[SOLVED] Draw Alternate Lines Gray in TListBox

[zxandris]

I did search how to do this, must be using the wrong search term because oddly didn't find a way.

I want to draw the alternate lines Grey and the other lines White and account for highlighted line.  I have the following

Code: Pascal  [Select][+][-]

1. procedure TfrmDLGOptions.lbDictDrawItem(Control: TWinControl; Index: Integer;
2.   ARect: TRect; State: TOwnerDrawState);
3. var
4.   ListBox: TListBox;
5.   Canvs: TCanvas;
6. begin
7.   ListBox := Control as TListBox;
8.   Canvs := ListBox.Canvas;
9.   if Index mod 2 = 0 then
10.   begin
11.        Canvs.Brush.Color := clSilver;
12.        Canvs.FillRect(ARect);
13.        canvs.Pen.color := clWindowText;
14.   end else
15.   begin
16.        Canvs.Brush.Color := clWindow;
17.        Canvs.FillRect(ARect);
18.        canvs.Pen.color := clWindowText;
19.   end;
20.   if ListBox.ItemIndex = Index then
21.   begin
22.        Canvs.Brush.Color := clHighlight;
23.        canvs.FillRect(ARect);
24.        canvs.Pen.color := clHighlightText;
25.   end;
26.   Canvs.TextOut(ARect.Left, ARect.Top, ListBox.Items[Index]);
27. end;
28.  

It works - ish, when selecting a line it highlights it okay, then for some reason on the 'white' lines it will then leave the background as the highlight color and not clWindowText.

Any help would be gratefully appreciated, I just don't see why it's not working!  As I said I did do a search, my google-fu must not be that strong.

CJ

[Nicole]

you can try a
.....refresh;

for some of your items. Give it a try, which one makes sense.

[zxandris]

Okay, thanks for the replies guys, but I actually did some experimentation and the below code seems to work for what I wanted. (It also draws a little graphic but that was extra).  But it colors alternate lines an accounts for selected items (even multiple).

Code: Pascal  [Select][+][-]

1. procedure TfrmDLGOptions.lbDictDrawItem(Control: TWinControl; Index: Integer;
2.   ARect: TRect; State: TOwnerDrawState);
3. var
4.    ListBox: TListBox;
5.    Canvs: TCanvas;
6.    bmp  : TBitmap;
7. begin
8.       ListBox := Control as TListBox;
9.       Canvs := ListBox.Canvas;
10.       if ListBox.selected[Index] then
11.       begin
12.            Canvs.Brush.Color := clHighlight;
13.            canvs.Pen.color := clHighlightText;
14.            Canvs.Font.color := clHighlightText;
15.            canvs.FillRect(ARect);
16.       end else
17.       begin
18.            if Index mod 2 = 0 then
19.            begin
20.                 Canvs.Brush.Color := clGray;
21.                 canvs.Pen.color := clWhite;
22.                 canvs.Font.Color := clWhite;
23.                 Canvs.FillRect(ARect);
24.            end else
25.            begin
26.                 Canvs.Brush.Color := clWindow;
27.                 canvs.Pen.color := clWindowText;
28.                 canvs.Font.Color := clWindowText;
29.                 Canvs.FillRect(ARect);
30.            end;
31.       end;
32.       bmp := TBitmap.create;
33.       try
34.          ilDict_16px.GetBitmap(0, bmp);
35.          Canvs.Draw(ARect.Left, ARect.Top, bmp);
36.       finally
37.              bmp.free;
38.       end;
39.       Canvs.TextOut(ARect.Left + 18, ARect.Top, ListBox.Items[Index]);
40. end;
41.  

Now that works for me, but you have to set the listbox to owner draw fixed and there is no resizing on my form as it's an options dialog anyway.

I put this here in the hopes it helps other peeps.

CJ

[Bart]

The proper way is to check for (odSeleted in State) to examine wether an item is selected or not.

Bart