依赖注入：SimpleTraceWriter 类型必须派生自 ITraceWriter

Question

我正在使用 Ninject 进行 DI。其中一行给了我奇怪的错误：

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

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

出错的代码行：

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。尝试在导致错误的行中指定名称空间：

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