a pointer to a buffer that receives the item text. Note that although the list-view control allows any length string to be stored as item text, only the first 260 TCHARs are displayed.If the value of pszText is LPSTR_TEXTCALLBACK, the item is a callback item. If the callback text changes, you must explicitly set pszText to LPSTR_TEXTCALLBACK and notify the list-view control of the change by sending an LVM_SETITEM or LVM_SETITEMTEXT message.Do not set pszText to LPSTR_TEXTCALLBACK if the list-view control has the LVS_SORTASCENDING or LVS_SORTDESCENDING style.

cchTextMax

Number of TCHARs in the buffer pointed to by pszText, including the terminating NULL. This member is only used when the structure receives item attributes. It is ignored when the structure specifies item attributes. For example, cchTextMax is ignored during LVM_SETITEM and LVM_INSERTITEM. It is read-only during LVN_GETDISPINFO and other LVN_ notifications.

Note  Never copy more than cchTextMaxTCHARs where cchTextMax includes the terminating NULL into pszText during an LVN_ notification, otherwise your program may fail.

iImage

Index of the item's icon in the control's image list. This applies to both the large and small image list. If this member is the I_IMAGECALLBACK value, the parent window is responsible for storing the index. In this case, the list-view control sends the parent an LVN_GETDISPINFO notification message to retrieve the index when it needs to display the image.

lParam

Value specific to the item. If you use the LVM_SORTITEMS message, the list-view control passes this value to the application-defined comparison function. You can also use the LVM_FINDITEM message to search a list-view control for an item with a specified lParam value.

HIMAGELIST ImageList_Create
(      
    int  cx,
    int  cy,
    UINT flags,
    int  cInitial,
    int  cGrow
);

cx

Width, in pixels, of each image.

cy

Height, in pixels, of each image.

flags

Set of bit flags that specify the type of image list to create.

This parameter can be a combination of the following values, but it can include only one of the ILC_COLOR values.

ILC_COLOR

Use the default behavior if none of the other ILC_COLOR* flags is specified. Typically, the default is ILC_COLOR4, but for older display drivers, the default is ILC_COLORDDB.

ILC_COLOR4

Use a 4-bit (16-color) device-independent bitmap (DIB) section as the bitmap for the image list.

ILC_COLOR8

Use an 8-bit DIB section. The colors used for the color table are the same colors as the halftone palette.

ILC_COLOR16

Use a 16-bit (32/64k-color) DIB section.

ILC_COLOR24

Use a 24-bit DIB section.

ILC_COLOR32

Use a 32-bit DIB section.

ILC_COLORDDB

Use a device-dependent bitmap.

ILC_MASK

Use a mask. The image list contains two bitmaps, one of which is a monochrome bitmap used as a mask. If this value is not included, the image list contains only one bitmap.

ILC_MIRROR

Version 6.00. Microsoft Windows can be mirrored to display languages such as Hebrew or Arabic that read right-to-left. If the image list is created on a mirrored version of Windows, then the images in the lists are mirrored, that is, they are flipped so they display from right to left. Use this flag on a mirrored version of Windows to instruct the image list not to automatically mirror images.

ILC_PERITEMMIRROR

Version 6.00. Specify this flag if ILC_MIRROR is used on an image list that contains a strip of images. ILC_MIRROR must be specified for this flag to have any effect.

cInitial

Number of images that the image list initially contains.

cGrow

Number of images by which the image list can grow when the system needs to make room for new images. This parameter represents the number of new images that the resized image list can contain.

Returns the handle to the image list if successful, or NULL otherwise.

HIMAGELIST hList = ImageList_Create(32,32, ILC_COLOR8 | ILC_MASK , 8, 1);

int CImageList::Add( CBitmap* pbmImage, CBitmap* pbmMask );
int CImageList::Add( CBitmap* pbmImage, COLORREF crMask  );
int CImageList::Add( HICON hIcon                         );

Pointer to the bitmap containing the image or images. The number of images is inferred from the width of the bitmap.

Das "Bildband" wird also auf die Zahl der Bilder in der Liste aufgeteilt. Dies ergibt die Abgrenzung.

Was ist, wenn ich z.B. acht Plätze habe, aber nur sechs Bilder in der Bitmap? Da gibt es nur eines: ausprobieren!

Wir schneiden bei IDB_IMAGES_SMALL einfach die zwei rechten Bilder weg.



Was passiert jetzt genau? Werden die sechs Bilder jetzt in der Breite auf acht aufgeteilt?



Nein das passiert nicht, sondern es werden jeweils 16 Pixel breite Bilder übernommen. Für zwei Items ist eben kein Bild mehr übrig.
Hier übrigens ohne ILC_MASK, daher der schwarze Hintergrund.

Diesbezüglich hilft nur üben, experimentieren, fremde Programme diesbezüglich genau analysieren.

• LVSIL_NORMAL: nur für LVS_ICON  (große Symbole, 32*32)
• LVSIL_SMALL: für LVS_SMALLICON, LVS_LIST und LVS_REPORT (kleine Symbole, 16*16)