INotifyPropertyChanged Revisited with .NET Framework 4.5

Introduction

Prior to this post, I have already discussed few ways of handling INotifyPropertyChanged interface. Now you might be thinking what's next? 

Well, today I'll talk about a much better and cleaner way of handling this interface, which is type-safe as well as less error prone. Till now, as a common practice, we were passing a property name as a parameter of our RaisedPropertyChanged method, which unfortunately has some demerits.

Let's say, what if user changed the name of the property and forgot to change the parameter passed inside RaisedPropertyChanged method. Now you might say that we can get rid of this by using Reflection. Even I agree with that, but again it comes with an additional associated cost. So, what's the solution now???

Enough of worries, this issue has been addressed in .NET 4.5, in which the developer can get rid of this parameter passing approach. Impressed?
An attribute titled CallerMemberName relieves us from all the worries because now this attribute will retrieve method and property name for us. Let's have a look at the code now.

Using the Code

public class ViewModelBase : INotifyPropertyChanged
    {

        public event PropertyChangedEventHandler PropertyChanged;
        protected void RaisePropertyChanged([CallerMemberName]string propertName="")
        {
            var temp = PropertyChanged;
            if (temp != null)
            {
                temp(this, new PropertyChangedEventArgs(propertName));
            }
        }
    } 

You will notice that the attribute is applied with the parameters supplied for RaisedPropertyChanged method. So, now the implementation of our property will be lot simpler as:

 private string _employeeName;
        public string EmployeeName
        {
            get { return _employeeName; }
            set
            {
                if (_employeeName != value)
                {
                    _employeeName = value;
                    RaisePropertyChanged();
                }
            }
        } 

Now user is not forced to pass parameter to this RaisedPropertyChanged method. Hope you enjoyed learning this new feature.

Previous Post

• http://www.codeproject.com/Tips/682124/Safest-way-to-use-RaisePropertyChanged-method