How to use the WTL multipane status bar control






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Sep 27, 2002
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This article explains how to use WTL's CMultiPaneStatusBarCtrl class in an application.

Introduction
This article explains how to use WTL's CMultiPaneStatusBarCtrl
class in an application. The sample project included with this article is a
wizard-generated SDI application enhanced with a three pane status bar that
displays status messages and the current date and time.
Status Bar
All of the relevant code for using the status bar is contained in the
mainframe.h
file of the sample project. The status bar is
initialized in the OnCreate
method, which also calls a workaround
for a bug in the WTL class. Another method provides a timer handler and is used
to display date and time in status bar panes.
Basics
A status bar provides users with various types of feedback and information as they use an application. WTL wizard-generated applications define a single pane status bar. It handles the basic functions of showing "Ready" and is switched to simple mode to display menu tips. Multipane status bars, on the other hand, are divided into multiple, independently controlled segments.
Initialization
Please note that you must include the atlctrlx.h
header file. It
defines the CMultiPaneStatusBarCtrl
class. You must also include
atlmisc.h
, as it defines AtlLoadIconImage()
and the
CString
class.
The following steps are needed to define and initialize a multipane status bar control for an application:
- Create a resource definition for each status bar pane
- Define a member variable:
CMultiPaneStatusBarCtrl m_status;
- Subclass the "simple" status bar created by the WTL wizard
- Enumerate and set the status bar panes
- Call the workaround method,
SetPaneWidths()
- Set the icons (if desired) for the individual status bar panes
The following resource definitions from resource.h
pertain to
the status bar panes and their icons. They were created by the resource editor
when the icons were imported and they are used to identify status bar panes as
well as the icons. You must manually enter similar values if you do not import
or create status bar icons for your application.
#define IDR_DEFAULT 201 #define IDR_DATE 202 #define IDR_TIME 203
In addition, WTL defines a default pane identifier, ID_DEFAULT_PANE
,
which it uses as a variable width pane for status messages such as "Ready".
Here is the OnCreate()
method from mainframe.h
.
Note that the width of the default pane is set to 0 in the array passed to
SetPaneWidths()
.
LRESULT OnCreate(UINT, WPARAM, LPARAM, BOOL&)
{
CreateSimpleStatusBar();
// subclass the status bar as multipane
m_status.SubclassWindow(m_hWndStatusBar);
// set status bar panes. ID_DEFAULT_PANE is defined by WTL
int arrPanes[] = { ID_DEFAULT_PANE, IDR_DATE, IDR_TIME };
m_status.SetPanes(arrPanes,
sizeof(arrPanes) / sizeof(int), false);
// set status bar pane widths using local workaround
int arrWidths[] = { 0, 90, 60 };
SetPaneWidths(arrWidths, sizeof(arrWidths) / sizeof(int));
// set the status bar pane icons
m_status.SetPaneIcon(ID_DEFAULT_PANE,
AtlLoadIconImage(IDR_DEFAULT, LR_DEFAULTCOLOR));
m_status.SetPaneIcon(IDR_DATE,
AtlLoadIconImage(IDR_DATE, LR_DEFAULTCOLOR));
m_status.SetPaneIcon(IDR_TIME,
AtlLoadIconImage(IDR_TIME, LR_DEFAULTCOLOR));
// initialize date/time and start a 1 second timer
OnTimer(0, 0, 0, bHandled);
SetTimer(1, 1000);
return 0;
}
Workaround
SetPaneWidths()
is a workaround that solves a bug in the
CMultiPaneStatusBarCtrl::SetPanes()
method. The bug limits the
width of all panes after the default pane to a combined total of 100 pixels.
This workaround allows arbitrary pane widths.
void SetPaneWidths(int* arrWidths, int nPanes)
{
// find the size of the borders
int arrBorders[3];
m_status.GetBorders(arrBorders);
// calculate right edge of default pane (0)
arrWidths[0] += arrBorders[2];
for (int i = 1; i < nPanes; i++)
arrWidths[0] += arrWidths[i];
// calculate right edge of remaining panes (1 thru nPanes-1)
for (int j = 1; j < nPanes; j++)
arrWidths[j] += arrBorders[2] + arrWidths[j - 1];
// set the pane widths
m_status.SetParts(m_status.m_nPanes, arrWidths);
}
Timer Handler
Here is the code for the timer handler. You must also create a message map
entry for the WM_TIMER
message.
LRESULT OnTimer(UINT, WPARAM, LPARAM, BOOL&)
{
// get the current date and time
SYSTEMTIME st;
::GetLocalTime(&st);
CString str;
// Pane 1: Display the date
str.Format("%i/%i/%i", st.wMonth, st.wDay, st.wYear);
m_status.SetPaneText(IDR_DATE, str);
// Pane 2: Display the time
str.Format("%i:%02i", st.wHour, st.wMinute);
m_status.SetPaneText(IDR_TIME, str);
return 0;
}
Terms Of Use
The sample application available with this article is free for any purpose.
THIS SOFTWARE IS DISTRIBUTED AS-IS, WITHOUT WARRANTIES OF ANY KIND.