A tall LINQ query puts each method call in the chain on its own line, so the expression grows vertically instead of stretching across the screen. Each step becomes easier to read, and easier to follow into the next one in the chain.
Wishing You a Warm Welcome
First, I want to welcome you to the first edition of Milan's .NET Weekly newsletter.
I hope that this newsletter can become a positive force in the .NET community. To bring many of us together so that we can all continue learning and improving.
With that out of the way, let's get into .NET!
The Problem With Wide LINQ
Let's consider the following LINQ expression from a code style perspective.
I call this a wide LINQ expression because it stretches horizontally across the entire screen.
dbContext.Animals.Where(animal => animal.HasBigEars)
.OrderBy(animal => animal.IsDangerous).Select(
animal => (animal.Id, animal.Name)).ToList();
- It is difficult to read.
- It is difficult to reason about.
- It is difficult to extend or maintain.
To improve this, I created a simple rule that you can follow:
When writing LINQ, try to go tall, not wide.
How to Write Tall LINQ
So how do we write tall LINQ expressions?
I'm going to rewrite the previous expression, to improve it.
Try to follow the one dot per line rule:
dbContext
.Animals
.Where(animal => animal.HasBigEars)
.OrderBy(animal => animal.IsDangerous)
.Select(animal => (animal.Id, animal.Name))
.ToList();
Is the new version easier to read? Yes, very much so.
It is easier to understand what each expression does, and how it feeds into the next one in the chain.
If you are working in a team, try to propose this as a coding standard (if it isn't one already).
You will see that over time this will make a noticeable difference.
Frequently Asked Questions
What is a tall LINQ query?
A tall LINQ query puts each method call in the chain on its own line, so the expression grows vertically instead of stretching across the screen. Each step becomes easier to read and to follow into the next one in the chain.
How do you format long LINQ method chains in C#?
Follow the one dot per line rule: start from the source, then place every Where, OrderBy, Select, and ToList call on its own line. The chain then reads top to bottom, one operation at a time.
Why are wide LINQ expressions a problem?
A wide LINQ expression stretches horizontally across the entire screen. That makes it difficult to read, difficult to reason about, and difficult to extend or maintain, because you cannot quickly see what each operator in the chain does.
Should LINQ formatting be part of a team coding standard?
Yes. Proposing tall LINQ as a coding standard keeps the codebase consistent, and over time the improved readability makes a noticeable difference for everyone maintaining the code.
