How to update a List with .Net/C# development?

Hello, I want to update a column (comp_status) of my Company list with .Net/C# development.

I know it is possible to use a Select Query with ResultsGrid.SelectSql method, but is there a solution for an update?

Here is my list:

List ResultsGrid = new List("CompanyGrid");

AddContent(ResultsGrid);

Thanks.