PropertyName.cs

public static string PropertyName<T>(Expression<Func<T>> expression)
{
    if (expression == null)
        throw new ArgumentNullException("expression");
    
    var body = expression.Body as MemberExpression;
    
    if (body == null)
        throw new ArgumentException("Invalid expression", "expression");

    var property = body.Member as PropertyInfo;
    
    if (property == null)
        throw new ArgumentException("Invalid expression", "expression");

    return property.Name;
}