How CallerMemberName works?

Question

1.00/5 (1 vote)

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.NET4.5

Hi,

i have seen some of the INotifyPropertyChanged member method using [CallerMemberName] as a method argument prefix. i want to know how actually it works. how to do some this similar to it? can any one explain me please?

Note:
I have already read some of the links [^]where we can find some additional improvements in .net4.5 regarding attribute usage. please let me know some links other than similar to this :)

My Custom attribute class

C#

namespace AttributeTesting
{
    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
    public class CallerMember : Attribute
    {
public string ParameterName { get; set; }
    }
}

Implemented employeeClass

C#

namespace AttributeTesting.Data
{
    [CallerMember]    
public class EmployeeData : INotifyPropertyChanged
    {
        private string _name;
        
        public string Name
        {
            get { return _name; }
            set { _name = value; OnPropertyChanged(); }
        }


        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged([CallerMember] string ParameterName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(ParameterName));
            }
        }

        #endregion
    }
}

try to make it work

C#

namespace AttributeTesting
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.Loaded += OnMainWindowLoaded;
        }

        void OnMainWindowLoaded(object sender, RoutedEventArgs e)
        {
            EmployeeData EmployeeData = new EmployeeData { Name = "GoldCoin" };

        }
    }
}

Unable to implement my custom attribute. what should i do next

Note:
I am trying to implement something that .net 4.5 has. The same in my solution which was developed in .net 4.0 :)

Posted 12-Mar-15 20:25pm

Gold$Coin

Updated 12-Mar-15 20:48pm

v5

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Comments

phil.o 13-Mar-15 6:21am

Better suffix your class name with 'Attribute'
public class CallerMemberAttribute : Attribute

Then:
private void OnPropertyChanged([CallerMember("yourParameterName")] string whatever = "")

2 solutions

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phil.o · Answer 1 · 2015-03-12T20:32:00

Solution 1

That is called an attribute.
Here is the MSDN page about the CallerMemberNameAttribute:
CallerMemberNameAttribute[^]

You can define your own attribute by deriving from Attribute Class[^].
The class name must be suffixed with 'Attribute' word, but this does not appear when you use it in your code.
Example:

C#

public class MyOwnAttrAttribute : Attribute
{
   // ...
}

[MyOwnAttr]
public class MyDecoratedClass
{
   // ...
}

Posted 12-Mar-15 20:32pm

phil.o

Comments

Gold$Coin 13-Mar-15 2:39am

well, that was not the solution i am looking for. sorry.

phil.o 13-Mar-15 6:18am

I'm sorry, obviously I misunderstood your question.

Gold$Coin 13-Mar-15 2:46am

have updated my implementation in my post please take a look and let me know what was wrong in my implementation.

BillWoodruff · Answer 2 · 2015-03-13T01:43:00

Try changing your implementation to this:

C#

public event PropertyChangedEventHandler PropertyChanged;

protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
    var handler = PropertyChanged;
    if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}