在 C# 中解析泛型方法参数

Question

我有一个方法重载了 3 次，功能完全相同，唯一的变化是一个参数，它是一个具体类型的列表。

private void _doWork(string name, List<TargetItem> members)
{
    foreach(var member in members)
    {
      _doExtraWork(member.TimeToWork);
    }
}

private void _doWork(string name, List<NonTargetItem> members)
{
    foreach(var member in members)
    {
      _doExtraWork(member.TimeToWork);
    }
}

这里要知道的是列表中的 2 个 classes 来自 WSDL 定义。迭代中的操作针对共享成员，因为它们派生自相同的基 class，但是这种继承在 WSDL 中被抽象化。

我试过这样做 -

private void _doWork<T>(string name, List<T> members)
{
    var commonList = new List<>(); /// what type should I use here?

    if(typeof (T) == typeof(TargetItem))
    {
      commonList = members; // assume equal to means copying members to commonList with type conversion
    }
    if(typeof (T) == typeof(NonTargetItem))
    {
      commonList = members;
    }
    foreach(var member in commonList)
    {
      _doExtraWork(member.TimeToWork);
    }
}

这是处理问题和重构此通用代码的正确方法，还是我在这里遗漏了什么？

Answer 1

你可以这样做

 private static void _doWork<T>(string name, T members) where T : IEnumerable
{
     foreach(var member in members)
    {
      _doExtraWork(member.TimeToWork);
    }
}

在您的调用代码中

_doWork("sdfsd", new List<TargetItem>()); // here just as example I am passing new instance
_doWork("sdfsd", new List<NonTargetItem>()); // here just as example I am passing new instance

因为 List<T> 是 IEnumerable<T> 类型，而 IEnumerable<T> 又是 IEnumerable 类型。您可以在泛型函数中添加 IEnumerable 泛型约束。这样，您就不必在泛型函数中进行类型检查。

如果您想实现单个 doExtraWork 方法，那么您需要为 TargetItem 和 NonTargetItem 使用 CommonType。您可以使用如下所示的适配器模式解决此问题

Interface IItem
{
 int TimeToWorkAdapt {get;}
}

//Now create a wrapper class for TargetItem and NonTargetItem

Class TargetItemAdapt : TargetItem,IItem
{
   public int TimeToWorkAdapt 
       {
           get { base.TimeToWork;}    
       }
}

Class NonTargetItemAdapt : NonTargetItem,IItem
{
   public int TimeToWorkAdapt 
       {
           get { base.TimeToWork;}    
       }
}
 // write a generic function which wrap calls to your do extra work method but with generic constriants to interface
private static void _doExtraWork<T>(T members) where T : IItem
    {
          _doExtraWork(member.TimeToWorkAdapt);

    }
// In your Main program...now use our wrapper classes

_doWork("sdfsd", new List<TargetItemAdapt>()); // here just as example I am passing new instance
_doWork("sdfsd", new List<NonTargetItemAdapt>()); // here just as example I am passing new instance

Answer 2

我选择了来电者的垂头丧气

_doWork("Target", Object.TargetItems.ToList<BaseClass>());
_doWork("NonTarget", Object.NonTargetItems.ToList<BaseClass>());

在 C# 中解析泛型方法参数

Resolving generic method parameters in C#

c#

wsdl