<s>
Windows	B-Application
Forms	I-Application
(	O
WinForms	B-Application
)	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
graphical	B-Application
(	O
GUI	B-Application
)	O
class	B-Library
library	I-Library
included	O
as	O
a	O
part	O
of	O
Microsoft	O
.NET	B-Application
,	O
.NET	B-Application
Framework	I-Application
or	O
Mono	B-Application
,	O
providing	O
a	O
platform	O
to	O
write	O
client	O
applications	O
for	O
desktop	O
,	O
laptop	O
,	O
and	O
tablet	O
PCs	O
.	O
</s>
<s>
While	O
it	O
is	O
seen	O
as	O
a	O
replacement	O
for	O
the	O
earlier	O
and	O
more	O
complex	O
C++	B-Language
based	O
Microsoft	B-Language
Foundation	I-Language
Class	I-Language
Library	I-Language
,	O
it	O
does	O
not	O
offer	O
a	O
comparable	O
paradigm	O
and	O
only	O
acts	O
as	O
a	O
platform	O
for	O
the	O
user	O
interface	O
tier	B-Operating_System
in	O
a	O
multi-tier	B-Operating_System
solution	O
.	O
</s>
<s>
At	O
the	O
Microsoft	O
Connect	O
event	O
on	O
December	O
4	O
,	O
2018	O
,	O
Microsoft	O
announced	O
releasing	O
Windows	B-Application
Forms	I-Application
as	O
an	O
open	O
source	O
project	O
on	O
GitHub	B-Application
.	O
</s>
<s>
It	O
is	O
released	O
under	O
the	B-License
MIT	I-License
License	I-License
.	O
</s>
<s>
With	O
this	O
release	O
,	O
Windows	B-Application
Forms	I-Application
has	O
become	O
available	O
for	O
projects	O
targeting	O
the	O
.NET	B-Application
Core	I-Application
framework	O
.	O
</s>
<s>
However	O
,	O
the	O
framework	O
is	O
still	O
available	O
only	O
on	O
the	O
Windows	O
platform	O
,	O
and	O
Mono	B-Application
's	I-Application
incomplete	O
implementation	O
of	O
Windows	B-Application
Forms	I-Application
remains	O
the	O
only	O
cross-platform	O
implementation	O
.	O
</s>
<s>
A	O
Windows	B-Application
Forms	I-Application
application	O
is	O
an	O
event-driven	B-Application
application	I-Application
supported	O
by	O
Microsoft	B-Application
's	I-Application
.NET	I-Application
Framework	I-Application
.	O
</s>
<s>
Unlike	O
a	O
batch	B-General_Concept
program	I-General_Concept
,	O
it	O
spends	O
most	O
of	O
its	O
time	O
simply	O
waiting	O
for	O
the	O
user	O
to	O
do	O
something	O
,	O
such	O
as	O
fill	O
in	O
a	O
text	O
box	O
or	O
click	O
a	O
button	O
.	O
</s>
<s>
The	O
code	O
for	O
the	O
application	O
can	O
be	O
written	O
in	O
a	O
.NET	B-Application
programming	O
language	O
such	O
as	O
C#	B-Application
or	O
Visual	B-Language
Basic	I-Language
.	O
</s>
<s>
Windows	B-Application
Forms	I-Application
provides	O
access	O
to	O
native	O
Windows	O
User	O
Interface	O
Common	O
Controls	O
by	O
wrapping	O
the	O
existent	O
Windows	B-Library
API	I-Library
in	O
managed	O
code	O
.	O
</s>
<s>
With	O
the	O
help	O
of	O
Windows	B-Application
Forms	I-Application
,	O
the	O
.NET	B-Application
Framework	I-Application
provides	O
a	O
more	O
comprehensive	O
abstraction	O
above	O
the	O
Win32	B-Library
API	I-Library
than	O
Visual	B-Language
Basic	I-Language
or	O
MFC	O
did	O
.	O
</s>
<s>
Windows	B-Application
Forms	I-Application
is	O
similar	O
to	O
Microsoft	B-Language
Foundation	I-Language
Class	I-Language
(	O
MFC	O
)	O
library	O
in	O
developing	O
client	O
applications	O
.	O
</s>
<s>
It	O
provides	O
a	O
wrapper	O
consisting	O
of	O
a	O
set	O
of	O
C++	B-Language
classes	O
for	O
development	O
of	O
Windows	B-Application
applications	I-Application
.	O
</s>
<s>
Every	O
control	O
in	O
a	O
Windows	B-Application
Forms	I-Application
application	O
is	O
a	O
concrete	O
instance	O
of	O
a	O
class	O
.	O
</s>
<s>
All	O
visual	O
elements	O
in	O
the	O
Windows	B-Application
Forms	I-Application
class	B-Library
library	I-Library
derive	O
from	O
the	O
Control	O
class	O
.	O
</s>
<s>
The	O
Microsoft	O
Active	O
Accessibility	O
support	O
in	O
the	O
Control	O
class	O
also	O
helps	O
impaired	O
users	O
to	O
use	O
Windows	B-Application
Forms	I-Application
better	O
.	O
</s>
<s>
In	O
Visual	B-Application
Studio	I-Application
,	O
forms	O
are	O
created	O
using	O
drag-and-drop	O
techniques	O
.	O
</s>
<s>
Controls	O
have	O
attributes	B-General_Concept
and	O
event	O
handlers	O
associated	O
with	O
them	O
.	O
</s>
<s>
Besides	O
providing	O
access	O
to	O
native	O
Windows	O
controls	O
like	O
button	O
,	O
textbox	O
,	O
checkbox	O
and	O
listview	O
,	O
Windows	B-Application
Forms	I-Application
added	O
its	O
own	O
controls	O
for	O
ActiveX	B-Application
hosting	O
,	O
layout	O
arrangement	O
,	O
validation	O
and	O
rich	O
data	O
binding	O
.	O
</s>
<s>
Those	O
controls	O
are	O
rendered	O
using	O
GDI+	O
.	O
</s>
<s>
Just	O
like	O
Abstract	B-Language
Window	I-Language
Toolkit	I-Language
(	O
AWT	O
)	O
,	O
the	O
equivalent	O
Java	B-Language
API	B-Application
,	O
Windows	B-Application
Forms	I-Application
was	O
an	O
early	O
and	O
easy	O
way	O
to	O
provide	O
graphical	B-Application
user	I-Application
interface	I-Application
components	O
to	O
the	O
.NET	B-Application
Framework	I-Application
.	O
</s>
<s>
Windows	B-Application
Forms	I-Application
is	O
built	O
on	O
the	O
existing	O
Windows	B-Library
API	I-Library
and	O
some	O
controls	O
merely	O
wrap	O
underlying	O
Windows	O
components	O
.	O
</s>
<s>
Some	O
of	O
the	O
methods	O
allow	O
direct	O
access	O
to	O
Win32	B-Library
callbacks	O
,	O
which	O
are	O
not	O
available	O
in	O
non-Windows	O
platforms	O
.	O
</s>
<s>
In	O
.NET	B-Application
Framework	I-Application
2.0	O
,	O
Windows	B-Application
Forms	I-Application
gained	O
richer	O
layout	O
controls	O
,	O
Office	O
2003	O
style	O
toolstrip	O
controls	O
,	O
multithreading	O
component	O
,	O
richer	O
design-time	O
and	O
data	O
binding	O
support	O
as	O
well	O
as	O
ClickOnce	B-Application
for	O
web-based	O
deployment	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
.NET	B-Application
Framework	I-Application
3.0	O
,	O
Microsoft	O
released	O
a	O
second	O
,	O
parallel	O
API	B-Application
for	O
rendering	O
GUIs	B-Application
:	O
Windows	B-Device
Presentation	I-Device
Foundation	I-Device
(	O
WPF	B-Device
)	O
based	O
on	O
DirectX	O
,	O
together	O
with	O
a	O
GUI	B-Application
declarative	O
language	O
called	O
XAML	B-Device
.	O
</s>
<s>
During	O
a	O
question-and-answer	O
session	O
at	O
the	O
Build	O
2014	O
Conference	O
,	O
Microsoft	O
explained	O
that	O
Windows	B-Application
Forms	I-Application
was	O
under	O
maintenance	O
mode	O
,	O
with	O
no	O
new	O
features	O
being	O
added	O
,	O
but	O
bugs	O
found	O
would	O
still	O
be	O
fixed	O
.	O
</s>
<s>
Most	O
recently	O
,	O
improved	O
high-DPI	O
support	O
for	O
various	O
Windows	B-Application
Forms	I-Application
controls	I-Application
was	O
introduced	O
in	O
updates	O
to	O
.NET	B-Application
Framework	I-Application
version	O
4.5	O
.	O
</s>
<s>
For	O
future	O
development	O
,	O
Microsoft	O
has	O
succeeded	O
Windows	B-Application
Forms	I-Application
with	O
an	O
XAML-based	O
GUI	B-Application
entry	O
using	O
frameworks	O
such	O
as	O
WPF	B-Device
and	O
UWP	B-Device
.	O
</s>
<s>
However	O
,	O
drag	O
and	O
drop	O
placement	O
of	O
GUI	B-Application
components	O
in	O
a	O
manner	O
similar	O
to	O
Windows	B-Application
Forms	I-Application
is	O
still	O
provided	O
in	O
XAML	B-Device
by	O
replacing	O
the	O
root	O
XAML	B-Device
element	O
of	O
the	O
Page/Window	O
with	O
a	O
"	O
Canvas	O
"	O
UI-Control	O
.	O
</s>
<s>
When	O
making	O
this	O
change	O
,	O
the	O
user	O
can	O
build	O
a	O
window	O
in	O
a	O
similar	O
fashion	O
as	O
in	O
Windows	B-Application
Forms	I-Application
by	O
directly	O
dragging	O
and	O
dropping	O
components	O
using	O
the	O
Visual	B-Application
Studio	I-Application
GUI	B-Application
.	O
</s>
<s>
While	O
XAML	B-Device
provides	O
drag	O
and	O
drop	O
placement	O
backwards	O
compatibility	O
through	O
the	O
Canvas	O
Control	O
,	O
XAML	B-Device
Controls	O
are	O
only	O
similar	O
to	O
Windows	B-Application
Forms	I-Application
Controls	I-Application
and	O
are	O
not	O
one-to-one	O
backwards	O
compatible	O
.	O
</s>
<s>
They	O
perform	O
similar	O
functions	O
and	O
have	O
a	O
similar	O
appearance	O
,	O
but	O
the	O
properties	O
and	O
methods	O
are	O
different	O
enough	O
to	O
require	O
remapping	O
from	O
one	O
API	B-Application
to	O
another	O
.	O
</s>
<s>
Mono	B-Application
is	O
a	O
project	O
led	O
by	O
Xamarin	B-Application
(	O
formerly	O
by	O
Ximian	O
,	O
then	O
Novell	O
)	O
to	O
create	O
an	O
Ecma	O
standard	O
compliant	O
.NET	B-Application
Framework	I-Application
compatible	O
set	O
of	O
tools	O
.	O
</s>
<s>
In	O
2011	O
,	O
Mono	B-Application
's	I-Application
support	O
for	O
System.Windows.Forms	B-Application
as	O
of	O
.NET	B-Application
2.0	O
was	O
announced	O
as	O
complete	O
;	O
</s>
<s>
System.Windows.Forms	B-Application
2.0	O
works	O
natively	O
on	O
Mac	O
OS	O
X	O
.	O
</s>
<s>
However	O
,	O
System.Windows.Forms	B-Application
has	O
not	O
been	O
actively	O
developed	O
on	O
Mono	B-Application
.	O
</s>
<s>
Full	O
compatibility	O
with	O
.NET	B-Application
was	O
not	O
possible	O
,	O
because	O
Microsoft	O
's	O
System.Windows	O
Forms	O
is	O
mainly	O
a	O
wrapper	O
around	O
the	O
Windows	B-Library
API	I-Library
,	O
and	O
some	O
of	O
the	O
methods	O
allow	O
direct	O
access	O
to	O
Win32	B-Library
callbacks	O
,	O
which	O
are	O
not	O
available	O
in	O
platforms	O
other	O
than	O
Windows	O
.	O
</s>
<s>
Mono	B-Application
has	O
been	O
upgraded	O
so	O
that	O
its	O
default	O
is	O
to	O
assume	O
a	O
64	O
bit	O
platform	O
.	O
</s>
<s>
However	O
,	O
System.Windows.Forms	B-Application
on	O
Mono	B-Application
for	O
the	O
Macintosh	O
OS	O
X	O
platform	O
has	O
been	O
built	O
using	O
a	O
32	O
bit	O
subsystem	O
,	O
Carbon	B-Operating_System
.	O
</s>
<s>
As	O
of	O
this	O
date	O
,	O
a	O
64-bit	O
version	O
of	O
System.Windows.Forms	B-Application
for	O
use	O
on	O
Mac	O
OS	O
X	O
remains	O
unavailable	O
and	O
only	O
.NET	B-Application
applications	O
built	O
for	O
the	O
32	O
bit	O
platform	O
can	O
be	O
expected	O
to	O
execute	O
.	O
</s>
