create array of object help

Question

I'm having the following classes. While trying to set the values of the employee class with the following code, i`m getting the error message:Object reference not set to an instance of an object.

How can I solve it?

public class Employee
{
     public Test[] test{ get; set; }

        public Employee()
        {
           this.test[0].Name = "Tom";
           this.test[0].age= 13;

        }
}



public class Test
{
    public string Name {get; set;}
    public int Age {get; set;}
}

Answer 1

You should create an instance of array, and array elements before trying to use tham

for example

test = new Test[1]{new Test()};

or

test = new Test[1];
test[0] = new Test();

than you can use tham

this.test[0].Name = "Tom";
this.test[0].age= 13;

If you want the array to actually contain constructed Test elements, then you can use this code:

Test[] arrT = new Test[N];
for (int i = 0; i < N; i++)
{
    arrT[i] = new Test();
}

Answer 2

You need to create an instance of test variable which is an array of Test[] objects before assigning any values to them. When creating an instance you have to set the number of elements it will hold.

    public class Test
    {
        public string Name { get; set; } public int age { get; set; }
    }

    public class Employee
    {
        public Test[] test { get; set; }

        public Employee()
        {
            test = new Test[1];
            this.test[0] = new Test();
            this.test[0].Name = "Tom";
            this.test[0].age = 13;

        }
    }

If you dont know the number of Test obejct the array will hold, consider using List or ArrayList

Edit. List Example:

    public class Employee
    {
        public List<Test> test { get; set; }

        public Employee()
        {
            this.test.Add(new Test());
            this.test[0].Name = "Tom";
            this.test[0].age = 13;

        }
    }

    public class Test
    {
        public string Name { get; set; } public int age { get; set; }
    }