Question

I have a method and I want to add this method as an extension method to properties of my class.
This method give an expression as input parameter. The method is like below :

    public static string GetPropertyName<T>(Expression<Func<T>> propertyExpression)
    {
        return (propertyExpression.Body as MemberExpression).Member.Name;
    }

I want to use this method like below example :

string propertyName = MyClass.Property1.GetPropertyName();

Is it possible? if yes, what is the solution?

Answer 1

No, it’s not possible to do that. It’s not clear whether MyClass is the name of a class (and Property1 is a static property) or whether it’s an instance property and MyClass.Property1 simply isn’t a valid member access. If it’s the latter, you probably want to change your method to something like:

public static string GetPropertyName<TSource, TResult>(
    Expression<Func<TSource, TResult>> propertyExpression)
{
    return (propertyExpression.Body as MemberExpression).Member.Name;
}

and call it as:

string propertyName = GetPropertyName<MyClass, string>(x => x.Property1);

Or you could use a generic class with a generic method, so that string can be inferred:

string propertyName = PropertyUtil<MyClass>.GetPropertyName(x => x.Property1);

That would be something like:

public static class PropertyUtil<TSource>
{
    public static string GetPropertyName<TResult>(
        Expression<Func<TSource, TResult>> propertyExpression)
    {
       return (propertyExpression.Body as MemberExpression).Member.Name;
    }
}