Solution for your Errors and Exceptions

Error: 'System.Net.Http. HttpClient '  does not contain a definition for 'PostAsJsonAsync ' and  no  extension method ' PostAsJsonAsync ' accepting a first argument of type 'System.Net.Http. HttpClient ' could be found Solution:  You need to add a reference to System . Net . Http . Formatting . dll This can be found in the extensions assemblies area. A good way of achieving this is by adding the NuGet package  System.Net.Http.Formatting.Extension  to your project. Faced this problem in  QFLES