how to set background image to TListview in Delphi XE?

how i can to to set backgr开发者_如何学Cound image to TListview in Delphi XE??

i want to make a application like Windows Explorer.

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In order to set a watermark in the listview you need to use the LVM_SETBKIMAGE message, and you need to override the TListView's default WM_ERASEBKGND message. The listview takes ownership of the bitmap handle, so you need to use TBitmap's ReleaseHandle, rather than just Handle.

If you want it aligned to the top-left, instead of the bottom right like Explorer, use LVBKIF_SOURCE_HBITMAP instead of LVBKIF_TYPE_WATERMARK for the ulFlags value.

uses
  CommCtrl, ...;

type
  TListView = class(ComCtrls.TListView)
  protected
    procedure WndProc(var Message: TMessage);
      override;
  end;

  TForm4 = class(TForm)
    ListView1: TListView;
    procedure FormCreate(Sender: TObject);
  end;

procedure TListView.WndProc(var Message: TMessage);
begin
  if Message.Msg = WM_ERASEBKGND then
    DefaultHandler(Message)
  else
    inherited WndProc(Message);
end;

procedure TForm4.FormCreate(Sender: TObject);
var
  Img: TImage;
  BkImg: TLVBKImage;
begin
  FillChar(BkImg, SizeOf(BkImg), 0);
  BkImg.ulFlags := LVBKIF_TYPE_WATERMARK;
  // Load image and take ownership of the bitmap handle
  Img := TImage.Create(nil);
  try
    Img.Picture.LoadFromFile('C:\Watermark.bmp');
    BkImg.hbm := Img.Picture.Bitmap.ReleaseHandle;
  finally
    Img.Free;
  end;
  // Set the watermark
  SendMessage(ListView1.Handle, LVM_SETBKIMAGE, 0, LPARAM(@BkImg));
end;

Stretched Watermark

The listview doesn't natively support stretching a bitmap across the entire background. To do so you need to do a StretchBlt in response to WM_ERASEBKGND yourself.

type
  TMyListView = class(TListView)
  protected
    procedure CreateHandle; override;
    procedure CreateParams(var Params: TCreateParams); override;
    procedure WMEraseBkgnd(var Msg: TWMEraseBkgnd); message WM_ERASEBKGND;
  public
    Watermark: TBitmap;
  end;

procedure TMyListView.CreateHandle;
begin
  inherited;
  // Set text background color to transparent
  SendMessage(Handle, LVM_SETTEXTBKCOLOR, 0, CLR_NONE);
end;

procedure TMyListView.CreateParams(var Params: TCreateParams);
begin
  inherited;
  // Invalidate every time the listview is resized
  Params.Style := Params.Style or CS_HREDRAW or CS_VREDRAW;
end;

procedure TMyListView.WMEraseBkgnd(var Msg: TWMEraseBkgnd);
begin
  StretchBlt(Msg.DC, 0, 0, Width, Height, Watermark.Canvas.Handle,
    0, 0, Watermark.Width, Watermark.Height, SrcCopy);
  Msg.Result := 1;
end;

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a Tlistview is nice but if you want more. i suggess you have to update with VirtualStringTree(VirtualTreeView) very flexible you can customize it almost anything you want and most of all its free.