SendMessage API

[Steve]

I am trying to use the SendMessage API function using
EM_POSFROMCHAR to get the x,y location of the current
character. I have declared the function and placed the
call into my code. How do I access the x,y coordinates.
Some example code in C# would be greatly appreciated.

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

Steve,

I think you can get away with this by using the following declaration
for SendMessage:

// Note, you have to set the function name, depending on the platform to do
this. You can't
// just use "SendMessage" for the entry point.
[DllImport("user32.dll", EntryPoint="SendMessageA")]
public static extern int SendPosFromCharMessage(
IntPtr hWnd,
[MarshalAs(UnmanagedType.U4)] int Msg,
ref Point wParam,
IntPtr lParam);

The Point structure in .NET has the same layout as the POINTL structure
that the EM_POSFROMCHAR message expects. Also, declaring it this way should
handle the marshaling of the structure automatically.

If you didn't want to use this method, then you would have to declare a
structure and marshal it using the static StructureToPtr method on the
Marshal class and then pass that to the SendMessage function declared with
the wParam and lParam parameters as IntPtr values.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Steve" <ho******@cmmts.com> wrote in message
news:03****************************@phx.gbl...

I am trying to use the SendMessage API function using
EM_POSFROMCHAR to get the x,y location of the current
character. I have declared the function and placed the
call into my code. How do I access the x,y coordinates.
Some example code in C# would be greatly appreciated.

Nicholas,

thank you for the response. I know this may sound dumb - I
understand how to declare the function (although the
MarshalAs was something I hadn't thought of). My problem
is, I am unsure of how to issue the call and where the
information (point) is for retrieving the information. I
think this may have something to do with my lack of
experience with CALLBACK routines and pointers. Further
explanation of this would be appreciated.

-----Original Message-----
Steve,

I think you can get away with this by using the following declarationfor SendMessage:

// Note, you have to set the function name, depending on the platform to dothis. You can't
// just use "SendMessage" for the entry point.
[DllImport("user32.dll", EntryPoint="SendMessageA")]
public static extern int SendPosFromCharMessage(
IntPtr hWnd,
[MarshalAs(UnmanagedType.U4)] int Msg,
ref Point wParam,
IntPtr lParam);

The Point structure in .NET has the same layout as the POINTL structurethat the EM_POSFROMCHAR message expects. Also, declaring it this way shouldhandle the marshaling of the structure automatically.

If you didn't want to use this method, then you would have to declare astructure and marshal it using the static StructureToPtr method on theMarshal class and then pass that to the SendMessage function declared withthe wParam and lParam parameters as IntPtr values.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Steve" <ho******@cmmts.com> wrote in message
news:03****************************@phx.gbl...

I am trying to use the SendMessage API function using
EM_POSFROMCHAR to get the x,y location of the current
character. I have declared the function and placed the
call into my code. How do I access the x,y coordinates.
Some example code in C# would be greatly appreciated.

.

[Mattias Sjögren]

Nicholas,

// Note, you have to set the function name, depending on the platform to do
this. You can't
// just use "SendMessage" for the entry point.

Why do you say that?

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

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

Mattias,

I'm going by the examples. In the examples for using the EntryPoint in
the documentation for the DllImport attribute, the EntryPoint property is
set to "SendMessageA". Trying this out myself, however, it would seem the
documentation is misleading.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Mattias Sjögren" <ma********************@mvps.org> wrote in message
news:ux**************@TK2MSFTNGP10.phx.gbl...

Nicholas,

// Note, you have to set the function name, depending on the platform to dothis. You can't
// just use "SendMessage" for the entry point.

Why do you say that?

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Mattias Sjögren]

I'm going by the examples. In the examples for using the EntryPoint in
the documentation for the DllImport attribute, the EntryPoint property is
set to "SendMessageA".
Oh, okay.

Trying this out myself, however, it would seem the
documentation is misleading.

Yep, as long as you don't set ExactSpelling=true you should be able to
specify just SendMessage.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Steve]

F.Y.I. I ended up using a rich text box and used the
GetPositionFromCharIndex function. This saved me from
using potentially unsafe code.

-----Original Message-----

I'm going by the examples. In the examples for using the EntryPoint inthe documentation for the DllImport attribute, the EntryPoint property isset to "SendMessageA".
Oh, okay.

Trying this out myself, however, it would seem the
documentation is misleading.

Yep, as long as you don't set ExactSpelling=true you

should be able tospecify just SendMessage.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.comPlease reply only to the newsgroup.
.