Property validation logic in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is property validation logic in C#?

Property validation logic is code inside a property setter that checks if the new value meets certain rules before assigning it. It helps keep data correct and safe.

beginner

Why use validation logic inside property setters?

To prevent invalid or unexpected values from being stored in an object, ensuring the object stays in a valid state.

intermediate

How do you throw an exception in a property setter if validation fails?

Use the throw keyword with an exception type, for example: <br>throw new ArgumentException("Invalid value");

beginner

Show a simple example of property validation logic for an Age property that must be between 0 and 120.

private int age;<br>public int Age<br>{<br>  get => age;<br>  set<br>  {<br>    if (value < 0 || value > 120)<br>      throw new ArgumentOutOfRangeException(nameof(value), "Age must be between 0 and 120.");<br>    age = value;<br>  }<br>}

beginner

What happens if you assign an invalid value to a property with validation logic?

The setter throws an exception, stopping the assignment and alerting the programmer or user that the value is invalid.

What keyword is used to stop a property setter when a value is invalid?

A throw

B return

C break

D continue

The 'throw' keyword raises an exception to stop the setter when validation fails.

Where do you put validation logic in a property?

A Outside the property

B In the getter

C In the setter

D In the constructor only

Validation logic belongs in the setter to check new values before assigning.

Which exception is commonly used for invalid argument values in property setters?

A NullReferenceException

B IndexOutOfRangeException

C InvalidOperationException

D ArgumentException

ArgumentException is used when a method or property receives an invalid argument.

What is the purpose of property validation logic?

A To improve performance

B To prevent invalid data

C To hide data

D To format output

Validation logic prevents invalid or unexpected data from being stored.

If a property setter throws an exception, what happens to the property value?

A It remains unchanged

B It changes to the new value

C It becomes null

D It resets to default

The property value stays the same because the assignment is stopped by the exception.

Explain how to add validation logic to a property setter in C# and why it is useful.

Think about checking the value before saving it.

Describe what happens when an invalid value is assigned to a property with validation logic.

Consider how the program reacts to bad input.