title: Entity Framework: 'The SqlParameter is already contained by another SqlParameterCollection'
body: <p>I am trying to execute below code. My goal is to check whether any user exists with the given email id or not.</p>
  
  <pre><code>var result = userDbContext.users.SqlQuery("SELECT * FROM USERS WHERE @email='@emailValue'",
  new SqlParameter("@email", "email"),
  new SqlParameter("@emailValue","abc@mail.com"));
  //new SqlParameter("p1", existingUser.password));
  
  if (result.Count() == 0) //getting exception here
  {
      ViewBag.comment = "Sorry. We can not find your credentials";
      return View();
  }
  </code></pre>
  
  <p>But I am getting exception at <code>result.count()</code> and don't know what is going wrong.</p>
  
  <p>Exception is: </p>
  
  <blockquote>
    <p>"The SqlParameter is already contained by another
    SqlParameterCollection"</p>
  </blockquote>
  
  <p>How can I solve this?</p>