Is there a performance difference between null-check and null-conditional-operator in C#?-CodePudding

I am wondering whether there is a difference in performance between these two if-statements:

if(myObject != null && myObject.someBoolean)
{
    // do soemthing
}

if (myObject?.someBoolean ?? false)
{
    // do soemthing
}

If there is a difference in performance, in favor of which approach and why?

Edit: This is not a bottleneck in my application, I am not trying to over-optimize, I am simply curious.

CodePudding user response：

When the code will be compiled, both if-statements will be the same. You can easily check it with

CodePudding user response：

Yes, there is a performance difference between null-checking and using the null-conditional operator in C#. In general, using the null-conditional operator (?.) is slightly faster than using a null-check (if (obj != null)) because the null-conditional operator is a more efficient way of checking for a null value.

The null-conditional operator is a shorthand syntax for checking for a null value and accessing a property or calling a method on an object only if the object is not null. It allows you to write code that is more concise and easier to read, while still ensuring that null-checks are performed.

For example, consider the following code that uses a null-check to access a property on an object:

if (obj != null)
{
    int x = obj.Value;
}

This code checks if the obj variable is not null, and if it is not null, it accesses the Value property of the obj object. This is equivalent to the following code that uses the null-conditional operator:

int x = obj?.Value;

Both of these pieces of code perform the same null-check and access the Value property of the obj object if it is not null. However, the second version is more concise and easier to read.

In terms of performance, the null-conditional operator is slightly faster than using a null-check because it is a more efficient way of checking for a null value. The null-conditional operator uses a special instruction in the generated machine code to perform the null-check, which is more efficient than the method used by a null-check. This means that using the null-conditional operator can result in slightly better performance in some cases.

However, the performance difference between null-checking and using the null-conditional operator is usually very small and not noticeable in most cases. In general, you should use the null-conditional operator because it makes your code more concise and readable, and the performance difference is not significant enough to warrant using a null-check instead.