Property Class having class object as a Property

Question

I am having a proeprty class PropUser:

public class PropUser
{
    public int UserId { get; set; }

    public int ParentId { get; set; }

    public PropProduct Product { get; set; }
}

here, 3rd property Product is object of PropProduct which is a another property class

 public class PropProduct
{
    public int ProductId { get; set; }

    public string  Name { get; set; }

    public int Price { get; set; }
}

Now, in below code:

PropUser user = new PropUser();
    user.Product.Name = "Reebok";

user.Product is throwing Exception of "Object reference not set to an instance of an object."

I know user.Product is null, so how to initialize that so that i can set user.Product.Name="Reebok"

possible duplicate of [What is a NullReferenceException and how do I fix it?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it) — Patrick Hofman, Jun 22 '14 at 04:19
wow i never knew there was such a thing as a "Property Class" what features does this so called "Property Class" include . Property Class. — eran otzap, Jun 22 '14 at 04:44

score 3 · Answer 1 · answered Jun 22 '14 at 04:16

3

If you want it initialized as soon as the class is created, create a constructor and initialize it there:

public class PropUser
{
    public PropUser
    {
        Product = new PropProduct();
    }

    public int UserId { get; set; }

    public int ParentId { get; set; }

    public PropProduct Product { get; set; }
}

answered Jun 22 '14 at 04:16

Grant Winney

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2

Heh beat me by couple of seconds. :) – Dimitar Dimitrov Jun 22 '14 at 04:17

score 1 · Answer 2 · edited Jun 22 '14 at 04:19

1

You need to initialise the PropProduct object by using the new operator and then assign the values.

Try This:

PropUser user = new PropUser();
user.Product = new PropProduct();
user.Product.Name = "Reebok";

edited Jun 22 '14 at 04:19

Patrick Hofman

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answered Jun 22 '14 at 04:15

Sudhakar Tillapudi

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score 1 · Answer 3 · answered Jun 22 '14 at 04:19

If you want to initialize Product as soon as a new PropUser is made, simply add a constructor initializing it in PropUser class.

public class PropUser
{ 
    //Your Properties

    public PropUser() 
    {
        Product = new PropProduct();
    }
}

If you want to do it "on demand" so it can be null sometimes, create a new PropProduct object before or while assigning your string :

PropUser user = new PropUser();
user.Product = new PropProduct {Name = "Reebok"};

Property Class having class object as a Property

3 Answers3