Null-conditional Operator | Simplify Delegate Invocation

Microsoft Docs / Null-conditional operator

Recommendation

The null-conditional operator should be used to simplify delegate invocation when possible.

Use:

this.LoadState?.Invoke(this, new LoadStateEventArgs(e.Parameter, null));

Not:

if (this.LoadState != null)
{
    this.LoadState(this, new LoadStateEventArgs(e.Parameter, null));
}

When there is no addition branch logic to handle null cases.

Justification

Both the Roslyn and .Net Core runtime teams agree that the null-conditional operator should be used to simplify delegate invocation.

Arguments

✔ Tends to eliminate a line dedicated to the null check, two lines for braces, and a level of indentation.

✔ Can introduce a significant performance improvement.

❌ Introduces a call to the Invoke method.

Performance

Note: there are no managed memory allocations, so this stat is omitted.

Benchmark code

Benchmark IL

Exceptions

Analyzers

Discussion

GitHub Discussion