JSON from List in C#

Question

I have a List in an MVC app that contains 141 entries. How do I create a JSON from that list and add other properties to it. I am currently trying the following but I get an error on the second iteration stating that the property already exists:

dynamic jsonOb = new JObject();

foreach(var titles in titleList)
{
    jsonOb.Add("TitleNumber", titles.ToString());
    jsonOb.Add("ProjectID", projid.ToString());
    jsonOb.Add("AddedBy", user);
    jsonOb.Add("DateAdded", Convert.ToString(DateTime.Now));
}

You’ll have to create several objects, not just try to set the values to a single object — Sami Kuhmonen
– Sami Kuhmonen, Commented Sep 3, 2018 at 12:20
Move the object declaration inside the loop to get rid of that error, and then take it from there. — Reinstate Monica Cellio
– Reinstate Monica Cellio, Commented Sep 3, 2018 at 12:22

Selman Genç · Accepted Answer · 2018-09-03 12:22:47Z

3

You need a JArray:

var jsonArr = new JArray();

 foreach(var titles in titleList)
 {
     var jsonOb = new JObject();
     jsonOb.Add("TitleNumber", "foo");
     jsonOb.Add("ProjectID", "foo");
     jsonOb.Add("AddedBy", "foo");
     jsonOb.Add("DateAdded", "foo");
     jsonArr.Add(jsonOb);
}

Btw since you are using JSON.NET already, SerializeObject method is easier and more straightforward than creating objects manually, so I suggest using that.

answered Sep 3, 2018 at 12:22

Selman Genç

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Rey · Accepted Answer · 2018-09-03 12:32:22Z

1

You can usee JsonConvert.SerializeObject(myObject) as well from Newtonsoft.Json package. Here is the doc for this.

var result = JsonConvert.SerializeObject(titleList);

If you don`t have it installed you can get it from nuget package manager.

answered Sep 3, 2018 at 12:32

Rey

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4 Comments

Allen Jones Over a year ago

I have it installed. If I Serialize my List, how do I add the other Properties (columns) to the JObject?

Rey Over a year ago

@AllenJones you serialize the list at the end of the process after you added all items in the list. And there is no need to use JObject anymore if you use this way. Just create the list, add all items to it and serialize at the end. If you want to name the properties differently you have properties for that but just check the documentation of this library because its very easy to add them

Allen Jones Over a year ago

Thanks for all the help. I ended up doing away with the List and creating a DataTable instead. This contains all the columns I need and then I just Serialized it using Json. Much easier way to achieve my desired end result.

Rey Over a year ago

@AllenJones yes List is just an example, but at the end you can use any type of collections or containers you want as long as they can be serialized.

Dipo · Accepted Answer · 2018-09-03 13:48:49Z

0

When you open up your visual studio, check => tools => Nuget Package Manager => Manage Nuget Package for solutions.

Go to the browse tab and search for 'Newtonsoft.Json'(without the quotes).

Once installed, import the namespace in your class and:

var convertedResult = JsonConvert.SerializeObject(titleList);

Easier that way.

answered Sep 3, 2018 at 13:48

Dipo

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