Question

我有一个简单的嵌套数组（下面）。我的目标是用C＃表示这些项目作为＆＃39;帐户＆＃39;包含＆＃39;项目列表的对象＆＃39;以及其他帐户信息。我可以在MongoDB中设置这个结构，但我不知道如何在单个帐户上的单个项目上更新StatusCode。

{  
   "Accounts":[  
      {  
         "Name":"SomeName1",
         "Email":"email1@site.com",
         "OwnedItems":[  
            {  
               "ItemId":55,
               "StatusCode":1
            },
            {  
               "ItemId":12,
               "StatusCode":2
            }
         ]
      },
      {  
         "Name":"SomeName2",
         "Email":"email2@site.com",
         "OwnedItems":[  
            {  
               "ItemId":100,
               "StatusCode":3
            },
            {  
               "ItemId":101,
               "StatusCode":4
            }
         ]
      }
   ]
}

我的问题是如何通过此设置查询和更新特定的StatusCode？

基本上我想做的是以下内容。当然，以下代码实际上不会更新数据库。

public void Update_StatusCode(string accountName, int itemId, int newStatusCode)
{
    var foundAccount = collection.Find(Builders<AccountSave>.Filter.Eq(acc => acc.Name, accountName)).FirstOrDefaultAsync().Result;
    foreach (var item in foundAccount.OwnedItems)
    {
        if (item.ItemId == itemId)
            item.StatusCode = newStatusCode;
    }
}

编辑：为了澄清，我正在使用2.0驱动程序。此外，是的，我知道没有＆＃39; _id＆＃39; s。举个例子，假设他们使用得当。

Answer 1

您可以加入条件

public async Task UpdateStatus(string accountName, int itemId, int newStatusCode)
{
    var filter = Builders<Account>.Filter.And(
        Builders<Account>.Filter.Where(x => x.Name == accountName),
        Builders<Account>.Filter.ElemMatch(x => x.OwnedItems, x => x.ItemId == itemId));

    var update = Builders<Account>.Update.Set("OwnedItems.$.StatusCode", newStatusCode);
    await collection.UpdateOneAsync(filter, update);
}

Answer 2

您也可以使用lambda表达式执行此操作：

public async Task UpdateStatus(string accountName, int itemId, int newStatusCode)
{
    var filter = Builders<Account>.Filter.And(
        Builders<Account>.Filter.Where(x => x.Name == accountName),
        Builders<Account>.Filter.ElemMatch(x => x.OwnedItems, x => x.ItemId == itemId));

    // -1 means update first matching array element
    var update = Builders<Account>.Update
                 .Set(x => x.OwnedItems[-1].StatusCode, newStatusCode);

    Console.WriteLine(update.Render(collection.DocumentSerializer, collection.Settings.SerializerRegistry).ToString());
    // { "$set" : { "OwnedItems.$.StatusCode" : 123 } }

    await collection.UpdateOneAsync(filter, update);
}

来源：http://www.mattburkedev.com/updating-inside-a-nested-array-with-the-mongodb-positional-operator-in-c-number/

如何在数组（数组中的对象）中查找和更新项目{Accounts [x] .Items [y] .StatusCode = ...}

2 个答案: