Formatting LINQ Code

Over time, I’ve adjusted my code formatting style – changing the white space that I insert, or where I place the parentheses. In this post, I detail some aspects of my current code formatting approach, focusing only on formatting LINQ queries that are written in the ‘method syntax’, not using LINQ query expressions (from --- select ---).

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Blog TOCOften in the past, I have leaned towards formatting code with an emphasis on reducing line code. I like to see more of my code in a given window, not less. However, when formatting queries, there is one situation where I have tended towards a coding style that increases line count. Of course, this doesn’t increase cyclomatic complexity.

First of all, formatting for a short lambda expression is written, of course, like this:

var t2 = t1.Select(l => l.ToUpper());

 

When newing up a nominal or anonymous type in a select statement, I place the arguments to the lambda expression on the same line as the Select call, and start the instantiation of the anonymous type on the next line, indented:

var paragraphs =

    mainPartDoc.Root

       .Element(w + "body")

       .Descendants(w + "p")

    .Select(p =>

        new

        {

            ParagraphNode = p,

            Style = (string)p

                .Elements(w + "pPr")

                .Elements(w + "pStyle")

                .Attributes(w + "val")

                .FirstOrDefault()

      }

    );

 

The above example also shows my already documented approach to lining up the “dots” for a longer query. In some earlier examples, I lined up the dots like so:

Style = (string)p.Elements(w + "pPr")

               .Elements(w + "pStyle")

  .Attributes(w + "val")

  .FirstOrDefault()

 

However, I find that sometimes this indents the ‘lined up method calls’ too far, so I now indent just four spaces:

Style = (string)p

    .Elements(w + "pPr")

    .Elements(w + "pStyle")

    .Attributes(w + "val")

    .FirstOrDefault()

 

When I have ‘statement lambda expressions’, I have a new way that I write it, where I place the opening parenthesis of the Select statement on its own line, place the argument(s) to the lambda expression on its own line, and the opening brace on its own line:

XElement xmlDoc = new XElement("Root",

    File.ReadAllLines("TextFile.txt")

        .Select

        (

            line =>

            {

                var split = line.CsvSplit();

                return new XElement("Quote",

                  new XElement("Person", split[0]),

                    new XElement("Text", split[1])

                );

            }

        )

);

 

The reason I like this – it more closely parallels declaration of methods in a class. I can clearly see the arguments to the lambda expression, and the body of the lambda. I normally like to have ‘lined-up’ braces, and in this case, the parentheses of the Select method call are at their own level of indentation, so I also like to line them up.

I’ve seen another coding style that looks like this:

XElement xmlDoc = new XElement("Root",

    File.ReadAllLines("TextFile.txt")

        .Select(line => {

                var split = line.CsvSplit();

                return new XElement("Quote",

                    new XElement("Person", split[0]),

                    new XElement("Text", split[1])

                );

            }));

 

This certainly conserves vertical space, but I find it inconvenient when making sure that my braces and parentheses are properly placed.

But this is all just a matter of style. I’d really like to hear how you do it. I invite you to leave comments on this post showing how you format code. I know that pasting comments in this blog doesn’t allow you to format code very nicely – if you shoot me an email, I’d be happy to reformat your comment so that it shows your intent in formatting.

Comments

• Anonymous
  October 07, 2008
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