將Ajax帖子中的數據綁定到傳遞給控制器​​的模型

Question

我需要使用Ajax調用來更新文檔，但是我一直沒有成功將Ajax調用中的數據綁定到傳遞給控制器​​的模型。

我在這裏做錯了什麼？

我也試過改變控制器的定義來期望一個字符串，它避免了下面的NullReferenceException，但是字符串被傳遞爲null。

請求負載

{"model":{"Text":"Test","LastUpdated":null,"TrainingSentiment":"Test","Sentiment":"Test","SentimentScore":"-1","Entities":[{"Start":0,"End":0,"Value":"Test","Orth":"Test","Label":"Test"}]}} 

預覽

System.NullReferenceException: Object reference not set to an instance of an object. 
    at Microsoft.Azure.Documents.Document.get_AttachmentsLink() 
    at Microsoft.Extensions.Internal.PropertyHelper.CallNullSafePropertyGetter[TDeclaringType,TValue](Func`2 getter, Object target) 
    at Microsoft.AspNetCore.Mvc.Internal.DefaultComplexObjectValidationStrategy.Enumerator.MoveNext() 
    at Microsoft.AspNetCore.Mvc.ModelBinding.Validation.ValidationVisitor.VisitChildren(IValidationStrategy strategy) 
    at Microsoft.AspNetCore.Mvc.ModelBinding.Validation.ValidationVisitor.VisitComplexType() 
    at Microsoft.AspNetCore.Mvc.ModelBinding.Validation.ValidationVisitor.Visit(ModelMetadata metadata, String key, Object model) 
    at Microsoft.AspNetCore.Mvc.Internal.DefaultControllerArgumentBinder.<BindModelAsync>d__8.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
    at Microsoft.AspNetCore.Mvc.Internal.DefaultControllerArgumentBinder.<BindArgumentsCoreAsync>d__6.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
    at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextResourceFilter>d__22.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ResourceExecutedContext context) 
    at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted) 
    at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__20.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
    at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
    at Microsoft.VisualStudio.Web.BrowserLink.BrowserLinkMiddleware.<ExecuteWithFilter>d__7.MoveNext() 
--- End of stack trace from previous location where exception was thrown --- 
    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() 
    at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
    at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext() 

阿賈克斯

var modelObj = { 
    model: { 
     Text: "Test", 
     LastUpdated: null, 
     TrainingSentiment: "Test", 
     Sentiment: "Test", 
     SentimentScore: "-1", 
     Entities: [ 
      { 
       Start: 0, 
       End: 0, 
       Value: "Test", 
       Orth: "Test", 
       Label: "Test" 
      } 
     ] 
    } 
}; 

$.ajax({ 
    type: "POST", 
    url: '/Tweets/DocumentUpdateAjax', 
    contentType: "application/json", 
    data: JSON.stringify(modelObj), 
    dataType: "html", 
    success: function (response) { 
     console.log("Success!"); 

     /** Replace the partial view with html contents from the response. **/ 
     $("#updateDocumentPartialView").html(response); 

    }, 
    failure: function (response) { 
     console.log("Failure!"); 

     /** Dump the JSON string to the console. **/ 
     console.log(JSON.stringify(response)); 
    }, 
    error: function (response) { 
     console.log("Error!"); 

     /** Dump the JSON string to the console. **/ 
     console.log(JSON.stringify(response)); 
    } 
}); 

控制器

[HttpPost] 
public IActionResult DocumentUpdateAjax(TrainingModel model) 
{ 
    .... 
} 

模型

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Threading.Tasks; 
using Microsoft.AspNetCore.Builder; 
using Microsoft.AspNetCore.Http; 
using Newtonsoft.Json; 

namespace TextualAnalytics.Models 
{ 
    public class TrainingModel : Microsoft.Azure.Documents.Document 
    { 

     [JsonProperty(PropertyName = "text")] 
     public string Text { get; set; } 

     [JsonProperty(PropertyName = "last_updated")] 
     public DateTime? LastUpdated { get; set; } 

     [JsonProperty(PropertyName = "training_sentiment")] 
     public string TrainingSentiment { get; set; } 

     [JsonProperty(PropertyName = "sentiment")] 
     public string Sentiment { get; set; } 

     [JsonProperty(PropertyName = "sentiment_score")] 
     public string SentimentScore { get; set; } 

     [JsonProperty(PropertyName = "entities")] 
     public List<Entity> Entities { get; set; } 

     public class Entity 
     { 

      [JsonProperty(PropertyName = "start")] 
      public long Start { get; set; } 

      [JsonProperty(PropertyName = "end")] 
      public long End { get; set; } 

      [JsonProperty(PropertyName = "value")] 
      public string Value { get; set; } 

      [JsonProperty(PropertyName = "orth")] 
      public string Orth { get; set; } 

      [JsonProperty(PropertyName = "label")] 
      public string Label { get; set; } 

     } 

    } 
} 

Answer 1

的[FromBody]屬性給出ASP.NET核心框架通過使用串行化器對所述請求的身體模型的數據綁定的線索。默認情況下，框架綁定表單域。嘗試將控制器方法更改爲

[HttpPost] 
public IActionResult DocumentUpdateAjax([FromBody] TrainingModel model) 
{ 
    .... 
} 

Answer 2

也許您正在使用普通POST發送數據。嘗試包所有的代碼是這樣的：

$('#buttonId').on('click', function(e){ 
    e.preventDefault(); 
    // and all of your ajax and js codes... 
}); 

而在阿賈克斯objext改變dataType屬性的值「html」到「json」。