将参数传递给 ajax 发布请求会返回错误

Posted 2023-04-01

【中文标题】将参数传递给 ajax 发布请求会返回错误

【英文标题】：passing argument to an ajax post request returns an error

【发布时间】：2021-10-16 19:42:13

【问题描述】：

我有一个用 c# 编写的应用程序 MVC。 我想向我的控制器方法发出 ajax 发布请求：

locationId = "2087";
jQuery.ajax(
    url: rootUrl + "SpaEmployeeAdmin/GetCurrentLocationDateTime",
    contentType: "application/json; charset=utf-8",
    data: "locationId=" + locationId,
    dataType: "json",
    type: "POST",
    async: false,
    success: function (data) 
        //data.someObject
    
);

我的方法签名如下：

[HttpPost]
public ActionResult GetCurrentLocationDateTime(int? locationId = null)

但是，我收到此 ajax 调用的错误异常：

"System.ArgumentException: Invalid JSON primitive: locationId.
   at System.Web.Script.Serialization.javascriptObjectDeserializer.DeserializePrimitiveObject()
   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)
   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)
   at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)
   at System.Web.Mvc.JsonValueProviderFactory.GetDeserializedObject(ControllerContext controllerContext)
   at System.Web.Mvc.JsonValueProviderFactory.GetValueProvider(ControllerContext controllerContext)
   at Castle.Proxies.Invocations.ValueProviderFactory_GetValueProvider.InvokeMethodOnTarget()
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Glimpse.Core.Extensibility.CastleInvocationToAlternateMethodContextAdapter.Proceed()
   at Glimpse.Core.Extensions.AlternateMethodContextExtensions.TryProceedWithTimer(IAlternateMethodContext context, TimerResult& timerResult)
   at Glimpse.Core.Extensibility.AlternateMethod.NewImplementation(IAlternateMethodContext context)
   at Glimpse.Core.Extensibility.AlternateTypeToCastleInterceptorAdapter.Intercept(IInvocation invocation)
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Castle.Proxies.ValueProviderFactoryProxy.GetValueProvider(ControllerContext controllerContext)
   at System.Web.Mvc.ValueProviderFactoryCollection.GetValueProvider(ControllerContext controllerContext)
   at System.Web.Mvc.ControllerBase.get_ValueProvider()
   at System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor)
   at System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__19(AsyncCallback asyncCallback, Object asyncState)"

如何正确编写这个参数？没有参数并从我的方法中删除输入参数，ajax 调用有效。

【参考方案1】：

它无法解析您的数据，因此您需要在发布之前将其序列化为 json。使用 LocationRequest 模型也会有所帮助。

试试这个：

locationId = 2087;
jQuery.ajax(
    url: rootUrl + "SpaEmployeeAdmin/GetCurrentLocationDateTime",
    contentType: "application/json; charset=utf-8",
    data: JSON.stringify(locationId), //serialize json
    dataType: "json",
    type: "POST",
    async: false,
    success: function (data) 
        //data.someObject
    
);

public class LocationRequest

  public int LocationId  get; set; 

[HttpPost]
public ActionResult GetCurrentLocationDateTime(LocationRequest request)

  //request.LocationId

【讨论】：

谢谢，有没有可能没有LocationRequest，只有一个参数int? locationId？

在这种情况下，您可以将 locationId 作为 URL 的一部分传递。 [HttpPost("GetCurrentLocationDateTime/locationId")] 并且不需要发布正文。您在客户端 ajax 请求上的 url 将是 "SpaEmployeeAdmin/GetCurrentLocationDateTime/" + locationId。

【参考方案2】：

ajax 调用的 data 参数应格式化为 JSON 对象，如下所示：

locationId = "2087";
jQuery.ajax(
    url: rootUrl + "SpaEmployeeAdmin/GetCurrentLocationDateTime",
    contentType: "application/json; charset=utf-8",
    data:  locationId: locationId ,
    dataType: "json",
    type: "POST",
    async: false,
    success: function (data) 
        //data.someObject
    
);

按照惯例，服务器端 C# 期望请求的主体是 JSON，方法参数名称定义为 JSON 对象的属性。