字段'_id'上'Null'的 BSON 数据类型无效

Question

与此问题类似，我正在尝试 LiteDB 文档中的示例，并在运行时收到错误：

Invalid BSON data type 'Null' on field '_id'.

我的代码如下，包括我解决问题的尝试，即添加从 github 上的评论中提取的 _id 和 Id 声明，这里

Public Class Customer
Public _id As LiteDB.BsonValue
Public Id As Integer
Public Name As String
Public Phones As String
Public IsActive As Boolean
End Class
Public Class ThisAddIn

Shared Sub testSub()
Dim db As New LiteDB.LiteDatabase(Directory.GetCurrentDirectory() & "DEPDB.db")
Dim col As LiteDB.LiteCollection(Of Customer)
col = db.GetCollection(Of Customer)("customer")
Dim tCustomer As New Customer
tCustomer.Id = 1
tCustomer.Name = "John Doe"
tCustomer.Phones = "12354534"
tCustomer.IsActive = True
col.Insert(tCustomer)
end sub
end class

Answer 1

将类声明稍微更改为：

Public Class Customer
Public Property Id As Integer
Public Property Name As String
Public Phones As String
Public IsActive As Boolean
End Class

允许代码编译和运行，并允许使用以下方法搜索"名称"字段：

col.EnsureIndex(Function(x) x.Name)
Dim tresult = col.FindOne(Function(x) x.Name.Contains("Jo"))
MsgBox(tresult.Name)

不过，我完全偶然发现了这个解决方案，在声明中添加了文字......任何解释将不胜感激。