InterFace And WebApi.. NullReference Exception

Krishna Kumar

public interface ILoginManager

{

IEnumerable GetLogins();

}

I have declared this methods in the interface and implemented in below class

class LoginManager : ILoginManager

{

private readonly ILoginRespository _loginRepository;

public LoginManager(ILoginRespository loginRepository)

{

_loginRepository = loginRepository;

}

public HR_Login Create(HR_Login login)

{

return _loginRepository.Create(login);

}

Now i am trying to access the method in webapi

private readonly ILoginManager _loginManager;

public LoginController()

{

}

public LoginController(ILoginManager loginManager)

{

this. _loginManager = loginManager;

}

[HttpGet, Route("logins")]

public HttpResponseMessage Get()

{

return Request.CreateResponse(HttpStatusCode.OK, _loginManager.GetLogins());

}

And when i complied this code... It is giving mr the Null Reference exception in the controller GET Method.

4 Replies

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Manas Mohapatra9y ago
Accepted answer
Mostly _loginManager value is null and you are trying to call the GetLogins(), so you are getting Null reference exception.

So you need to check why you are getting null value, check the value assigned in constructor.
+1
Krishna Kumar9y ago
Yes.. _loginmanager is the variable I am getting the null value.. can you rectify that error.. how can I declare the interface variable to get the method
0
Krishna Kumar9y ago
The error is on the line
return Request.CreateResponse(HttpStatusCode.OK, _loginManager.GetLogins());
How can i rectify this error
0
Manas Mohapatra9y ago
Check the object is null before using it. Secondly at which line it throwing exception..
0