接收“null”而不是 null

Question

I'm trying to pass a null argument to a web api controller but I'm getting "null" instead of null.

Eg: my route should be like this

[Route("api/student/GetStudent/{studentId}/{studentFname}/{studentLname}/")]

public Student GetStudent(int studentId,string studentFname,string studentLname) 
{
         //Code 
}

Note that at least user should insert first name or last name and isn't required to have both

• In the above code, both firstname and lastname are required but I don't want this. So I change my code to be like this

  [Route("api/student/GetStudent/{studentId}/{studentFname?}/{studentLname?}/")] public Student GetStudent(int studentId,string studentFname,string studentLname) { //Code }

As I said that when I call this method and pass a null argument for student firstname. I am getting "null" and when it pass to the database stored procedure it will pass as a value.

Answer 1

This is most likely because the method is called as

api/student/GetStudent/xxx/null/something

null in this case is provided and is in fact "null".

You may need to expose

• api/student/GetStudentByLastName/{lname}
• api/student/GetStudentByFirstName/{fname}
• api/student/GetStudentById/{id}

---

Depending on your setup you may be able to do

• api/student/GetStudent/IdHere?fname=xxx (lname will be null )
• api/student/GetStudent/IdHere?lname=xxx (fname will be null )

(btw. I'm not sure why you pass the name parts, if id is required)

Answer 2

I suppose you should call your API with below format:

api/student/GetStudent/studentId=&studentFname=&studentLname=