Enable Rating Settings on SharePoint list programmatically
public static void EnableRatingOnList(SPList list)
{
Assembly assembly = Assembly.Load("Microsoft.SharePoint.Portal, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c");
Type reputationHelper = assembly.GetType("Microsoft.SharePoint.Portal.ReputationHelper");
//MethodInfo method1 = reputationHelper.GetMethod("DisableReputation", BindingFlags.Static ' BindingFlags.NonPublic);
//method1.Invoke(null, new Object[] { list });
MethodInfo method2 = reputationHelper.GetMethod("EnableReputation", BindingFlags.Static ' BindingFlags.NonPublic);
// "Likes" or "Ratings" as per your requirement.
method2.Invoke(null, new Object[] { list, "Likes", false });
list.Update();
}