HtmlSelect.OnPreRender Method

Raises the PreRender event for the HtmlSelect control.

Namespace: System.Web.UI.HtmlControls
Assembly: System.Web (in system.web.dll)

protected public:
virtual void OnPreRender (
	EventArgs^ e
) override
protected void OnPreRender (
	EventArgs e
)
protected internal override function OnPreRender (
	e : EventArgs
)

Parameters

e

An EventArgs that contains the event data.

If the Size property is greater than 1, then the OnPreRender method registers the HtmlSelect control with the Page control as one that requires postback processing.

The following code example demonstrates how to override the OnPreRender method so that it allows multiple selections in a custom HtmlSelect server control.

No code example is currently available or this language may not be supported.
<%@ 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> &nbsp;&nbsp; " 
                            + 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">&nbsp;&nbsp;
      </p>
      
      <p>
      <DIV id="Div1" runat="server" 
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" 
        ms_positioning="FlowLayout" />
      </p>
       
		</form>
	</body>
</HTML>

No code example is currently available or this language may not be supported.
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.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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