Web.Api not deserializing properties of Child Array in Post

问题

I have a complex object that is correctly deserialized from json in the browser, but when I post the same data back with jQuery, the child objects of an array aren't getting deserialized - they are all set to default values.

I've tried changing the collections types from List, to IEnumerables, but that has changed nothing. It is interesting that the number of elements I get back is the correct amount.

Also this is a CORS POST, but I haven't had any problems otherwise.

Models

public class Document 
{
    public int DocumentId { get; set; }
    public DocumentType DocumentType { get; set; }
    public string Name { get; set; }
    public string Path { get; set; }
    public IEnumerable<DocumentField> Fields { get; set; }
}

public class DocumentField
{
    public int FieldId { get; set; }
    public string Path { get; set; }
    public IEnumerable<FieldRelationship> RelatedFields { get; set; }
}

public class FieldRelationship
{
    public int RelationshipId { get; set; }
    public int FieldId { get; set; }
}

Here is my controller method signature (notice I don't have [FromBody] attribute on the parameter, when I did I got a null result).

[HttpPost]
public void Post(Web.Document webDoc)

jQuery

var res = $.get('http://localhost:11786/api/documents/1');
res.then(function (data) {   
  $.ajax({
     type: 'POST',
     url: 'http://localhost:11786/api/documents/',
     crossDomain: true,
     data: data,
     success: function (responseData, textStatus, jqXHR) {
       console.log('yes');
     },
     error: function (responseData, textStatus, errorThrown) {
       console.log('failed');
     }
   });
 });

What the Response Body looks like:

Fields[0][FieldId]=1410
&Fields[0][Path]=TestField
&Fields[0][RelatedFields][0][RelationshipId]=1
&Fields[0][RelatedFields][0][FieldId]=503
&Fields[0][RelatedFields][1][FieldId]=501
&Fields[1][Path]=cookies
&DocumentId=1
&DocumentType=2
&Name=Test Document
&Path=test.docx 

What the values are in the resulting C# Documents instance

DocumentId: 1
DocumentType: 2
Name: "Test Document"
Path: "test.docx"
Fields: [{
  FieldId: 0,             <--- Bad
  Path: null,             <--- Bad
  RelatedFields: null,    <--- Bad
}, {
  FieldId: 0,             <--- Bad
  Path: null,             <--- Bad
  RelatedFields: null
}]

Edit

Here are the results if I change how I send the data in the ajax call. Remember data is the variable that holds the result from get.

ajax.data         [FromBody]  Result
---------         ----------  ------
data                   false  Props set, array count correct, array object props null
JSON.stringfy(data)    false  Object not null, but props null
{ "": data }           false  Object not null, but props null
"=" + JSON.stringfy    false  Object not null, but props null
data                    true  null
JSON.stringfy(data)     true  null
{ "": data }            true  null
"=" + JSON.stringfy     true  null

If I use angular's $http.post ($http.post('http://localhost:11786/api/documents/', res.data);) and add the [FromBody] attribute to the method parameter, I get the correct results. It seems like somehow what I'm passing to data in $.ajax is not the right thing, even though I tried the four methods above.

回答1:

Add contentType to your ajax setting object, JSON.stringify your doc object, post json string to server:

var doc = { DocumentId: 1 };
var jsonDoc = JSON.stringify(doc);
jQuery.ajax('api/test', {
    type: 'POST',
    data: jsonDoc,
    contentType: 'application/json'
})
.done(function(data, status, jqr) {
    alert(status);
})

It should works.

回答2:

Looks like you are hitting a known issue where binding to JQuery formurlencoded array format is not supported by model binding. Following issue is tracking it.

https://github.com/aspnet/Mvc/issues/211

Curious, is it on purpose that you are not setting the [FromBody]..my question is as to why not send the data as json format when you are using ajax calls...Is it to avoid CORS pre-flight request?

来源：https://stackoverflow.com/questions/28465156/web-api-not-deserializing-properties-of-child-array-in-post