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我不断收到以下错误与下面的代码：MEF，ImportingConstructor似乎导致了错误
Error: "No exports were found that match the constraint:
ContractName MefTestSample.Contracts.ICanDoSomethingImportant"
Program.cs是如下：
namespace MefTestSample
{
class Program
{
private static CompositionContainer m_Container;
static void Main(string[] args)
{
UseMockedUpTypes();
ICanDoSomethingImportant cool = m_Container.GetExport<ICanDoSomethingImportant>().Value;
cool.DoSomethingClever();
Console.ReadLine();
}
private static void UseMockedUpTypes()
{
//The commented out section works just by itself.
/*
m_Container =
new CompositionContainer(
new AssemblyCatalog(
typeof(MefTestSample.Mocks.ClassesDoNotNecessarly).Assembly));
*/
//This fails if i dont comment out the [ImportingConstructor] block.
var assemblyCatalog1 = new AssemblyCatalog(typeof (MefTestSample.Mocks.ClassesDoNotNecessarly).Assembly);
var myassembly = new AssemblyCatalog(typeof (ServiceLibrary.MoonService).Assembly);
var aggregateCatalog = new AggregateCatalog(assemblyCatalog1, myassembly);
m_Container = new CompositionContainer(aggregateCatalog);
}
}
}
下面是ClassesDoNotNecessarly代码：
namespace MefTestSample.Mocks
{
[Export(typeof(ICanDoSomethingImportant))]
public class ClassesDoNotNecessarly : ICanDoSomethingImportant
{
//private IServicesContract _isc;
#region ICanDoSomethingImportant Members
/* This seems to be causing the problem.
[ImportingConstructor]
public ClassesDoNotNecessarly([Import("Moon")]IServicesContract isc)
{
string temp = isc.DisplayMessage();
Console.WriteLine(temp);
}
*/
public void DoSomethingClever()
{
Console.WriteLine("Hehe, I'm actually procrastinating!");
}
#endregion
}
}
MoonService如下：
namespace ServiceLibrary
{
[Export(typeof(IServicesContract))]
public class MoonService : IServicesContract
{
public string DisplayMessage()
{
return "Moon services were accessed.";
}
}
}
我相信问题是。如果我将program.cs保持原样，并在ClassesDoNotNecessarly类中注释掉[ImportingConstructor]属性+构造函数，程序将显示该类中的文本。
如果我取消注释[ImportingConstructor]属性n的构造函数，然后我开始得到这个问题顶部显示的错误。
任何想法，将不胜感激。