WebApi JSON輸出

Question

所以我在MVC4中創建了一個WebApi項目，並且無法理解JSON輸出。我不完全確定這是否是JSON的預期輸出或者我是否做了不正確的事情。

我有三個表，（pb_Project，pb_Tasks和pb_Priority）。關係如下： 項目可能有很多任務，每個項目可以有一個優先級別。現在

entities http://img705.imageshack.us/img705/9294/stackoverflowentities.png

，那我收到的輸出是很奇怪的，而不是真正直觀。我不確定這是否是預期的JSON（因爲我是全新的）。當我運行網站來檢索項目的JSON輸出時，我得到以下結果。

[ 

    { 
     "$id": "1", 
     "pb_Priority": { 
      "$id": "2", 
      "pb_Projects": [ 
       { 
        "$ref": "1" 
       }, 
       { 
        "$id": "3", 
        "pb_Priority": { 
         "$ref": "2" 
        }, 
        "pb_Tasks": [ 
         { 
          "$id": "4", 
          "pb_Projects": { 
           "$ref": "3" 
          }, 
          "TASK_ID": 3, 
          "PROJECT_ID": 2, 
          "USER_ID": 2, 
          "DUE_DATE": "2012-11-19T00:00:00", 
          "PRIORITY_ID": 2, 
          "TASK_NAME": "project 2 task 1", 
          "DESCRIPTION": "asdf" 
         } 
        ], 
        "PROJECT_ID": 2, 
        "USER_ID": 2, 
        "NAME": "Project2", 
        "DESCRIPTION": "project 2 description", 
        "BUDGET": 1, 
        "LOCATION": "CANADA", 
        "START_DATE": "2012-11-18T00:00:00", 
        "PRIORITY_ID": 1, 
        "PROJ_SCALE": null, 
        "NOTES": null 
       } 
      ], 
      "PRIORITY_ID": 1, 
      "PRIORITY_LEVEL": 1 
     }, 
     "pb_Tasks": [ 
      { 
       "$id": "5", 
       "pb_Projects": { 
        "$ref": "1" 
       }, 
       "TASK_ID": 1, 
       "PROJECT_ID": 1, 
       "USER_ID": 1, 
       "DUE_DATE": "2012-11-19T00:00:00", 
       "PRIORITY_ID": 1, 
       "TASK_NAME": "project 1 task 1", 
       "DESCRIPTION": "adsf" 
      }, 
      { 
       "$id": "6", 
       "pb_Projects": { 
        "$ref": "1" 
       }, 
       "TASK_ID": 2, 
       "PROJECT_ID": 1, 
       "USER_ID": 2, 
       "DUE_DATE": "2012-11-19T00:00:00", 
       "PRIORITY_ID": 1, 
       "TASK_NAME": "project 1 task 2 user 2", 
       "DESCRIPTION": "asd" 
      } 
     ], 
     "PROJECT_ID": 1, 
     "USER_ID": 1, 
     "NAME": "Project1", 
     "DESCRIPTION": "project 1 description", 
     "BUDGET": 1000, 
     "LOCATION": "USA", 
     "START_DATE": "2012-11-18T00:00:00", 
     "PRIORITY_ID": 1, 
     "PROJ_SCALE": null, 
     "NOTES": null 
    }, 
    { 
     "$ref": "3" 
    } 

] 

該控制器如下：

public IEnumerable<pb_Projects> Getpb_Projects() 
{ 
    return db.pb_Projects.AsEnumerable(); 
} 

我期望從這一JSON結果會是什麼項目（對象）與任何其他相對FK的和這樣的列表。而我在這裏得到一個大對象，而另一個參考是第二個對象。難道我做錯了什麼，我希望這樣的事情（不要擔心它只是試驗數據，因此沒有真正的密碼：P）...

[ 

{ 
    "$id": "1", 
    "UserId": 1, 
    "CreateDate": "2012-11-18T21:46:56.78", 
    "ConfirmationToken": null, 
    "IsConfirmed": true, 
    "LastPasswordFailureDate": null, 
    "PasswordFailuresSinceLastSuccess": 0, 
    "Password": "AIGvGbJIedgTyY+m08DCVhZbVnRTWzW6kvl1JMOqsFqOCSjnJTBlGUGmVveAYIONJw==", 
    "PasswordChangedDate": "2012-11-18T21:46:56.78", 
    "PasswordSalt": "", 
    "PasswordVerificationToken": null, 
    "PasswordVerificationTokenExpirationDate": null 
}, 
{ 
    "$id": "2", 
    "UserId": 2, 
    "CreateDate": "2012-11-18T21:48:05.067", 
    "ConfirmationToken": null, 
    "IsConfirmed": true, 
    "LastPasswordFailureDate": null, 
    "PasswordFailuresSinceLastSuccess": 0, 
    "Password": "ACeoUpOVNEvgumvmSkFziRkNQzTlZC8+KAy32egXQseKLmhmJGX/VDXRXylkBUph3Q==", 
    "PasswordChangedDate": "2012-11-18T21:48:05.067", 
    "PasswordSalt": "", 
    "PasswordVerificationToken": null, 
    "PasswordVerificationTokenExpirationDate": null 
}, 
{ 
    "$id": "3", 
    "UserId": 3, 
    "CreateDate": "2012-11-19T00:35:49.163", 
    "ConfirmationToken": null, 
    "IsConfirmed": true, 
    "LastPasswordFailureDate": null, 
    "PasswordFailuresSinceLastSuccess": 0, 
    "Password": "AF7W+1FNLcaA2qJ3nmrB7S9mkJmJGZCpAZYbyH5+iXryq1epr8i67ddgSbvFQF1bQw==", 
    "PasswordChangedDate": "2012-11-19T00:35:49.163", 
    "PasswordSalt": "", 
    "PasswordVerificationToken": null, 
    "PasswordVerificationTokenExpirationDate": null 
}, 
{ 
    "$id": "4", 
    "UserId": 4, 
    "CreateDate": "2012-11-19T00:39:00.667", 
    "ConfirmationToken": null, 
    "IsConfirmed": true, 
    "LastPasswordFailureDate": null, 
    "PasswordFailuresSinceLastSuccess": 0, 
    "Password": "ABPdfSj8jZAWqhHMDuTVQuL3AiEmiplSujA/GNjQoGoMQm0zhNwAAOaInbqrXFrM0g==", 
    "PasswordChangedDate": "2012-11-19T00:39:00.667", 
    "PasswordSalt": "", 
    "PasswordVerificationToken": null, 
    "PasswordVerificationTokenExpirationDate": null 
} 

]

這裏是原始未格式化的JSON

[{"$id":"1","pb_Priority":{"$id":"2","pb_Projects":[{"$ref":"1"},{"$id":"3","pb_Priority":{"$ref":"2"},"pb_Tasks":[],"PROJECT_ID":2,"USER_ID":2,"NAME":"test2","DESCRIPTION":"test2","BUDGET":1.0,"LOCATION":"test","START_DATE":"2012-11-18T00:00:00","PRIORITY_ID":1,"PROJ_SCALE":null,"NOTES":null}],"PRIORITY_ID":1,"PRIORITY_LEVEL":1},"pb_Tasks":[{"$id":"4","pb_Projects":{"$ref":"1"},"TASK_ID":1,"PROJECT_ID":1,"USER_ID":1,"DUE_DATE":"2012-11-19T00:00:00","PRIORITY_ID":1,"TASK_NAME":"asdf","DESCRIPTION":"adsf"},{"$id":"5","pb_Projects":{"$ref":"1"},"TASK_ID":2,"PROJECT_ID":1,"USER_ID":2,"DUE_DATE":"2012-11-19T00:00:00","PRIORITY_ID":1,"TASK_NAME":"sdf","DESCRIPTION":"asd"},{"$id":"6","pb_Projects":{"$ref":"1"},"TASK_ID":3,"PROJECT_ID":1,"USER_ID":2,"DUE_DATE":"2012-11-19T00:00:00","PRIORITY_ID":2,"TASK_NAME":"dsf","DESCRIPTION":"asdf"}],"PROJECT_ID":1,"USER_ID":1,"NAME":"test","DESCRIPTION":"test","BUDGET":null,"LOCATION":"test","START_DATE":"2012-11-18T00:00:00","PRIORITY_ID":1,"PROJ_SCALE":null,"NOTES":null},{"$ref":"3"}] 

Answer 1

如果您使用EF，默認情況下，它將延遲加載導航屬性中的所有數據。當序列化器序列化模型時，它將訪問模型中的每個屬性，EF將加載所有嵌套的數據。

作爲一種最佳實踐，您不應該將您的數據庫模型公開爲web api模型。您最好創建另一個DTO模型，您可以準確控制將返回給客戶端的內容以及您希望從客戶端接收的內容。

或者您可以通過修改器隱藏這些導航屬性（標記爲內部）或使用[IgnoreDataMember]屬性快速解決該問題。它告訴序列化程序在序列化和非序列化時不要訪問它們。