How to use Managed DLL in Unmanaged DLL and vice versa...

[Arif]

Hi All,
I was tring to create some dialogs with basic windows
controls like tabs,checkbox, picture control, buttons, URL links
etc....

I discovered that's it's very time copnsuming doing it pure Win32
way ... then I thought of exploring other technology/apps...

Delphi/ MFC/.NET

I discovered creating forms using .NET is very easy it's almost like
VB...where you just design what you want and code gets generated.....

In VS2008 I created a New Project-> Visual C++-> CLR ->Windows Form
Application .... and it worked fine

Now I wanted to create a ..NET DLL which would hold my all
dialogs ...provide some exported helper functions to invoke them from
pure Win32 Application or DLL

I created New Project-> Visual C++-> CLR ->Windows Form Control
Library.....

which does generate a DLL ...but I am not able to export any
function from this DLL
when I try to export any function

I get following two error

error C3389: __declspec(dllexport) cannot be used with /clr:pure or /
clr:safe
error C3395: 'myfunction' : __declspec(dllexport) cannot be applied to
a function with the __clrcall calling convention

how do i get of rid of this i went to propject properties and tried if
i could remove those flag /clr:pure and /clr:safe
but i could not find any option there....

I also want to used some exported structure ( which contain only
member variable and no functions)
of Win32 DLL...

This was first time ever i used .NET ..
Any URLs to learn how to do what i want to do , would be really
helpful....

Thanking you all in advance
-Arif

[David Lowndes]

> I was tring to create some dialogs with basic windows
>controls like tabs,checkbox, picture control, buttons, URL links
>etc....
>
>I discovered that's it's very time copnsuming doing it pure Win32
>way

All the things you mention should be fairly straightforward to do with
the Win32 dialog editor, however...

>Now I wanted to create a ..NET DLL which would hold my all
>dialogs ...provide some exported helper functions to invoke them from
>pure Win32 Application or DLL
>
>I created New Project-> Visual C++-> CLR ->Windows Form Control
>Library.....

I think most people would recommend that you probably choose C# for a
.Net project - things in the IDE just work easily with it.

>which does generate a DLL ...but I am not able to export any
>function from this DLL
>when I try to export any function
>
>I get following two error
>
>error C3389: __declspec(dllexport) cannot be used with /clr:pure or /
>clr:safe
>error C3395: 'myfunction' : __declspec(dllexport) cannot be applied to
>a function with the __clrcall calling convention

Since you're creating a .Net module you'd probably find it easier to
interface using .Net techniques and have your Visual C++/CLI program
interface to it that way.

Dave

[Arif]

Thanks dave....
I converted my Win32 dll written in C++ to .net using /clr switch....

I added the tnew forms (I think It's same as you do form C#) ....

but now my problem was I wanted to use some Win32 DLLs written in C+
+..

I chose to use p?Invoke for it....
I am successfully able to invoke functions in Win32 DLL....

but now I am facing problem with Types....

I called following three native functions in my managed code

int function1(void);
bool function2(void);
wchar_t *function3(void);

when using the function1 , i am getting correct return value ...but
when using function2... I am always getting return value as true... i
had put a break point in function2 and i see that when it returns
false ...even then ...in managed code it is received as ... .true....

and about function3, that's also not working if I am returning say
L"Test"
and in managed code when i received it as String^ i just get "T"...

this how i have delcared native functions mentioned above in my
managed code

[System::Runtime::InteropServices::DllImportAttribute
("SystemHook.dll")]
static bool function2(void);

[System::Runtime::InteropServices::DllImportAttribute
("SystemHook.dll")]
static int function1(void);

[System::Runtime::InteropServices::DllImportAttribute
("SystemHook.dll")]
static String^ function3(void);

and this is how I am using them...

Boolean result = function2(); // here it self i can
see result is always true....
int iRes = function1();
this->checkBox6->Checked =result;

this->Text = function3(); //setting the
dialog's title

[David Lowndes]

>I converted my Win32 dll written in C++ to .net using /clr switch....
>
>I added the tnew forms (I think It's same as you do form C#) ....
>
>but now my problem was I wanted to use some Win32 DLLs written in C+
>+..
>
>I chose to use p?Invoke for it....

There's no need to use PInvoke with C++/CLI - just do it as though it
was pure C++/Windows, it just works! That's the beauty of C++/CLI in
the managed world over the other .Net languages.

I've never used PInvoke so I don't know if you have anything wrong
there.

Dave