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, Jun 07 '13 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, Apr 11 '17 at 10:43
Possible duplicate of [is it possible to have a conditional field in an anonymous type](https://stackoverflow.com/questions/3090218/is-it-possible-to-have-a-conditional-field-in-an-anonymous-type) — KyleMit, Nov 30 '17 at 15:39

score 11 · Accepted Answer · edited Jun 23 '19 at 22:11

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 '19 at 22:11

Jeppe

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answered Jun 27 '13 at 11:16

Tepu

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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. – Suciu Eus Sep 07 '21 at 12:08

score 5 · Answer 2 · answered Jun 07 '13 at 13:36

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 07 '13 at 13:36

Serge

6,554
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You cannot use conditional initializer in anonymous types – Mikhail Sokolov Apr 28 '17 at 07:55
2

Yes, you can use a ternary operator :| – AndreaCi Jul 21 '17 at 15:06
2

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. – Suciu Eus Sep 07 '21 at 12:07

score 5 · Answer 3 · answered Apr 26 '19 at 09:12

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 '19 at 09:12

gbubemi smith

135
4
10

There is no mention of JSON on this question other than in a comment from someone else. – Lasse V. Karlsen Apr 26 '19 at 09:27
1

that's why i put a "But" – gbubemi smith Apr 26 '19 at 10:43
2

actually, this is very useful. it solved my problem – Vland Feb 04 '22 at 09:05

score 0 · Answer 4 · answered Jun 12 '19 at 23:59

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;
        }

    }

C# Conditional Anonymous Object Members in Object initialization

4 Answers4