Having trouble deserializing json to C#

Question

I have an example of what I'm trying to deserialize below and I'm getting a bunch of different errors when I try to pull the data. All I want is to pull the id value but I can't seem to figure it out.

{"object":"payments","entry":[{"id":"546787862118679","time":1417135022,"changed_fields":["actions"]}]}

    public class Entry
    {
        public string id { get; set; }
        public int time { get; set; }
        public List<string> changed_fields { get; set; }
    }

    public class RootObject
    {
        public string @object { get; set; }
        public List<Entry> entry { get; set; }
    }

    dynamic result = new StreamReader(request.InputStream).ReadToEnd();
    var items = JsonConvert.DeserializeObject<RootObject>(result);
    string paymentID = items.entry.FirstorDefault().id;

Returns this error:

'System.Collections.Generic.List' does not contain a definition for 'FirstOrDefault()'

try adding using System.Linq; to top of the file.

Erik Philips
– Erik Philips

2014-11-28 03:17:24 +00:00
Commented Nov 28, 2014 at 3:17 — Erik Philips
– Erik Philips, Commented Nov 28, 2014 at 3:17
@ErikPhilips It is already there

DarthVegan
– DarthVegan

2014-11-28 03:17:53 +00:00
Commented Nov 28, 2014 at 3:17 — DarthVegan
– DarthVegan, Commented Nov 28, 2014 at 3:17

Tyress · Accepted Answer · 2014-11-28 04:10:34Z

3

I have a feeling it would work if your code:

string paymentID = items.entry.FirstorDefault().id;

were

string paymentID = items.entry.FirstOrDefault().id;

And that your error is actually

'System.Collections.Generic.List' does not contain a definition for 'FirstorDefault'

As Collections.Generic.List does contain a definition for FirstOrDefault (System.Linq)

answered Nov 28, 2014 at 4:10

Tyress

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Comments

Rohit · Accepted Answer · 2014-11-28 04:30:06Z

2

try this

string paymentID = (items.entry.FirstOrDefault()).id;

Get the first item from list entry and then get idfrom that item.

edited Nov 28, 2014 at 4:30

answered Nov 28, 2014 at 3:21

Rohit

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3 Comments

DarthVegan Over a year ago

I'm getting this error when I try this: 'System.Collections.Generic.List<HomeworkHelpers.RTUSubscriptionActionFilter.Entry>' does not contain a definition for 'FirstorDefault'

Rohit Over a year ago

see this FirstorDefault() works with collection. this entry is a list or collection right ?

trashr0x Over a year ago

@RohitGupta there's a typo in your answer, it should be FirstOrDefault (capital O)

trashr0x · Accepted Answer · 2014-12-02 02:05:48Z

1

From a quick look at the error you get, it occurs on this line:

string paymentID = items.entry.FirstorDefault().id; //should be .FirstOrDefault().id;

...to enumerate through each Entry item in items.entry which is a List<Entry>:

if (items.entry != null && items.entry.Count > 0)
{
    foreach(Entry entryItem in items.entry)
    {
        if (!string.IsNullOrEmpty(entryItem.id))
        {
            string paymentID = entryItem.id;
        }
    }
}

...to only access the first Entry item:

if (items.entry != null && items.entry.Count > 0)
{        
    if (!string.IsNullOrEmpty(items.entry[0].id))
    {
        string paymentID = items.entry[0].id;
    }

}

edited Dec 2, 2014 at 2:05

answered Nov 28, 2014 at 3:20

trashr0x

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6 Comments

DarthVegan Over a year ago

I'm getting this error: 'System.Collections.Generic.List<HomeworkHelpers.RTUSubscriptionActionFilter.Entry>' does not contain a definition for 'id'

trashr0x Over a year ago

see my updated answer. you're trying to access List<Entry>.id which doesn't make sense, you need to access the id property of each individual Entry object in List<Entry> instead

DarthVegan Over a year ago

the json string is always the exact same. There is only one entry object so still use the same code?

trashr0x Over a year ago

yes, if there's only one Entry object then List<Entry> will only contain one item so the foreach loop will only execute once

trashr0x Over a year ago

@user3610374 please consider removing the downvote from my answer as well

|

Aydin · Accepted Answer · 2014-11-28 03:20:56Z

1

Why are you loading the result into a dynamic type??? Use a string.

void Main()
{
    string json = @"{""object"":""payments"",""entry"":[{""id"":""546787862118679"",""time"":1417135022,""changed_fields"":[""actions""]}]}";

    Root root = JsonConvert.DeserializeObject<Root>(json);

    Entry entry = root.Entry.FirstOrDefault();
}


public class Entry
{

    [JsonProperty("id")]
    public string Id { get; set; }

    [JsonProperty("time")]
    public int Time { get; set; }

    [JsonProperty("changed_fields")]
    public string[] ChangedFields { get; set; }
}

public class Root
{

    [JsonProperty("object")]
    public string Object { get; set; }

    [JsonProperty("entry")]
    public Entry[] Entry { get; set; }
}

answered Nov 28, 2014 at 3:20

Aydin

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1 Comment

DarthVegan Over a year ago

I'm getting this error when I try this: Value cannot be null. Parameter name: source

Phil-R · Accepted Answer · 2014-11-28 03:50:28Z

1

For some reason (I still don't know why), your code works when you change the type of result from dynamic to string.

string result = new StreamReader(request.InputStream).ReadToEnd();
if (!string.IsNullOrWhiteSpace(result)) {
    var items = JsonConvert.DeserializeObject<RootObject>(result);
    string paymentID = items.entry.FirstorDefault().id;
}

answered Nov 28, 2014 at 3:50

Phil-R

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1 Comment

trashr0x Over a year ago

FirstorDefault should be FirstOrDefault else you'll get System.Collections.Generic.List<Ent‌ry>' does not contain a definition for 'FirstorDefault'

ViBi · Accepted Answer · 2014-11-28 05:58:38Z

0

Do it like this

string paymentID = (items.entry as List<Entry>).FirstOrDefault().id;

answered Nov 28, 2014 at 5:58

ViBi

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