C# CosmosDb 查询错误 CS0266：无法将类型 'System.Linq.IQueryable<System.Collections.Generic.List<xxxx>' 隐式转换为

Question

我有这个 CosmosDb 调用来检索租约列表。

List<Lease> leases = null;

var response = client.CreateDocumentQuery<List<Lease>>(
    UriFactory.CreateDocumentCollectionUri("demo", "Leases"), 
    "select * from c");

leases = response;

但我在 leases = response; 处收到 CS0266 错误完整的错误消息（只是为了获得比代码更多的文字/细节）

无法将类型 'System.Linq.IQueryable<System.Collections.Generic.List<Demo.Shared.Lease>>' 隐式转换为 'System.Collections.Generic.List<Demo.Shared.Lease>'

不过，如果我尝试这样做，它对一条记录有效。好吧，没有异常，响应为空。

var response = this.client.CreateDocumentQuery<Lease>(
    UriFactory.CreateDocumentCollectionUri("demo", "Users"), queryOptions)
                       .Where(f => f.lease == "3114/968").AsEnumerable().ToArray().FirstOrDefault();

租约class：

public class Lease
{
    public string id { get; set; }

    public string lease { get; set; }

    public Rent rent { get; set; }
}

public class Rent
{
    public string type { get; set; }
    public DateTime? dateFrom { get; set; }
    public DateTime? dateTo { get; set; }
    public double? amountIncTax { get; set; }
    public string datePaid { get; set; }
    public double? amountExTax { get; set; }
    public double? taxAmount { get; set; }
    public string chequeNumber { get; set; }
    public string comment { get; set; }
    public string receiptNumber { get; set; }
    public string createdBy { get; set; }
    public DateTime? createdDate { get; set; }
    public string modifiedBy { get; set; }
    public DateTime? modifiedDate { get; set; }
}

Cosmos 数据库中的JSON：

{
"lease": "E16/445",
"rent": {
    "type": "Rent Payment",
    "dateFrom": "2015-04-09T00:00:00.0000000",
    "dateTo": "2016-04-08T00:00:00.0000000",
    "amountIncTax": 244.2,
    "datePaid": "2015-04-01T00:00:00.0000000",
    "amountExTax": 244.2,
    "taxAmount": 0,
    "chequeNumber": "ONLINE",
    "comment": null,
    "receiptNumber": "MT-210010243602",
    "createdBy": "SBM\Sandy.Thuel",
    "createdDate": "2015-04-21T07:36:56.1400000",
    "modifiedBy": "SBM\Sandy.Thuel",
    "modifiedDate": "2015-04-21T07:36:56.4830000"
},
"id": "337ed2fa-44f3-4474-9b51-923c6635fb11",
"r_id": etc,

}

请有任何想法，

TIA

Answer 1

您必须将 IQueryable 转换为 List。您可以通过在 Linq 查询末尾添加 .ToList() 来实现。同时将类型更改为 <Lease>。试试这个查询，

var response = client.CreateDocumentQuery<Lease>(
    UriFactory.CreateDocumentCollectionUri("demo", "Leases"), 
    "select * from c").ToList();

C# CosmosDb 查询错误 CS0266：无法将类型 'System.Linq.IQueryable<System.Collections.Generic.List<xxxx>' 隐式转换为

C# CosmosDb Query error CS0266: Cannot implicitly convert type 'System.Linq.IQueryable<System.Collections.Generic.List<xxxx>' to

c#

json-deserialization

azure-cosmosdb