Casting a Windows Handle. Can it be Done?

[ink]

Hi all,

If I have a Windows 32 pointer to and object (Handle) and I know what that
object is (Button) can I some how cast that pointer to a type of
System.Windows. Forms.Button and then use its methods and properties?

I am using C# compact framework 2.0
I have obtained the handle using the Windows 32 API and PInvoce.
I am using one dot.net application to control another application.

Thanks,
ink

[=?ISO-8859-1?Q?Lasse_V=E5gs=E6ther_Karlsen?=]

ink wrote:

>
Hi all,

If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Windows. Forms.Button and then use its methods and properties?

I am using C# compact framework 2.0
I have obtained the handle using the Windows 32 API and PInvoce.
I am using one dot.net application to control another application.

Thanks,
ink

No, sorry, the best you can do in this context is to send messages to
the other control using Win32 api.

--
Lasse Vågsæther Karlsen
mailto:la***@vk arlsen.no

[cody]

ink wrote:

>
Hi all,

If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Windows. Forms.Button and then use its methods and properties?

I am using C# compact framework 2.0
I have obtained the handle using the Windows 32 API and PInvoce.
I am using one dot.net application to control another application.

Thanks,
ink

No. You will have to use interop/pinvoke, that is you have to call
Windows API, also things like SendMessage.

[Peter Duniho]

ink wrote:

If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Windows. Forms.Button and then use its methods and properties?

Yes.

For example:

Button ButtonFromHandl e(IntPtr handle)
{
return Control.FromHan dle(handle) as Button;
}

This will return a Button instance reference if the handle is valid and
represents a Button control, or null if not.

Pete

[ink]

Hi Peter

Thanks for the advice. I will defiantly give this a test.

thanks,
ink


"Peter Duniho" <Np*********@Nn OwSlPiAnMk.comw rote in message
news:13******** *****@corp.supe rnews.com...

ink wrote:

>If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Windows .Forms.Button and then use its methods and properties?

Yes.

For example:

Button ButtonFromHandl e(IntPtr handle)
{
return Control.FromHan dle(handle) as Button;
}

This will return a Button instance reference if the handle is valid and
represents a Button control, or null if not.

Pete

[Mark Rae [MVP]]

"ink" <in*@notmyemail .comwrote in message
news:%2******** ********@TK2MSF TNGP05.phx.gbl. ..

I will defiantly give this a test.

That's the spirit! Don't let anyone get in your way... ;-)
--
Mark Rae
ASP.NET MVP
http://www.markrae.net

[ink]

Bollocks..


"Peter Duniho" <Np*********@Nn OwSlPiAnMk.comw rote in message
news:13******** *****@corp.supe rnews.com...

ink wrote:

>If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Windows .Forms.Button and then use its methods and properties?

Yes.

For example:

Button ButtonFromHandl e(IntPtr handle)
{
return Control.FromHan dle(handle) as Button;
}

This will return a Button instance reference if the handle is valid and
represents a Button control, or null if not.

Pete

Indeed. It's not supported in the CF, and if it were, it still won't turn a
handle from outside your managed app's scope of resources into a Control.
That said, you could still create your own wrapper that takesn in a Handle
and then exports things like Text by wrapping the necessary P/Invoke calls.
--

Chris Tacke, Embedded MVP
OpenNETCF Consulting
Managed Code in an Embedded World
www.OpenNETCF.com

"ink" <in*@notmyemail .comwrote in message
news:eT******** ******@TK2MSFTN GP04.phx.gbl...

>
Bollocks..


"Peter Duniho" <Np*********@Nn OwSlPiAnMk.comw rote in message
news:13******** *****@corp.supe rnews.com...

>ink wrote:

>>If I have a Windows 32 pointer to and object (Handle) and I know what
that object is (Button) can I some how cast that pointer to a type of
System.Window s.Forms.Button and then use its methods and properties?

Yes.

For example:

Button ButtonFromHandl e(IntPtr handle)
{
return Control.FromHan dle(handle) as Button;
}

This will return a Button instance reference if the handle is valid and
represents a Button control, or null if not.

Pete

[Peter Duniho]

ink wrote:

>
Bollocks..

I don't know what your problem is. You claimed to have a Button
instance in your original post. If you don't actually have a Button
instance, it's true that FromHandle won't get you an instance, but that
doesn't change the veracity of my answer. It just means you need to
learn to ask better questions (ie, don't make statements that aren't true).

As far as whether it's supported in Compact Framework, well...this isn't
a CF newsgroup. You will need to take responsibility for any specific
difference in your own environment from the more general environment
relevant to the forum in which you ask your question.

I'm sorry that in your specific case my answer wasn't applicable. But I
don't see any need for you to be so rude about it.

Pete

[Christian Resma Helle]

not to butt in a make things worse but,
'microsoft.publ ic.dotnet.frame work.compactfra mework' is actually a .NETCF
newsgroup...
"Peter Duniho" <Np*********@Nn OwSlPiAnMk.comw rote in message
news:13******** *****@corp.supe rnews.com...

ink wrote:

>>
Bollocks..

I don't know what your problem is. You claimed to have a Button instance
in your original post. If you don't actually have a Button instance, it's
true that FromHandle won't get you an instance, but that doesn't change
the veracity of my answer. It just means you need to learn to ask better
questions (ie, don't make statements that aren't true).

As far as whether it's supported in Compact Framework, well...this isn't a
CF newsgroup. You will need to take responsibility for any specific
difference in your own environment from the more general environment
relevant to the forum in which you ask your question.

I'm sorry that in your specific case my answer wasn't applicable. But I
don't see any need for you to be so rude about it.

Pete