Joe White’s Blog

Life, .NET, and Cats


ReSharper, day 21: Code transformations with Alt+Enter

Welcome to day 21 of my 31 Days of ReSharper. Today, I’ll wrap up the topic of Alt+Enter.

We’ve already seen how Alt+Enter can fix errors and warnings by modifying your code: it shows the red light bulb, and you can press Alt+Enter to see quick fixes.

There are also discretionary quick fixes — things that you can do to your code, but that you don’t have to. These are just things that people do a lot, so ReSharper automates them to make them a little easier.

The discretionary quick fixes are indicated with a yellow light bulb.

These can be a bit hard to find, because you have to have the cursor in the right place. That’s true of the quick fixes for errors and warnings, too, but you can see the places where those apply; they’re red or gray or squiggly; and you can jump to the next one with F12. With the discretionary quick-fixes, there’s no visual clue until you put the cursor in the right place and wait half a second or so, and there’s no keystroke to jump to the next one. You pretty much have to either (a) already know they exist, or (b) stumble onto them.

Which is why I’m covering a few of them, so you’ll know what to look for.

Removing unused braces

Suppose you have an if block that used to contain multiple statements, so you had curly braces. And now you’ve changed the code so that there’s only one line of code, so you don’t want the curly braces anymore.

Where to put the cursor: At either the open or the close curly brace (either right before it, or right after).

ReSharper's discretionary quick fix for removing unneeded braces in an 'if' statement

Changing visibility

If you position the cursor over a private, protected, internal, or public keyword, you’ll get a yellow light bulb. Press Alt+Enter, and you can change the visibility. It doesn’t save much typing, but occasionally it’s handy.

Where to put the cursor: Anywhere within the visibility keyword.

ReSharper's discretionary quick fixes for changing a member's visibility

Split Variable and Assignment

If you’ve got a variable that’s being assigned as part of its declaration, and now you want that assignment to be conditional or some such, you can use Split Declaration and Assignment to quickly split the assignment into a separate statement.

Where to put the cursor: over either the variable name, or the ‘=’ sign.

ReSharper's discretionary quick fix for splitting a variable declaration from its assignment

Join Variable and Assignment

Reverse transformations are good. Join Declaration and Assignment moves the variable declaration to the line where the variable is first assigned.

Where to put the cursor: on the line where the variable is first assigned, over either the variable name or the ‘=’ sign.

ReSharper's discretionary quick fix for joining a variable declaration and its first assignment

Here’s what it looks like after the transformation. Note that it moved the declaration down to the assignment, rather than moving the assignment up to the declaration, so it’s not going to break any ordering dependencies in your code.

After using ReSharper's discretionary quick fix to join the variable declaration and its first assignment

Invert If

This is one of my favorites. It just reverses the condition on an if statement, and swaps the “if” and “else” blocks. It’s purely a cosmetic change, with no effect on what the code actually does.

Where to put the cursor: on the if keyword.

Sounds pretty predictable, and I won’t give a boring example. But it is a little bit smarter than just inverting the condition and the blocks. Here’s an example of why it’s my favorite:

An 'if' statement that spans an entire method: code that ReSharper can improve

This happens from time to time: an if statement that spans the entire method. Here’s what happens after Invert If:

After using ReSharper to invert the full-method 'if'

It realizes that the if statement is the last thing in the method, so it generates a return to bail out of the method early if there’s nothing to do. One less level of indentation on a large block of code, and one less line of code in the method. Cool!

There are no responses to “ReSharper, day 21: Code transformations with Alt+Enter” yet.

Leave a Reply

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>


Joe White's Blog copyright © 2004-2011. Portions of the site layout use Yahoo! YUI Reset, Fonts, and Grids.
Proudly powered by WordPress. Entries (RSS) and Comments (RSS). Privacy policy