Steve Fenton

Show Reassigned Variables in Visual Studio

There is a really neat new feature in Visual Studio 2022, which is off by default. So, I thought I’d tell you about it to encourage you to switch it on. The feature will highlight variables that get reassigned by underlining them in the editor.

When you enable this feature, variables that are assigned once are left alone, but if a variable is later assigned a new value, it will be underlined in all locations.

Examples that will not be highlighted:

// Example 1 - this is never reassigned, so isn't highlighted
int example1 = 1;

// Example 2 - although this is assigned on a different line, it is never reassigned, so isn't highlighted
int example2;

example2 = 2;

Examples that will be highlighted:

// Example 1 - this is reassigned later, so will be highlighted
int example1 = 1;

// Example 2 - this is assigned on another line, but it is the later reassignment that means it will be highlighted
int example 2;

example 2 = 2;

example1 = 10;
example2 = 20;

Here is a screenshot to show this in action, you’ll see the notAfter variable is underlined, because it is reassigned. The other variables are not highlighted because they are never reassigned.

Screenshot showing a variable underlined because it is reassigned

How to enable this feature

You can enable this feature in Tools -> Options by navigating to Text Editor -> C# -> Advanced and selecting the option Underline reassigned variables.

Finding the underline reassigned variables option in the options dialog.

Written by Steve Fenton on