Question

I have a DataSet that contains a column, call it Type which contains ints. I’m using LINQ to manipulate the DataSet and I want to sort by Type. The Type column only contains 3 values right now (1, 2, 3). I would like to sort so that Type 2 are first in the list and then 1 and 3.

Is there an easy solution for this or am I going to have to customize the OrderBy?

Answer 1

Few solutions :

table.AsEnumerable()
.OrderBy(r => r.Field<int>("Type")==2 ? 0 : 1)
.ThenBy(r => r.Field<int>("Type"));

or probably better

table.AsEnumerable().
OrderBy(r => r.Field<int>("Type")==2 
   ? 0 
   : r => r.Field<int>("Type"))

or also elegant Tim Schmelter’s solution

table.AsEnumerable()
.OrderByDescending(r => r.Field<int>("Type")==2)
.ThenBy(r => r.Field<int>("Type"))

Advantage or Tim Schmelter’s solution : you’re not depending on a “pseudo-value”.

In the two first solutions, we assert that 0 is ((min possible value of the field) -1).

Is this real, can it change, we don’t know.