Chỉnh sửa

Chia sẻ qua

CStatusBar Class

  • Bài viết

A control bar with a row of text output panes, or "indicators."

Syntax

class CStatusBar : public CControlBar

Members

Public Constructors

Name Description
CStatusBar::CStatusBar Constructs a CStatusBar object.

Public Methods

Name Description
CStatusBar::CommandToIndex Gets index for a given indicator ID.
CStatusBar::Create Creates the status bar, attaches it to the CStatusBar object, and sets the initial font and bar height.
CStatusBar::CreateEx Creates a CStatusBar object with additional styles for the embedded CStatusBarCtrl object.
CStatusBar::DrawItem Called when a visual aspect of an owner-draw status bar control changes.
CStatusBar::GetItemID Gets indicator ID for a given index.
CStatusBar::GetItemRect Gets display rectangle for a given index.
CStatusBar::GetPaneInfo Gets indicator ID, style, and width for a given index.
CStatusBar::GetPaneStyle Gets indicator style for a given index.
CStatusBar::GetPaneText Gets indicator text for a given index.
CStatusBar::GetStatusBarCtrl Allows direct access to the underlying common control.
CStatusBar::SetIndicators Sets indicator IDs.
CStatusBar::SetPaneInfo Sets indicator ID, style, and width for a given index.
CStatusBar::SetPaneStyle Sets indicator style for a given index.
CStatusBar::SetPaneText Sets indicator text for a given index.

Remarks

The output panes commonly are used as message lines and as status indicators. Examples include the menu help-message lines that briefly explain the selected menu command and the indicators that show the status of the SCROLL LOCK, NUM LOCK, and other keys.

CStatusBar::GetStatusBarCtrl, a member function new to MFC 4.0, allows you to take advantage of the Windows common control's support for status bar customization and additional functionality. CStatusBar member functions give you most of the functionality of the Windows common controls; however, when you call GetStatusBarCtrl, you can give your status bars even more of the characteristics of a Windows 95/98 status bar. When you call GetStatusBarCtrl, it will return a reference to a CStatusBarCtrl object. See CStatusBarCtrl for more information about designing toolbars using Windows common controls. For more general information about common controls, see Common Controls in the Windows SDK.

The framework stores indicator information in an array with the leftmost indicator at position 0. When you create a status bar, you use an array of string IDs that the framework associates with the corresponding indicators. You can then use either a string ID or an index to access an indicator.

By default, the first indicator is "elastic": it takes up the status-bar length not used by the other indicator panes, so that the other panes are right-aligned.

To create a status bar, follow these steps:

  1. Construct the CStatusBar object.

  2. Call the Create (or CreateEx) function to create the status-bar window and attach it to the CStatusBar object.

  3. Call SetIndicators to associate a string ID with each indicator.

There are three ways to update the text in a status-bar pane:

  1. Call CWnd::SetWindowText to update the text in pane 0 only.

  2. Call CCmdUI::SetText in the status bar's ON_UPDATE_COMMAND_UI handler.

  3. Call SetPaneText to update the text for any pane.

Call SetPaneStyle to update the style of a status-bar pane.

For more information on using CStatusBar, see the article Status Bar Implementation in MFC and Technical Note 31 : Control Bars.

Inheritance Hierarchy

CObject

CCmdTarget

CWnd

CControlBar

CStatusBar

Requirements

Header: afxext.h

CStatusBar::CommandToIndex

Gets the indicator index for a given ID.

int CommandToIndex(UINT nIDFind) const;

Parameters

nIDFind
String ID of the indicator whose index is to be retrieved.

Return Value

The index of the indicator if successful; -1 if not successful.

Remarks

The index of the first indicator is 0.

CStatusBar::Create

Creates a status bar (a child window) and associates it with the CStatusBar object.

virtual BOOL Create(
    CWnd* pParentWnd,
    DWORD dwStyle = WS_CHILD | WS_VISIBLE | CBRS_BOTTOM,
    UINT nID = AFX_IDW_STATUS_BAR);

Parameters

pParentWnd
Pointer to the CWnd object whose Windows window is the parent of the status bar.

dwStyle
The status-bar style. In addition to the standard Windows styles, these styles are supported.

  • CBRS_TOP Control bar is at top of frame window.

  • CBRS_BOTTOM Control bar is at bottom of frame window.

  • CBRS_NOALIGN Control bar is not repositioned when the parent is resized.

nID
The toolbar's child-window ID.

Return Value

Nonzero if successful; otherwise 0.

Remarks

Also sets the initial font and sets the status bar's height to a default value.

CStatusBar::CreateEx

Call this function to create a status bar (a child window) and associate it with the CStatusBar object.

virtual BOOL CreateEx(
    CWnd* pParentWnd,
    DWORD dwCtrlStyle = 0,
    DWORD dwStyle = WS_CHILD | WS_VISIBLE | CBRS_BOTTOM,
    UINT nID = AFX_IDW_STATUS_BAR);

Parameters

pParentWnd
Pointer to the CWnd object whose Windows window is the parent of the status bar.

dwCtrlStyle
Additional styles for the creation of the embedded CStatusBarCtrl object. The default specifies a status bar without a sizing grip or tooltip support. Status bar styles supported are:

  • SBARS_SIZEGRIP The status bar control includes a sizing grip at the right end of the status bar. A sizing grip is similar to a sizing border; it is a rectangular area that the user can click and drag to resize the parent window.

  • SBT_TOOLTIPS The status bar supports tooltips.

For details on these styles, see Settings for the CStatusBarCtrl.

dwStyle
The status bar style. The default specifies that a visible status bar be created at the bottom of the frame window. Apply any combination of status bar control styles listed in Window Styles and CDialogBar::Create. However, this parameter should always include the WS_CHILD and WS_VISIBLE styles.

nID
The status bar's child-window ID.

Return Value

Nonzero if successful; otherwise 0.

Remarks

This function also sets the initial font and sets the status bar's height to a default value.

Use CreateEx, instead of Create, when certain styles need to be present during the creation of the embedded status bar control. For example, set dwCtrlStyle to SBT_TOOLTIPS to display tooltips in a status bar object.

CStatusBar::CStatusBar

Constructs a CStatusBar object, creates a default status-bar font if necessary, and sets the font characteristics to default values.

CStatusBar();

CStatusBar::DrawItem

This member function is called by the framework when a visual aspect of an owner-drawn status bar changes.

virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);

Parameters

lpDrawItemStruct
A pointer to a DRAWITEMSTRUCT structure that contains information about the type of drawing required.

Remarks

The itemAction member of the DRAWITEMSTRUCT structure defines the drawing action that is to be performed. Override this member function to implement drawing for an owner-draw CStatusBar object. The application should restore all graphics device interface (GDI) objects selected for the display context supplied in lpDrawItemStruct before the termination of this member function.

CStatusBar::GetItemID

Returns the ID of the indicator specified by nIndex.

UINT GetItemID(int nIndex) const;

Parameters

nIndex
Index of the indicator whose ID is to be retrieved.

Return Value

The ID of the indicator specified by nIndex.

CStatusBar::GetItemRect

Copies the coordinates of the indicator specified by nIndex into the structure pointed to by lpRect.

void GetItemRect(
    int nIndex,
    LPRECT lpRect) const;

Parameters

nIndex
Index of the indicator whose rectangle coordinates are to be retrieved.

lpRect
Points to a RECT structure or a CRect object that will receive the coordinates of the indicator specified by nIndex.

Remarks

Coordinates are in pixels relative to the upper-left corner of the status bar.

CStatusBar::GetPaneInfo

Sets nID, nStyle, and cxWidth to the ID, style, and width of the indicator pane at the location specified by nIndex.

void GetPaneInfo(
    int nIndex,
    UINT& nID,
    UINT& nStyle,
    int& cxWidth) const;

Parameters

nIndex
Index of the pane whose information is to be retrieved.

nID
Reference to a UINT that is set to the ID of the pane.

nStyle
Reference to a UINT that is set to the style of the pane.

cxWidth
Reference to an integer that is set to the width of the pane.

CStatusBar::GetPaneStyle

Call this member function to retrieve the style of a status bar's pane.

UINT GetPaneStyle(int nIndex) const;

Parameters

nIndex
Index of the pane whose style is to be retrieved.

Return Value

The style of the status-bar pane specified by nIndex.

Remarks

A pane's style determines how the pane appears.

For a list of styles available for status bars, see Create.

CStatusBar::GetPaneText

Call this member function to retrieve the text that appears in a status-bar pane.

CString GetPaneText(int nIndex) const;  void GetPaneText(int nIndex, CString& rString) const;

Parameters

nIndex
Index of the pane whose text is to be retrieved.

rString
A reference to a CString object that contains the text to be retrieved.

Return Value

A CString object containing the pane's text.

Remarks

The second form of this member function fills a CString object with the string text.

CStatusBar::GetStatusBarCtrl

This member function allows direct access to the underlying common control.

CStatusBarCtrl& GetStatusBarCtrl() const;

Return Value

Contains a reference to a CStatusBarCtrl object.

Remarks

Use GetStatusBarCtrl to take advantage of the functionality of the Windows status-bar common control, and to take advantage of the support CStatusBarCtrl provides for status-bar customization. For example, by using the common control, you can specify a style that includes a sizing grip on the status bar, or you can specify a style to have the status bar appear at the top of the parent window's client area.

For more general information about common controls, See Common Controls in the Windows SDK.

CStatusBar::SetIndicators

Sets each indicator's ID to the value specified by the corresponding element of the array lpIDArray, loads the string resource specified by each ID, and sets the indicator's text to the string.

BOOL SetIndicators(
    const UINT* lpIDArray,
    int nIDCount);

Parameters

lpIDArray
Pointer to an array of IDs.

nIDCount
Number of elements in the array pointed to by lpIDArray.

Return Value

Nonzero if successful; otherwise 0.

CStatusBar::SetPaneInfo

Sets the specified indicator pane to a new ID, style, and width.

void SetPaneInfo(
    int nIndex,
    UINT nID,
    UINT nStyle,
    int cxWidth);

Parameters

nIndex
Index of the indicator pane whose style is to be set.

nID
New ID for the indicator pane.

nStyle
New style for the indicator pane.

cxWidth
New width for the indicator pane.

Remarks

The following indicator styles are supported:

  • SBPS_NOBORDERS No 3-D border around the pane.

  • SBPS_POPOUT Reverse border so that text "pops out."

  • SBPS_DISABLED Do not draw text.

  • SBPS_STRETCH Stretch pane to fill unused space. Only one pane per status bar can have this style.

  • SBPS_NORMAL No stretch, borders, or pop-out.

CStatusBar::SetPaneStyle

Call this member function to set the style of a status bar's pane.

void SetPaneStyle(
    int nIndex,
    UINT nStyle);

Parameters

nIndex
Index of the pane whose style is to be set.

nStyle
Style of the pane whose style is to be set.

Remarks

A pane's style determines how the pane appears.

For a list of styles available for status bars, see SetPaneInfo.

CStatusBar::SetPaneText

Call this member function to set the pane text to the string pointed to by lpszNewText.

BOOL SetPaneText(
    int nIndex,
    LPCTSTR lpszNewText,
    BOOL bUpdate = TRUE);

Parameters

nIndex
Index of the pane whose text is to be set.

lpszNewText
Pointer to the new pane text.

bUpdate
If TRUE, the pane is invalidated after the text is set.

Return Value

Nonzero if successful; otherwise 0.

Remarks

After you call SetPaneText, you must add a UI update handler to display the new text in the status bar.

Example

//Sets and displays text for pane index 3 and id ID_INDICATOR_SCRL
m_wndStatusBar.SetPaneText(3, _T("My New Status Bar Text"), TRUE);

 

//UI handler in the message map updates the status bar text:
ON_UPDATE_COMMAND_UI(ID_INDICATOR_SCRL, &CMainFrame::OnUpdatePane)

 

void CMainFrame::OnUpdatePane(CCmdUI* pCmdUI)
{
   pCmdUI->Enable();
}

See also

MFC Sample CTRLBARS
MFC Sample DLGCBR32
CControlBar Class
Hierarchy Chart
CStatusBarCtrl Class
CControlBar Class