public static class PBuilder    {        /// 
        /// 机关函数应用True时：单个AND有效，多个AND有效；单个OR无效，多个OR无效；混应时写在AND后的OR有效          /// 
        /// 
             /// 
             public static Expression
     
      
       > True
       
        () { return f => true; }        /// 
        
        /// 机关函数应用False时：单个AND无效，多个AND无效；单个OR有效，多个OR有效；混应时写在OR后面的AND有效          /// 
        /// 
                /// 
                public static Expression
        
         
          > False
          
           () { return f => false; } public static Expression
           
            
             > Or
             
              (this Expression
              
               
                > expr1, Expression
                
                 
                  > expr2) { var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast
                  
                   ()); return Expression.Lambda
                   
                    
                     > (Expression.Or(expr1.Body, invokedExpr), expr1.Parameters); } public static Expression
                     
                      
                       > And
                       
                        (this Expression
                        
                         
                          > expr1, Expression
                          
                           
                            > expr2) { var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast
                            
                             ()); return Expression.Lambda
                             
                              
                               > (Expression.And(expr1.Body, invokedExpr), expr1.Parameters); } }