C# Conditional Anonymous Object Members in Object initialization

Question

I building the following anonymous object:

var obj = new {
    Country = countryVal,
    City = cityVal,
    Keyword = key,
    Page = page
};

I want to include members in object only if its value is present.

For example if cityVal is null, I don't want to add City in object initialization

var obj = new {
    Country = countryVal,
    City = cityVal,  //ignore this if cityVal is null 
    Keyword = key,
    Page = page
};

Is this possible in C#?

What would that even mean? The object would be missing a property that the rest of your code expects. What would obj.City mean? Semantically undefined. — usr
– usr, Commented Jun 7, 2013 at 13:38
In my case I need to create an object which gets serialized into JSON (and send it using RestSharp) - no other manipulation of the object in c#. Based on conditions some of the members should be there, some not. As it is a large object, using accepted answer requires a lot of code. So this question is reasonable. Using some kind of conditional initialization would spare coding — przno
– przno, Commented Apr 11, 2017 at 10:43
Possible duplicate of is it possible to have a conditional field in an anonymous type — KyleMit
– KyleMit ♦, Commented Nov 30, 2017 at 15:39

Jeppe · Accepted Answer · 2019-06-23 22:11:59Z

11

Its not even posibble with codedom or reflection, So you can end up doing if-else if you really need this

if (string.IsNullOrEmpty(cityVal)) {
    var obj = new {
        Country = countryVal,
        Keyword = key,
        Page = page
    };

    // do something
    return obj;
} else {
    var obj = new {
        Country = countryVal,
        City = cityVal,
        Keyword = key,
        Page = page
    };

    //do something 
    return obj;
}

edited Jun 23, 2019 at 22:11

Jeppe

2,3474 gold badges30 silver badges42 bronze badges

answered Jun 27, 2013 at 11:16

Tepu

1,7123 gold badges21 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Suciu Eus Over a year ago

This works and seems like the only method for an anonymous object. But I would be against it because it adds duplication and complexity. The better way is to adjust the rest of the codebase to handle/ignore null fields.

Serge · Accepted Answer · 2013-06-07 13:36:16Z

5

You can't do that.

But what you could do is provide the default value (null?) of those properties.

var obj=  new
            {
                Country= countryVal,
                City = condition ? cityVal : null,
                Keyword = condition ? key : null,
                Page = condition ? page : null
            };

answered Jun 7, 2013 at 13:36

Serge

6,7425 gold badges33 silver badges58 bronze badges

3 Comments

Mikhail Sokolov Over a year ago

You cannot use conditional initializer in anonymous types

AndreaCi Over a year ago

Yes, you can use a ternary operator :|

Suciu Eus Over a year ago

You can use the ternary operator, but it will still add the field to the object. It will have a null value though. I think this is the way to go and the code should be adjusted to handle or ignore null values.

gbubemi smith · Accepted Answer · 2019-04-26 09:12:40Z

5

Well you would have if else conditions. But, if you are serilizing this as a JSON object with newtonsoft JSON this could help:

   var json = JsonConvert.SerializeObject(value, Formatting.None,
                    new JsonSerializerSettings
                    {
                        NullValueHandling = NullValueHandling.Ignore
                    });

answered Apr 26, 2019 at 9:12

gbubemi smith

1354 silver badges10 bronze badges

4 Comments

Lasse V. Karlsen Over a year ago

There is no mention of JSON on this question other than in a comment from someone else.

gbubemi smith Over a year ago

that's why i put a "But"

Vland Over a year ago

actually, this is very useful. it solved my problem

srbrills Over a year ago

For those using System.Text.Json::JsonSeriliazerOptions, the property now to use is DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull.

Chris Portwood · Accepted Answer · 2019-06-12 23:59:26Z

You could use an ExpandoObject and a functional extension method.

    pubic class SomeClass

        public dynamic DomainFunction(
            object countryVal = null
          , object cityVal = null
          , object key = null
          , object page = null
        )
        {
            dynamic obj = new ExpandoObject();

            cityVal?.Tee(x => obj.City = x);
            countryVal?.Tee(x => obj.Country = x);
            key?.Tee(x => obj.Keyword = x);
            page?.Tee(x => obj.Page = x);

            return obj;
        }

    }

    public static class FunctionalExtensionMethods{

        public static T Tee<T>(this T source, Action<T> action)
        {
          if (action == null)
            throw new ArgumentNullException(nameof (action));
          action(source);
          return source;
        }

    }

Collectives™ on Stack Overflow

C# Conditional Anonymous Object Members in Object initialization

4 Answers 4

1 Comment

3 Comments

4 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

1 Comment

3 Comments

4 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related