What is difference between OrderBy().ToLisT() and ToList().OrderBy() ?

Question

0.00/5 (No votes)

See more:

Hi,

I happened to asked a question in interview that what is difference between OrderBy().ToLisT() and ToList().OrderBy()? I replied there is performance overhead using first one as ToList forces everything to be evaluated. But he didn't' agree with my argument and asked me to explain comprehensively. Can you please help me to understand these in depth ?

Thanks in advance

Posted 21-Sep-15 10:43am

touseef4pk

Add a Solution

Comments

PIEBALDconsult 21-Sep-15 17:36pm

Both should have ToList removed from them.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Kornfeld Eliyahu Peter · Accepted Answer · 2015-09-21T11:05:00

You were right about the performance thing (at the global level at least)...
The reason that the OrderBy().ToList() version should perform better is that LINQ to Entities will translate that OrderBy() to an SQL ORDER BY statement that perform much better than any sorting method...
It is not always true as the expression for order may be too complex to pass it to SQL in which case LINQ to Entities will evaluate data first anyway...