Author: Jonas Bilinkevicius

How to change the color of a specific subitem in a TListView.

Answer:

To change the color of a specific SubItem in a TListView all you have to do is to 
put some code in the OnCustomDrawSubItems event of the TListView. Your probably 
thinking of putting the OwnerDraw property of the ListView to True...
don't do this, yes I know normally it should be set to True, but in case of a 
TListView this is not the case...a bug somewhere in Delphi. Unlike the OnCustomDraw 
the OnCustomDrawSubItems event is sent no matter the state of the OwnerDraw 
property. 

The OnCustomDrawSubItems is fired prior to drawing the SubItem on the TListView.
To alter the default drawing process at other stages (e.g. after the SubItem is 
drawn,... .), you must use the OnAdvancedCustomDrawSubItem event.
You can put code here to change the appeance of the SubItems, the ViewStyle of the 
TListView must be set to vsReport in order for this to function correctly.
Then you can use the canvas of the ListView as a drawing surface.

Let's say you want the font color of a SubItem to turn red whenever it's below is 
negative then put the following code in the OnCustomDrawSubItems event:

1   
2   procedure TForm1.ListViewCustomDrawSubItem(
3     Sender: TCustomListView; Item: TListItem; SubItem: Integer;
4     State: TCustomDrawState; var DefaultDraw: Boolean);
5   begin
6     //Check if the value of the third column is negative,
7     //if so change it's font color to Red (clRed).
8     if SubItem = 3 then
9     try
10      if StrToInt(Item.SubItems.Strings[SubItem - 1]) < 0 then
11        Sender.Canvas.Font.Color := clRed;
12    except
13      on EConvertError do
14        next;
15    end;
16  end;



Used Parameters:

Sender : Specifies the ListView that owns the SubItems

Item  : Is the current Item being drawn

SubItem: Index of the SubItem of the ListItem (Item) in its SubItems property

State  : Indicates various attributes that affect the way the SubItem is drawn

DefaultDraw: Set it to False to prevent the ListView from adding the SubItem's text 
after the event handler exits.


Tested with Delphi 6 Professional on Windows 2000 Professional.