C# Cosmos DB 补丁 - 将元素插入子集合

Question

尝试将新项目添加到父对象的子集合中。例如，在下面的代码中，如何将一个新项目添加到 Items 集合中？

{
    "id": "SalesOrder2",
    "ponumber": "PO15428132599",
    "OrderDate": "2005-07-01T00:00:00",
    "AccountNumber": "Account2",
    "Items": [
        {
            "Id": 1,
            "OrderQty": 3,
            "ProductCode": "A-123",
            "ProductName": "Product 1",
            "CurrencySymbol": "$",
            "CurrencyCode": "USD",
            "UnitPrice": 17.1,
            "LineTotal": 5.7
        },
        {
            "Id": 2,
            "OrderQty": 2,
            "ProductCode": "A-456",
            "ProductName": "Product 2",
            "CurrencySymbol": "$",
            "CurrencyCode": "USD",
            "UnitPrice": 10,
            "LineTotal": 20
        }
    ],
    "_rid": "BsMkAMc43s4CAAAAAAAAAA==",
    "_self": "dbs/BsMkAA==/colls/BsMkAMc43s4=/docs/BsMkAMc43s4CAAAAAAAAAA==/",
    "_etag": "\"00000000-0000-0000-e136-0dbec04601d7\"",
    "_attachments": "attachments/",
    "_ts": 1637760030
}

做这样的事情：

public async Task AddProduct(Item item)
{
        var response = await CosmosDbContainer.PatchItemAsync<Product>(
        id: "a1dc8286-bb5e-4ac0-beb4-f9f1dfc79711",
        partitionKey:new PartitionKey("a1dc8286-bb5e-4ac0-beb4-f9f1dfc79711"),
        patchOperations: new[] { PatchOperation.Add("/Items", item) });
}

返回以下错误：

无法将当前 JSON 对象（例如 {"name":"value"}）反序列化为类型 'System.Collections.Generic.List`1[TestApp.Models.Item]'，因为该类型需要 JSON 数组（例如 [1, 2,3]) 正确反序列化

传入一个 Items 列表是可行的，但它会替换所有的子项，例如：

public async Task AddProduct(Item item)
{
    var itemList = new List<Item>();
    itemList.Add(item);
    var response = await CosmosDbContainer.PatchItemAsync<Product>(
        id: "a1dc8286-bb5e-4ac0-beb4-f9f1dfc79711",
        partitionKey:new PartitionKey("a1dc8286-bb5e-4ac0-beb4-f9f1dfc79711"),
        patchOperations: new[] { PatchOperation.Add("/Items", ItemList) });
}

任何建议将不胜感激。先感谢您！

Answer 1

您尝试过通过索引吗？您需要通过传递要更新的对象的特定索引来使用添加操作，

 patchOperations: new[] { PatchOperation.Add("/Items/1", item) });

或者用“-”追加

 patchOperations: new[] { PatchOperation.Add("/Items/-", item) });