interop between VB.NET and eVC++

[Eric BOUXIROT]

hi there,

i'm working on a smart application project on VB.NET. i must call API
(custom eVC++ DLL) but i have some trouble with mashalas attribute.....
i have copy/past a sample on msdn help but it's not working..
IDE says "unknown 'mashalAs' attribute".....and i don't know why....

i have try exactly the same code on a normal windows project and it work
(compile) fine...

i don't know what i've missed....

here some lines of my code...

thank a lot...

Imports System.Runtime.InteropServices

Public Class Form1

Public Declare Function F_BDO_MessageBoxOK Lib "PDA_BDO.dll" (ByRef
IN_title() As Byte, <MarshalAs(UnmanagedType.LPStr)> ByRef IN_msg As String)
As Int32

 

[Alex Feinman [MVP]]

MarshalAs attribute is not supported in CF - simply drop it, and your string
will be passed as LPCWSTR (note the constant part)
As for a byte array, replace ByRef with ByVal - the array will be passed
down as LPBYTE

 

[Eric BOUXIROT]

oh ok.....

thank, but i have one more question...
in my eVC++ DLL some functions use non-unicode strings (unsigned char*)

how i can tell VB to call DLL with non-UNICODE string format ?

thank a lot !

 

[Chris Tacke, eMVP]

Pass a byte array.

-Chris

oh ok.....

thank, but i have one more question...
in my eVC++ DLL some functions use non-unicode strings (unsigned char*)

how i can tell VB to call DLL with non-UNICODE string format ?

thank a lot !

 

[Eric BOUXIROT]

yes i have already test this....it's ok but in my VB code i can't directly
convert String to byte array..

like this..
DLLFunction ("Toto".tobytearray)

i must declare one byte array then fill it with the string chars....then
call my function...
Dim bytearray(50) as byte
convertstring2bytearray ("toto",bytearray)
DLLFunction(bytearray)

i prefer the first method....but how i can implement the toByteArray method
to the string class ?

thank a lot .

 

[Chris Tacke, eMVP]

Use the Encoding class to change it.

-Chris

yes i have already test this....it's ok but in my VB code i can't directly
convert String to byte array..

like this..
DLLFunction ("Toto".tobytearray)

i must declare one byte array then fill it with the string chars....then
call my function...
Dim bytearray(50) as byte
convertstring2bytearray ("toto",bytearray)
DLLFunction(bytearray)

i prefer the first method....but how i can implement the toByteArray method
to the string class ?

thank a lot .

"Chris Tacke, eMVP" <[email protected]> a écrit dans le message
de news: (e-mail address removed)...

 

[Eric BOUXIROT]

an small example ?

thank a lot !

Use the Encoding class to change it.

-Chris

 

[Alex Feinman [MVP]]

Dim chars as Byte() = System.Text.Encoding.ASCII.GetBytes(myString)
THis is what you need to pass down to the unmanaged code

 

[Chris Tacke, eMVP]

Take a look at the sample in MSDN:

http://msdn.microsoft.com/library/en-us/cpref/html/frlrfSystemTextEncodingClassConvertTopic.asp


-Chris

 

[Peter Foot [MVP]]

asciibytes = System.Text.Encoding.ASCII.GetBytes("Hello World")

Peter

--
Peter Foot
Windows Embedded MVP
www.inthehand.com | www.opennetcf.org

Do have an opinion on the effectiveness of Microsoft Windows Mobile and
Embedded newsgroups? Let us know!
https://www.windowsembeddedeval.com/community/newsgroups

 

[Eric BOUXIROT]

ok thank a lot for your very quick answers...
it work fine....