Select Multiple Files with OpenDialog.

posted 17 Mar 2010, 18:55 by Delphi Basics
Allows you to select multiple files with the OpenDialog component.

uses ActiveX, ShlObj, ComObj;

function SHMultiFileProperties(pDataObj: IDataObject; Flag: DWORD): HRESULT;
  stdcallexternal 'shell32.dll';

function GetFileListDataObject(Files: TStrings): IDataObject;
type
  
PArrayOfPItemIDList = ^TArrayOfPItemIDList;
  TArrayOfPItemIDList = array[0..0] of PItemIDList;
var
  
Malloc: IMalloc;
  Root: IShellFolder;
  p: PArrayOfPItemIDList;
  chEaten, dwAttributes: ULONG;
  i, FileCount: Integer;
begin
  
Result := nil;
  FileCount := Files.Count;
  if FileCount = 0 then Exit;

  OleCheck(SHGetMalloc(Malloc));
  OleCheck(SHGetDesktopFolder(Root));
  p := AllocMem(SizeOf(PItemIDList) * FileCount);
  try
    for 
i := 0 to FileCount - 1 do
      try
        if not 
(DirectoryExists(Files[i]) or FileExists(Files[i])) then Continue;
        OleCheck(Root.ParseDisplayName(GetActiveWindow,
          nil,
          PWideChar(WideString(Files[i])),
          chEaten,
          p^[i],
          dwAttributes));
      except
      end
;
    OleCheck(Root.GetUIObjectOf(GetActiveWindow,
      FileCount,
      p^[0],
      IDataObject,
      nil,
      Pointer(Result)));
  finally
    for 
i := 0 to FileCount - 1 do
    begin
      if 
p^[i] <> nil then Malloc.Free(p^[i]);
    end;
    FreeMem(p);
  end;
end;

procedure ShowFileProperties(Files: TStrings; aWnd: HWND);
type
  
PArrayOfPItemIDList = ^TArrayOfPItemIDList;
  TArrayOfPItemIDList = array[0..0] of PItemIDList;
var
  
Data: IDataObject;
begin
  if 
Files.Count = 0 then Exit;
  Data := GetFileListDataObject(Files);
  SHMultiFileProperties(Data, 0);
end;

Usage:
procedure TForm1.Button1Click(Sender: TObject);
begin
  if 
OpenDialog1.Execute then
    
Memo1.Lines.AddStrings(OpenDialog1.Files);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  
ShowFileProperties(Memo1.Lines, 0);
end;
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