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Hello Experts,

I have created a Native Dll (myNativeDll.dll) just to keep it simple it exposes one method.

__declspec(dllexport)char * GetStringFromDll( )

const size_t alloc_size = 128;
STRSAFE_LPSTR result = (STRSAFE_LPSTR)CoTaskMemAlloc( alloc_size );
STRSAFE_LPCSTR retstr = "This value is returned from native dll";
StringCchCopyA( result, alloc_size, retstr );
return (char *) result;

on the client side (Managed App) defined a helper class to use this dll as

namespace MarshalStringApp
    public class MyDllWrapper
        //  Calling Standard Windows Functions.
        [DllImport("User32.dll", EntryPoint = "MessageBox", CharSet = CharSet.Auto)]
        public static extern int MsgBox(int hWnd, String text, String caption, uint type);

        //  Calling Functions from our Dll.
        public static extern String GetStringFromDll();

and added a handler to the form to call this function.
private void btnGetStringFromDll_Click(object sender, EventArgs e)
           String str = "";
               str = MyDllWrapper.GetStringFromDll();
               MessageBox.Show("String Returned [" + str + "]");
           catch (Exception eX)

I am getting an exception Code (0x8007007E), suggesting that DLL "myNativeDll.dll" is not found, i tried copying it to the client's folder to (where exe resides) but no avail. where should i copy this native dll, for this app to work. or i am missing something.

any help will be highly appreciated.

Updated 8-Jul-13 5:47am
[no name] 8-Jul-13 11:11am    
Have you tried [DllImport("myNativeDll.dll")]?
Katiyar S. 8-Jul-13 11:50am    
Yes I have tried that only, DllImport("myNativeDll.dll")], extremely sorry, i made a mistake in dll name while typing on forum.

1 solution

Quickest solution is to put this dll in WINDOWS\SYSTEM32 folder and see whether it gets loaded or not.
Share this answer
Katiyar S. 9-Jul-13 4:19am    
No, i tried that too
_Asif_ 9-Jul-13 4:43am    
For debugging purpose hardcode the path of the dll. For example

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