Property validation logic in C Sharp (C#) - Mini Project: Build & Apply

Property validation logic

📖 Scenario: You are creating a simple program to store information about a person. You want to make sure the person's age is always a positive number. This means you need to add validation logic to the Age property.

🎯 Goal: Build a Person class with a property Age that only accepts positive numbers. If a negative number or zero is given, the property should keep the old value and not change.

📋 What You'll Learn

Create a class called Person with a private field age of type int.

Add a public property Age with getter and setter.

In the setter of Age, add validation to accept only values greater than zero.

If the value is invalid (zero or negative), do not change the private age field.

Create an instance of Person and test setting valid and invalid ages.

Print the final age to confirm validation works.

💡 Why This Matters

🌍 Real World

Property validation is used in many programs to keep data clean and correct, like ensuring ages, prices, or names are valid.

💼 Career

Understanding property validation is important for writing safe and reliable code in professional software development.

1

Create the Person class with private age field

Create a class called Person with a private integer field named age initialized to 0.

C Sharp (C#)

class Person
{
    // Your code here
}

Need a hint?

Use private int age = 0; inside the class.

2

Add the Age property with getter and setter

Add a public property called Age with a getter that returns age and a setter that sets age to the given value without validation yet.

C Sharp (C#)

class Person
{
    private int age = 0;

    // Your code here
}

Need a hint?

Use a property with get and set blocks.

3

Add validation logic to the Age setter

Modify the setter of the Age property to only set age if the given value is greater than zero. Otherwise, do not change age.

C Sharp (C#)

class Person
{
    private int age = 0;

    public int Age
    {
        get { return age; }
        // Your code here
    }
}

Need a hint?

Use an if statement inside the setter to check value > 0.

4

Create a Person instance and test Age property

Create a Person object called person. Set person.Age to 25, then set person.Age to -5. Finally, print person.Age to show the age is still 25.

C Sharp (C#)

class Person
{
    private int age = 0;

    public int Age
    {
        get { return age; }
        set
        {
            if (value > 0)
            {
                age = value;
            }
        }
    }
}

// Your code here

Need a hint?

Remember to create the Person object, set the ages, and print the final age.