How to check if a DLL file is registered?

Question

How do I find whether a DLL file written in C# is registered or not programmatically?

I already tried this code, but it doesn\'t come off.

If I register a DL

Answer 1

[DllImport("kernel32")]    
public extern static bool FreeLibrary(int hLibModule);

[DllImport("kernel32")]    
public extern static int LoadLibrary(string lpLibFileName);



public bool IsDllRegistered(string DllName)    
{

      int libId = LoadLibrary(DllName);    
      if (libId>0) FreeLibrary(libId);    
      return (libId>0);    
}

Answer 2

You can use this:

My.Computer.Registry.ClassesRoot.GetSubKeyNames.Contains("gEncrypt.clsEncrypt")

Where "gEncrypt.clsEncrypt" is ComName.ClassName.

Answer 3

1. Declare a pointer to Interface
2. Call CoCreateInstance on the CLSID and IID
3. If return value is not S_OK then class is not registered

Answer 4

class TestDll
{
    //Import your tested DLL here
    [DllImport("kernel32")]
    public extern static int LoadLibrary(string lpLibFileName);
}

try
{
    TestDll test = new TestDll();
}
catch(DllNotFoundException ex)
{
    return false;
}

Answer 5

If you mean registered in GAC, here is my consideration: to be registered in GAC, an assembly must be signed with a strong name (have a public key token in it's name).

So you can try load it using Assembly.Load(string), if you got FileNotFoundException - assembly was not registered in GAC.

If got no error, but result Assembly.GetName().GetPublicKeyToken() is null or empty -- this mean you found assembly in application directory, not in GAC.

Answer 6

If you know the CLSID of the COM dll, you can just check if there's a key with that CLSID on HKEY_CLASSES_ROOT\CLSID\{CLSID-of-your-COM-component} or HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{CLSID-of-your-COM-component} (Wow6432Node => 32-bit COM registered on a 64-bit machine)

Here is an example:

private bool IsAlreadyRegistered()
{
    using (var classesRootKey = Microsoft.Win32.RegistryKey.OpenBaseKey(
           Microsoft.Win32.RegistryHive.ClassesRoot, Microsoft.Win32.RegistryView.Default))
    {
        const string clsid = "{12345678-9012-3456-7890-123456789012}";

        var clsIdKey = classesRootKey.OpenSubKey(@"Wow6432Node\CLSID\" + clsid) ??
                        classesRootKey.OpenSubKey(@"CLSID\" + clsid);

        if (clsIdKey != null)
        {
            clsIdKey.Dispose();
            return true;
        }

        return false;
    }
}