请教Lambda表达式num => num如何用ParameterExpression的方式表示?
问题:此中的num=>num 如何用ParameterExpression方式表示呢?
如下例子:
List<decimal> decimals =
new List<decimal> { 6.2m, 8.3m, 0.5m, 1.3m, 6.3m, 9.7m };
IEnumerable<decimal> query =
decimals.AsQueryable()
.OrderByDescending(num => num, new SpecialComparer());
foreach (decimal num in query)
Console.WriteLine(num);
//如何通过Expression直接返回参数值? 效果等同于num=>num
ParameterExpression param = Expression.Parameter(typeof(decimal),"num");
var orderby = Expression.Lambda<Func<decimal>>(??, param);
var query =
decimals.AsQueryable()
.OrderByDescending(orderby, new SpecialComparer());