TFormStand

TFormStand is the twin of TFrameStand that uses TForm descendants as subjects. Everything described for frames (stands, animations, Common Actions, injection, lifecycle, responsive) works the same way; only the type names change.

Why forms? The form designer has features frames lack: Fire UI views (a different layout per device: phone, tablet, Android, iOS...), the style preview of the selected platform, a TStyleBook per form. With TFormStand you design a piece of UI as a form, with all those tools, and then show its content inside any control of another form, with a stand.

How it works

The form is created (with Owner = nil) but never shown as a window. When it is put on a stand, TFormStand:

1. creates a TLayout, the form container, as large as the form's client area;
2. moves all the direct children of the form into it;
3. adds the form container to the stand's container.

When the subject is closed, the children are moved back to the form (when the form is not owned) or the form is freed (when it is owned, as with New).

Since the form object stays alive, its fields, its methods and the event handlers of its controls keep working: you write the form as usual.

uses FormStand, SubjectStand, Forms.Second;

procedure TMainForm.ShowSecondButtonClick(Sender: TObject);
begin
  FormStand1.NewAndShow<TSecondForm>(ContentLayout, 'card');
end;

procedure TMainForm.CloseSecondButtonClick(Sender: TObject);
begin
  FormStand1.HideAndCloseAll([TSecondForm]);
end;

type
  TSecondForm = class(TForm)
    CloseButton: TButton;
    procedure CloseButtonClick(Sender: TObject);
  private
    [FormInfo] FI: TFormInfo<TSecondForm>;
  end;

procedure TSecondForm.CloseButtonClick(Sender: TObject);
begin
  FI.HideAndClose;
end;

Layout attributes

Two attributes on the form class control the form container:

Attribute	Default	Effect
[Align(TAlignLayout.xxx)]	TAlignLayout.Client	Align of the form container inside the stand's container
[ClipChildren(True)]	False	ClipChildren of the form container

type
  [Align(TAlignLayout.Left), ClipChildren(True)]
  TMenuForm = class(TForm)
    ...
  end;

With an alignment other than Client the form's design size is kept: a form designed 300 pixels wide and aligned Left becomes a 300-pixel side panel.

API

TFormStand mirrors TFrameStand:

TFrameStand	TFormStand
TFrameInfo<T>, Frame, FrameIsOwned	TFormInfo<T>, Form, FormIsOwned, plus FormContainer
New<T>, Use<T>, NewAndShow<T>, GetFrameInfo<T>	New<T>, Use<T>, NewAndShow<T>, GetFormInfo<T>
FrameInfo(...), FrameInfos, VisibleFrames, LastShownFrame	FormInfo(...), FormInfos, VisibleForms, LastShownForm
[FrameInfo], [FrameStand]	[FormInfo], [FormStand]

The non-generic overloads New(AClassName) and Use(AFrame) exist only on TFrameStand.

Things to keep in mind

• Form-level events tied to the window (OnShow, OnActivate, OnClose, OnResize...) do not fire, because the form is never shown. OnCreate and OnDestroy do. Use the lifecycle methods instead.
• Properties of the form itself (Fill, its StyleBook, Caption...) are not carried over: only its children are moved. Put a TRectangle aligned to the client as the first child if you need a background.
• Non-visual components (data modules, action lists, bindings) stay on the form and keep working.
• While a form adopted with Use is shown, its controls are children of the stand: if the parent of the stand is destroyed, they are destroyed with it (the form itself survives, empty). Close the subject first if you want to show the form again.
• The TFormStand_HelloWorld, TFormStand_ActionList and TFormStand_LiveBindings demos show Fire UI views, actions and LiveBindings working inside a form shown on a stand.