It is possible to display the windows context menu for multiple files using DisplayContextMenu form JEDI JCL library?

Question

It is possible to display the windows context menu for multiple files using DisplayContextMenu form JEDI JCL library ?

This is the code:

function DisplayContextMenu(const Handle: THandle; const FileName: string;
  Pos: TPoint): Boolean;
var
  ItemIdList: PItemIdList;
  Folder: IShellFolder;
begin
  Result := False;
  ItemIdList := PathToPidlBind(FileName, Folder);
  if ItemIdList <> nil then
  begin
    Result := DisplayContextMenuPidl(Handle, Folder, ItemIdList, Pos);
    PidlFree(ItemIdList);
  end;
end;

function DisplayContextMenuPidl(const Handle: THandle; const Folder: IShellFolder;
  Item: PItemIdList; Pos: TPoint): Boolean;
var
  Cmd: Cardinal;
  ContextMenu: IContextMenu;
  ContextMenu2: IContextMenu2;
  Menu: HMENU;
  CommandInfo: TCMInvokeCommandInfo;
  CallbackWindow: THandle;
begin
  Result := False;
  if (Item = nil) or (Folder = nil) then
    Exit;
  Folder.GetUIObjectOf(Handle, 1, Item, IID_IContextMenu, nil,
    Pointer(ContextMenu));
  if ContextMenu <> nil then
  begin
    Menu := CreatePopupMenu;
    if Menu <> 0 then
    begin
      if Succeeded(ContextMenu.QueryContextMenu(Menu, 0, 1, $7FFF, CMF_EXPLORE)) then
      begin
        CallbackWindow := 0;
        if Succeeded(ContextMenu.QueryInterface(IContextMenu2, ContextMenu2)) then
        begin
          CallbackWindow := CreateMenuCallbackWnd(ContextMenu2);
        end;
        ClientToScreen(Handle, Pos);
        Cmd := Cardinal(TrackPopupMenu(Menu, TPM_LEFTALIGN or TPM_LEFTBUTTON or
          TPM_RIGHTBUTTON or TPM_RETURNCMD, Pos.X, Pos.Y, 0, CallbackWindow, nil));
        if Cmd <> 0 then
        begin
          ResetMemory(CommandInfo, SizeOf(CommandInfo));
          CommandInfo.cbSize := SizeOf(TCMInvokeCommandInfo);
          CommandInfo.hwnd := Handle;
          CommandInfo.lpVerb := MakeIntResourceA(Cmd - 1);
          CommandInfo.nShow := SW_SHOWNORMAL;
          Result := Succeeded(ContextMenu.InvokeCommand(CommandInfo));
        end;
        if CallbackWindow <> 0 then
          DestroyWindow(CallbackWindow);
      end;
      DestroyMenu(Menu);
    end;
  end;
end;

Answer 1

To show the context menu of several items, you must modify the code a little bit.

First you must allocate an array of PItemIDList and fill each element of the array and finally pass to the GetUIObjectOf method the array with the number of elements.

Try this sample

uses
  JclShell,
  ShlObj;

function MenuCallback(Wnd: THandle; Msg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
var
  ContextMenu2: IContextMenu2;
begin
  case Msg of
    WM_CREATE:
      begin
        ContextMenu2 := IContextMenu2(PCreateStruct(lParam).lpCreateParams);
        SetWindowLongPtr(Wnd, GWLP_USERDATA, LONG_PTR(ContextMenu2));
        Result := DefWindowProc(Wnd, Msg, wParam, lParam);
      end;
    WM_INITMENUPOPUP:
      begin
        ContextMenu2 := IContextMenu2(GetWindowLongPtr(Wnd, GWLP_USERDATA));
        ContextMenu2.HandleMenuMsg(Msg, wParam, lParam);
        Result := 0;
      end;
    WM_DRAWITEM, WM_MEASUREITEM:
      begin
        ContextMenu2 := IContextMenu2(GetWindowLongPtr(Wnd, GWLP_USERDATA));
        ContextMenu2.HandleMenuMsg(Msg, wParam, lParam);
        Result := 1;
      end;
  else
    Result := DefWindowProc(Wnd, Msg, wParam, lParam);
  end;
end;

function CreateMenuCallbackWnd(const ContextMenu: IContextMenu2): THandle;
const
  IcmCallbackWnd = 'ICMCALLBACKWND';
var
  WndClass: TWndClass;
begin
  ZeroMemory(@WndClass, SizeOf(WndClass));
  WndClass.lpszClassName := PChar(IcmCallbackWnd);
  WndClass.lpfnWndProc := @MenuCallback;
  WndClass.hInstance := HInstance;
  Winapi.Windows.RegisterClass(WndClass);
  Result := CreateWindow(IcmCallbackWnd, IcmCallbackWnd, WS_POPUPWINDOW, 0,
    0, 0, 0, 0, 0, HInstance, Pointer(ContextMenu));
end;

type
  PArrayOfPItemIDList = ^TArrayOfPItemIDList;
  TArrayOfPItemIDList = array[0..0] of PItemIDList;

function DisplayContextMenuPidl(const Handle: THandle; const Folder: IShellFolder;
  Item: PArrayOfPItemIDList; ItemsCount :Integer; Pos: TPoint): Boolean;
var
  Cmd: Cardinal;
  ContextMenu: IContextMenu;
  ContextMenu2: IContextMenu2;
  Menu: HMENU;
  CommandInfo: TCMInvokeCommandInfo;
  CallbackWindow: THandle;
begin
  Result := False;
  if (Item = nil) or (Folder = nil) then
    Exit;
  //pass the number of elements oif the array (ItemsCount)
  Folder.GetUIObjectOf(Handle, ItemsCount, Item[0], IID_IContextMenu, nil,
    Pointer(ContextMenu));
  if ContextMenu <> nil then
  begin
    Menu := CreatePopupMenu;
    if Menu <> 0 then
    begin
      if Succeeded(ContextMenu.QueryContextMenu(Menu, 0, 1, $7FFF, CMF_EXPLORE)) then
      begin
        CallbackWindow := 0;
        if Succeeded(ContextMenu.QueryInterface(IContextMenu2, ContextMenu2)) then
        begin
          CallbackWindow := CreateMenuCallbackWnd(ContextMenu2);
        end;
        ClientToScreen(Handle, Pos);
        Cmd := Cardinal(TrackPopupMenu(Menu, TPM_LEFTALIGN or TPM_LEFTBUTTON or
          TPM_RIGHTBUTTON or TPM_RETURNCMD, Pos.X, Pos.Y, 0, CallbackWindow, nil));
        if Cmd <> 0 then
        begin
          ZeroMemory(@CommandInfo, SizeOf(CommandInfo));
          CommandInfo.cbSize := SizeOf(TCMInvokeCommandInfo);
          CommandInfo.hwnd := Handle;
          CommandInfo.lpVerb := MakeIntResourceA(Cmd - 1);
          CommandInfo.nShow := SW_SHOWNORMAL;
          Result := Succeeded(ContextMenu.InvokeCommand(CommandInfo));
        end;
        if CallbackWindow <> 0 then
          DestroyWindow(CallbackWindow);
      end;
      DestroyMenu(Menu);
    end;
  end;
end;

function DisplayContextMenu(const Handle: THandle; const  FileNames: array of string;  Pos: TPoint): Boolean;
var
  ItemIdList: PArrayOfPItemIDList;
  Folder: IShellFolder;
  ItemsCount : integer;

  procedure AllocItems;
  var
    i : integer;
  begin
    for i := 0 to  ItemsCount- 1 do
      ItemIdList[i] := PathToPidlBind(FileNames[i], Folder);
  end;

  procedure ReleaseItems;
  var
    i : integer;
  begin
    for i := 0 to  ItemsCount- 1 do
      PidlFree(ItemIdList[i]);
  end;

begin
  Result := False;
  ItemsCount := Length(FileNames);
  if ItemsCount>0 then
  begin
    //Allocate the array
    ItemIdList := AllocMem(SizeOf(PItemIDList) * ItemsCount);
    try
       AllocItems; //fill each item 
      try
        Result := DisplayContextMenuPidl(Handle, Folder, ItemIdList, ItemsCount, Pos);
      finally
        ReleaseItems; //release the items 
      end;
    finally
       FreeMem(ItemIdList); //release the array
    end;
  end;
end;

And use like so

 DisplayContextMenu(Handle, ['C:\Foo\Bar.txt', 'C:\Foo\Bar2.txt'], Point(0, 0));