What is the best or most interesting use of Extension Methods you've seen? [closed]

Answer 1

I'm not a fan of the INotifyPropertyChanged interface requiring that property names are passed as strings. I want a strongly-typed way to check at compile time that I'm only raising and handling property changes for properties that exist. I use this code to do that:

public static class INotifyPropertyChangedExtensions
{
    public static string ToPropertyName(this Expression> @this)
    {
        var @return = string.Empty;
        if (@this != null)
        {
            var memberExpression = @this.Body as MemberExpression;
            if (memberExpression != null)
            {
                @return = memberExpression.Member.Name;
            }
        }
        return @return;
    }
}

In classes that implement INotifyPropertyChanged I include this helper method:

protected void NotifySetProperty(ref T field, T value,
    Expression> propertyExpression)
{
    if (field == null ? value != null : !field.Equals(value))
    {
        field = value;
        this.NotifyPropertyChanged(propertyExpression.ToPropertyName());
    }
}

So that finally I can do this kind of thing:

private string _name;
public string Name
{
    get { return _name; }
    set { this.NotifySetProperty(ref _name, value, () => this.Name); }
}

It's strongly-typed and I only raise events for properties that actually change their value.