Question

Straight from the w3schools web site,
why would I want to put these items into a hashtable?

Is this more for large amounts of data and this is just a simple demo?
Otherwise why would I spend the time to put it into a hashtable why not just put it in an array?

dim mycountries=New Hashtable
  mycountries.Add("N","Norway")
  mycountries.Add("S","Sweden")
  mycountries.Add("F","France")
  mycountries.Add("I","Italy")
  rb.DataSource=mycountries
  rb.DataValueField="Key"
  rb.DataTextField="Value"
  rb.DataBind()

Answer 1

An array holds a bunch of single-valued things.

dim mycountries = new Collection ' My VB.Net is very rusty... hope this is right
mycountries.Add("Norway")
mycountries.Add("Sweden")
mycountries.Add("France")
mycountries.Add("Italy")

A Hashtable (or indeed also a Dictionary) holds a bunch of key-value pairs.

mycountries.Add("N","Norway")
' etc.

When one later enumerates a Hashtable, one gets back a KeyValuePair<string,string> rather than just a string one would get from the Collection.

This example sets the key to a short version of the value, so an array would not work (it can only hold a value).

Certainly you could use an array that holds a type that in turn has a key and a value, but using a Hashtable is more straightforward.