Correctly ORDER BY Date That Has Been Cast As A Varchar

how do you get it to sort correctly for the date? at the minute its sorting on the characters rather than actual date value





Code Snippet
INSERT INTO @TempItems (OrderID)
SELECT OrderID
FROM Orders o
INNER JOIN Customers c ON c.CustomerID = o.CustomerID
INNER JOIN Employees e ON e.EmployeeID = o.EmployeeID
ORDER BY
CASE @SortOrder --Order ASC
WHEN 0 THEN cast(OrderID as varchar(100))
WHEN 1 THEN cast(c.CompanyName as varchar(100))
WHEN 2 THEN cast(e.FirstName as varchar(100))
WHEN 3 THEN cast(o.OrderDate as varchar(100))
WHEN 4 THEN cast(o.RequiredDate as varchar(100))
WHEN 5 THEN cast(o.ShippedDate as varchar(100))
ELSE '1'
END,