HttpRequestMessage' does not contain a definition for 'Form'

HttpRequestMessage' does not contain a definition for 'Form' and no extension method 'Form' accepting a first argument of type 'HttpRequestMessage' could be found (are you missing a using directive or an assembly reference?);

// UPDATE
        [Microsoft.AspNet.Mvc.HttpPut]
        public void UpdateVendor()
        {
            try
            {

                var item = new Vendor()
                {
                    Company = Request.Form["Company"],
                    // other columns
                };
                _vendorRespository.UpdateVendor(item);
            }
            catch (Exception e)
            {
                Debug.WriteLine(e.Message);
            }
        }