GetNextWindow API in C#

[Tim Mulholland]

I'm trying to call the GetNextWindow API function via C#.

I've tried two different definitions for it (both are similar), but i always
get the same error:

An unhandled exception of type 'System.EntryPo intNotFoundExce ption' occurred
in MsgTestCSharp.e xe
Additional information: Unable to find an entry point named GetNextWindow in
DLL user32.dll.

The most recent way i tried was:

[DllImport("user 32.dll", CharSet=CharSet .Auto)]
public static extern IntPtr GetNextWindow(I ntPtr hwnd, IntPtr wFlag);


what am i doing wrong here?

Thanks in advance,

-Tim

[Nicholas Paldino [.NET/C# MVP]]

Re: GetNextWindow API in C#

Tim,

GetNextWindow isn't actually an API function, but rather, a macro that
just calls GetWindow. So you should define GetWindow, and call that. If
you really want to call a method named GetNextWindow, then you can define
the entry point, like this:

[DllImport("user 32.dll", CharSet=CharSet .Auto, EntryPoint="Get Window",
SetLastError=tr ue)]
public static extern IntPtr GetNextWindow(
IntPtr hwnd,
[MarshalAs(Unman agedType.U4)] int wFlag);

I changed the wFlag parameter because it would end up failing on 64-bit
systems.

Hope this helps.


--
- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard. caspershouse.co m

"Tim Mulholland" <TimMulholland@ nospamaddress.c om> wrote in message
news:e8XJVMk0EH A.2196@TK2MSFTN GP14.phx.gbl...[color=blue]
> I'm trying to call the GetNextWindow API function via C#.
>
> I've tried two different definitions for it (both are similar), but i
> always
> get the same error:
>
> An unhandled exception of type 'System.EntryPo intNotFoundExce ption'
> occurred
> in MsgTestCSharp.e xe
> Additional information: Unable to find an entry point named GetNextWindow
> in
> DLL user32.dll.
>
> The most recent way i tried was:
>
> [DllImport("user 32.dll", CharSet=CharSet .Auto)]
> public static extern IntPtr GetNextWindow(I ntPtr hwnd, IntPtr wFlag);
>
>
> what am i doing wrong here?
>
> Thanks in advance,
>
> -Tim
>
>[/color]

[Tim Mulholland]

Re: GetNextWindow API in C#

I dug into the .dll with depends and found that out for myself just a few
minutes ago.
I had read that a while back, but i thought it was the other way around (why
make a macro that has a longer name than the original?)

Thanks for the top on the one parameter.

-Tim

"Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard .caspershouse.c om> wrote in
message news:eea78dk0EH A.3820@TK2MSFTN GP11.phx.gbl...[color=blue]
> Tim,
>
> GetNextWindow isn't actually an API function, but rather, a macro that
> just calls GetWindow. So you should define GetWindow, and call that. If
> you really want to call a method named GetNextWindow, then you can define
> the entry point, like this:
>
> [DllImport("user 32.dll", CharSet=CharSet .Auto, EntryPoint="Get Window",
> SetLastError=tr ue)]
> public static extern IntPtr GetNextWindow(
> IntPtr hwnd,
> [MarshalAs(Unman agedType.U4)] int wFlag);
>
> I changed the wFlag parameter because it would end up failing on[/color]
64-bit[color=blue]
> systems.
>
> Hope this helps.
>
>
> --
> - Nicholas Paldino [.NET/C# MVP]
> - mvp@spam.guard. caspershouse.co m
>
> "Tim Mulholland" <TimMulholland@ nospamaddress.c om> wrote in message
> news:e8XJVMk0EH A.2196@TK2MSFTN GP14.phx.gbl...[color=green]
> > I'm trying to call the GetNextWindow API function via C#.
> >
> > I've tried two different definitions for it (both are similar), but i
> > always
> > get the same error:
> >
> > An unhandled exception of type 'System.EntryPo intNotFoundExce ption'
> > occurred
> > in MsgTestCSharp.e xe
> > Additional information: Unable to find an entry point named[/color][/color]
GetNextWindow[color=blue][color=green]
> > in
> > DLL user32.dll.
> >
> > The most recent way i tried was:
> >
> > [DllImport("user 32.dll", CharSet=CharSet .Auto)]
> > public static extern IntPtr GetNextWindow(I ntPtr hwnd, IntPtr wFlag);
> >
> >
> > what am i doing wrong here?
> >
> > Thanks in advance,
> >
> > -Tim
> >
> >[/color]
>
>[/color]

[Mattias Sjögren]

Re: GetNextWindow API in C#

Tim,
[color=blue]
>(why make a macro that has a longer name than the original?)[/color]

It started out as a real function in the Win16 API. In Win32 it's a
macro mostly available for backward compatibility.



Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
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