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Colin_Dawson

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How to add a glyph to a column on a TListView.

How do I add a Glyph to a Column on a TListView like windows explorer?  I want to do this to a TListview, preferably with some an API call.
I wish to add the Up/Down glyphs that you see in windows explorer when you sort a column.
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Russell Libby
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Colin_Dawson

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Close, but no cigar.  The image that I want is on the right hand side of the text.  Load Windows explorer and set the contents of a folder to "Details".  Now click on the filename header button.  You'll see an arrow pointing down.  Click again and the arrow will point up - and the list will be re-sorted.   I know how to make the list sort, so that's not a problem.   What I'm after is putting in the visual style, so that my tree view can behave more like the one in windows explorer.

The reason that I'm being so picky about this is that I want my Listview to be compatible with the Windows Themes in XP.
Ok, I've done a little digging about on the net, and found the windows message that controlls the headers.  The message is  HDM_SETITEM.   I can see that the Sort items look new with Version 6 of Comctrl32. I'm now looking at how to implement it.
OK, Getting closer still.

http://www.delphipages.com/tips/thread.cfm?ID=74

It doesn't mention that you need to add CommCtrl to your uses clause.    Now all I need to do is add the extra bit for the windows XP theme.
Getting even closer now.  Got the icon working with XP, here's my variation on the code.  Notice that I needed to declare a couple of new Constants, these are missing from Delphi's API headers.

  Procedure SetColumnImage(List: TListView; Column, Image: Integer; ShowImage: Boolean);
  Const
    HDF_SORTDOWN = $200;
    HDF_SORTUP = $400;
  var
   Align,hHeader: integer;
   HD: HD_ITEM;

  begin
   hHeader := SendMessage(List.Handle, LVM_GETHEADER, 0, 0);
   with HD do
   begin
       case List.Columns[Column].Alignment of
         taLeftJustify:  Align := HDF_LEFT;
         taCenter:       Align := HDF_CENTER;
         taRightJustify: Align := HDF_RIGHT;
       else
         Align := HDF_LEFT;
       end;

       mask := HDI_IMAGE or HDI_FORMAT;

       pszText := PChar(List.Columns[Column].Caption);

       if ShowImage then
         fmt := HDF_STRING or HDF_IMAGE or HDF_BITMAP_ON_RIGHT
       else
         fmt := HDF_STRING or Align;

       If Image = 0
       Then fmt := fmt or HDF_SORTDOWN
       Else fmt := fmt or HDF_SORTUP;

       iImage := Image;
   end;

   SendMessage(hHeader, HDM_SETITEM, Column, Integer(@HD));
  end;

Now for the icing on the cake, I need to get the column itself to highligh in the way that windows explorer does in Windows XP.
Having taken a little closer look I think it's only fair to ask about putting the shading onto the column as a seperate question.  Using the Columns.ImageIndex for the bitmap that I wanted was in the right direction for the correct solution, but as you can plainly see it's a hell of a long way short of the right answer.