Access a property of a DbSet by name

Question

I have a DbSet<T>

I want to access one of the properties on it by name.

Is this possible?

I'm basically making a generic function, so that for any DbSet I have, I can specify a column and have it list the values of that column.

You can get the DbSet itself from the context by doing context.Set(T) but I am not sure about the fields.

Answer 1

I did something similar a while back using reflection.

T item = context.Set(T).First();
string propName = "MyProperty";
object value = item.GetType().GetProperty(propName).GetValue(item, null);

Of course note that you'll either need to cast the values to a specific type manually, or use ToString , which should work quite well on all basic types.

This assumes you already have the data from the server, and now need to process it.

EDIT:

If you want to create a query, then I found this !

Apparently, what you're looking for is available as part of Entity Framework these days.

An extension method is available which allows you to use .Select("propertyName") which returns IQueriable . Remember to add System.Linq.Dynamic to your using section.

You can then create select queries by specifying the name of the parameter.

List<object> data = (db.Set<SetType>()
                       .Where("propertyName == @0 && someOtherProperty == @1", propertyValue, someOtherPropertyValue)
                       .Select("propertyName") as IEnumerable<object>).ToList();

Answer 2

Check out this article on Dynamic LINQ .

Using the provided code, I was able to write a LINQ to Entities query like this:

var query = context.Set(Type.GetType("Person")).Select("Name");