Are you looking for this, where 'Your_Entities' is your entity Name and 'Users' is the name of the table.
Your_Entities context = new Your_Entities();
private void simpleButton1_Click(object sender, EventArgs e)
{
var query = from c in context.Users
where c.UserName == "James"
select new { c.UserName, c.Password, c.Description };
var results = query.ToList();
gridControl1.DataSource = results;
}