i have made the slider control in c++ using MFC. there is my code.
void CImageAnalyserDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
if(nSBCode == SB_THUMBPOSITION)
{
slidervalue.Format(_T("%d"), nPos);
UpdateData(false);
}
else
{
CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
}
}
every thing is done, i just wanna know where should i write the implementaion of slider control, i mean where should i write this
if(slidervalue="10")
{
//do something
}
Why would you want to put the slider position into a string and compare it at some other place in your code?
In the OnHScroll handler, you already got the slider position. Do whatever you want to do in that function, or call some other function from the handler.
You can add an integer variable 'slidervalue' to your slider and set its max and min values to 100 and 0 respectively. Instead of reading the nPos parameter you can read this variable easily.
void CImageAnalyserDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
UpdateData(TRUE);
if(slidervalue==10)
{
//do something
}
}
Hope this helps!
Related
I am writing an MFC application which uses the CSliderCtrl class to control a slider. I have the ON_WM_HSCROLL() message in my message map, but this arises with the problem that this disables the default window scrollbar that appears at the bottom of the view when the windows is too small. Manipulating it does nothing to the window. What do I have to do in order to preserve functionality in that scrollbar?
Currently, my OnHScroll() function simply looks like:
void myClass::OnHScroll(UINT nSHCode, UINT nPos, CScrollBar* pScrollBar)
{
if (*pScrollBar == mySlider)
{
// do stuff
}
}
You still need to call the default handler defined in base/parent class: CDialog::OnHScroll(nSBCode, nPos, pScrollBar); in case of dialog window or CFormView::OnHScroll(nSBCode, nPos, pScrollBar); in case of SDI/MDI view.
So your handler will look like this:
void myClass::OnHScroll(UINT nSHCode, UINT nPos, CScrollBar* pScrollBar)
{
if (*pScrollBar == mySlider)
{
// do stuff
}
CDialog::OnHScroll(nSBCode, nPos, pScrollBar)
}
I have a CSliderCtrl and I set it up like this:
m_sliderServerTimeout.SetRange(10, 600);
I have an event handler:
void COtherSettingsEmailInfoPage::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
if (pScrollBar->GetDlgCtrlID() == IDC_SLIDER)
{
UpdateServerTimeoutDescription();
}
CMFCPropertyPage::OnHScroll(nSBCode, nPos, pScrollBar);
}
Works fine but I want the slider to move in 10 unit intervals.
How?
Update
I tried using SetLineSize and SetPageSize but they don't apply to when the slider is dragged.
Just use the slider metric you want. So just use 1/10th in the range of the values.
m_sliderServerTimeout.SetRange(1, 60);
And finally when you want to use the data, just scale the set value by *10.
There doesn't seem to be a Trackbar Control Message to handle this.
One option is to override OnHScroll manually. Watch for SB_THUMBTRACK message and save the value for nPos. When SB_ENDSCROLL is called, use CSliderCtrl::SetPos to set to the desired value. Example:
void CMyDialog::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
static int track = -1;
if(nSBCode == SB_THUMBTRACK)
track = nPos;
if(nSBCode == SB_ENDSCROLL && track >= 0)
{
m_sliderServerTimeout.SetPos(10 * int(track / 10));
track = -1;
}
}
I am new to C++ and seem to be stuck. I basically have a Window and a Button inside it(also created with CreateWindow()). I want to have the button moving on the X axis, I tried doing with MoveWindow() but I cant seem to do the animation effect. I tried writing it in a for loop but I have not found what to use to delay the animation. I would appreciate any help.
for (int i = 0; i < 50; i++) {
MoveWindow(g_MovingDot, i, ButtonTop, ButtonWidth, ButtonHeight, true);
//Delay it somehow
}
Would this be the right way to do it? I just want the button to move slowly to the right.
Use the SetTimer function to be notified when the time-out value is elapse.
Implement a function with the signature
VOID (CALLBACK* TIMERPROC)(HWND, UINT, UINT_PTR, DWORD);
and pass a function pointer to SetTimer, to register a callback procedure .
Use a global control variable, which controls the animation of the window. In the following code snippet the control variable is named i_g.
When the timer is elapsed, then the callback procedure is called. Increment the control variable, slightly move the dialog element and restart the timer, until the final position is reached.
The animation time is controlled by the number of animation steps and the time interval of a single step.
int g_i=0;
void CALLBACK BtnTimer( HWND hwnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime )
{
KillTimer( hwnd, idEvent );
if ( g_i < 50 )
{
MoveWindow(g_MovingDot, i, ButtonTop, ButtonWidth, ButtonHeight, true);
g_i ++;
SetTimer( hwnd, idEvent, 100 /* time milliseconds */, &BtnTimer );
}
}
void AnimateButton( HWND hDialogWnd //* HWND from Dialog */)
{
g_i = 0;
SetTimer( hDialogWnd, 0 /* idEvent */, 100 /* time milliseconds */, &BtnTimer );
}
I have a CEdit derived control that displays the string "N/A" when the undelying data is null. I recently added code to empty the control(SetWindowText("");) when it gains focus and set if back to "N/A"(SetWindowText("N/A")) when the focus is lost if the user left the control empty.
The only problem is that setting the window text to "" or "N/A" triggers EN_CHANGE, so my dialog thinks that the data has changed.
How can I avoid EN_CHANGE from being fired when calling SetWindowText (WM_SETTEXT)?
NOTES
-I know I can set the edit control to Multiline=TRUE but that's not accpectable for me.
-My application is MBCS so I can't use SetCueBanner
-I want an elegant solution. Setting the parent window to NULL temporarily is not an elegant solution.
EDIT:
-I want the solution to be in my custom control, not in each dialog
Thanks
The way I've done it before (last time, like 20 minutes ago; in fact I was thinking about asking the same question), is by setting a flag. When I'm about to set the text programatically, I set the flag, and I check it in the EN_CHANGE handler:
void CMyDialog::MyFunction()
{
setEditTextProgramatically = true;
c_Edit.SetWindowText(_T("Whatever"));
setEditTextProgramatically = false;
}
void CMyDialog::OnEnChangeEdit()
{
if (!setEditTextProgramatically)
{
// Do whatever you need to do
}
}
I know it's not the most elegant solution, but it works, at least for me.
I've always wondered why MFC doesn't provide a way to distinguish user input from changes from code, but that's the way it is.
I finally found a suitable solution to my problem.
First, I added a flag to my derived control's header file and I initialized it to false in the constructor
bool m_bNoEnChange;
I overrode the OnChildNotify in my derived control's header file and in the implementation, I checked for the WM_COMMAND message with the EN_CHANGE parameter. I then returned TRUE to prevent the message from being sent to the parent(dialog/page)
virtual BOOL OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pLResult);
BOOL CADEdit::OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pLResult)
{
if(message == WM_COMMAND && HIWORD(wParam) == EN_CHANGE)
{
//If the flag is set, don't send the message to the parent window
if(m_bNoEnChange)
return TRUE;
}
return CEdit::OnChildNotify(message, wParam, lParam, pLResult);
}
Finally, when the control gains and loses focus, I wrapped the problematic SetWindowText with my flag
m_bNoEnChange = true;
SetWindowText(_T(""));
m_bNoEnChange = false;
This solution is the best in my case because I don't have to modify each dialog.
You could disable (EnableWindow(FALSE) or send WM_ENABLE with param FALSE) the control prior to sending WM_SETTEXT then enabling it afterwards. That should prevent the EN_CHANGE
There is probably some more elegant method :p
The below code uses a C++ 11 feature, but that can easily be changed.
HEADER
// CEditOptionalNotify.h
//
// CEdit derived class allowing the control's text value to be
// set without (optionally) causing EN_CHANGE processing.
//
#pragma once
class CEditOptionalNotify : public CEdit
{
//DECLARE_DYNAMIC(CEditOptionalNotify)
// Enable use of RUNTIME_CLASS macro and CObject::IsKindOf()
public:
CEditOptionalNotify();
virtual ~CEditOptionalNotify();
enum class PerformOnChangeProcessing { No, Yes };
void vSetText(const TCHAR* pText, PerformOnChangeProcessing e);
protected:
afx_msg BOOL bConsiderEnChangeAsHandled();
bool m_bChangeNotificationsEnabled;
DECLARE_MESSAGE_MAP()
};
IMPLEMENTATION
// EditOptionalNotify.cpp : implementation file
//
#include "stdafx.h"
#include <EditOptionalNotify.h>
//IMPLEMENT_DYNAMIC(CEditOptionalNotify, CEdit)
CEditOptionalNotify::CEditOptionalNotify() :
m_bChangeNotificationsEnabled(true)
{
}
CEditOptionalNotify::~CEditOptionalNotify()
{
}
BEGIN_MESSAGE_MAP(CEditOptionalNotify, CEdit)
ON_CONTROL_REFLECT_EX(EN_CHANGE, bConsiderEnChangeAsHandled)
END_MESSAGE_MAP()
BOOL CEditOptionalNotify::bConsiderEnChangeAsHandled()
{
return (m_bChangeNotificationsEnabled ? FALSE : TRUE);
}
void CEditOptionalNotify::vSetText(const TCHAR* pText, PerformOnChangeProcessing e)
{
bool bChangeNotificationsDesired = (PerformOnChangeProcessing::No == e ? false : true);
if (bChangeNotificationsDesired != m_bChangeNotificationsEnabled)
{
m_bChangeNotificationsEnabled = bChangeNotificationsDesired;
CEdit::SetWindowText(pText);
m_bChangeNotificationsEnabled = (bChangeNotificationsDesired ? false : true);
}
else
CEdit::SetWindowText(pText);
}
LRESULT CMainDlg::OnEnUpdateEditID(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/)
{
//using static variable
static bool isCodeChangeText = false;
if(isCodeChangeText)
return 0;
……//Deal Window Text
if(old == new)
return 0;
int nSel = m_editPID.GetSel();//record cursor pos
isCodeChangeText = true;
m_editID.SetWindowText(new);
m_editID.SetSel(nSel);
isCodeChangeText = false;
return 0;
}
In case somebody else finds this discussion...
As Steven wrote UpdateData does not cause an EN_CHANGE being sent.
Under the hood MFC calls AfxSetWindowText with which one can specify one hwnd.
(I'm using VS++2005)
I put edit box control (with ID - ID_edit_box) on my dialog, and associate (with handler wizard) two varibles for it: control (c_editbox) and value (v_editbox) variable. Also I associate handler function OnEnChangeedit_box with that edit box control. Suppose that we may enter just one digit in edit box, and that digit can be 0 or 1. If we enter some other value - what I want is that content of that edit box is automaticaly cleared, so user can't see that he type anything (in other words user can not enter anything except 0/1 in edit box). I do that check in onEnChangeedit_box function. Here is the code:
void CSDRDlg::OnEnChangeedit_box()
{
CWnd* pWnd;
CString edit_box_temp;
pWnd = GetDlgItem(ID_edit_box);
pWnd->GetWindowText(edit_box_temp);
if ((edit_box_temp == "0" || edit_box_temp == "1")
{...do something - i.e. setfocus on some other edit box }
else
{
pWnd->SetWindowText(""); // clear the content of edit box
//... any other statement below will not be executed because the
//above line cause again call of this function
}
}
I debug and discover that line: pWnd->SetWindowText(""); cause an infinite loop because we change control content in this function which triggers again her call.
But I change above code like this:
void CSDRDlg::OnEnChangeedit_box()
{
UpdateData(TRUE);
if ((v_editbox == "0" || v_editbox== "1")
{...do something - i.e. setfocus on some other edit box }
else
{
v_editbox = "";
UpdateData(FALSE);
}
}
and that works what I want but can someone explain to me why when we call
v_editbox = "";
UpdateData(FALSE);
that doesn't cause an infinite loop.
Why don't you Set Min/Max value to 0/1 or Set Value Type as bool when you Add Variable for your EditBox
You should probably do this by subclassing CEdit and filter out invalid characters. eg:
class CSDREdit public CEdit
{
afx_msg void OnChar(UINT nChar, UINT nRepCnt, UINT nFlags);
DECLARE_MESSAGE_MAP()
};
BEGIN_MESSAGE_MAP(CSDREdit, CEdit)
ON_WM_CHAR()
END_MESSAGE_MAP()
void CSDREdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags)
{
if (nChar != _T('0') && nChar != _T('1'))
return;
CEdit::OnChar(nChar, nRepCnt, nFlags);
}