HtmlSelect.OnPreRender Method
.NET Framework 2.0
Raises the PreRender event for the HtmlSelect control.
Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)
Assembly: System.Web (in system.web.dll)
The following code example demonstrates how to override the OnPreRender method so that it allows multiple selections in a custom HtmlSelect server control.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSl.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
<HEAD>
<title>Custom HtmlSelect - OnPreRender - VJ# Example</title>
<script runat="server">
void HtmlInputButton1_ServerClick(Object sender, EventArgs e)
{
if (HtmlSelect1.get_SelectedIndex() >= 0) {
if (HtmlSelect1.get_Multiple() == true) {
Div1.set_InnerHtml("You selected:");
for (int i=0; i<=HtmlSelect1.get_Items().get_Count() - 1; i++) {
if (HtmlSelect1.get_Items().get_Item(i).
get_Selected() == true) {
Div1.set_InnerHtml(Div1.get_InnerHtml()
+ "<br> "
+ HtmlSelect1.get_Items().get_Item(i).get_Value());
}
}
}
else {
Div1.set_InnerHtml("You selected " + HtmlSelect1.get_Value());
}
}
else {
Div1.set_InnerHtml("You did not select an item.");
}
} //HtmlInputButton1_ServerClick
</script>
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - OnPreRender - VJ# Example</h3>
<p>
<aspSample:CustomHtmlSelectOnPreRender
id="HtmlSelect1"
name="HtmlSelect1"
runat="server">
<OPTION value="Option1">Option1</OPTION>
<OPTION value="Option2">Option2</OPTION>
<OPTION value="Option3">Option3</OPTION>
</aspSample:CustomHtmlSelectOnPreRender>
</p>
<p>
<INPUT
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1">
</p>
<p>
<DIV id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
ms_positioning="FlowLayout" />
</p>
</form>
</body>
</HTML>
package Samples.AspNet.JSL.Controls;
public class CustomHtmlSelectOnPreRender
extends System.Web.UI.HtmlControls.HtmlSelect
{
protected void OnPreRender(System.EventArgs e)
{
// Call the base's OnPreRender method.
super.OnPreRender(e);
// Allow multiple selections.
this.set_Multiple(true);
} //OnPreRender
} //CustomHtmlSelectOnPreRender
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
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