c# - 合并两个 LINQ 查询？

Question

我想我有精神障碍，但有人可以告诉我如何将这两个 LINQ 语句合并为一个吗？

/// <summary>
/// Returns an array of Types that implement the supplied generic interface in the
/// current AppDomain.
/// </summary>
/// <param name="interfaceType">Type of generic interface implemented</param>
/// <param name="includeAbstractTypes">Include Abstract class types in the search</param>
/// <param name="includeInterfaceTypes">Include Interface class types in the search</param>
/// <returns>Array of Types that implement the supplied generic interface</returns>
/// <remarks>
/// History.<br/>
/// 10/12/2008      davide       Method creation.<br/>
/// </remarks>
public static Type[] GetTypesImplementingGenericInterface(Type interfaceType, bool includeAbstractTypes, bool includeInterfaceTypes)
{
    // Use linq to find types that implement the supplied interface.
    var allTypes = AppDomain.CurrentDomain.GetAssemblies().ToList()
                    .SelectMany(s => s.GetTypes())
                    .Where(p => p.IsAbstract == includeAbstractTypes  
                                    && p.IsInterface == includeInterfaceTypes);

    var implementingTypes = from type in allTypes
                            from intf in type.GetInterfaces().ToList()
                            where intf.FullName != null && intf.FullName.Contains(interfaceType.FullName)
                            select type;

    return implementingTypes.ToArray<Type>();
}

我正在避免使用 IsAssignableFrom，因为它在不提供特定类型的通用接口(interface)时似乎会失败，因此我相信在 IsAssignableFrom 上使用 FullName caparison 应该就足够了，例如:

namespace Davide
{
    interface IOutput<TOutputType> { }

    class StringOutput : IOutput<string> { }
}

typeof(IOutput<>).FullName 将返回“Davide+IOutput`1”

typeof(StringOutput).GetInterfaces()[0].FullName 将返回“Davide+IOutput`1[[System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]”

因此使用 FullName.Contains 就足够了

Answer 1

SelectMany 转换为第二个“来自”:

var implementors = from assembly in AppDomain.CurrentDomain.GetAssemblies()
                   from type in assembly.GetTypes()
                   where type.IsAbstract == includeAbstractTypes
                   where type.IsInterface == includeInterfaceTypes
                   from intf in type.GetInterfaces()
                   where intf.FullName != null && 
                         intf.FullName.Contains(interfaceType.FullName)
                   select type;

为了主观清晰，我将条件分成多个“where”子句，顺便说一下。

这可以编译，但我还没有测试它是否真的有效 :) 正如另一个答案所示，您可以将“Any”与 GetInterfaces() 一起使用，而不是最后的“from”子句。

请注意，无需到处调用 ToList() - LINQ 旨在能够处理整个序列。

顺便说一句，我不确定您为什么要通过 type.GetInterfaces() 进行检查。与使用 Type.IsAssignableFrom 相比，有什么不同(和可取的)吗？ ？这将使它更简单:

var implementors = from assembly in AppDomain.CurrentDomain.GetAssemblies()
                   from type in assembly.GetTypes()
                   where type.IsAbstract == includeAbstractTypes
                   where type.IsInterface == includeInterfaceTypes
                   where interfaceType.IsAssignableFrom(type)
                   select type;

您实际上在某个地方的不同程序集中有相同的接口(interface)类型名称吗？