类型强制转换支持

可以使用 ClassMemberBinding 类的 Cast 方法将一种类型的对象转换为另一个兼容类型的对象。 目前，业务规则编辑器工具不支持使用 强制转换 方法创建规则。 您必须使用规则引擎对象模型通过编程方式来创建规则，以充分利用此功能。

以下示例代码演示如何使用 Cast 方法将 System.Object 类的实例转换为 Cls2 类的实例。 此示例还演示如何访问类的嵌套成员，如 访问类的嵌套成员中所述。

using Microsoft.RuleEngine;  
  
namespace RuleTypeCasting  
{  
    class Cls1  
    {  
        //Note that return type is 'object', not Cls2  
        public object GetCls2Obj()  
        {  
            return new Cls2();  
        }  
    }  
  
    class Cls2  
    {  
        public void Log()  
        {  
            Console.WriteLine("In Cls2.Log method");  
        }  
    }  
  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            //Create the condition list IF 1 == 1  
            Equal eq = new Equal(new Constant(1), new Constant(1));  
  
            //Create the action collection  
            ActionCollection ac = new ActionCollection();  
  
            //Create the class binding for the Cls1 class  
            ClassBinding cbCls1 = new ClassBinding(typeof(Cls1));  
  
            //Create the class member binding for the GetCls2Obj method in the Cls1 class  
            ClassMemberBinding cmGetCls2Obj = new ClassMemberBinding("GetCls2Obj", cbCls1);  
  
            //Type casting the return value of GetCls2Obj method (object) to Cls2 type  
            cmGetCls2Obj.Cast(typeof(Cls2));  
  
            //Create the class member binding to the Log method of Cls2 type   
            ClassMemberBinding cmLog = new ClassMemberBinding("Log", cmGetCls2Obj);  
  
            //Create a user function based on cmLog and add it to the action collection  
            UserFunction ufLog = new UserFunction(cmLog);  
            ac.Add(ufLog);  
  
            // Create the rule  
            Rule rl = new Rule("InvokeLogRule", eq, ac);  
  
            // Create the rule set or policy  
            RuleSet rs = new RuleSet("InvokeLogPolicy");  
            rs.Rules.Add(rl);  
  
            //Create the facts  
            Cls1 Cls1Obj = new Cls1();  
  
            //Execute the policy  
            PolicyTester tester = new PolicyTester(rs);  
            tester.Execute(Cls1Obj);  
  
        }  
    }  
}  

另请参阅

业务规则引擎中对类继承的支持
访问类的嵌套成员