Tutorial 3

Slider Control Variables

1. Open the Toolbox
2. Drag a Static Text to the dialog window, rename
   1. Caption to "Vertical Bar"
3. Create a Text Label with
   1. ID to "IDC_V_SLIDER_ECHO"
   2. Caption to "0"
   3. Client Edge to True
4. Add an output Control Variable to the Text Label, with
   1. Access to private
   2. Category to Value
   3. Variable Name to "m_VSliderEcho"
   4. Variable Type to CString

1. Drag a Slider Control to the dialog window, inside the Properties window, change
   1. ID to "IDC_V_SLIDER_BAR"
   2. Orientation to "Vertical"
2. Add an output Control Variable to the vertical slider, with
   1. Category to Control
   2. Variable Name to "m_VSliderBar"
   3. Variable Type to CSliderCtrl

1. Select the main application window and bring up theProperties window,
   1. Select the Messages button
   2. Scroll down to "WM_VSCROLL"
   3. Left-Mouse-Button click in the drop-down menu and click "<Add> OnVScroll"
   
   Figure 3.1 - Message Properties
2. In 'TutorialDlg.cpp', initialize the slider inside the OnInitDialog() function:
   BOOL CTutorialDlg::OnInitDialog(){
      ...
      m_VSliderBar.SetRange(0, 100, TRUE);
      m_VSliderBar.SetPos(0);
      m_VSliderEcho.Format("%d", 0);
   }
3. Now inside the function code block for OnVScroll(...), add the following code:
   if (pScrollBar == (CScrollBar *) &m_VSliderBar)
   {
      int value = m_VSliderBar.GetPos();
      m_VSliderEcho.Format("%d", value);
      UpdateData(FALSE);
   }else{
     CDialog::OnVScroll(nSBCode, nPos, pScrollBar);
   }

1. Repeat the steps for Adding Vertical Slider Bar with the following changes
2. Inside the Slider Control Properties window, change
   1. ID to "IDC_H_SLIDER_BAR"
   2. Orientation to "Horizontal"
3. Add an output Control Variable to the horizontal slider, with
   1. Category to Control
   2. Variable Name to "m_HSliderBar"
   3. Variable Type to CSliderCtrl
4. Create a Service Routine as "WM_HSCROLL" and click "<Add> OnHScroll"
5. In 'TutorialDlg.cpp', initialize the slider inside the OnInitDialog() function:
   BOOL CTutorialDlg::OnInitDialog(){
      ...
      m_HSliderBar.SetRange(0, 100, TRUE);
      m_HSliderBar.SetPos(0);
      m_HSliderEcho.Format("%d", 0);
   }
6. Now inside the function code block for OnHScroll(...), add the following code:
   if (pScrollBar == (CScrollBar *) &m_HSliderBar)
   {
      int value = m_HSliderBar.GetPos();
      m_HSliderEcho.Format("%d", value);
      UpdateData(FALSE);
   }else{
     CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
   }

• In the Visual Studio project window, click
  1. Build >> Build Solution
  2. Debug >> Start to run
  
  Figure 3.2 - Application Window