How to POST using HTTPclient content type = application/x-www-form-urlencoded

Question

var nvc = new List<KeyValuePair<string, string>>();
nvc.Add(new KeyValuePair<string, string>("Input1", "TEST2"));
nvc.Add(new KeyValuePair<string, string>("Input2", "TEST2"));
var client = new HttpClient();
var req = new HttpRequestMessage(HttpMethod.Post, url) { Content = new FormUrlEncodedContent(nvc) };
var res = await client.SendAsync(req);

Or

var dict = new Dictionary<string, string>();
dict.Add("Input1", "TEST2");
dict.Add("Input2", "TEST2");
var client = new HttpClient();
var req = new HttpRequestMessage(HttpMethod.Post, url) { Content = new FormUrlEncodedContent(dict) };
var res = await client.SendAsync(req);

 var params= new Dictionary<string, string>();
 var url ="Please enter URLhere"; 
 params.Add("key1", "value1");
 params.Add("key2", "value2");
             
 using (HttpClient client = new HttpClient())
 {
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    HttpResponseMessage response = client.PostAsync(url, new FormUrlEncodedContent(params)).Result;
    var token = response.Content.ReadAsStringAsync().Result;
}
               
//Get response as expected

The best solution for me is:

// Add key/value
var dict = new Dictionary<string, string>();
dict.Add("Content-Type", "application/x-www-form-urlencoded");

// Execute post method
using (var response = httpClient.PostAsync(path, new FormUrlEncodedContent(dict))){}

Another variant to POST this content type and which does not use a dictionary would be:

StringContent postData = new StringContent(JSON_CONTENT, Encoding.UTF8, "application/x-www-form-urlencoded");
using (HttpResponseMessage result = httpClient.PostAsync(url, postData).Result)
{
    string resultJson = result.Content.ReadAsStringAsync().Result;
}