“数组初始化程序中的冗余逗号”为什么应该修复它

Question

With ReSharper 6.0 I've received a new warning:

redundant comma in array initializer

for the case when I have a list of array initializer parameters with comma in the end.

What bad in that? Why I like "my" approach is that I often need to comment the latest value and don't want to bother with fixing those 'leading' commas:

    private readonly string[] _tables
        = new[]
              {
                  "users",
                  "user_account",
                  "user_budget_type",
                  //"user_budget"
              };

Please advise what is good in following that suggestion.

Thank you.

Answer 1

I agree that it shouldn't matter that there is a comma at the end, however, if you write your arrays like so, you don't have this problem.

private readonly string[] _tables
    = new[]
          {
              "users"
              ,"user_account"
              ,"user_budget_type"
              //,"user_budget"
          };

Answer 2

ReSharper is full of suggestions. Just like any other productivity tool, in the end it's up to you whether to act upon those suggestions.

For example, while the C# language allows a trailing comma or an empty control statement bodies (placing a ; for a loop body), or even typing duplicate ;; at the end of the statement. For all those things ReSharper will suggest you removing redundancies, because it's what it does - heuristically detects redundancies. If you know better, there are several ways you could "silence" ReSharper from suggesting it:

1. Temp. suppress the warning using special comments (choose the "Suppress inspection ... with comment" quickfix):

    private readonly string[] _tables = new[] { "users", "user_account", // ReSharper disable RedundantCommaInArrayInitializer "user_budget_type", // ReSharper restore RedundantCommaInArrayInitializer //"user_budget" }; 

or 2. Suppress this warning completely by selecting "Inspection options for ...", and choosing "Do not show" in the options.

It's all about choice and personal preference - you can configure just about anything you want in the tool.

Answer 3

The clue is in the text of the message:

redundant comma in array initializer

What does it mean by that? Well, your code:

private readonly string[] _tables
    = new[]
          {
              "users",
              "user_account",
              "user_budget_type",
              //"user_budget"
          };

and the code with the inspection acted upon:

private readonly string[] _tables
    = new[]
          {
              "users",
              "user_account",
              "user_budget_type"
              //"user_budget"
          };

are semantically equivalent . That is, the CIL produced in each case is identical - there is no difference in behaviour. So the comma changes nothing and is therefore redundant.

Now, as to your question:

What bad in that?

That's largely up to you. R# merely has this redundancy as an inspection , but it is you (through your acceptance of the default settings) that has it categorised as a warning .

If this construct is acceptable to your style, then by all means go ahead and change the Inspection Severity in R# options; but in general , the defaults for R# options are those that produce pretty close to the minimum amount of code necessary.

Answer 4

你可以压制那个警告，Resharper只是说，以防万一你在乎:)

Answer 5

@Budda, Unlike other have said, this redundant comma is eval! In some browsers, for example IE8, this could cause the browser to misunderstand you and mis-create the object.

See this answer for example, where the trailing comma caused the Highcharts library to stop working.

Keeping your code clean is not only a matter of easier reading and debugging. Even if you see your code working with this comma, it doesn't mean that it will be working the same with all browsers.