How to add a JProperty based on conditional statement within a Json.Net object

Question

I want to add a JProperty field in a JObject based on the result of a conditional statement, but I'm having trouble formatting the code.

string zip = "00000";
bool isNull = string.IsNullOrEmpty(str);

JObject jsonContent = new JObject(
            new JProperty("email_address", subscriber.Email),
            new JProperty("status", "subscribed"),
            if(!isNull)
            {
                 new JProperty("ZIP", str),
            }
            new JProperty("state": "NY")
        );

Problem is how to handle the comma on the previous row and just how in particular to format the conditional statement within the JSON object.

Answer 1

You can add the property later based on your condition, what about the following?

string zip = "00000";
bool isNull = string.IsNullOrEmpty(str);

JObject jsonContent = new JObject(
            new JProperty("email_address", subscriber.Email),
            new JProperty("status", "subscribed"),
            new JProperty("state": "NY")
        );
if(isNull) {
    jsonContent["ZIP"] = str;
}

Answer 2

You could instantiate a JProperty or null based on a condition, and then setup a query around the properties to skip those that are null, as in:

var obj =
    new JObject(
        from p in new[]
        {
            new JProperty("email_address", subscriber.Email),
            new JProperty("status", "subscribed"),
            // conditional property:
            zip is not null ? new JProperty("ZIP", zip) : null,
            new JProperty("state", "NY")
        }
        where p is not null // skip null properties
        select p);

This can be helpful when you are setting up a complex JSON object as a single expression. If the query part bothers, then it can be tucked behind a helper method:

using static JsonNetHelpers; // import members of this type

var obj =
    JObject( // invokes "JObject" method; not "JObject" constructor (new missing)
        new JProperty("email_address", subscriber.Email),
        new JProperty("status", "subscribed"),
        // conditional property:
        zip is not null ? new JProperty("ZIP", zip) : null,
        new JProperty("state", "NY"));

static class JsonNetHelpers
{
    public static JObject JObject(params JProperty?[] properties) =>
        new JObject(from p in properties where p is not null select p);
}