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ASP.NET Web Forms - The SortedList Object


The SortedList object joins the highlights of both the ArrayList object and the Hashtable object.



The SortedList Object

The SortedList object contains things in key/esteem pairs.

A SortedList object consequently sorts the things in alphabetic or numeric order.

Items are added to the SortedList with the Add() method.

A SortedList can be measured to its last size with the TrimToSize() method.

The following code makes a SortedList named mycountries and four components are added:

<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  diminish 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 item may consequently create the content and qualities to the accompanying controls:

  • asp:RadioButtonList
  • asp:CheckBoxList
  • asp:DropDownList
  • asp:Listbox

To tie information to a RadioButtonList control, first make a RadioButtonList control (without any asp:ListItem components) in an .aspx page:

<html>
<body>

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

</body>
</html>

Then include the content that assembles the list:

<script runat="server">
sub Page_Load
if Not Page.IsPostBack then
  diminish 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 client taps on a thing in the RadioButtonList control. At the point when a radio catch is clicked, a content will show up in a label:

Example

<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 most loved nation 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>