How to create the latest file list in Delphi 2009?

Question

I have TActionManager and TActionMainMenuBar, and I know how to add TActionClientItem for each MRU file to the main menu bar. But should I create a separate action for each MRU file in the list? Or is there a way to create only one action and somehow pass a tag or something to an OnExecute action based on which MRU file was clicked?

Delphi help says: "For more information about MRU lists, sample code, and methods for finding actions in lists, see FindItemByAction and FindItemByCaption in the online help." But I can not find anything in those subjects that are useful, and, of course, not an example of code. I would really like to avoid using a third-party component to do this.

Answer 1

In any case, you will have a separate TActionmenu for each item so that they can have different values Caption. But you do not need to have separate event handlers OnExecute. The event handler will receive a link to the action in its parameter Sender. Use the sender property Tagto reference the list where your file names are stored. (Do not use the property Captionto open which file to open, which prevents you from doing nice things, such as adding accelerators or shortening uncomfortable paths.)

, , . FindItemByAction , . MRU, , , . , , , . .

Answer 2

, . , , - IAbbreviatedFileName, Windows API PathCompactPath. , - . , - - !

type
  TFileAwareMenuItem = class(TMenuItem)
  private
    FFileName: string;
  public
    property FileName: string read FFileName write FFilename;
  end;

  TMRU = class
  private
    FParent: array of TMenuItem;
    FMenuItemStart: array of TMenuItem;
    FMenuItemFinish: array of TMenuItem;
    FMenuCount: Integer;
    FRegistryKey: string;
    FOwner: TCustomForm;
    FMRUFileNames: TStringList;
    FAction: TAction;
    function GetCount: Integer;
    function GetItem(Index: Integer): string;
    procedure SetAction(Value: TAction);
    procedure Read;
    procedure Write;
    procedure UpdateMenu;
  public
    constructor Create(const RegistrySubKey: string; const Owner: TCustomForm);
    destructor Destroy; override;
    procedure RegisterBoundingMenuItems(Start, Finish: TMenuItem);
    procedure Add(const FileName: string);
    procedure Delete(ItemNum: Integer);
    property Count: Integer read GetCount;
    property Action: TAction read FAction write SetAction;
    property Items[Index: Integer]: string read GetItem; default;
  end;

const
  MRUSize=9;
  AppRegistryKey='??put your apps registry key here??';

var
  Registry: TRegistry;

constructor TMRU.Create(const RegistrySubKey: string; const Owner: TCustomForm);
begin
  inherited Create;
  FRegistryKey := Format('%s\%s', [AppRegistryKey, RegistrySubKey]);
  FOwner := Owner;
  FMRUFileNames := TStringList.Create;
  Read;
end;

destructor TMRU.Destroy;
begin
  Write;
  FreeAndNil(FMRUFileNames);
  inherited;
end;

procedure TMRU.RegisterBoundingMenuItems(Start, Finish: TMenuItem);
begin
  inc(FMenuCount);
  SetLength(FParent, FMenuCount);
  SetLength(FMenuItemStart, FMenuCount);
  SetLength(FMenuItemFinish, FMenuCount);

  FMenuItemStart[FMenuCount-1] := Start;
  FMenuItemFinish[FMenuCount-1] := Finish;
  Assert(Start.Parent=Finish.Parent);
  FParent[FMenuCount-1] := Start.Parent;

  UpdateMenu;
end;

procedure TMRU.UpdateMenu;
var
  Intf: IAbbreviatedFileName;
  i, j: Integer;
  FileName: string;
  NewMenuItem: TFileAwareMenuItem;
begin
  Intf := FOwner as IAbbreviatedFileName;
  for i := 0 to FMenuCount-1 do begin
    j := FMenuItemStart[i].MenuIndex+1;
    while j<FMenuItemFinish[i].MenuIndex do begin
      FParent[i][j].Free;
    end;
    for j := 0 to Count-1 do begin
      NewMenuItem := TFileAwareMenuItem.Create(FMenuItemStart[i].Owner);
      NewMenuItem.Action := Action;
      NewMenuItem.FileName := FMRUFileNames[j];
      FileName := ReplaceString(Intf.AbbreviatedFileName(NewMenuItem.FileName, False), '&', '&&');
      NewMenuItem.Caption := Format('&%d. %s', [j+1, FileName]);
      FParent[i].Insert(FMenuItemFinish[i].MenuIndex, NewMenuItem);
    end;
    FMenuItemStart[i].Visible := (Count>0) and (FMenuItemStart[i].MenuIndex>0);
    FMenuItemFinish[i].Visible := (FMenuItemFinish[i].MenuIndex<FParent[i].Count-1);
  end;
end;

procedure TMRU.Read;
var
  i: Integer;
  s: string;
begin
  if Registry.OpenKey(HKEY_CURRENT_USER, FRegistryKey) then begin
    FMRUFileNames.Clear;
    for i := 0 to MRUSize-1 do begin
      s := Registry.ReadString(IntToStr(i+1), '');
      if s<>'' then begin
        FMRUFileNames.Add(s);
      end;
    end;
    UpdateMenu;
    Registry.CloseKey;
  end;
end;

procedure TMRU.Write;
var
  i: Integer;
  ValueName: string;
begin
  if Registry.OpenKey(HKEY_CURRENT_USER, FRegistryKey, KEY_ALL_ACCESS, True) then begin
    Registry.WriteInteger('Size', MRUSize);
    for i := 0 to MRUSize-1 do begin
      ValueName := IntToStr(i+1);
      if i<Count then begin
        Registry.WriteString(ValueName, FMRUFileNames.Strings[i]);
      end else begin
        if Registry.ValueExists(ValueName) then begin
          Registry.DeleteValue(ValueName);
        end;
      end;
    end;
    Registry.CloseKey;
  end;
end;

function TMRU.GetCount: Integer;
begin
  Result := Min(FMRUFileNames.Count, MRUSize);
end;

function TMRU.GetItem(Index: Integer): string;
begin
  Result := FMRUFileNames[Index];
end;

procedure TMRU.SetAction(Value: TAction);
begin
  if Value<>FAction then begin
    FAction := Value;
    UpdateMenu;
  end;
end;

procedure TMRU.Add(const FileName: string);
var
  i, Index: Integer;
begin
  Index := -1;
  for i := 0 to FMRUFileNames.Count-1 do begin
    if FileNamesEqual(FileName, FMRUFileNames[i]) then begin
      Index := i;
      break;
    end;
  end;

  if Index<>-1 then begin
    FMRUFileNames.Move(Index, 0);
  end else begin
    FMRUFileNames.Insert(0, FileName);
    if FMRUFileNames.Count>MRUSize then begin
      FMRUFileNames.Delete(FMRUFileNames.Count-1);
    end;
  end;

  UpdateMenu;
  Write;
end;

procedure TMRU.Delete(ItemNum: Integer);
begin
  FMRUFileNames.Delete(ItemNum);
  UpdateMenu;
end;

initialization
  Registry := TRegistry.Create;
  if not Registry.KeyExists(AppRegistryKey) then begin
    Registry.CreateKey(AppRegistryKey);
  end;

finalization
  FreeAndNil(Registry);