学习笔记: Expression表达式目录树详解和扩展封装

1. 表达式链接扩展封装,ORM常用 And  Or

///

/// 表达式访问者
///

public class ExpressionVisitorTest
{

    public static void Show()
     {
        

        #region 表达式链接
         {
             Expression> lambda1 = x => x.Age > 5;
             Expression> lambda2 = x => x.Id > 5;
             Expression> lambda3 = lambda1.And(lambda2);
             Expression> lambda4 = lambda1.Or(lambda2);
             Expression> lambda5 = lambda1.Not();
             Do1(lambda3);
             Do1(lambda4);
             Do1(lambda5);
         }
         #endregion

     }
     #region PrivateMethod
     private static void Do1(Func func)
     {
         List people = new List();
         people.Where(func);
     }
     private static void Do1(Expression> func)
     {
         List people = new List()
         {
             new People(){Id=4,Name="123",Age=4},
             new People(){Id=5,Name="234",Age=5},
             new People(){Id=6,Name="345",Age=6},
         };

        List peopleList = people.Where(func.Compile()).ToList();
     }

    private static IQueryable GetQueryable(Expression> func)
     {
         List people = new List()
         {
             new People(){Id=4,Name="123",Age=4},
             new People(){Id=5,Name="234",Age=5},
             new People(){Id=6,Name="345",Age=6},
         };

        return people.AsQueryable().Where(func);
     }
     #endregion
}

转载于:https://www.cnblogs.com/xtxtx/p/9162432.html