TRichView doesn't work with TabletPCs software

Author

Message

A Drennan

Posted: 01/23/2003 5:43:15

We are seeing more and more customers using TabletPCs who claim that

TRichView doesn't operate with the writing pad software for TabletPCs

running on Windows XP.

Apparently, according to Microsoft the problem below exists and probably

explains why TRichView doesn't work. In my opinion its more a bug of

Microsoft and the way they implemented the writing pad features, but is

there any workaround for TRichView?

From Microsoft Rep:

Ok... this sounded interesting so I did a little test... I suspect the

problem you describe is related to the way that the program is

"listening"

for input.

As developers, there are several keyboard actions that we can choose to

react to. For example, let's look at the .NET TextBox control... the

TextBox control lets us respond to any combination of these events:

KeyDown

KeyPress

TextChanged

KeyUp

When you use a standard keyboard, the operating system notifies the

program

of all 4 of these events (in that order). When you use the Tablet Input

Panel Keyboard, the exact same thing happens.

However, when you use the Tablet Input Panel Writing Pad, the operating

system only notifies the program of 2 of these events (in this order):

KeyPress

TextChanged

(Note to developers: the KeyPress event is raised *once per character*

being

sent and then TextChanged is raised *once per character*. For example,

you write "Hi" then this is the order of events raised: KeyPress,

KeyPress,

TextChanged, TextChanged).

So what does this all mean? Programs that are written to only listen

for

KeyDown and/or KeyUp events will not work with the Writing Pad. Contact

the

software developer and ask them to change their algorithm to use the

KeyPress or TextChanged events instead.

On a related note, when you paste text into a textbox, only a single

event

is raised: TextChanged.

Robert Levy

Microsoft MVP - Mobile Devices