Question

I have created this Update method

 public void Update(Person updated)
   {
       var oldProperties = GetType().GetProperties();
       var newProperties = updated.GetType().GetProperties();
       for (var i = 0; i < oldProperties.Length; i++)
       {
           var oldval = oldProperties[i].GetValue(this, null);
           var newval = newProperties[i].GetValue(updated, null);
           if (oldval != newval)
               oldProperties[i].SetValue(this, newval, null);
       }
   }

What it does is comparing two Person objects and if there is any new values. It updates the original object. This works great, but being a lazy programmer, I would like it to be more reusable.

I would like it to work like this.

Person p1 = new Person(){Name = "John"};
Person p2 = new Person(){Name = "Johnny"};

p1.Update(p2);
p1.Name  => "Johnny"

Car c1 = new Car(){Brand = "Peugeot"};
Car c2 = new Car(){Brand = "BMW"};

c1.Update(c2);
c1.Brand => "BMW"

c1.Update(p1); //This should not be possible and result in an error.

I was thinking about using and Abstract Class to hold the Method and then use some Generic, but I don’t know how to make it Class specific.

Answer 1

   public static void Update(object original, object updated)
   {
       var oldProperties = original.GetType().GetProperties();
       var newProperties = updated.GetType().GetProperties();
       for (var i = 0; i < oldProperties.Length; i++)
       {
           var oldval = oldProperties[i].GetValue(original, null);
           var newval = newProperties[i].GetValue(updated, null);
           if (!Equals(oldval,newval))
               oldProperties[i].SetValue(original, newval, null);
       }
   }

or if you want to ensure the same type:

   public static void Update<T>(T original, T updated)
   {
       var properties = typeof(T).GetProperties();
       for (var i = 0; i < properties.Length; i++)
       {
           var oldval = properties[i].GetValue(original, null);
           var newval = properties[i].GetValue(updated, null);
           if (!Equals(oldval,newval))
               properties[i].SetValue(original, newval, null);
       }
   }