The Hashtable object contains items in the form of key/value pairs.
The SortedList Object
The Hashtable object contains items in the form of key/value pairs and the keys are used as indexes, and very quick searches can be made for values by searching through their keys.
A D V E R T I S E M E N T
With the Add() method,items are added to the Hashtable.
The code below creates a Hashtable named mycountries and four elements are added:
<script runat="server">
Sub Page_Load
if Not Page.IsPostBack then
dim mycountries=New Hashtable
mycountries.Add("N","Norway")
mycountries.Add("S","Sweden")
mycountries.Add("F","France")
mycountries.Add("I","Italy")
end if
end sub
</script>
Data Binding
A Hashtable object may automatically generate the values and text
to the following controls:
asp:RadioButtonList
asp:CheckBoxList
asp:DropDownList
asp:Listbox
First create a RadioButtonList control (without any asp:ListItem elements) in
an .aspx page to bind data to a RadioButtonList control:
Then add the following script that builds the list:
<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
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()
end if
end sub
</script>
<html>
<body>
<form runat="server">
<asp:RadioButtonList id="rb" runat="server"
AutoPostBack="True" />
</form>
</body>
</html>
Then in the RadioButtonList control,we add a sub routine to be executed when the user clicks on an item.A text will appear in a label,when a radio button is clicked:
<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
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()
end if
end sub
sub displayMessage(s as Object,e As EventArgs)
lbl1.text="Your favorite country is: " & rb.SelectedItem.Text
end sub
</script>
<html>
<body>
<form runat="server">
<asp:RadioButtonList id="rb" runat="server"
AutoPostBack="True" onSelectedIndexChanged="displayMessage" />
<p><asp:label id="lbl1" runat="server" /></p>
</form>
</body>
</html>
Note: You cannot choose the sort order of items added to the Hashtable.
Use the SortedList object,to sort items alphabetically or numerically.
