Custom header to HttpClient request

I have found the answer to my question.

client.DefaultRequestHeaders.Add("X-Version","1");

That should add a custom header to your request

Here is an answer based on that by Anubis (which is a better approach as it doesn't modify the headers for every request) but which is more equivalent to the code in the original question:

using Newtonsoft.Json;...var client = new HttpClient();var httpRequestMessage = new HttpRequestMessage    {        Method = HttpMethod.Post,        RequestUri = new Uri("https://api.clickatell.com/rest/message"),        Headers = {             { HttpRequestHeader.Authorization.ToString(), "Bearer xxxxxxxxxxxxxxxxxxx" },            { HttpRequestHeader.Accept.ToString(), "application/json" },            { "X-Version", "1" }        },        Content = new StringContent(JsonConvert.SerializeObject(svm))    };var response = client.SendAsync(httpRequestMessage).Result;

var request = new HttpRequestMessage {    RequestUri = new Uri("[your request url string]"),    Method = HttpMethod.Post,    Headers = {        { "X-Version", "1" } // HERE IS HOW TO ADD HEADERS,        { HttpRequestHeader.Authorization.ToString(), "[your authorization token]" },        { HttpRequestHeader.ContentType.ToString(), "multipart/mixed" },//use this content type if you want to send more than one content type    },    Content = new MultipartContent { // Just example of request sending multipart request        new ObjectContent<[YOUR JSON OBJECT TYPE]>(            new [YOUR JSON OBJECT TYPE INSTANCE](...){...},             new JsonMediaTypeFormatter(),             "application/json"), // this will add 'Content-Type' header for the first part of request        new ByteArrayContent([BINARY DATA]) {            Headers = { // this will add headers for the second part of request                { "Content-Type", "application/Executable" },                { "Content-Disposition", "form-data; filename=\"test.pdf\"" },            },        },    },};