How to specify negative range for slider control?

Question

I am developing a MFC based SDI VC++ application. In my application I need to specify negative range value for my Slider Control. The minimum range for the Slider is -40 and maximum range is 255. I tried it using SetRange function. But it is not working. How can I set this range in the slider?Please Help..

My code for the Slider is as follows: Slider is declared as

CSliderCtrl m_ctrlECTSlider;

OnInitialUpdate function contains

m_ctrlECTSlider.SetRangeMin(-40);
int iValMin = m_ctrlECTSlider.GetRangeMin();
m_ctrlECTSlider.SetRangeMax(255);
int iValMax = m_ctrlECTSlider.GetRangeMax();

m_ctrlECTSlider.SetPos(0);
SetDlgItemInt( IDC_ECT_VALUE, m_ctrlECTSlider.GetPos(), FALSE);
SetDlgItemInt( IDC_MIN_ECT, iValMin, FALSE);
SetDlgItemInt( IDC_MAX_ECT, iValMax, FALSE);

OnBnClickedSet function contains

int nMin = GetDlgItemInt(IDC_MIN_ECT, 0, FALSE);
int nMax = GetDlgItemInt(IDC_MAX_ECT, 0, FALSE);

m_ctrlECTSlider.SetRange(nMin, nMax);
m_ctrlECTSlider.SetPos(nMin);

int pos = m_ctrlECTSlider.GetPos();
SetDlgItemInt(IDC_ECT_VALUE, m_ctrlECTSlider.GetPos(), FALSE);      
m_ctrlECTSlider.RedrawWindow();

Here the problem is the value returned during debugg is all correct. But when it comes to UI on running the min value is 429496 and not -40 in the edit box..Why is it so..I am developing SDI application using CFormView class..

Thanks in advance.

score 2 · Answer 1 · answered Oct 09 '13 at 02:31

Your minimum value is '-40'which is signed integer and You are treating as unsigned integer as last parameter of 'SetDlgItemInt' and 'GetDlgItemInt' method is 'FALSE'. That's why you are getting wrong value in place of '-40'. Use following code for correct behavior.

//For setting value

SetDlgItemInt( IDC_ECT_VALUE, m_ctrlECTSlider.GetPos(), TRUE);

SetDlgItemInt( IDC_MIN_ECT, iValMin, TRUE);

SetDlgItemInt( IDC_MAX_ECT, iValMax, TRUE);

// For getting value use as follows

int nMin = GetDlgItemInt(IDC_MIN_ECT, 0, TRUE);

int nMax = GetDlgItemInt(IDC_MAX_ECT, 0, TRUE);

You can use this link http://msdn.microsoft.com/en-us/library/c7t43w0s%28v=vs.90%29.aspx for more details.

Rohit Vipin Mathews · Answer 2 · 2013-10-07T07:53:05.503

0

Call void SetRangeMin(int nMin, BOOL bRedraw = FALSE); as :

m_Slider.SetRangeMin(0);

And call void SetRangeMax(int nMax, BOOL bRedraw = FALSE); as :

m_Slider.SetRangeMax(50);

Also before calling GetPos() verify that the slider is in the range by calling the VerifyPos()

This is good tutorial on MFC Sliders - Windows Controls: Sliders (Track Bars).

edited Oct 07 '13 at 07:53

answered Oct 07 '13 at 06:38

Rohit Vipin Mathews

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Range accepts values < 0, unless you have tied it up to something else. Maybe posting the relevant part of code might help us to sort out the problem. – Rohit Vipin Mathews Oct 07 '13 at 06:50
These pieces of code would have been better of with the question. Also with the declaration of Slider. – Rohit Vipin Mathews Oct 07 '13 at 07:10
Will you please update the question with code for declaration, usage, etc of slide? – Rohit Vipin Mathews Oct 07 '13 at 07:25
Is your value of `nMin` and `nMax` in `OnBnClickedSet` function correct? – Rohit Vipin Mathews Oct 07 '13 at 07:54

How to specify negative range for slider control?

2 Answers2