ASP.NET SortedList

From http://www.w3schools.com (Copyright Refsnes Data)

# ASP.NET - The SortedList Object

The SortedList object combines the features of both the ArrayList object and the Hashtable object.

## Examples

Example 1 - SortedList RadioButtonList

Example 2 - SortedList RadiobuttonList

Example 3 - SortedList DropDownList

## The SortedList Object

The SortedList object contains items in key/value pairs. A SortedList object automatically sort the items in alphabetic or numeric order.

Items are added to the SortedList with the Add() method. A SortedList can be sized to its final size with the TrimToSize() method.

The following code creates a SortedList named mycountries and four elements are added:

    <script runat="server">
    sub Page_Load
    if Not Page.IsPostBack then
      dim mycountries=New SortedList
      mycountries.Add("N","Norway")
      mycountries.Add("S","Sweden")
      mycountries.Add("F","France")
      mycountries.Add("I","Italy")
    end if
    end sub
    </script>

## Data Binding

A SortedList object may automatically generate the text and values to the following controls:

- asp:RadioButtonList
- asp:CheckBoxList
- asp:DropDownList
- asp:Listbox

To bind data to a RadioButtonList control, first create a RadioButtonList control (without any asp:ListItem elements) in an .aspx page:

    <html>
    <body>

    <form runat="server">
    <asp:RadioButtonList id="rb" runat="server"
    AutoPostBack="True" />
    </form>

    </body>
    </html>

Then add the script that builds the list:

    <script runat="server">
    sub Page_Load
    if Not Page.IsPostBack then
      dim mycountries=New SortedList
      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 we add a sub routine to be executed when the user clicks on an item in the RadioButtonList control. When a radio button is clicked, a text will appear in a label:

    <script runat="server">
    sub Page_Load
    if Not Page.IsPostBack then
      dim mycountries=New SortedList
      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>

From http://www.w3schools.com (Copyright Refsnes Data)