Read original post by Scott Lovegrove at Windows Phone 7 Nuggets
Those doing development for Windows Phone or Windows 8 and using an MVVM approach will be familiar with their ViewModels having properties that look something like this
private string progressText;
public string ProgressText
{
get { return progressText; }
set
{
if (value != progressText)
{
progressText = value;
NotifyPropertyChanged("ProgressText");
}
}
}