httpclient post nested dictionary

Question

I'm having an error :

Severity Code Description Project File Line Suppression State Error CS1503 Argument 1: cannot convert from 'System.Collections.Generic.Dictionary<string, System.Collections.Generic.Dictionary<string, string>>' to 'System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, string>>

When I am posting nested dictionary using HttpClient

var arg_employee = new Dictionary<string, Dictionary<string, string>>
{
    {
        "filter_data",
        new Dictionary<string, string>
        {
            {"user_name", "admin"},
        }
    },
};

var content = new FormUrlEncodedContent(arg_employee);
// ... Use HttpClient.
using (HttpClient client = new HttpClient())
using (HttpResponseMessage response = await client.PostAsync(uRL, content))
using (HttpContent responseContent = response.Content)
{
    // ... Read the string.
    return await responseContent.ReadAsStringAsync();

How I can post nested dictionary or array ?

Answer 1

FormUrlEncodedContent accepts IEnumerable<KeyValuePair<string, string>> nameValueCollection , not Dictionary. See this

To pass dictionary you should serialize it to json, for example.

First step, getting json representation of your dictionary using Newtonsoft.Json (you can manually serialize it or use another library)

using Newtonsoft.Json

var arg_employee = new Dictionary<string, Dictionary<string, string>>
{
    {
        "filter_data",
        new Dictionary<string, string>
        {
            {"user_name", "admin"},
        }
    },
};

var jsonDictionary = JsonConvert.SerializeObject(arg_employee );

Second step, post it as StringContent instead of FormUrlEncodedContent:

var content = new StringContent(jsonDictionary , Encoding.UTF8, "application/json");