Implementation of Binding complier error

[wlwhitman]

I am attempting to use binding in creating a win7Phone application
I get the error:
An object reference is required for the non-static field, method or property 'MyCode.myClass.NotifyPropertyChanged(string)'
on Line 15.

Does anybody know where I went astray??
Thanks for any assistance

namespace MyCode
{
   public class myClass : INotifyPropertyChanged
    {
        private static string productNumber;
 
        public static string ProductNumber
        {
            get { return productNumber; }
            set
            {
                if (!object.Equals(value, productNumber))
                {
                    productNumber = value;
                    NotifyPropertyChanged("IOA_ProdNum");
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        protected void NotifyPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (null != handler)
                handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}
 

[Curtis Rutland]

You can't call a non-static resource (method/property/field) from a static one.

[wlwhitman]

I tried this. And it just moved the problem elsewhere.
Boy, I sure have my problems:
Now 'this' has the error
Keyword 'this' is not valid in a static property, static method or static field initializer

 public class myClass: INotifyPropertyChanged
    {
        private static string productNumber;
 
        public static string ProductNumber
        {
            get { return productNumber; }
            set
            {
                if (!object.Equals(value, productNumber))
                {
                    productNumber = value;
                    NotifyPropertyChanged("IOA_ProdNum");
                }
            }
        }
        public event PropertyChangedEventHandler PropertyChanged;
        private static void NotifyPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = this.PropertyChanged;
            if (null != handler)
                handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
 

[Curtis Rutland]

That's really the key problem, trying to implement INotifyPropertyChanged on static properties. I suggest you try googling "INotifyPropertyChanged static" and see what some others have to say about it. There's discussions about it out there.

[hype261]

The reason you are getting an error is because the handler expects a this pointer on this line.

handler(this, new PropertyChangedEventArgs(propertyName));

Static methods and variables don't have a this pointer because they exist at class scope instead of instance scope.

PropertyChangedEventHandler expects an Object sender and PropertyChangedEventArgs e in its arguments. You may be able to use NULL for the sender or another dummy argument to get around this.

[Curtis Rutland]

If you used null, Observable Collections (or anything else that subscribes) wouldn't know which item in the collection changed.