HttpClient.PostAsync Method

Asynchronously sends an HTTP POST request to the specified URI. This method does not block the calling thread.

public System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> PostAsync(
    string requestUri,
    System.Net.Http.HttpContent? content
);
            

Parameters

Returns

The Task<HttpResponseMessage> object that represents the asynchronous operation. The task result contains the HttpResponseMessage.

Exceptions

• ArgumentNullException: The requestUri or content is null.
• InvalidOperationException: The HttpClient instance has been disposed.
• HttpRequestException: An error occurred during the execution of the HTTP request.

Example

The following example demonstrates how to send a POST request with JSON content.

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;

public class Example
{
    private static readonly HttpClient client = new HttpClient();

    public static async Task Main(string[] args)
    {
        string apiUrl = "https://api.example.com/data";

        var postData = new { name = "John Doe", age = 30 };
        var jsonContent = new StringContent(JsonSerializer.Serialize(postData), Encoding.UTF8, "application/json");

        try
        {
            HttpResponseMessage response = await client.PostAsync(apiUrl, jsonContent);
            response.EnsureSuccessStatusCode(); // Throws if the status code is not a success code

            string responseBody = await response.Content.ReadAsStringAsync();
            Console.WriteLine($"Response: {responseBody}");
        }
        catch (HttpRequestException e)
        {
            Console.WriteLine($"Request error: {e.Message}");
        }
    }
}
            

Overloads

This method has several overloads to accommodate different scenarios, including sending a request with a cancellation token.

• HttpClient.PostAsync(string requestUri, HttpContent? content, CancellationToken cancellationToken)