Post call for XML content using HttpClient

Question

How to make XML content compatible with HttpClient.PostAsync() operation for the content and where do you specify the headers for Content-Type = application/xml.

Error -> Cannot convert string to HttpContent

public async Task GetCustomersAsync(string firstname, string lastname)
{
        using (var client = new HttpClient())
        {
            var content = "<soapenv:Envelope xmlns:xsi...";

            var response = await client.PostAsync("https://example.com/scripts/WebObj.exe/Client.woa/2/ws/ABC", content);

            var responseString = await response.Content.ReadAsStringAsync();
        }
    }

Answer 1

My guess is what you want to do is the following:

public async Task<string> GetCustomersAsync(string firstname, string lastname)
{
    using (var client = new HttpClient())
    {
        var content = new StringContent("<soapenv:Envelope xmlns:xsi...", Encoding.UTF8, "application/xml");;

        var response = await client.PostAsync("https://example.com/scripts/WebObj.exe/Client.woa/2/ws/ABC", content);

        return await response.Content.ReadAsStringAsync();
    }
}

OR

using (var request = new HttpRequestMessage { RequesteUri = new Uri("POST_URL"), Method = HttpMethod.Post })
{
    var content = new StringContent("<soapenv:Envelope xmlns:xsi...");
    request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/xml");
}

You can refer here to more information about other Content types that can be created and passed.