title: why my Null substitution is not working in automapper
body: <p>I have written a programme in c# and used automapper to map.I have used Null substitution but it is not substituting the given value in result i am getting null only.please check the below code.I want my result to show 8099000078.</p>
  
  <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  using Automapper;
  
  namespace Automapper
  {
      public class User
      {
          public string FirstName { get; set; }
          public string LastName { get; set; }
          public string Address { get; set; }
          public string Mobile { get; set; }
      }
      public class Patient
      {
          public string Name { get; set; }
          public string Location { get; set; }
          public int age { get; set; }
          public string phone { get; set; }
  
  
          static void Main(string[] args)
          {
              User obj = new User();
              obj.FirstName = "sujit";
              obj.LastName = "kumar";
              obj.Address = "Bangalore";
              obj.Mobile = "";
  
              AutoMapper.Mapper.CreateMap&lt;User, Patient&gt;().ForMember(
                  emp =&gt; emp.Name, map =&gt; map.MapFrom(p =&gt; p.FirstName + " " + p.LastName))
                  .ForMember(dest =&gt; dest.Location, source =&gt; source.MapFrom(x =&gt; x.Address))
                 .ForMember(dest =&gt; dest.phone, source =&gt; source.NullSubstitute("8099000078"));
  
              var result = AutoMapper.Mapper.Map&lt;User, Patient&gt;(obj);
  
             // Console.WriteLine(result.Name);
             // Console.WriteLine(result.Location);
              Console.WriteLine(result.phone);
              Console.ReadLine();
  
          }
      }
  }
  </code></pre>