Cannot implicitly convert type <DocAdminPannel.Models.DocMaster>'.An explicit conversion exists (are you missing a cast?)
<blockquote>
  <p>Cannot implicitly convert type
  'System.Web.Http.Results.OkNegotiatedContentResult'
  to 'System.Linq.IQueryable'. An
  explicit conversion exists (are you missing a cast?)</p>
</blockquote>

<pre><code>public class DoctorController : ApiController
{

    Doctor_infoEntities db = new Doctor_infoEntities();

    public IQueryable&lt;DocMaster&gt; GetDocMasters(string searchString)
    {
        //var Doctor = db.DocMaster.ToList();
        if (searchString == "" || searchString == null)
        {
            return db.DocMaster;
        }
        else
        {
            DocMaster Doctor = db.DocMaster.Find(searchString);
            return Ok(Doctor);
        }
    }
}
</code></pre>