依赖注入：SimpleTraceWriter类型必须从ITraceWriter派生

Question

我使用Ninject进行DI。其中一行给了我一个奇怪的错误：

The type SimpleTraceWriter must derive from ITraceWriter.
Parameter name: service

{"The type SimpleTraceWriter must derive from ITraceWriter.\r\nParameter name: service"}

给出错误的代码行：

config.Services.Replace(typeof(ITraceWriter), new SimpleTraceWriter(WebContainerManager.Get<ILogManager>()));

但是SimpleTraceWriter实现了ITraceWriter：

SimpleTraceWriter代码：

 public class SimpleTraceWriter : ITraceWriter
    {
        private readonly ILog _log;

        public SimpleTraceWriter(ILogManager logManager)
        {
            _log = logManager.GetLog(typeof(SimpleTraceWriter));
        }

        public void Trace(HttpRequestMessage request, string category, TraceLevel level, Action<TraceRecord> traceAction)
        {
            var rec = new TraceRecord(request, category, level);
            traceAction(rec); WriteTrace(rec);
        }

...

ITraceWriter代码：

public interface ITraceWriter
{   
    void Trace(HttpRequestMessage request, string category, TraceLevel level, Action<TraceRecord> traceAction);
}

Answer 1

System.Web.Http.Tracing命名空间中还有另一个ITraceWriter接口。尝试在行中指定名称空间，这会导致错误：

config.Services.Replace(typeof(MyNamespace.ITraceWriter), new SimpleTraceWriter(WebContainerManager.Get<ILogManager>()));