How to Call API using C# with Headers and Body?

using System.Net.Http;
using System.Collections.Generic;

// ...

// create an instance of the HttpClient class
var client = new HttpClient();

// specify the API endpoint you want to call
var url = "http://example.com/api/endpoint";

// create a dictionary to hold the request headers
var headers = new Dictionary<string, string>();

// add the headers to the dictionary
headers.Add("header1", "value1");
headers.Add("header2", "value2");

// create the request body as a string
var body = "{\"key1\":\"value1\",\"key2\":\"value2\"}";

// create a new HttpRequestMessage object with the specified method, url, and body
var request = new HttpRequestMessage(HttpMethod.Post, url)
{
    Content = new StringContent(body)
};

// add the headers to the request
foreach (var header in headers)
{
    request.Headers.Add(header.Key, header.Value);
}

// make the API call using the SendAsync method of the HttpClient
var response = await client.SendAsync(request);

// check the status code of the response to make sure the call was successful
if (response.IsSuccessStatusCode)
{
    // if the call was successful, read the response content
    var content = await response.Content.ReadAsStringAsync();

    // do something with the response content
    // ...
}