c# - 错误 500 "Queries cannot be applied to the response content of type ' System.Net.Http.ByteArrayContent'

Question

我正在尝试在我的 Webapi 中输出缓存。我已经按照下面文章中的讨论安装了 Nuget 包“Strathweb.CacheOutput.WebApi2”https://github.com/filipw/Strathweb.CacheOutput .安装后我使用了:

[CacheOutput(ClientTimeSpan = 100, ServerTimeSpan = 100, AnonymousOnly = true)]
    public HttpResponseMessage Get()
    {
        var list = context.Colors.ToList();
        return Request.CreateResponse(HttpStatusCode.OK,list.AsQueryable<Color>() );
    }

它返回这个错误:

{"Message":"An error has occurred.","ExceptionMessage":"Queries can not be applied to a response content of type 'System.Net.Http.ByteArrayContent'. The response content must be an ObjectContent.\r\nParameter name: actionExecutedContext","ExceptionType":"System.ArgumentException","StackTrace":" at System.Web.Http.OData.EnableQueryAttribute.OnActionExecuted(HttpActionExecutedContext actionExecutedContext)\r\n at System.Web.Http.Filters.ActionFilterAttribute.OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Filters.ActionFilterAttribute.d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Filters.ActionFilterAttribute.d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Controllers.ActionFilterResult.d__2.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Controllers.AuthenticationFilterResult.d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.d__1.MoveNext()"}

我该怎么做才能解决这个问题。我是 Web Api 的新手。谢谢

Answer 1

由于 Web Api 是服务器侧链中的最后一步，因此在将其与响应一起发送之前，需要执行/评估 IQueryable。所以简单的解决方案就是按原样发送列表

public HttpResponseMessage Get()
{
    var list = context.Colors.ToList();
    return Request.CreateResponse(HttpStatusCode.OK,list);
}