使用Linq到实体从表和相关的相关表中获取记录
问题描述：
我使用LINQ进行实体检索以从表中检索记录，并从另一个表中检索相关记录.
I use LINQ to entity to retrive records from table and there related records from another table.
这是与我有关的表:
这是我的LINQ to实体，用于从Sensor Measure和相关的表警报描述中检索记录.
And here is my LINQ to entity to retrieve records from Sensors Measure and related table alert description.
public IEnumerable<SensorsMeasure> GetSensorsMeasureWithAlertDescription()
{
return SensorObservationEntities.SensorsMeasures.Include(d => d.AlertsDescription.AlertDescription).ToList();
}
但是在上面的查询中，我收到此错误:
But on the query above I get this error:
A specified Include path is not valid. The EntityType 'SensorObservationModel.AlertsDescription' does not declare a navigation property with the name 'AlertDescription'.
有什么主意，为什么我会得到上面的错误以及如何解决?
Any idea why I get the error above and how to fix it?
答
这是因为AlertDescription不是AlertsDescription类型的 navigation 属性-它只是常规属性，因此您无需包含它.只要做:
That's because AlertDescription is not navigation property of AlertsDescription type - it's just regular property, so you don't need to include it. Just do:
public IEnumerable<SensorsMeasure> GetSensorsMeasureWithAlertDescription()
{
return SensorObservationEntities.SensorsMeasures.Include(d => d.AlertsDescription).ToList();
}