Deserialize Json in C# - How to Handle null Return Values

Question

I am using the following code:

myObj jsonStream = ser.Deserialize<myObj>(jsonStream);

And all was working fine until the JSON that came back had a null value for one of the fields. i.e.:

"name" : null

During the deserialization process, it's throwing an exception. In my myObj, I have a member:

public string name;

How can I gracefully handle the odd null value coming back from my datasource using the System.Web.Script.Serialization assembly? I tried:

public string name = "";

But that didn't work.

I can't gather from your question what the type of "ser" is. — Jauco
– Jauco, Commented Nov 13, 2009 at 9:07

Valentin Golev · Accepted Answer · 2009-11-13 09:07:36Z

5

Try to use nullable type

public string? name;

answered Nov 13, 2009 at 9:07

Valentin Golev

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2 Comments

Valentin Golev Over a year ago

oh, I didn't know. But I'd try :)

Brandon Watson Over a year ago

This is actually the right answer in that I had to allowable nullable. It turns out the example I used was a string, but it was the int that needed to be int?. I just used a string for my example. So, don't do "string?" for the reasons that Jauco points out, but this is the answer to my issue.

MayankD · Accepted Answer · 2018-10-10 09:25:05Z

2

You can supply settings to JsonConvert.DeserializeObject to tell it how to handle null values, in this case, and much more:

var settings = new JsonSerializerSettings
                    {
                        NullValueHandling = NullValueHandling.Ignore,
                        MissingMemberHandling = MissingMemberHandling.Ignore
                    };
var jsonModel = JsonConvert.DeserializeObject<Customer>(jsonString, settings);

answered Oct 10, 2018 at 9:25

MayankD

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1 Comment

abhi Over a year ago

Still be useful in 2022.

Darin Dimitrov · Accepted Answer · 2009-11-13 09:09:46Z

Maybe the problem lies somewhere else because the following code worked fine for me using JavaScriptSerializer (it correctly handled the null without throwing any exception):

public class MyObj
{
    public string name;
}

class Program
{
    static void Main(string[] args)
    {
        JavaScriptSerializer ser = new JavaScriptSerializer();
        var json = "{\"name\" : null}";
        var myObj = ser.Deserialize<MyObj>(json);
        Console.WriteLine(myObj.name);
    }
}

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