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Super Combo Box - combo-box with columns, colors and more

, 12 Apr 2004
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A CComboBox derived class that contains colors, columns, bold fonts, and images.

Sample Image - SuperComboBox.jpg

Motivation

I was looking around for a CComboBox derived class that would combine some features I needed - multiple columns, colors, icons and more.

Some of these features are found in other controls, but not under one roof, so I've decided to put them all together, in a simple way that will also have room for future growth.

Introduction

This class is a CComboBox derived class that enhances its functionalities:

  1. Multi-columns, when each column's width is controllable.
  2. An optional image-list can be supplied and an image can be set to the left of each row.
  3. Color of each row can be set.
  4. Each row can be bolded.

The code is based on Alex Hazanov's ComboBox Bold, just took it a bit further... thanks Alex.

Implementation

The WIN32/MFC implementation of a CComboBox provides DWORD element - Item Data, accessed via the SetItemData() and GetItemData() for storing extra information for each item of the combo-box. I used this member to store all the extra data I need to know of each row. This data is stored in the nested ItemData structure which is constructed for each element in the combo-box:

struct ItemData
{
    ItemData() : crTextColor(RGB(0,0,0)),nImageIndex(-1),bBold(FALSE),dwItemData(0){}
    COLORREF crTextColor;                // Row's color.
    int nImageIndex;                     // Index of the image in the image-list.
    std::map<int,CString> mapStrings;    // Map of string of all columns.
    BOOL bBold;                          // TRUE if the row is bolded.
    DWORD dwItemData;                    // Giving back the Item Data to the user...
};

All the new interface functions are added for setting the extra attributes of the combo-box by modifying the ItemData structure, and invalidating the combo-box.

For not loosing the original functionality of the CComboBox's SetItemData() and GetItemData(), the ItemData contains a DWORD member as well, that is accessed via the CComboBoxSuper.

A vector of all columns' width stores the width of all columns, and the size of this vector is also the number of columns in the combo-box.

Most of the job is done in the DrawItem function. This function is called for each item's drawing, and reads its item data, and draw the item accordingly.

Another function implemented is the virtual OnDeleteItem, which is called each time an element is removed from the combo-box, and deletes the ItemData of the element deleted from the combo-box, including ResetContent().

Usage

To use in a dialog - add a normal combo to the dialog, and replace the class from CComboBox to CComboBoxSuper.

Make sure to change the combo style to Owner Drawn Fixed and Has String in the resource editor, or by code.

To create on the fly - call create of the CComboBoxSuper object, and don't forget the styles.

Note: I always used the combo as a drop-list, in dropdown you get the first column's text only for editing.

During init function or all around the code, the following functions can be called:

  1. Setting to column number, and column width:

    void SetColumnCount(int nColumnCount); 
    /** Sets the number of columns to use - 
    new columns are inserted at default width. */
    
    void SetColumnWidth(int nColumnIndex, int nWidth); 
    /** Sets the width of a specific column. */
    m_ctrlSuperCombo.SetColumnCount(5);
    
    m_ctrlSuperCombo.SetColumnWidth(0, 100);
  2. Adding rows the combo (normal CComboBox function):

    m_ctrlSuperCombo.AddString("Row 1");
    m_ctrlSuperCombo.AddString("Row 2");
  3. Adding sub-item strings:

    void SetItemText(int nItemIndex, int nColumn, CString str); 
    /** Sets an item or sub-item text. */
    m_ctrlSuperCombo.SetItemText(1,1,"Yes");
    
    m_ctrlSuperCombo.SetItemText(2,1,"No");
  4. Setting a row color:

    void SetItemColor(int nItemIndex, COLORREF rcTextColor); 
    /** Sets a row's color. */
    m_ctrlSuperCombo.SetItemColor(1, RGB(255,0,0));
    
    m_ctrlSuperCombo.SetItemColor(2, RGB(0,128,0));
  5. Setting a row to bold (default is not bolded for all added rows):

    void SetItemBold(int nItemIndex, BOOL bBold = TRUE); 
    /** Set a specific row to bold. */
    m_ctrlSuperCombo.SetItemBold(2);
    
    m_ctrlSuperCombo.SetItemBold(1, FALSE);
  6. Setting images:

    void SetImageList(CImageList* pImageList); 
    /** Sets the image list to use - will be show 
    only if SetUseImage is called. */
    
    void SetItemImage(int nItemIndex, int nImageIndex); 
    /** Sets a row's image index. */
    
    void SetUseImage(BOOL bUseImage=TRUE) 
    /** Sets to TRUE for using the image list, 
    of FALSE to disable the use of the image-list. */
    m_ctrlSuperCombo.SetImageList(&m_ImageList);
    
    m_ctrlSuperCombo.SetUseImage();
    
    m_ctrlSuperCombo.SetItemImage(1, 1);

History

  • 20-03-2004 : Version 1.0 - First release.
  • 03-04-2004 : Change in documentations according to readers' requests.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

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About the Author

ronhash
Web Developer
United States United States
No Biography provided

Comments and Discussions

 
QuestionCombo-box's dropdown button color? Pinmemberddas-edEN24-Jul-08 0:36 

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