TListView.OnDrawItem

[WojTec]

I wanted make list with recent files. I also wanted make grey these items, that match file not exists (click File-->Reopen-->Properties in Delphi to see what I want to do). This is what I have:

Delphi-Quellcode:

begin
  with lvRecentFiles, lvRecentFiles.Canvas do
  begin
    if FileExists(Item.Caption) then
      Pen.Color := clBlack
    else
      Pen.Color := clGrayText
    ;

    TextOut(Rect.Left + 2, Rect.Top + 2, Item.Caption);
  end;
end;

I want just grey text if file not exists. Any help with this? :(

[mkinzler]

Delphi-Quellcode:

if FileExists(Item.Caption) then
      Font.Color := clBlack
    else
      Font.Color := clGrayText;

[WojTec]

Oh, why I didn't think about this :D

Delphi-Quellcode:

begin
  with lvRecentFiles, lvRecentFiles.Canvas do
  begin
    if FileExists(Item.Caption) then
      Font.Color := clBlack
    else
      Font.Color := clGrayText
    ;

    //TextOut(Rect.Left + 2, Rect.Top + 2, Item.Caption);

    R := Classes.Rect(Rect.Left + 6, Rect.Top + 3, Rect.Right, Rect.Bottom - 2);
    S := Item.Caption;
    TextRect(R, S, [tfEndEllipsis]);
  end;
end;

There is grey, but can't be selected as when OwnerDraw is False (in system style). In Delphi can be. Any idea?

[mkinzler]

You have to evaluate the state

[Luckie]

The item gets selected, but you don't see it because it is your responsiblity to give the user visual feedback if you draw the items yourself.

[WojTec]

So, how I can draw it in current Windows's style?

[Luckie]

Markus gave you the answer.

[WojTec]

Yes, but how about in current system style. For example in XP there is solid color, but on Vista+ there is gradiented. I want to just grey text, all other should be "original". Are you understand what I mean ;)

[mkinzler]

Call the standard Draw-Routine after you set the new Color

[WojTec]

What you mean? I'm not pro in owner drawing :( Could you give me an example?

[mkinzler]

Have a look on onCustomDraw

[WojTec]

I tried OnCustomDraw and OnCustomDrawItem and set in both DefaultDraw to True. And I still don't have default selection. How to use it?

[Namenloser]

TListview doesn't support the themed selection rectangle out of the box. You have to activate it manually by calling

Delphi-Quellcode:

SetWindowTheme(Listview.Handle, 'Explorer', nil);

[WojTec]

I added it to OnCreate, this is good procedere?
Still no effect :( OnDrawItem should be in OnCustomDrawItem? But this don't have Rect parameter. Don't have idea how to do it :(

[Namenloser]

Does it work if you don't use any owner/custom drawing code?

Btw: As you're already using

Delphi-Quellcode:

clGrayText

, why not use

Delphi-Quellcode:

clWindowText

for regular text as well? Depending on the settings, text may not always be black by default. In general, you should avoid combining environment colors with hard coded colors, because it can get ugly (e.g. black text on a black background) if someone uses different settings.

[WojTec]

If I don't use owner draw (in owner draw event I put my drawing code) items selection is as in all other listview components (system too). When enable owner drawing I don't have selection, though in custom draw event default draw is on.

[Namenloser]

You could use DrawThemedBackground from the UxTheme api. Here's a quick example:

Delphi-Quellcode:

uses UxTheme;

TMyForm = class(TForm)
private
  Theme: hTheme;
end;

procedure TMyForm.FormCreate(Sender: TObject);
begin
  Theme := OpenThemeData(0, 'ListView');
end;

procedure TMyForm.FormDestroy(Sender: TObject);
begin
  CloseThemeData(Theme);
end;

procedure TMyForm.ListViewCustomDraw(...);
var
  StateId: Integer;
begin
  StateId := LIS_SELECTED; // LIS_SELECTEDNOTFOCUS // LIS_NORMAL
  DrawThemeBackground(
    Theme, 
    ListView.Canvas.Handle, 
    LVP_LISTITEM, 
    StateId,
    Rect, 
    nil
  );
  { Other drawing code... }
end;

But if you do this, be careful to check if Themes are available or else your program will not work on older systems.

[edit]
In order to see any difference, you have to execute the SetWindowTheme-code from above first (before you acquire the theme handle). Or you could replace

Delphi-Quellcode:

'ListView'

with

Delphi-Quellcode:

'Explorer::ListView'

. But the former version is preferable.
[/edit]

[WojTec]

Don't working, when try select item, all what is inside control is erased, so component is blank.

Maybe I'm calling in wrong order? I have: OwnerDraw is True, OnDrawItem to make grey text, OnCustom* event with DefaultDraw set to True. Now selection is don't visible, but items are with black and grey text. Then I added your first code for themes to form OnCreate - result was the same, then repleaced it with next example - control area is cleared.

:cry:

[Namenloser]

Maybe you should post your source code along with a screenshot.

[WojTec]

Form:

Delphi-Quellcode:

object Form20: TForm20
  Left = 0
  Top = 0
  Caption = 'Form20'
  ClientHeight = 202
  ClientWidth = 331
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  PixelsPerInch = 96
  TextHeight = 13
  object lvRecentFiles: TListView
    Left = 8
    Top = 8
    Width = 225
    Height = 175
    Columns = <
      item
        Caption = 'Recent files'
        Width = 221
      end>
    ColumnClick = False
    DoubleBuffered = True
    Groups = <
      item
        Header = 'Recent files'
        GroupID = 0
        State = [lgsNormal]
        HeaderAlign = taLeftJustify
        FooterAlign = taLeftJustify
        TitleImage = -1
        ExtendedImage = -1
      end>
    Items.ItemData = {
      03C60000000300000000000000FFFFFFFFFFFFFFFF0000000000000000000000
      001F43003A005C00570069006E0064006F00770073005C007300790073007400
      65006D00330032005C005300680065006C006C00330032002E0064006C006C00
      00000000FFFFFFFFFFFFFFFF0000000000000000000000000B43003A005C0062
      006F006F0074002E0069006E00690000000000FFFFFFFFFFFFFFFF0000000000
      000000000000001258003A005C006E006F006E00650078006900730074006500
      6E0074002E00640061007400}
    OwnerDraw = True
    GroupView = True
    ReadOnly = True
    RowSelect = True
    ParentDoubleBuffered = False
    ShowColumnHeaders = False
    TabOrder = 0
    ViewStyle = vsReport
    OnCustomDraw = lvRecentFilesCustomDraw
    OnCustomDrawItem = lvRecentFilesCustomDrawItem
    OnDrawItem = lvRecentFilesDrawItem
  end
end

Source:

Delphi-Quellcode:

unit Unit20;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, UxTheme;

type
  TForm20 = class(TForm)
    lvRecentFiles: TListView;
    procedure lvRecentFilesDrawItem(Sender: TCustomListView; Item: TListItem;
      Rect: TRect; State: TOwnerDrawState);
    procedure lvRecentFilesCustomDraw(Sender: TCustomListView;
      const ARect: TRect; var DefaultDraw: Boolean);
    procedure lvRecentFilesCustomDrawItem(Sender: TCustomListView;
      Item: TListItem; State: TCustomDrawState; var DefaultDraw: Boolean);
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    Theme: hTheme;
  public
    { Public declarations }
  end;

var
  Form20: TForm20;

implementation

{$R *.dfm}

procedure TForm20.FormCreate(Sender: TObject);
begin
  SetWindowTheme(lvRecentFiles.Handle, 'Explorer', nil);
  Theme := OpenThemeData(0, 'ListView');
end;

procedure TForm20.FormDestroy(Sender: TObject);
begin
  CloseThemeData(Theme);
end;

procedure TForm20.lvRecentFilesCustomDraw(Sender: TCustomListView;
  const ARect: TRect; var DefaultDraw: Boolean);
//var
//  StateId: Integer;
begin
//  StateId := LIS_SELECTED; // LIS_SELECTEDNOTFOCUS // LIS_NORMAL
//  DrawThemeBackground(
//    Theme,
//    lvRecentFiles.Canvas.Handle,
//    LVP_LISTITEM,
//    StateId,
//    ARect,
//    nil
//  );
  DefaultDraw := True;
end;

procedure TForm20.lvRecentFilesCustomDrawItem(Sender: TCustomListView;
  Item: TListItem; State: TCustomDrawState; var DefaultDraw: Boolean);
begin
  DefaultDraw := True;
end;

procedure TForm20.lvRecentFilesDrawItem(Sender: TCustomListView;
  Item: TListItem; Rect: TRect; State: TOwnerDrawState);
var
  R: TRect;
  S: string;
begin
  S := Item.Caption;

  with lvRecentFiles, lvRecentFiles.Canvas do
  begin
    if FileExists(S) then
      Font.Color := clWindowText
    else
      Font.Color := clGrayText
    ;

    R := Classes.Rect(Rect.Left + 6, Rect.Top + 3, Rect.Right, Rect.Bottom - 2);
    TextRect(R, S, [tfEndEllipsis]);
  end;
end;

end.

Group header has selection, items not :(

Screen attached.

[Namenloser]

One thing I immediately spotted:

Delphi-Quellcode:

procedure TForm20.FormCreate(Sender: TObject);
begin
  SetWindowTheme(lvRecentFiles.Handle, 'Explorer', nil);
  Theme := OpenThemeData(0, 'ListView');
end;

has to be

Delphi-Quellcode:

procedure TForm20.FormCreate(Sender: TObject);
begin
  SetWindowTheme(lvRecentFiles.Handle, 'Explorer', nil);
  Theme := OpenThemeData(lvRecentFiles.Handle, 'ListView');
end;

Because, as I said, you have to manually activate the "explorer style" for each window by calling SetWindowTheme. If you do this for a specific window, but then open the theme data of a different window handle (0), of course it won't work.

Not saying, that this is the only issue (might be, might not be), but at least it's one reason why it can't work. If it doesn't work after changing this, try to set

Delphi-Quellcode:

DefaultDraw

to

Delphi-Quellcode:

False

because it's possible that the default drawing routine overdraws the background again (I don't know about that and I'm too lazy to look it up in the VCL sources).

Also, I don't know what the difference between

Delphi-Quellcode:

OnDrawItem

and

Delphi-Quellcode:

OnCustomDrawItem

is, and in which order they are called. But I would suggest moving the

Delphi-Quellcode:

DrawThemedBackground

-code to the

Delphi-Quellcode:

OnDrawItem

routine.

[WojTec]

Now working :D Thanks so much!

Delphi-Quellcode:

    Brush.Style := bsClear;
    FillRect(Rect);

    if odSelected in State then
    begin
      DrawThemeBackground(Theme, lvRecentFiles.Canvas.Handle,
        LVP_LISTITEM, LIS_SELECTED, Rect, nil
      );
    end;

Yes, OnCustom* are not required, just OnDrawItem is needed. This cod I putten between font color and text render. And now I have list liki in Delphi :D