System.Linq.Expressions 的 Lambda 表示式
Expression<Func<int, bool>> checkEvenExpression = i => i%2 == 0;
// lambda expression is automatically converted to an Expression<Func<int, bool>>
Expression<Func<int, bool>> checkEvenExpression = i => i%2 == 0;
// lambda expression is automatically converted to an Expression<Func<int, bool>>