CODEWITHSUNDEEP
linqc#-4.0dynamic
Goran
Goran

Reputation: 6518

Linq with DynamicObject

I have List where MyType : DynamicObject. The reason for MyType inheriting from DynamicObject, is that I need a type that can contain unknown number of properties.

It all works fine until I need to filter List. Is there a way I can do a linq that will do something like this:

return all items where any of the properties is empty string or white space?

Upvotes: 5

Views: 6823

Answers (2)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726479

(from the comment) can I do above linq query with List?

Yes, here is how you can do it with ExpandoObject:

var list = new List<ExpandoObject>();
dynamic e1 = new ExpandoObject();
e1.a = null;
e1.b = "";
dynamic e2 = new ExpandoObject();
e2.x = "xxx";
e2.y = 123;
list.Add(e1);
list.Add(e2);
var res = list.Where(
    item => item.Any(p => p.Value == null || (p.Value is string && string.IsNullOrEmpty((string)p.Value)))
);

The ExpandoObject presents an interface that lets you enumerate its property-value pairs as if they were in a dictionary, making the process of checking them a lot simpler.

Upvotes: 3

jbtule
jbtule

Reputation: 31799

Well as long as each object's properties are not unknown internally to themselves you could do it.

There isn't a great generic way to test all the properties of a dynamic object, if you don't have control over the DynamicObject you hope the implementer implemented GetDynamicMemberNames() and you can use the nuget package ImpromptuInterface's methods for getting the property names and dynamically invoking those names.

return allItems.Where(x=> Impromptu.GetMemberNames(x, dynamicOnly:true)
                       .Any(y=>String.IsNullOrWhiteSpace(Impromptu.InvokeGet(x,y));

Otherwise, since it's your own type MyType you can add your own method that can see internal accounting for those member values.

return allItems.Where(x => x.MyValues.Any(y=>String.IsNullOrWhitespace(x));

Upvotes: 1

Related Questions