4 methods to handle Nullable Reference in .NET

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Background

Reference types in C# have always been nullable, meaning that variables of any reference type can be assigned a value of null. In previous versions of C#, dereferencing a null variable was permitted without any checks.

The Nullable Reference Types feature was introduced in C# 8 to address this issue, and with the release of .NET 6, this feature is now enabled by default.

Example

Let's say we have a class:

In .Net we will get a warning for underlined properties:

CS8618: Non-nullable field 'Name' must contain a non-null value when exiting the constructor. Consider declaring the field as nullable.

How to handle it? Method #1

Steps:

• Open the .csproj project file

• Inside the PropertyGroup change Nullable to disable

Result: We won't get any more warnings for null references, but we can potentially run into a Null Reference Exception if we don't check objects for null before using them.

Method #2

Steps

• Make properties nullable reference type by using "?" .

Method #3

Steps

• Assign a default value to properties

Method #4

Steps

• Write a compiler directive #nullable to disable (or enable) feature.

If you have a (at least) .NET 6 project, open it now and try it.

Dream big!