.NET C# Null Handling using inbuilt operators

Null-coalescing operators(?? and ??=)

Instead of using the If condition and then assigning a default value, we can do it neatly by using the null-coalescing operator.

Example

public class MyClass
    {
        public string Message { get; set; }
        public int? Count { get; set; } = null;
                
        public MyClass(string message)
        {
            //Example of Null Coalescing operator(??)
            Message = message ?? "Default Message";

            //Example of Null Coalescing assignment operator(??=)
            Count ??= 1000;

            Console.WriteLine($"Message: {Message} \n Count: {Count}");
        }
    }

MyClass myClass = new MyClass(null);

Output

Null-conditional operators (?. and ?[])

Operation to its left hand side operand only if that operand evaluates to non-null; otherwise, it returns null.

Example

public class TestNullConditionalOperator
    {
        private readonly Order _order;

        public TestNullConditionalOperator(Order order)
        {
            _order = order;

            //Here we are using Null Conditional Operator(?.) with Null Coalescing Operator(??).
            //If _order is null then it will not throw exception and will return "Default Order".            
            Console.WriteLine("Example of Operator(?.)");
            Console.WriteLine($"Order: {_order?.Name??"Default Order"}");

            _order=new Order() { Id = 1, Name = "Order 1"};
            //Here _order is not null so it will return "Order 1".
            Console.WriteLine($"Order: {_order?.Name}");

            List<string> listNull = null;
            List<string> listNotNull = new List<string>() { "Abhishek", "Vinod" };

            //Here we are using Null Conditional Operator(?[]) with Null Coalescing Operator(??).
            //If listNull is null then it will not throw exception and will return "Default Value".
            Console.WriteLine("\nExample of Operator(?[])");
            Console.WriteLine($"ListNull First Value: {listNull?[0] ?? "Default Value"} \nListNotNull First Value: {listNotNull?[0]}");
        }       
    }

    //Order class
    public class Order
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }


TestNullConditionalOperator testNullConditionalOperator = 
new TestNullConditionalOperator(new Order() { Id=1001});

Output

Happy coding. Thanks for reading.