异常已被调用的目标引发MVC

Question

我有一个ajax调用，我需要从我的控制器获取JSON数据列表。我继续得到这个例外。

下面给出的是我的Ajax调用：

$('#button1').click(function (e) { 
e.preventDefault(); 
var id= $("#textboxvalue").val(); 
debugger; 
var url = "@Url.Action("GetList", "xyz")"; 
console.log(url); 
$.ajax({ 
    url: url, 
    type: "GET", 
    async: false, 
    data: { id: id}, 
    dataType: "json", 
    traditional: true, 
    contentType: "application/json; charset=utf-8", 
    success: function (data) { 
     debugger; 
     for (var i in data) {  
     } 
    }, 
    error: function (xhr, ajaxOptions, thrownError) { 
     //Always goes to error function 
     alert("An error has occured!!!"); 
    } 
}); 
}); 

控制器代码：

我可以从阿贾克斯的参数值，并从数据库获取所有值。

[HttpGet] 
    public ActionResult GetList(string id) 
    { 

     var pList = new List<Property>(); 
     using (var db = new LiensTrackerEntities()) 
     { 

      var recipient = db.Recipients.FirstOrDefault(x => x.id== id); 
      //Need to make sure there is an Properties object 
      if (recipient != null && 
recipient.RecipientPropertyCollections.Count() != 0) 
      { 
       List<int> properties = 
recipient.RecipientPropertyCollections.Select(p => p.Property_ID).ToList(); 

       foreach (var item in properties) 
       { 
        Property p1 = db.Properties.FirstOrDefault(u => 
u.PropertyID == item); 
        pList.Add(p1); 
       } 
// I can see the values in pList on continue it goes to ERROR function in 
Ajax with 500 error 
       return Json(pList, JsonRequestBehavior.AllowGet); 
      } 
     } 
     return Json(" No spouse info in Medicaid", 
JsonRequestBehavior.AllowGet); 
    } 

异常消息：

异常已被调用的目标抛出。

异常堆栈跟踪：

at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] 
arguments, Signature sig, Boolean constructor) 
    at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, 
Object[] parameters, Object[] arguments) 
    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags 
invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) 
    at System.Web.SecurityUtils.MethodInfoInvoke(MethodInfo method, Object target, Object[] args) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeEnumerable(IEnumerable enumerable, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeEnumerable(IEnumerable enumerable, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) 
    at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, StringBuilder output, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, SerializationFormat serializationFormat) 
    at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj) 
    at System.Web.Mvc.JsonResult.ExecuteResult(ControllerContext context) 
    at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) 
    at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) 
    at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) 
    at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() 
    at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) 

Answer 1

基于堆栈跟踪，它看起来像在MVC试图发生错误JSON序列化的返回值。由于此值为List<Property>，因此Property类有可能在某些情况下调用时引发异常。

考虑创建一个单独的数据传输对象类来返回，而不是您正在使用的模型类。或者，检查实体模型类，看看为什么调用其属性可能会抛出异常。

作为一个侧面说明，如果你的实体模型设置正确，你应该能够简化您的查询逻辑颇有几分：

using (var db = new LiensTrackerEntities()) 
    { 
     var pList = db.Properties 
      .Where(p => p.RecipientPropertiesCollection 
       .Any(rp => rp.RecipientId == id)) 
      .ToList(); 
     return Json(pList, JsonRequestBehavior.AllowGet); 
    } 

这将在一个数据库往返完成，而您目前的代码会进行多次往返。