Visual Studio MFC GUI Frequently Asked Questions

Below you will find a hodge-podge of notes from the instructor's experience (and frustration) with developing GUIs using the Microsoft Foundation Classes in Visual Studio. Since the Microsoft people seem to go out of their way to make GUI development complicated and cryptic herein is an attempt to blow away some of their smoke.

If your application is a Microsoft Foundation Classes project it is assumed that you have done the following: (1) In the Solution Explorer pane right click the project name and select Properties. (2) In the Properties dialog box that appears click General in the list on the left. (3) Click in the text area to the right of Character Set. (4) In the dropdown combo box select Not Set. This will allow you to use ordinary character array strings instead of Unicode strings. A number of the function examples given below will not compile if you have not done this.


This page is still under construction.


  1. How do I add a variable to a widget in a dialog box that can be used to access that widget in my code?
  2. How do I add an event handler to a widget in a dialog box?
  3. How do I handle clicks on the OK or Cancel button in a dialog box?
  4. How do I create and use a button in a dialog box?
  5. How do I create and use a check box in a dialog box?
  6. How do I create and use radio buttons in a dialog box?
  7. How do I create and use a text box (Edit Control) in a dialog box?
  8. How do I create and use a list box in a dialog box?
  9. How do I create and use a combo box in a dialog box?
  10. How do I set the font in a Static Text widget?
  11. How do I import a bitmap resource?




How do I add a variable to a widget in a dialog box that can be used to access that widget in my code?

    In the dialog resource editor right click the widget you want to add a variable to and select Add Variable from the popup menu. A dialog box will appear in which you can enter the variable name. Click OK and the variable will be added to your ProgramNameDlg.cpp file.

How do I add an event handler to a widget in a dialog box?

    In the dialog resource editor right click the widget you want to add an event handler to and select Add Event Handler from the popup menu. A dialog box will appear in which you can specify the message type (example: BN_CLICKED for a button), the Class to contain the function (usually your ProgramNameDlg.cpp file), and the handler name (example: OnBnClickedButton1). You will usually want to use the default message type and class but you may want to give the function a more meaningful name, like OnBnClickedRunSimButton instead of the more cryptic default name of OnBnClickedButton1

How do I handle clicks on the OK or Cancel button in a dialog box?

    In the dialog resource editor right click the OK or the Cancel buttons and select Add Event Handler from the popup menu. A function like the ones below will be created in your ProgramNameDlg.cpp file. Add your code to handle clicks on either of these buttons just before the call to the OnOK or OnCancel function. Note: in the initInstance function found in the ProgramName.cpp file there is a place where you will see comments like: "// Place code here to handle when the dialog is dismissed with OK/Cancel". Unfortunately at this point you will no longer be able access any of the dialog box widgets. If you need to do something like read text from an edit control after the OK or the Cancel buttons have been clicked you must do it in one of these functions. Note: if you dismiss the dialog box by clicking the X button on the right in the title bar it is the same as if you clicked the Cancel button.
    void CWidgetsTestDlg::OnBnClickedOk()
{
	// TODO: Add your control notification handler code here
	OnOK();
}

void CWidgetsTestDlg::OnBnClickedCancel()
{
	// TODO: Add your control notification handler code here
	OnCancel();
}

How do I create and use a button in a dialog box?

    In the dialog resource click the Toolbox tab and select Button from the list. Use the mouse to click and drag the size and location of the button. With the new text box selected you will see the properties listed. The image below indicates what the most important properties.
    Add an event handler to the button and place in the function the code you want executed when the user clicks the button.

    In the sample function calls below the variable m_DemoBtn is a CButton variable added to a button in an application: 
    m_DemoBtn.EnableWindow(true);               // Make the button active/editable

    
m_DemoBtn.EnableWindow(false);              // Make the button inactive/not editable

    
m_DemoBtn.ShowWindow(false);                // Make the button invisible

    
m_DemoBtn.ShowWindow(true);                 // Make the button visible
    And, why do all of these functions refer to a "Window" instead of a "Button"? Because Microsoft defines every widget in a dialog box as a subclass of CWnd. That is, a window. Go figure!

How do I create and use a check box in a dialog box?

    In the dialog resource click the Toolbox tab and select CheckBox from the list. Use the mouse to click and drag the size and location of the check box. The height of a check box in the dialog box is constant but the width of the area set for the check box determines how much of the associated text will be visible. With the new check box selected you will see the properties listed. The image below indicates what the most important properties.
    In the sample function calls below the variable m_DemoCB is a CButton variable added to a check box in an application. And yes, that is a CButton. There is no CCheckBox class: 
    bool isChecked = m_DemoCB.GetCheck();     // See if the check box is checked

    
m_DemoCB.SetCheck(true);                  // Set the checked state, true=checked

    
m_DemoCB.EnableWindow(true);              // Make the check box active/editable

    
m_DemoCB.EnableWindow(false);             // Make the check box inactive/not editable

    
m_DemoCB.ShowWindow(false);               // Make the check box invisible

    
m_DemoCB.ShowWindow(true);                // Make the check box visible
    And, why do all of these functions refer to a "Window" instead of a "Check Box"? Because Microsoft defines every widget in a dialog box as a subclass of CWnd. That is, a window. Go figure!

How do I create and use radio buttons in a dialog box?

    This section is still under construction.

How do I create and use a text box (Edit Control) in a dialog box?

    Visual Studio calls a text box an Edit control. In the dialog resource click the Toolbox tab and select Edit Control from the list. Use the mouse to click and drag the size and location of the text box. With the new text box selected you will see the properties listed. The image below indicates what the most important properties.
    In the sample function calls below the variable m_DemoEC is a CEdit variable added to an Edit Control in an application: 
    m_DemoEC.SetWindowText("Just Testing");     // Set the text using a string constant
char line[32];                              // Set the text using a character array
strcpy(line, "Just Testing");
m_DemoEC.SetWindowText(line);

    
char line[32];                             // Get the text in a character array
m_DemoEC.GetWindowText(line, 31);          // Arg1=char array, Arg2=Max characters to copy

    
m_DemoEC.EnableWindow(true);               // Make the edit control active/editable

    
m_DemoEC.EnableWindow(false);              // Make the edit control inactive/not editable

    
m_DemoEC.ShowWindow(false);                // Make the edit control invisible

    
m_DemoEC.ShowWindow(true);                 // Make the edit control visible
    And, why do all of these functions refer to a "Window" instead of an "Edit Control" or "Text Box"? Because Microsoft defines every widget in a dialog box as a subclass of CWnd. That is, a window. Go figure!

How do I create and use a list box in a dialog box?

    In the dialog resource click the Toolbox tab and select List Box from the list. Use the mouse to click and drag the size and location of the list box. With the new list box selected you will see the properties listed. The image below indicates what the most important properties.
    In the sample function calls below the variable m_DemoLB is a CListBox variable added to a List Box in an application: 
    m_DemoLB.AddString("Just Testing");     // Add a string to a list box
char line[32];                          // Add a string using a char array
strcpy(line, "Just Testing");
m_DemoLB.AddString(line);

    
m_DemoLB.GetCurSel();                   // Get the index of the selected item

    
char line[32];                          // Get the text for a string in a character array
m_DemoLB.GetWindowText(index, line);    // Arg1=index of item starting with 0, Arg2=char array

    
m_DemoLB.ResetContent();                // Remove all strings from the list box

    
m_DemoLB.EnableWindow(true);            // Make the list box active/items selectable

    
m_DemoLB.EnableWindow(false);           // Make the list box inactive/items not selectable

    
m_DemoLB.ShowWindow(false);             // Make the list box invisible

    
m_DemoLB.ShowWindow(true);              // Make the list box visible

    And, why do all of these functions refer to a "Window" instead of a "List Box"? Because Microsoft defines every widget in a dialog box as a subclass of CWnd. That is, a window. Go figure!

How do I create and use a combo box in a dialog box?

    This section is still under construction.

How do I set the font in a Static Text widget?

    When you create a Static Text widget in a GUI it will be given the ID of IDC_STATIC by default. This goes for all static widgets whether static text or things like group boxes. You wil need to change the ID property of the Static Text widget. In the code sample below this was changed to IDC_STATIC_DF where "DF" stood for a Static Text widget with the text set to "Data File". Put this code in the OnInitDialog() function in your programnameDlg.cpp file. 
    	// Set font for static text items
	CFont font;
	font.CreatePointFont(18, "Arial", NULL); // 18 point font

	CWnd* pStatic = GetDlgItem(IDC_STATIC_DF);
	pStatic->SetFont(&font);

How do I import a bitmap resource?

  1. From the Solution Explorer pane right click the Resource folder and select "Add->Resource" from the popup menu, or right click in the Resource View and select "Add Resource" from the popup menu.
  2. In the dialog box shown below select "Bitmap" then click the Import button.
  3. In the open file dialog box that appears locate the .BMP file you want to import. The bitmap will be added to the resources. Note the ID/Name given to the bitmap so you can add it where you want it.
  4. If you want to display the bitmap image in a Picture Control, then add one to your dialog box in the Resource Editor. In the properties list for the Picture Control set the Type property to "Bitmap". Click in the space to the right of the Image property and select the bitmap from the dropdown combobox. If needed resize the Picture Control to the correct size to hold the image.






This page is still under construction.