hi ,everyone ,please check my codes,i am really confused.

the codes of win32 dll is as follows:
***********************the win32 DLL writen in c++*****************


extern "C"
{
__declspec(dllexport) WCHAR*  __stdcall getWNameOfComponnet();

}

WCHAR name[100];

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
    return TRUE;
}


WCHAR*  getWNameOfComponnet(){
	return name;
}

************************************************
*********************the win32 .def file************

EXPORT
getWNameOfComponnet  @1
*****************************************************


and I try to use the export in c#,but I can not get anything from
getprocaddress(,.)

**************import the prototype of api**
[DllImport ("kernel32.dll",EntryPoint="LoadLibraryW",
CharSet=CharSet.Unicode,CallingConvention=CallingConvention.StdCall,
SetLastError =true)]
public extern static IntPtr   LoadLibrary(String  lpFileName);

[DllImport("Kernel32", EntryPoint = "GetProcAddress",
CharSet=CharSet.Unicode ,CallingConvention =
CallingConvention.StdCall,
SetLastError = true)]
 public extern static IntPtr  GetProcAddress(
            IntPtr handle,
            [MarshalAs(UnmanagedType.LPWStr)]string funcname);

**********************
**************get the export from my dll***
public delegate string getwname();

        private static Delegate GetAddress(IntPtr  dllModule, string
functionname, Type t)
        {

            IntPtr  addr = GetProcAddress(dllModule, functionname);
//addr is always zero.why?

            if (addr == IntPtr.Zero )
                return null;
            else
                return Marshal.GetDelegateForFunctionPointer(addr, t);
        }

        public String callGetWname()
        {
            IntPtr  huser32 =IntPtr.Zero ;
            huser32 = LoadLibrary("my.dll");//the huser32 is ok,the
dll is loaded.
            getwname mygetw = (getwname)GetAddress(huser32,
"getWNameOfComponnet",
 typeof(getwname));

        }

********************************


the getProcAddress(..) doesn't work.Where am i wrong?

> the getProcAddress(..) doesn't work.Where am i wrong?

Does the filename of the DLL you need to load change after compile time?  If 
not, let p/invoke handle all the dynamic loading mess for you and just use 
DllImport and declare the function you need to call.

hi,Ben

the export of the DLL is right. I check them with a tool software.


and I change the prototype of getProcAddress(..) in C# as follows:
**************************
        [DllImport("Kernel32.dll", EntryPoint = "GetProcAddress", CharSet = 
CharSet.Ansi, CallingConvention = CallingConvention.StdCall , SetLastError = 
true)]
        public extern static IntPtr  GetProcAddress(
            IntPtr handle,
            [MarshalAs(UnmanagedType.LPStr)]string funcname);
***************************

if I change it into unicode ,everything go wrong. I don't why ,maybe 
GetProcAddress() only has ANSI version.

just put result here for someone may encounter the same problem.





"Ben Voigt [C++ MVP]" <rbv@nospam.nospam> дÈëÏûÏ¢ÐÂÎÅ:eCwjTSR4IHA.1420@TK2MSFTNGP06.phx.gbl...
>> the getProcAddress(..) doesn't work.Where am i wrong?
>
> Does the filename of the DLL you need to load change after compile time? 
> If not, let p/invoke handle all the dynamic loading mess for you and just 
> use DllImport and declare the function you need to call.
>

> **************import the prototype of api**
> [DllImport ("kernel32.dll",EntryPoint="LoadLibraryW",
> CharSet=CharSet.Unicode,CallingConvention=CallingConvention.StdCall,
> SetLastError =true)]
> public extern static IntPtr   LoadLibrary(String  lpFileName);

Just FYI, you shouldn't specify the LoadLibraryW entry point unless you 
specified ExactSpelling = true on the DllImport attribute. You're already 
specifying to use the Unicode character set, as such that would be handled 
automatically. Also, you don't need to specify the EntryPoint unless it's 
different than the name of the function you're defining. Just some nice 
things you might want to do to help simplify your code. :o)

For example: This would need it.
[DllImport("myfile.dll", EntryPoint = "Foo")]
public static extern void Bar();

After looking in both the WinBase.h and Windows.h header files the MSDN 
documentation states they're located in there was only a single declaration 
for the GetProcAddress function - which leads me to believe you are correct 
when you said that only the ANSI version is available. Not to mention there 
is no information in the MSDN documentation indicating there is both a 
Unicode and ANSI version available.

Perhaps because old C didn't allow Unicode characters in their definitions. 
I don't know, I'm completely guessing there. Never used it before so I 
couldn't say either way for sure. That's the only reason I could think of 
why there wouldn't be a unicode version of the definition.

"Ryanivanka"  wrote in message 
news:%23BH0N5W4IHA.2332@TK2MSFTNGP03.phx.gbl...
> hi,Ben
>
> the export of the DLL is right. I check them with a tool software.
>
>
> and I change the prototype of getProcAddress(..) in C# as follows:
> **************************
>        [DllImport("Kernel32.dll", EntryPoint = "GetProcAddress", CharSet = 
> CharSet.Ansi, CallingConvention = CallingConvention.StdCall , SetLastError 
> = true)]
>        public extern static IntPtr  GetProcAddress(
>            IntPtr handle,
>            [MarshalAs(UnmanagedType.LPStr)]string funcname);
> ***************************
>
> if I change it into unicode ,everything go wrong. I don't why ,maybe 
> GetProcAddress() only has ANSI version.
>
> just put result here for someone may encounter the same problem.
>
>
>
>
>
> "Ben Voigt [C++ MVP]" <rbv@nospam.nospam> 
> дÈëÏûÏ¢ÐÂÎÅ:eCwjTSR4IHA.1420@TK2MSFTNGP06.phx.gbl...
>>> the getProcAddress(..) doesn't work.Where am i wrong?
>>
>> Does the filename of the DLL you need to load change after compile time? 
>> If not, let p/invoke handle all the dynamic loading mess for you and just 
>> use DllImport and declare the function you need to call.
>>
>
>

On Jul 8, 6:34 pm, Ryanivanka  wrote:

> the getProcAddress(..) doesn't work.Where am i wrong?

Here:

> [DllImport("Kernel32", EntryPoint = "GetProcAddress",
> CharSet=CharSet.Unicode ,CallingConvention =
> CallingConvention.StdCall,
> SetLastError = true)]

You either need to use CharSet=CharSet.Auto, or
EntryPoint="GetProcAddressW". If you specify CharSet explicitly, P/
Invoke won't auto-decorate the function name.

Ryanivanka wrote:
> hi,Ben
>
> the export of the DLL is right. I check them with a tool software.

Why are you using GetProcAddress?  Use a DllImport attribute on *your* 
function setting EntryPoint correctly and p/invoke will call LoadLibrary and 
GetProcAddress for you.

>
>
> and I change the prototype of getProcAddress(..) in C# as follows:
> **************************
>        [DllImport("Kernel32.dll", EntryPoint = "GetProcAddress",
> CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall ,
> SetLastError = true)]
>        public extern static IntPtr  GetProcAddress(
>            IntPtr handle,
>            [MarshalAs(UnmanagedType.LPStr)]string funcname);
> ***************************
>
> if I change it into unicode ,everything go wrong. I don't why ,maybe
> GetProcAddress() only has ANSI version.
>
> just put result here for someone may encounter the same problem.
>
>
>
>
>
> "Ben Voigt [C++ MVP]" <rbv@nospam.nospam>
> дÈëÏûÏ¢ÐÂÎÅ:eCwjTSR4IHA.1420@TK2MSFTNGP06.phx.gbl...
>>> the getProcAddress(..) doesn't work.Where am i wrong?
>>
>> Does the filename of the DLL you need to load change after compile
>> time? If not, let p/invoke handle all the dynamic loading mess for
>> you and just use DllImport and declare the function you need to call.

Thank you, Pavel.
  It does work if I kick out the"CharSet" attribute.

  
----------------------------------------- 
  ÔÚ Wed, 9 Jul 2008 07:20:02 -0700 (PDT)  £¬Pavel MinaevдµÀ£º
>On Jul 8, 6:34 pm, Ryanivanka  wrote:
>
>> the getProcAddress(..) doesn't work.Where am i wrong?
>
>Here:
>
>> [DllImport("Kernel32", EntryPoint = "GetProcAddress",
>> CharSet=CharSet.Unicode ,CallingConvention =
>> CallingConvention.StdCall,
>> SetLastError = true)]
>
>You either need to use CharSet=CharSet.Auto, or
>EntryPoint="GetProcAddressW". If you specify CharSet explicitly, P/
>Invoke won't auto-decorate the function name.

----------------------------------------- 

  Ö Àñ£¡
             Ryanivanka
             sarah.hhyy@gmail.com

hi,Ben.
what you ask remind me of another question.

I was told if I use LoadLibrary(..)to load a DLL, I have to freeLibrary(..) by myself too,because CLR won't do that for me? is this correct?

I use LoadLibrary(..) to control the bind of DLL by myself.And if I import my function using EntryPoint,would the DLL stay in the process's virtual address space until the process is ended?



----------------------------------------- 
  ÔÚ Wed, 9 Jul 2008 11:21:38 -0500  £¬Ben Voigt [C++ MVP]дµÀ£º
>Ryanivanka wrote:
>> hi,Ben
>>
>> the export of the DLL is right. I check them with a tool software.
>
>Why are you using GetProcAddress?  Use a DllImport attribute on *your* 
>function setting EntryPoint correctly and p/invoke will call LoadLibrary and 
>GetProcAddress for you.
>
>>
>>
>> and I change the prototype of getProcAddress(..) in C# as follows:
>> **************************
>>        [DllImport("Kernel32.dll", EntryPoint = "GetProcAddress",
>> CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall ,
>> SetLastError = true)]
>>        public extern static IntPtr  GetProcAddress(
>>            IntPtr handle,
>>            [MarshalAs(UnmanagedType.LPStr)]string funcname);
>> ***************************
>>
>> if I change it into unicode ,everything go wrong. I don't why ,maybe
>> GetProcAddress() only has ANSI version.
>>
>> just put result here for someone may encounter the same problem.
>>
>>
>>
>>
>>
>> "Ben Voigt [C++ MVP]" <rbv@nospam.nospam>
>> дÈëÏûÏ¢ÐÂÎÅ:eCwjTSR4IHA.1420@TK2MSFTNGP06.phx.gbl...
>>>> the getProcAddress(..) doesn't work.Where am i wrong?
>>>
>>> Does the filename of the DLL you need to load change after compile
>>> time? If not, let p/invoke handle all the dynamic loading mess for
>>> you and just use DllImport and declare the function you need to call. 
>
>

----------------------------------------- 

  Ö Àñ£¡
             Ryanivanka
             sarah.hhyy@gmail.com

On Jul 10, 4:39 am, Ryanivanka  wrote:

> I was told if I use LoadLibrary(..)to load a DLL, I have to freeLibrary(..) by myself too,because CLR won't do that for me? is this correct?

Yes. CLR garbage collector only collects memory, everything else is
"unmanaged resources", and you have to take care of it yourself.

> I use LoadLibrary(..) to control the bind of DLL by myself.And if I import my function using EntryPoint,would the DLL stay in the process's virtual address space until the process is ended?

Yes.