c# - C#ASP.NET无法转换或从System.String转换为PagedList.PagedList

Question

我正在使用ASP.NET-MVC，但在处理JSON字符串时遇到了麻烦。

这是服务器端的操作：

    [HttpPost]
    public string Post([FromBody] GetIncidentsRequest value)
    {
        List<Incident> incidentList = ReadIncidentsFromTable(value.Status);
        PagedList<Incident> pagedIncidentList = new PagedList<Incident>(incidentList, value.Page, value.PageSize);
        string serialisedJSON = JsonConvert.SerializeObject(pagedIncidentList);

        return serialisedJSON;
    }

这是客户端操作：

    public ActionResult AppHistoricalIncidents(string sortOrder = "id", int page = 1, int pageSize = 1)
    {            
        string serialisedJSON = JsonConvert.SerializeObject(new GetIncidentsRequest
        {
            SortOrder = sortOrder,
            Page = page,
            PageSize = pageSize,
            Enumber = GetCurrentUserEnumber(),
            Status = Incident.EnumStatus.Completed
        });

        string response = string.Empty;
        using (WebClient wc = new WebClient())
        {
            wc.Headers[HttpRequestHeader.ContentType] = "application/json";
            try
            {
                response = wc.UploadString(new Uri("http://localhost:25657/api/GetIncidents"), serialisedJSON);
            }
            catch (Exception ex)
            {
                Debug.Print(ex.ToString());
                Console.WriteLine(ex.ToString());
            }
            PagedList<Incident> retVal = JsonConvert.DeserializeObject<PagedList<Incident>>(response);

            return PartialView(retVal);
        }
    }

返回的字符串serializedJSON的内容为

[{"Type":0,"ID":2,"BusinessAreaID":3,"AppID":70,"SubProcess":71,"SubProcessName":"something something","SitesAffected":["Teesside"],"Example":"Doesnt work","Replication":"meh","initialComment":null,"RaiserContactNumber":"07703555555","RaiserContactEmail":"test@test.co.uk","RaisedBy":"E0000001","AssignedTo":"E0000002","RootCause":"lots lol","LastModifiedBy":null,"LastModifiedDate":"0001-01-01T00:00:00","CreationDate":"0001-01-01T00:00:00","TimeTakenByDev":0,"Status":1,"ShouldEmail":false,"AffectedWorkstations":["B0123123"],"Comments":[]}]

我得到错误：

Could not cast or convert from System.String to PagedList.PagedList`1[Shared.Models.Incident]. 

就像Post操作返回的是PagedList而不是字符串，但这是不对的，我在这里做错了什么？

错误似乎来自这一行：

            response = wc.UploadString(new Uri("http://localhost:25657/api/GetIncidents"), serialisedJSON);

完整的堆栈跟踪如下：

[ArgumentException: Could not cast or convert from System.String to System.Collections.Generic.List`1[CIADashShared.Models.Incident].]
   Newtonsoft.Json.Utilities.ConvertUtils.EnsureTypeAssignable(Object value, Type initialType, Type targetType) +225
   Newtonsoft.Json.Utilities.ConvertUtils.ConvertOrCast(Object initialValue, CultureInfo culture, Type targetType) +123
   Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType) +348

[JsonSerializationException: Error converting value "[{"Type":0,"ID":2,"BusinessAreaID":3,"AppID":70,"SubProcess":71,"SubProcessName":"something something","SitesAffected":["Teesside"],"Example":"Doesnt work","Replication":"meh","initialComment":null,"RaiserContactNumber":"07703555555","RaiserContactEmail":"test@test.co.uk","RaisedBy":"E000001","AssignedTo":"E0000002","RootCause":"lots lol","LastModifiedBy":null,"LastModifiedDate":"0001-01-01T00:00:00","CreationDate":"0001-01-01T00:00:00","TimeTakenByDev":0,"Status":1,"ShouldEmail":false,"AffectedWorkstations":["B0123123"],"Comments":[]}]" to type 'System.Collections.Generic.List`1[CIADashShared.Models.Incident]'. Path '', line 1, position 42538.]
   Newtonsoft.Json.Serialization.JsonSerializerInternalReader.EnsureType(JsonReader reader, Object value, CultureInfo culture, JsonContract contract, Type targetType) +420
   Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) +273
   Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) +453
   Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) +209
   Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) +137
   Newtonsoft.Json.JsonConvert.DeserializeObject(String value, JsonSerializerSettings settings) +66
   CIA_Dash.Controllers.MaintenanceController.AppHistoricalIncidents(String sortOrder, Int32 page, Int32 pageSize) in C:\dev\CIA Dash\CIA Dash\Controllers\MaintenanceController.cs:364
   lambda_method(Closure , ControllerBase , Object[] ) +192
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +157
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
   System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) +22
   System.Web.Mvc.Async.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +32
   System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +50
   System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +228
   System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +34
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +26
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.Mvc.<>c__DisplayClassa.<EndProcessRequest>b__9() +22
   System.Web.Mvc.<>c__DisplayClass4.<Wrap>b__3() +10
   System.Web.Mvc.ServerExecuteHttpHandlerWrapper.Wrap(Func`1 func) +27
   System.Web.Mvc.ServerExecuteHttpHandlerWrapper.Wrap(Action action) +64
   System.Web.Mvc.ServerExecuteHttpHandlerAsyncWrapper.EndProcessRequest(IAsyncResult result) +71
   System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +1436

[HttpException (0x80004005): Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'.]
   System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride) +3472700
   System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage) +76
   System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) +29
   System.Web.HttpServerUtilityWrapper.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm) +24
   System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter) +461
   System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues) +83
   System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName) +11
   ASP._Page_Views_Apps_Support_cshtml.Execute() in c:\dev\CIA Dash\CIA Dash\Views\Apps\Support.cshtml:66
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +105
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +90
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +235
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107
   System.Web.Mvc.HtmlHelper.RenderPartialInternal(String partialViewName, ViewDataDictionary viewData, Object model, TextWriter writer, ViewEngineCollection viewEngineCollection) +277
   System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model, ViewDataDictionary viewData) +91
   System.Web.Mvc.Html.PartialExtensions.Partial(HtmlHelper htmlHelper, String partialViewName, Object model) +33
   ASP._Page_Views_Apps_AppID_cshtml.Execute() in c:\dev\CIA Dash\CIA Dash\Views\Apps\AppID.cshtml:70
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +105
   System.Web.WebPages.StartPage.RunPage() +17
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +64
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +78
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +235
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +291
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +52
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +173
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9765901
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

好的，我解决了这个问题，并在反序列化之前对响应字符串应用了以下方法来解决此问题

    private string FixApiResponseString(string input)
    {
        input = input.Replace("\\", string.Empty);
        input = input.Trim('"');
        return input;
    }

问题是，API所返回的字符串在每次出现“之前都具有\转义字符，并将该字符串括在另一组不必要的引号中。去除这些引号可以解决问题。