如何在外部文件（或TStream）中保留TListView.Items（TListItems）？

它是與TListItems.DefineProperties ...這是我寫作的嘗試：如何在外部文件（或TStream）中保留TListView.Items（TListItems）？

Stream := TFileStream.Create('ListView.dat', fmCreate); 
    Writer := TWriter.Create(Stream, 4096); 
    TListItemsHelper(ListView.Items).DefineProperties(Writer); 
    Writer.Free; 
    Stream.Free;

...它顯然作品，但讀取代碼

Stream := TFileStream.Create('ListView.dat', fmOpenRead or fmShareDenyWrite); 
    Reader := TReader.Create(Stream, 4096); 
    TListItemsHelper(ListView.Items).DefineProperties(Reader); 
    Reader.Free; 
    Stream.Free;

...不填充項目與文件內容。我在這裏做錯了什麼？

來源

2012-11-10 OnTheFly

嘗試'Writer.WriteRootComponent（ListView控件）'和'Reader.ReadRootComponent（ListView控件）' – kobik

@kobik：如果你作出這樣的回答，我會給予好評，因爲這正是被後失蹤DefineProperties語句。沒有它們似乎可行，但這意味着沒有錯誤發生。有了它們，數據實際上被寫入文件並從中讀取。 –

@MarjanVenema，我仍然沒有看到OP的任何迴應，所以我現在將其留作評論。 – kobik

procedure ListViewSaveToStream(aListView: TListView; Stream: TStream); 
var 
    i: integer; 
    aItem: TListItem; 
    n: longint; 
    buffer: smallint; 
    b: boolean; 
    s: string; 
begin 
    Stream.Size := 0; 
    n := aListView.Items.Count; 
    Stream.Write(n, SizeOf(n)); 

    if n > 0 then 
    begin 
    if aListView.ItemFocused <> nil then 
     n := aListView.ItemFocused.Index 
    else 
     n := -1; 
    Stream.Write(n, SizeOf(n)); 

    for i := 0 to aListView.Items.Count - 1 do 
    begin 
     aItem := aListView.Items[i]; 

     s := aItem.Caption; 
     buffer := Length(s); 
     Stream.Write(buffer, SizeOf(buffer)); 
     if buffer > 0 then 
     Stream.Write(s[1], buffer); 

     s := aItem.SubItems.CommaText; 
     n := Length(s); 
     Stream.Write(n, SizeOf(n)); 
     if n > 0 then 
     Stream.Write(s[1], n); 

     b := aItem.Checked; 
     Stream.Write(b, SizeOf(b)); 

     buffer := aItem.ImageIndex; 
     Stream.Write(buffer, SizeOf(buffer)); 

     buffer := aItem.StateIndex; 
     Stream.Write(buffer, SizeOf(buffer)); 

     buffer := aItem.OverlayIndex; 
     Stream.Write(buffer, SizeOf(buffer)); 

     buffer := aItem.Indent; 
     Stream.Write(buffer, SizeOf(buffer)); 

     n := integer(aItem.Data); 
     Stream.Write(n, SizeOf(n)); 

     b := aItem.Selected; 
     Stream.Write(b, SizeOf(b)); 

    end; 
    end; 
end; 

procedure ListViewVLoadFromStream(aListView: TListView; Stream: TStream); 

var 
    i: integer; 
    aItem: TListItem; 
    cnt, n, ItemFocusedIndex: longint; 
    buffer: smallint; 
    b: boolean; 
    s: string; 
begin 
    aListView.Items.BeginUpdate; 
    try 
    aListView.Items.Clear; 

    Stream.Position := 0; 

    Stream.Read(cnt, SizeOf(cnt)); 
    if cnt > 0 then 
    begin 
     aListView.AllocBy := cnt; 

     Stream.Read(ItemFocusedIndex, SizeOf(ItemFocusedIndex)); 

     for i := 0 to cnt - 1 do 
     begin 
     aItem := aListView.Items.Add; 

     Stream.Read(buffer, SizeOf(buffer)); 
     if buffer > 0 then 
     begin 
      SetLength(s, buffer); 
      Stream.Read(s[1], buffer); 
      aItem.Caption := s; 
     end; 

     Stream.Read(n, SizeOf(n)); 
     if n > 0 then 
     begin 
      SetLength(s, n); 
      Stream.Read(s[1], n); 
      aItem.SubItems.CommaText := s; 
     end; 

     Stream.Read(b, SizeOf(b)); 
     aItem.Checked := b; 

     Stream.Read(buffer, SizeOf(buffer)); 
     aItem.ImageIndex := buffer; 

     Stream.Read(buffer, SizeOf(buffer)); 
     aItem.StateIndex := buffer; 

     Stream.Read(buffer, SizeOf(buffer)); 
     aItem.OverlayIndex := buffer; 

     Stream.Read(buffer, SizeOf(buffer)); 
     aItem.Indent := buffer; 


     Stream.Read(n, SizeOf(n)); 
     aItem.Data := TObject(n); 

     Stream.Read(b, SizeOf(b)); 

     end; 
    end; 


    finally 
    aListView.Items.EndUpdate; 
    end; 
end; 

procedure LVSaveToFile(const Filename: string; aListView: TListView); 
var 
    FS: TFileStream; 
begin 
    FS := TFileStream.Create(Filename, fmCreate); 
    try 
    ListViewSaveToStream(aListView, FS); 
    finally 
    FS.Free; 
    end; 
end; 

procedure ListViewLoadFromFile(const Filename: string; aListView: TListView); 

var 
    FS: TFileStream; 
begin 
    if FileExists(Filename) then 
    begin 
    FS := TFileStream.Create(Filename, fmOpenRead or fmShareDenyNone); 
    try 
     ListViewVLoadFromStream(aListView, FS); 
    finally 
     FS.Free; 
    end; 
    end; 
end; 

// Example... 
procedure TForm3.Button1Click(Sender: TObject); 
begin 
    LVSaveToFile('C:\temp\test.sav', ListView1); 
end; 

procedure TForm3.Button2Click(Sender: TObject); 
begin 
    ListViewLoadFromFile('C:\temp\test.sav', ListView2); 

end;

來源

2012-11-10 08:05:52 bummi

如何在外部文件（或TStream）中保留TListView.Items（TListItems）？

回答

相關問題