Ignoring null fields in Json.net

Question

I have some data that I have to serialize to JSON. I'm using JSON.NET. My code structure is similar to this:

public struct structA {     public string Field1;     public structB Field2;     public structB Field3; }  public struct structB {     public string Subfield1;     public string Subfield2; } 

Problem is, my JSON output needs to have ONLY Field1 OR Field2 OR Field3 - it depends on which field is used (i.e. not null). By default, my JSON looks like this:

{     "Field1": null,     "Field2": {"Subfield1": "test1", "Subfield2": "test2"},     "Field3": {"Subfield1": null, "Subfield2": null}, } 

I know I can use NullValueHandling.Ignore, but that gives me JSON that looks like this:

{     "Field2": {"Subfield1": "test1", "Subfield2": "test2"},     "Field3": {} } 

And what I need is this:

{     "Field2": {"Subfield1": "test1", "Subfield2": "test2"}, } 

Is there simple way to achieve this?

Answer 1

Yes you need to use JsonSerializerSettings.NullValueHandling = NullValueHandling.Ignore.

But because structs are value types you need to mark Field2, Field3 nullable to get the expected result:

public struct structA {     public string Field1;     public structB? Field2;     public structB? Field3; } 

Or just use classes instead of structs.

Documentation: NullValueHandling Enumeration