delphi - 使用Delphi windows api获取文件信息

Question

使用 Delphi 和 Windows API 可以从 PItemIDList 获取文件是否是文件夹？通过这段代码，我可以获得文件的唯一名称。

procedure TMain.FolderMonitorFileChange(aSender: TObject; aPIDL: PItemIDList);
var
  FileInfo : SHFILEINFOW;
begin
  SHGetFileInfo(LPCTSTR(aPIDL), 0 , FileInfo, SizeOf(FileInfo), SHGFI_PIDL or SHGFI_DISPLAYNAME or SHGFI_TYPENAME or SHGFI_ATTRIBUTES);
  ShowMessage('File change notification: ' + FileInfo.szDisplayName + ' ' + FileInfo.szTypeName );
end;

谢谢

Answer 1

对于相对PIDL，您可以获得IShellFolder PIDL的父文件夹的接口(interface)，然后将PIDL传递给IShellFolder::GetAttributesOf()方法。

function IsFolder(Parent: IShellFolder; aChildPIDL: PItemIDList): Boolean;
var
  Attrs: SFGAOF;
begin
  Result := Succeeded(Parent.GetAttributesOf(1, @aChildPidl, @Attrs))
    and (Attrs and SFGAO_FOLDER <> 0);
end;

对于绝对 PIDL，您有几种不同的选择:

• 将 PIDL 传递给 SHBindToParent()将其转换为相对 PIDL 并检索其父文件夹的 IShellFolder，然后调用 IShellFolder::GetAttributesOf()。

  function IsFolder(aPIDL: PItemIDList): Boolean;
  var
    Parent: IShellFolder;
    Child: PItemIDList;
    Attrs: SFGAOF;
  begin
    Result := Succeeded(SHBindToParent(aPidl, IShellFolder, @Parent, @Child))
      and Succeeded(Parent.GetAttributesOf(1, @Child, @Attrs))
      and (Attrs and SFGAO_FOLDER <> 0);
  end;
  

• 将 PIDL 传递给 SHGetFileInfo()使用 SHGFI_PIDL 标志。启用 SHGFI_ATTRIBUTES 标志来请求项目的属性。

  function IsFolder(aPIDL: PItemIDList): Boolean;
  var
    FileInfo : SHFILEINFO;
  begin
    Result := (SHGetFileInfo(LPCTSTR(aPIDL), 0, @FileInfo, SizeOf(FileInfo), SHGFI_PIDL or  SHGFI_ATTRIBUTES) <> 0)
      and (FileInfo.dwAttributes and SFGAO_FOLDER <> 0);
  end;
  

• 将 PIDL 传递给 SHCreateItemFromIDList()检索 IShellItem接口(interface)，然后调用IShellItem::GetAttributes() .

  function IsFolder(aPIDL: PItemIDList): Boolean;
  var
    Item: IShellItem;
    Attrs: SFGAOF;
  begin
    Result := Succeeded(SHCreateItemFromIDList(aPidl, IShellItem, @Item))
      and Succeeded(Item.GetAttributes(SFGAO_FOLDER, @Attrs))
      and (Attrs and SFGAO_FOLDER <> 0);
  end;