web api HttpConfiguration

//设置web api configuration

public static void Register(HttpConfiguration config)
{

　　 config.Services.Replace(typeof(ITraceWriter), new NLogger());

}

//设置asp.net 应用程序 全局configuration

GlobalConfiguration.Configuration.Services.Replace(typeof(ITraceWriter), new NLogger());

//获取 全局configuration

var writer = GlobalConfiguration.Configuration.Services.GetTraceWriter();

//获取 actionContext 当前configuration

ITraceWriter writer = actionContext.ControllerContext.Configuration.Services.GetTraceWriter();