Linq - reuse expression on child property
- by user175528
Not sure if what I am trying is possible or not, but I'd like to reuse a linq expression on an objects parent property.
With the given classes:
class Parent {
int Id { get; set; }
IList<Child> Children { get; set; }
string Name { get; set; }
}
class Child{
int Id { get; set; }
Parent Dad { get; set; }
string Name { get; set; }
}
If i then have a helper
Expression<Func<Parent,bool> ParentQuery() {
Expression<Func<Parent,bool> q = p => p.Name=="foo";
}
I then want to use this when querying data out for a child, along the lines of:
using(var context=new Entities.Context) {
var data=context.Child.Where(c => c.Name=="bar"
&& c.Dad.Where(ParentQuery));
}
I know I can do that on child collections:
using(var context=new Entities.Context) {
var data=context.Parent.Where(p => p.Name=="foo"
&& p.Childen.Where(childQuery));
}
but cant see any way to do this on a property that isnt a collection.
This is just a simplified example, actually the ParentQuery will be more complex and I want to avoid having this repeated in multiple places as rather than just having 2 layers I'll have closer to 5 or 6, but all of them will need to reference the parent query to ensure security.
