RASCREATE API call

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Guest

VB.net 2000
Windows XP only

I have an app that (among other things) allows the user to create a new
"phonebook" entry. API is defined this way:

Declare Auto Function RasCreate Lib "Rasapi32.dll"_ Alias
"RasCreatePhonebookEntry" (ByVal hwnd As Integer,_
<MarshalAs(UnmanagedType.LPStr)> Byval lpszPhonebook As String) As Integer

(I use the same MarshalAs directive for the RASSETCREDENTIALS API and it
works perfectly.)

If I pass vbnull as the phonebook name like this:

APIResult = RasCreate(Me.Handle.ToInt32, VBNULL)

it works fine, but the entry is always created in the "All Users" phonebook.
I want the user to be able to select the private phonebook if he wants, so I
need to pass the phonebook name as a variable.

I use:
dim phonebook as string
dim APIResult as integer

phonebook =
Environment.GetFolderPath_(Environment.SpecialFolder.CommonApplicationData)_
& "\Microsoft\Network\Connections\Pbk\rasphone.pbk"

or:

phonebook =
Environment.GetFolderPath_(Environment.SpecialFolder.ApplicationData)_ &
"\Microsoft\Network\Connections\Pbk\rasphone.pbk"

depending on if the user wants the public or private phonebook. Then:

APIResult = RasCreate(Me.Handle.ToInt32, phonebook)

always returns "Error 621: The system could not open the phonebook file".

As I mentioned earlier, i use the exact same method to pass the phonebook to
RasSetCredentials and it works fine.

What am I missing?
 
Well I got it to work, but I'm as confused as ever. Maybe someone can explain
this.
I got it to work by leaving out the <marshalas..> directive so the delare is
just:

Declare Auto Function RasCreate Lib "Rasapi32.dll"_
Alias "RasCreatePhonebookEntry" (ByVal hwnd As Integer,_
Byval lpszPhonebook As String) As Integer

I'm confused because leaving out the <marshalas...> directive has caused an
error with every other RAS api i've used when passing a string variable. Can
anyone out there explain why RasCreatePhonebookEntry is different?
 
Doug,
I'm confused because leaving out the <marshalas...> directive has caused an
error with every other RAS api i've used when passing a string variable. Can
anyone out there explain why RasCreatePhonebookEntry is different?
Click to expand...

The Auto modifier will cause the CLR to call the Unicode version of
the API on NT-based systems (which I assume you're running on), but
using MarshalAs(UnmanagedType.LPStr) will cause the string parameter
to marshal as an ANSI string. And passing an ANSI string to a function
expecting a Unicode string will of course not work. You could have
used MarshalAs(UnmanagedType.LPTStr), but leaving out the MarshalAs
attribute and relying on the default behavior works just as well.

BTW, I recommend changing the type of the hwnd parameter to IntPtr.



Mattias
 
So since this is strictly for our internal use and I don't care if it handles
unicode strings, would i be better off not using the Auto modifier and just
explicitly specifing Ansi?
 
NOW I get it!

On all my other API declarations, I had explicity listed the Ansi version in
the alias parameter (e.g. alias "RasSetCredentialsA") on this one I left off
the "A" in the alias. That's why I had to use the <MarshalAs...> directive on
the other calls to force an Ansi string.

Live and learn.
 
So since this is strictly for our internal use and I don't care if it handles
unicode strings, would i be better off not using the Auto modifier and just
explicitly specifing Ansi?
Click to expand...

No, I definitely recommend using Auto.



Mattias
 
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