.NET Core: Remove null fields from API JSON response

Question

On a global level in .NET Core 1.0 (all API responses), how can I configure Startup.cs so that null fields are removed/ignored in JSON responses?

Using Newtonsoft.Js

Answer 1

I found that for dotnet core 3 this solves it -

services.AddControllers().AddJsonOptions(options => {
     options.JsonSerializerOptions.IgnoreNullValues = true;
});

Answer 2

This can also be done per controller in case you don't want to modify the global behavior:

public IActionResult GetSomething()
{
   var myObject = GetMyObject();
   return new JsonResult(myObject, new JsonSerializerSettings() 
   { 
       NullValueHandling = NullValueHandling.Ignore 
   });
};

Answer 3

The following works for .NET Core 3.0, in Startup.cs > ConfigureServices():

services.AddMvc()
    .AddJsonOptions(options =>
    {
        options.JsonSerializerOptions.IgnoreNullValues = true;
    });

Answer 4

In Asp.Net Core you can also do it in the action method, by returning

return new JsonResult(result, new JsonSerializerOptions
{
   IgnoreNullValues = true,
});

Answer 5

The code below work for me in .Net core 2.2

services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

Answer 6

[.NET Core 1.0]

In Startup.cs, you can attach JsonOptions to the service collection and set various configurations, including removing null values, there:

public void ConfigureServices(IServiceCollection services)
{
     services.AddMvc()
             .AddJsonOptions(options => {
                options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore;
     });
}

[.NET Core 3.1]

Instead of:

options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore;

Use:

options.JsonSerializerOptions.IgnoreNullValues = true;