ModelState Validation Error when get value from User.Identity.GetUserId()

Question

in my WebApi controller post function I assign user id to my posted object through User.identity.GetUserId() but ModelState.isValid always return validation error that

user id is required

while the value is assigned to the required property. So I removed the required attribute from userId property. It is working but I need to know as to why ModelState does not know that the user id has already been provided with User.Identity.GetUserId() .

Answer 1

If you are using Web API 2, instead of User.identity.GetUserId() use

RequestContext.Principal.Identity.GetUserId()

or

using Microsoft.AspNet.Identity;
using Microsoft.AspNet.Identity.Owin;

Request.GetOwinContext().GetUserManager<ApplicationUserManager>()