Add column in IEnumerable in C #

Question

I don't think I can add a field (column) to an existing IEnumerable. But I want a new IEnumerable that is derived from an existing IEnumerable with a computed field. The pseudocode in WebMatrix using web pages looks like this:

var db = Database.Open("LOS"); var ie = db.Query(sqlAssignments); // make a new ie2 that has an extra field // ??? ie2 <=== ie with new field c = ie.a + ie.b var grid = new WebGrid( ie2, extra parameters ); 

I know how to do this by looping through all the lines in ie. But I hope that there is something more elegant.

Answer 1

What about:

 var ie2 = ie.Select(x => new { x.Foo, x.Bar, Sum = x.Abc + x.Def }); var grid = new WebGrid(ie2); 

Answer 2

You can do this using Select . Try the following:

 ie2 = ie.Select( e => new { IE = e, NewParam = e.X+eY }); 

Answer 3

 ie2 = ie.Select(v => new {va, vb, c = va + vb}); 

Answer 4

Using Linq!

 var newIe = from item in ie select new {item.NewField, item.OldFiedl1 etc... } 

Also, it might be best (if you intend to use outside of this method) to assign to an anonymous type.

Answer 5

First of all, IEnumerable is probably a list of something - an object. This is an object that you can expand.

Perhaps you can do something like this:

 var ie = db.Query( ... ); var ie2 = ie.Select(i => new MyIe2Object { Prop1 = i.Prop1, NewProp = i.Prop1 + i.Prop2 });