linq - MongoDB C# Linq driver with nullable types

Question

I am using mongodb c# driver and tried the following query

collection.AsQueryable().Where(x => x.IsArchived.GetValueOrDefault())

where IsArchived is of type bool? (nullable).

I get the following runtime error:

Unsupported where clause: x.IsArchived.GetValueOrDefault().

Does anybody know how I can query nullable types?

score 1 · Accepted Answer

我找到了一个解决方法，虽然它不是很好：

collection.AsQueryable().Where(x => x.IsArchived ?? false)

score 1 · Accepted Answer

我知道我们在我们的域中使用可为空的类型，但似乎找不到任何特定的查询它们的实例。你可以试试这个：

collection.AsQueryable().Where(x => x.IsArchived == true)

或者这个如果不编译：

collection.AsQueryable().Where(x => x.IsArchived == (bool?) true)

score 0 · Accepted Answer

尝试

collection.AsQueryable().Where(x => x.IsArchived!= null && x.IsArchived)

您的表达式被转换为 mongo 查询，这不支持GetValueOrDefault给您异常的 C#

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