How to get the key and value from dictionary

Question

I have dictionary like this :

"parameters": [ { "name": "a", "value": "b" }, { "name": "c", "value": "d" } ],

Have defined the dictionary like this :

Dictionary<string, atypeModel>

where atypeModel is like this :

 public class atypeModel { public string Name { get; set; } public string Value { get; set; } }

now , what Im not getting is how to retrieve the value by key . I did below :

var myKey = types.FirstOrDefault(a => a.Value == "b").Key;

but it is giving below error :

Operator '==' cannot be applied to operands of type 'atypeModel' and 'string '

please suggest

You can't deserialize that JSON to a dictionary, because it's a list of objects. — ProgrammingLlama
– ProgrammingLlama, Commented Jul 21, 2022 at 10:03
This is terrible code in general, I suggest a rewrite! Please accept OMANSAK's answer and I hope you getting paid bro. — Nicolas Tyler
– Nicolas Tyler, Commented Jul 21, 2022 at 10:57

OMANSAK · Accepted Answer · 2022-07-21 10:02:45Z

2

try var myKey = types.FirstOrDefault(a => a.Value.Value == "b").Key;

your dictonary like as :

[ { "name": "a", "value": { "Name": "a", "Value": "b" } } ]

If you want this

[ { "name": "a", "value": "b" }, { "name": "c", "value": "d" } ]

you should make List<atypeModel>

answered Jul 21, 2022 at 10:02

OMANSAK

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2 Comments

user2315104 Over a year ago

I cant change anything in the code. I have to just use the Dictionary and model as it is and get the keys and values

OMANSAK Over a year ago

.FirstOrDefault(a => a.Value.Value == "b").Key use this.

Ricardo Rodrigues · Accepted Answer · 2022-07-21 10:28:34Z

The word "Value" is used by "Dictionary" and also your class "atypeModel". It may be a little confuse to use both "properties". I sugest you change your class "Value" property for "TypeValue" and then:

(...).FirstOrDefault(a => a.Value.TypeValue == "b").Key

...just like OMANSAK said on comments.

Prasad Telkikar · Accepted Answer · 2022-07-21 10:11:31Z

You can not deserialize above json into the form of Dictionary<string, atypeModel>. You need List in the value, because value of "parameters" is of type List.

First change your model to Dictionary<string, List<atypeModel>>.

Now once you change your model, now things are easy, just apply same logic on the types["parameters"]

Like,

Dictionary<string, List<atypeModel>> types = JsonConvert.DeserializeObject<Dictionary<string, List<atypeModel>>(json) var myKey = types["parameters"].FirstOrDefault(a => a.Value == "b").Key; //^^^^^^^^^^^^^^ This was missing

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