title: Custom JsonConverter that can convert decimal.MinValue to empty string and back
body: <p>I need to create a custom JSON.NET converter for a legacy system that flags null decimal values with...</p>
  
  <pre><code>var nulldec = decimal.MinValue;
  </code></pre>
  
  <p>(This was created before nullable types were introduced, and to change how this works will be a ton of work.)</p>
  
  <p>When these min-values are serialized to JSON they need to be serialized as an empty string.  When they are deserialized, if the value is empty string, it needs to convert to <code>decimal.MinValue</code>.</p>
  
  <p>Here is what I have so far (yes, not much).  I think this is a simple conversion, but I am not seeing any articles that point me to how to work this for my situation nor any documentation on how to create custom converters.  Can someone help please?</p>
  
  <pre><code>public class DecimalJsonConverter : JsonConverter
  {
      public override object ReadJson(JsonReader reader, Type objectType, 
                                      object existingValue, JsonSerializer serializer)
      {
      }
      public override void WriteJson(JsonWriter writer, object value, 
                                     JsonSerializer serializer)
      {
      }
      public override bool CanConvert(Type objectType)
      { 
          return typeof(System.Decimal).IsAssignableFrom(objectType); 
      }
  }
  </code></pre>