使用 LINQ 读取 app.config

Question

我已经实现了（使用 System.Configuration 命名空间）并配置了下一个 App.config 结构：

<bot>
    <strategies>
        <add name="TestStrategy" type="Bot.Strategy.Test" >
            <indicators>
                <add name="Foo" type="Bot.Indicators.Foo, Bot" />
                <add name="Bar" type="Bot.Indicators.Bar, Bot" />  
            </indicators>
            <orders>
                <add id="123" amount="0.1" />
            </orders>
        </add>
    </strategies>
</bot>

对于下一个类：

class TestStrategy : IStrategy
{
    public TestStrategy(IEnumerable<IIndicator> indicators, IEnumerable<Order> orders) { }
}

interface IIndicator { }

class Order
{
    public int ID { get; set; }
    public double Amount { get; set; }
}

那么我如何读取我的 App.config 来实例化 IEnumerable 使用 LINQ 使用适当的 IEnumerable 和 IEnumerable 调用每个的构造函数？

我已经有了下一个：

var section = ((BotSection)ConfigurationManager.GetSection("bot"));
return from strategy in section.Strategies
       let strategyType = Type.GetType(strategy.Type)
       where !strategyType.IsInterface && !strategyType.IsAbstract && typeof(IStrategy).IsAssignableFrom(strategyType)
       select (IStrategy)Activator.CreateInstance(strategyType, ?);

Answer 1

如果您的 BotSection 定义正确，您可以执行以下操作（注意子查询）：

return
    from strategy in section.Strategies
    let strategyType = Type.GetType(strategy.Type)
    where !strategyType.IsInterface && !strategyType.IsAbstract
        && typeof(IStrategy).IsAssignableFrom(strategyType)
    let indicators = (
        from indicator in strategy.Indicators
        let indicatorType = Type.GetType(indicator.Type)
        select (IIndicator)Activator.CreateInstance(indicatorType))
    let orders = (
        from order in strategy.Orders
        let id = order.Id
        select new Order { Id = order.Id, Amount = order.Amount })
    select (IStrategy)Activator.CreateInstance(strategyType, indicators, orders);