Shorthand for create new instance if null?

Question

In Javascript I can do this:

var myVar = returnNull() || new MyObject();

In C# I am currenly doing this:

var myVar = returnObjec         


        

Answer 1

use ?? operator

foo ?? new Foo();

Or in your case

var myVar = returnObjectOrNull() ?? new MyObject();

The ?? operator is called the null-coalescing operator and is used to define a default value for nullable value types or reference types. It returns the left-hand operand if the operand is not null; otherwise it returns the right operand.

Answer 2

Yes there is, it's called the null coalescing operator:

var myVar = returnObjectOrNull() ?? new MyObject();

Note that this operator will not evaluate the right-hand side if the left-hand side is not null, which means that the above line of code will not create a new MyObject unless it has to.

Here's an example LINQPad program to demonstrate:

void Main()
{
    var myVar = returnObjectOrNull() ?? new MyObject();
}

public MyObject returnObjectOrNull()
{
    return new MyObject();
}

public class MyObject
{
    public MyObject()
    {
        Debug.WriteLine("MyObject created");
    }
}

This will output "MyObject created" once, meaning that there is only one object being created, in the returnObjectOrNull method, not the one in the ?? statement line.

Answer 3

Use the null-coalescing operator:

var myvar = returnObjectOrNull() ?? new MyObject();

Answer 4

You can use ?? Operator (C# Reference) operator like;

var myVar = returnObjectOrNull() ?? new MyObject();

The ?? operator is called the null-coalescing operator and is used to define a default value for nullable value types or reference types. It returns the left-hand operand if the operand is not null; otherwise it returns the right operand.

Answer 5

Use the null coalescing operator

var myVar = returnObjectOrNull();

myVar = myVar ?? new MyObject();