Question

I have this code and I am using it to raise the PropertyChanged event without passing the name of property to the function.

private void RaisePropertyChanged<TValue>(Expression<Func<TValue>> propertySelector)
    {
        var memberExpression = propertySelector.Body as MemberExpression;
        if (memberExpression != null)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(memberExpression.Member.Name));
            }
        }
    }

and I am calling it in this way:

  this.RaisePropertyChanged(() => this.IsReady);

Which will raise the PropertyChanged event for the IsReady property. I like the idea as writing code in this way will help to change the name of the property very easily.

Now I want to use the same technique to pass the name and value of a property to a method. Is there any way that I can do this?

Answer 1

You already have it:

string name = memberExpression.Member.Name;
TValue value = propertySelector.Compile()();

An alternative would be to look at the member.MemberType, cast to PropertyInfo or FieldInfo respectively:

var member = memberExpression.Member;
string name = member.Name;
object value;
switch(member.MemberType) {
    case MemberTypes.Field:
       value = ((FieldInfo)member).GetValue(this);
       break;
    case MemberTypes.Property:
       value = ((PropertyInfo)member).GetValue(this, null);
       break;
    default:
       throw new NotSupportedException(member.MemberType.ToString());
}

However, a simpler approach is… to simply pass the name and value to the method:

Foo("IsReady", IsReady);

It depends a bit on how efficient it needs to be, though (reflection/expression does add an overhead – whether that is significant depends on the context).