Checking out Jouni Heikniemi’s excellent map of What’s new in .NET 4.5 I spotted this comment:

Methods can access call site info as parameter (CallerInfo)

Intrigued, some google-fu revealed that Anders Hejlberg demoed this in his session at build - new attributes [CallerFilePath], [CallerLineNumber] and [CallerMemberName], available for use on method parameters and automatically filled in by the compiler.

The immediate use that springs to mind is for the implementation of the INotifyPropertyChanged interface:

public string Name
{
    get { return mName; }
    set {
        if (!Equals(mName, value)) {
            mName = value;
            OnNotifyPropertyChanged();
        }
    }
}

protected void OnNotifyPropertyChanged(
    [CallerMemberName] string propertyName = "")
{
    ... 
}

Note how we no longer need to pass the name of the property as a magic string to OnNotifyPropertyChanged() because the compiler will fill it in for us.

I’m sure there’ll be more inventive uses though …

Comments

blog comments powered by Disqus
Next Post
A story about Magic  10 Dec 2011
Prior Post
NUnit to the Rescue  01 Dec 2011
Related Posts
Equality of validation  18 Aug 2018
Short-circuiting validation  11 Aug 2018
Aggregation of validation  04 Aug 2018
Recovery of validation types  28 Jul 2018
Basic validation  21 Jul 2018
Why we need better validation  07 Jul 2018
A question of struct performance  30 Jun 2018
Equality has Symmetry  17 Mar 2018
Type Miscellany  05 Mar 2017
Testing Immutable Types  25 Feb 2017
More csharp posts »
Archives
December 2011
2011