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Black listBox with white items ...

Posted on 1997-11-18
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Last Modified: 2013-11-20
I'd like to change the default colors of a CListBox in a tab control in order to draw white items on a black background.
I know that the DRAWITEMSTRUCT structure can probably be used, but I don't know exactly the way to handle it.
I hope someone can send me the code to perform this task.
Many thanks in advance.

vencese
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Question by:vencese
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4 Comments
 
LVL 7

Accepted Solution

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galkin earned 440 total points
ID: 1310200
You must handle WM_DRAWITEM and WM_MEASUREITEM(if you list box has LBS_OWNERDRAWVARIABLE  style) messages in your dialog box. If you add message handlers for these messages your will get OnDrawItem( int nIDCtl, LPDRAWITEMSTRUCT lpDrawItemStruct ) and afx_msg void OnMeasureItem( int nIDCtl, LPMEASUREITEMSTRUCT lpMeasureItemStruct ). First parameter in this function determins what control sends message, so if it is ODT_LISTBOX message is sent by list box. DRAWITEMSTRUCT structure passed as second parameter to OnDrawItem contains all neccessary information including handle of device context, list box item bounding rectangle, so you can draw using colors and fonts you need.
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Author Comment

by:vencese
ID: 1310201
I like your answer, but I have problems (I'm a beginner with MFC).
Can you send me the code to perform this task?
(I increased points to 200 and I'll grade you A)
Thanks in advance!

vencese

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LVL 7

Expert Comment

by:galkin
ID: 1310202
If you new to MFC I suggest you more simple solution. I derived class from CListBox and overwrote its DrawItem and MeasureItem functions( you can also do this instead of overwriting OnDrawItem and OnMeasureItem in parent dialog) and this is its implementation

class COwnerDrawListBox : public CListBox

{ public:
// Operations

// Implementation
      virtual void DrawItem(LPDRAWITEMSTRUCT lpDIS);
      virtual void MeasureItem(LPMEASUREITEMSTRUCT lpMeasureItemStruct);
};

void COwnerDrawListBox::MeasureItem(LPMEASUREITEMSTRUCT lpMeasureItemStruct)

{

    LOGFONT LogFont;
    GetParent()->GetFont()->GetLogFont( &LogFont );
    int nHeight= abs( LogFont.lfHeight ) + 2;
 
  lpMeasureItemStruct->itemHeight = nHeight;
}

void COwnerDrawListBox::DrawItem(LPDRAWITEMSTRUCT lpDIS)

{
   CDC* pDC = CDC::FromHandle(lpDIS->hDC);
//--------- Order number of the curretn string
  int itemNumber = (int)lpDIS->itemData;  


//--------------- Now we set color of selected item
  COLORREF bkColor, textColor;
  if ( !(lpDIS->itemState & ODS_SELECTED) )  
// The item is not selected
  { bkColor =   pDC->SetBkColor( RGB( 255, 255, 255 ) );
    textColor = pDC->SetTextColor( RGB( 0, 0, 0 ) );
  }
  else  // Selected item
  { bkColor =   pDC->SetBkColor( RGB( 0, 0, 128 ) );
    textColor = pDC->SetTextColor( RGB( 255, 255, 0 ) );
  }
 
  CString rString;
  GetText(itemNumber , rString );

  pDC->ExtTextOut( lpDIS->rcItem.left, lpDIS->rcItem.top, ETO_CLIPPED | ETO_OPAQUE, &lpDIS->rcItem,
                   rString, rString.GetLength() + 1, NULL );
//--------- Restore base settings
  pDC->SetTextColor( textColor);
  pDC->SetBkColor( bkColor );
}

Now if you add list box to your document template use class wizard to add to it mmber variable associated with this list box. Class Wizard will add member variable of type CListBox, so change it to COwnerDrawListBox.
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Author Comment

by:vencese
ID: 1310203
I tried the way you suggested, but at runtime I got an error:
"Debug Assertion Failed
 file strcore.cpp, line 499:
 LPSTR CString::GetBufferSetLength(int nNewLength)
 { ASSERT (nNewLength >= 0);
   ....
 }"

The program stops at the line: GetText(itemNumber, rString);
with nNewLength=-1.

Have I to define a DRAWITEMSTRUCT and call DrawItem(...) to add
items to the list box?
Can I add items to the list box with addString(...)?

Many thanks for your time!

vencese

0

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