c# - Static method return an object of it's containing class type -

i have:

class person {      public person(string name, int age)     {         this.name = name;     }      public string name { get; set; }      public virtual void speak()     {         console.write("hello person");     }      public static t generaterandominstance<t>() t: person     {         var p = new t("hello", 4); // error not compile         // rondomize properties         return p;                     } }  class student : person {     // constructor call base class here     public student(string name, int age)         : base(name, age)     {         }      public override void speak()     {         console.write("hello student");     } } 

the problem have when do:

student.generaterandominstance(); 

i person instead of student. how can fix generaterandominstance method returns student instead of person. casting person student gives me error

you can't. static method cannot overridden in child class , there's no way distinguish between student.generaterandominstance , person.generaterandominstance—in fact generate same cil when compiled.

you use generic method instead:

public static t generaterandominstance<t>() t : person, new {     var p = new t();     // randomize properties     return p; }  person.generaterandominstance<student>(); 

but work if type has parameterless constructor. if you'd pass arguments constructor, becomes more difficult. assuming know values want pass constructor can this:

public static t generaterandominstance<t>() t : person {     var p = (t)activator.createinstance(typeof(t), "hello", 4);     // randomize properties     return p; } 

of course, fail if specified type not contain suitable constructor.