I want to create a json file with same key and different value using dictionary in c#

Question

Here is the sample i need to form. I tried hash set it is showing as key and value but i need my output to be in the below format.

[{
    "data": "Name"

},
{
    "data": "Description"
}]

My sample code:

var items = new List<KeyValuePair<string, string>>();

foreach (DataColumn col in dt.Columns)
        {
            if (col.ColumnName !="DataType")
            {
                items.Add(new KeyValuePair<string, string>("data", 
col.ColumnName));
            }
        }
var lookup = items.ToLookup(kvp => kvp.Key, kvp => kvp.Value);

When i try to add dictionary it throws me error saying key has already been added. Any guide to learn dictionary concepts in c#

Thanks

Possible duplicate of [Duplicate keys in .NET dictionaries?](https://stackoverflow.com/questions/146204/duplicate-keys-in-net-dictionaries) — Balagurunathan Marimuthu, Aug 09 '17 at 07:22
A dictionary should have unique keys. You can't use a key more than once. — Christos, Aug 09 '17 at 07:26
@Eliotjse, this post should help you : https://stackoverflow.com/questions/1056121/how-to-create-json-string-in-c-sharp — praguan, Aug 09 '17 at 07:30
I think it is not duplicate i tried all the possibilities so then asked the question. — Eliotjse, Aug 09 '17 at 08:14

score 3 · Accepted Answer · answered Aug 09 '17 at 07:48

3

The given json is an array of objects and can be created with

var source = new List<object>{
    new Dictionary<string,object>{ { "data", "Name" }, },
    new Dictionary<string,object>{ { "data", "Description" }, },
};

var json = JsonConvert.SerializeObject( source, Formatting.Indented );

.NET fiddle Sample

answered Aug 09 '17 at 07:48

Sir Rufo

16,671
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Thanks exactly what i was looking for @Sir Rufo – Eliotjse Aug 09 '17 at 08:18
You never accepted/upvoted any answer to your questions. Please read https://stackoverflow.com/help/someone-answers – Sir Rufo Aug 09 '17 at 08:21
I upvoted but it did not reflect due to less points i have. But i marked it as useful thanks again – Eliotjse Aug 09 '17 at 09:25

score 0 · Answer 2 · answered Aug 09 '17 at 07:22

0

You cannot add two key-value pairs to the same dictionary. The dictionary uses the key to calculate a hash. If you add two keys that are the same, you'll get a collision of the hashes. This will prevent the dictionary from working properly - when you try to get an item with that key, which item should the dictionary return?

answered Aug 09 '17 at 07:22

Dido

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I want to create duplicate and i achieved using previous answer. – Eliotjse Aug 10 '17 at 14:24

I want to create a json file with same key and different value using dictionary in c#

2 Answers2