title: Default value for all string properties when source properties are null
body: <p>Is it possible to set all string properties that are null in my source object to some default value within my destination object using AutoMapper?</p>
  
  <p>For example, let's say I had the following two class definitions:</p>
  
  <pre><code>public class UniversalForm
  {
      public string LastName { get; set; }
      public string FirstName { get; set; }
      public string MiddleName { get; set; }
      public string FaxNumber { get; set; }
      ...
  }
  
  public class UniversalFormDto
  {
      public string LastName { get; set; }
      public string FirstName { get; set; }
      public string MiddleName { get; set; }
      public string FaxNumber { get; set; }
      ...
  }
  </code></pre>
  
  <p>Now, MiddleName and FaxNumber are properties that are likely to be null in the UniversalForm class.  So what I would like to be able to do is if FaxNumber or MiddleName are null then in UniversalFormDto object I would like for the value of the corresponding properties to be set to "N/A".  </p>
  
  <p>I know this can be accomplished by creating a mapping for each individual member, but I would like to avoid that if at all possible.</p>
  
  <p>I'm looking for a way to define a default value for all my string properties to be used when the corresponding property on my source object (UniversalForm) is null.</p>