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
Caching without Race Conditions  13 Jun 2020
Improved Caching  09 May 2020
Caching Speech  25 Apr 2020
Speech Middleware  11 Apr 2020
Redux Middleware Implementation  28 Mar 2020
Redux Middleware  14 Mar 2020
Always review code you copy  29 Feb 2020
Speech API  15 Feb 2020
Logging Implementation  25 Jan 2020
Logging Demonstrated  11 Jan 2020
More csharp posts »
Archives
December 2011
2011