While investigating a routine bug fix today, I came across some code that can only be described as a buried cry for help …

public void Adjust(
    DateTime? open, DateTime? due, DateTime? close)
{
    if (!open.HasValue)
        throw new ArgumentNullException("open");
    if (!due.HasValue)
        throw new ArgumentNullException("due");
    if (!close.HasValue)
        throw new ArgumentNullException("close");
    // ...
}

Why would a developer declare parameters as nullable DateTimes and then immediately write guard clauses to prevent nulls from being accepted.

If you don’t want to support nulls, use a regular date time.

There are two lessons to learn here, one specific and one general.

The specific lesson: Use the right type for each parameter - use the most liberal type that makes sense (for example, use IEnumerable<T> instead of IList<T> unless you need indexed access), but no more liberal (don’t use DateTime? unless you’re willing to accept nulls).

The general lesson: Don’t make code more complex than it needs to be - do things the simplest way that makes sense. Being a developer is hard enough, we shouldn’t go out of our way to make it harder.

Comments

blog comments powered by Disqus
Next Post
Looking forward to 2012  31 Dec 2011
Prior Post
A story about Magic  10 Dec 2011
Related Posts
Add Word View  25 May 2019
Add Word View Model  11 May 2019
Add Word Screen  04 May 2019
WPF Projects & ViewModelBase  20 Apr 2019
Static Analysis  13 Apr 2019
Redux Store  06 Apr 2019
Commandline Builds  30 Mar 2019
Application Model  23 Mar 2019
Vocabulary Set  16 Mar 2019
Vocabulary Word  09 Mar 2019
More csharp posts »
Archives
December 2011
2011