实体框架6.将edmx DbFunctions迁移为首先进行编码

Question

我们正在从DataBase优先方法过渡到Entity Framework 6的代码优先我们拥有模型

public class Parent
{
    public virtual  int Id { get; set; }
    public virtual DateTimeOffset DateFrom { get; set; }
    public virtual DateTimeOffset DateTo { get; set; }
    //navigation property
    public virtual ICollection<Child> Cildren { get; set; }
}

public class Child {
    public int Id { get; set; }
    public DateTimeOffset DateFrom { get; set; }
    public DateTimeOffset DateTo { get; set; }
    //navigation property
    public virtual Parent Parent { get; set; }
}

像这样在edmx中有几个函数（但是有点复杂，函数彼此调用）

    <Function Name="IsParentActive" ReturnType="Edm.Boolean">
      <Parameter Name="Parent" Type="MyContext.Parent" />
      <Parameter Name="time" Type="Edm.DateTimeOffset" Nullable="false" />
      <DefiningExpression>
        (Parent.DateFrom &lt;= time) AND (Parent.DateTo &gt; time)
      </DefiningExpression>
    </Function>

   <Function Name="IsChildActive" ReturnType="Edm.Boolean">
      <Parameter Name="Child" Type="MyContext.Child" />
      <Parameter Name="time" Type="Edm.DateTimeOffset" Nullable="false" />
      <DefiningExpression>
        (Child.DateFrom &lt;= time) AND (Child.DateTo &gt; time) AND
           MyContext.IsParentActive(Child.Parent, time)
      </DefiningExpression>
    </Function>

在C＃代码中，我们有下一个映射

[DbFunction("MyContext", "IsParentActive")]
public static bool IsActive(this Parent parent, DateTimeOffset time) {
  return time >= parent.DateFrom && time < parent.DateTo
}

[DbFunction("MyContext", "IsChildActive")]
public static bool IsActive(this Child child, DateTimeOffset time) {
  return time >= child.DateFrom && time < child.DateTo
     && child.Parent.IsActive(time);
}

而且我们可以在任何地方的IQueryable中使用它

var result = context.Parents.Where(p => p.IsActive(time));
var result = context.Parents.Where(p => p.Cildren.Any(c => !c.IsActive(time));
var result = context.Cildren.Where(p => p.Parent.IsActive(time));

现在，我找不到替代此方法的好方法。

我尝试将C＃函数与表达式一起使用，但不适用于子查询（context.Cildren.Where（p => p.Parent.IsActive（time）））