How to remove charset=US-ASCII from GetContentType() in C#

Question

I'm using the RetsSession to download document Files from an MLS but looks like the content type comes in as "application/pdf;charset=US-ASCII" is there anyway to remove the charset=US-ASCII from the content type ? I should see only application/pdf, OR image/png as content type.

            DocFiles tx = new DocFiles (DocFilesId, account);
            RetsSession session = new RetsSession(m_LogInUrl);
            session.SetUserAgentAuthType(UserAgentAuthType.USER_AGENT_AUTH_RETS_1_7);

            var loggedIn = session.Login(m_LogInUser, m_LogInPass);
            var documentCount = 1;

                ObjectDescriptor obj;
                do
                {
                    using (librets.GetObjectRequest request = new GetObjectRequest("Property", "PDF"))
                    {
                        request.AddObject("MLS123", documentCount);

                        GetObjectResponse response = session.GetObject(request);
                        obj = response.NextObject();
                        if (obj != null)
                        {
                            var ContentType = obj.GetContentType(); // output is = application/pdf;charset=US-ASCII
                            var description = obj.GetDescription();
                            var Errorcode = obj.GetRetsReplyCode().ToString();

                            //<RETS ReplyCode="20403" ReplyText="No such object available for this resource"/>
                            if (Errorcode == "20403")
                            {
                                obj = null;
                            }
                            documentCount++;
                        }
                    }
                } while (obj != null);

Answer 1

Try parsing the ContentType using Microsoft.Net.Http.Headers MediaTypeHeaderValue.Parse:

var mediaType = MediaTypeHeaderValue.Parse("application/pdf;charset=US-ASCII");
Console.WriteLine(mediaType.MediaType.ToString()); //"application/pdf"