Use and evaluate the Rule field type

In sitecore one of the field you can use is the "Rule" field. This field is very powerfull and you can easilly implmeent your own rules. Here is a very small tutorial on it.

First of all, on your template you should select the field of thype "Rule":

Now on your item you have an editor like this one:

And the following function return is a rule field is true:

public bool EvaluateRule(string fieldName, Item item) 
{
 var ruleContext = new RuleContext();
 foreach (Rule<RuleContext> rule in RuleFactory.GetRules<RuleContext>(new[] { item }, fieldName).Rules)
 {
     if (rule.Condition != null)
     {
  var stack = new RuleStack();
  rule.Condition.Evaluate(ruleContext, stack);

  if (ruleContext.IsAborted)
  {
      continue;
  }
  if ((stack.Count != 0) && ((bool)stack.Pop()))
  {
      return true;
  }
     }
 }
 
 return false;
}