64 bit dll in 64 bit process Vista fails - Unable to load DLL 'dllname': The specified module could not be found

Question

I have a native C code, I compiled the code in vc++ 2008 and its compiled with 'x64' as platform in configuration manager and I have an c# application which is also compiled with 'x64' as platform and it calls the dll function. I have used Dllimport to call the function from the dll like below.

using System.Runtime.InteropServices;

namespace test            
{    
public partial class Form1 : Form                                                     
  {

      [DllImport("mtest", CharSet = CharSet.Ansi)]
        public extern static void e_path(string path);

        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("test");
            swe_set_ephe_path("E:\\Gan");
        }
    }
}

at the time of running the application I am getting the error as below:

An unhandled exception of type 'System.DllNotFoundException' occurred in test.exe

Additional information: Unable to load DLL 'mydll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

Could any you please help me out to resolve this. If I run both the dll and the applicaition its working fine. But I need the dll functions to be called from my ASP pages so I need both the dll and application as 64 bit.

ADDITIONAL INFORMATION : when I checked the dll for dependency using dependency walker for 64-bit It shows that the Kernel32.dll and NTDLL.DLL and mydll.dll is x64.

please help me out with this.

Thanks in Advance,

Answer 1

on x64 platforms the SYSWOW64 directory contains files for 32bit applications. You will find the same differentiation in the registry, where SYSWOW64 contains entries for x32 applications. Greetings

Comment: The registry key containing 32bit entries is Wow6432Node and resides in //HKEY_LOCAL_MACHINE

Answer 2

问题在于您的dll依赖于其他某个dll，并且无法找到其他dll，因为它位于加载程序无法搜索它的某个路径上，或者该dll不是64位。