HtmlSelect コントロールのリストの選択項目を消去し、すべての項目の ListItem.Selected プロパティを false に設定します。
名前空間: System.Web.UI.HtmlControls
アセンブリ: System.Web (system.web.dll 内)
構文
'宣言
Protected Overridable Sub ClearSelection
'使用
Me.ClearSelection
protected virtual void ClearSelection ()
protected:
virtual void ClearSelection ()
protected void ClearSelection ()
protected function ClearSelection ()
適用できません。
解説
ClearSelection メソッドは、HtmlSelect コントロールの Items プロパティで表される ListItemCollection コレクションを反復処理し、各 ListItem オブジェクトの Selected プロパティを false に設定します。
使用例
カスタム サーバー コントロールの ClearSelection メソッドをオーバーライドし、HtmlSelect コレクションのすべての選択された項目を常に消去する方法を次のコード例に示します。
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Custom HtmlSelect - ClearSelection - VB.NET Example</title>
<script runat="server">
Sub HtmlInputButton1_ServerClick(sender As Object, e As EventArgs)
If HtmlSelect1.SelectedIndex >= 0 Then
If HtmlSelect1.Multiple = True Then
Div1.InnerHtml = "You selected:"
Dim i As Integer
For i = 0 To HtmlSelect1.Items.Count - 1
If HtmlSelect1.Items(i).Selected = True Then
Div1.InnerHtml += "<br /> " & HtmlSelect1.Items(i).Value
End If
Next i
Else
Div1.InnerHtml = "You selected " & HtmlSelect1.Value
End If
Else
Div1.InnerHtml = "You did not select an item."
End If
End Sub
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - ClearSelection - VB.NET Example</h3>
<p>
<aspSample:CustomHtmlSelectClearSelection
id="HtmlSelect1" multiple
name="HtmlSelect1"
runat="server">
<option value="Option1">Option1</option>
<option value="Option2">Option2</option>
<option value="Option3">Option3</option>
<option value="Option4">Option4</option>
</aspSample:CustomHtmlSelectClearSelection>
</p>
<p>
<input
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1" />
</p>
<br />
<div id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Custom HtmlSelect - ClearSelection - C# Example</title>
<script runat="server">
void HtmlInputButton1_ServerClick(Object sender, EventArgs e)
{
if (HtmlSelect1.SelectedIndex >= 0)
{
if (HtmlSelect1.Multiple == true)
{
Div1.InnerHtml = "You selected:";
for (int i=0; i<=HtmlSelect1.Items.Count - 1; i++)
{
if (HtmlSelect1.Items[i].Selected == true)
{
Div1.InnerHtml += "<br /> " + HtmlSelect1.Items[i].Value;
}
}
}
else
{
Div1.InnerHtml = "You selected " + HtmlSelect1.Value;
}
}
else
{
Div1.InnerHtml = "You did not select an item.";
}
}
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom HtmlSelect - ClearSelection - C# Example</h3>
<p>
<aspSample:CustomHtmlSelectClearSelection
id="HtmlSelect1" multiple
name="HtmlSelect1"
runat="server">
<option value="Option1">Option1</option>
<option value="Option2">Option2</option>
<option value="Option3">Option3</option>
<option value="Option4">Option4</option>
</aspSample:CustomHtmlSelectClearSelection>
</p>
<p>
<input
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1" />
</p>
<br />
<div id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
</form>
</body>
</html>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Custom HtmlSelect - ClearSelection - 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 - ClearSelection - VJ# Example</h3>
<p>
<aspSample:CustomHtmlSelectClearSelection
id="HtmlSelect1" multiple
name="HtmlSelect1"
runat="server">
<option value="Option1">Option1</option>
<option value="Option2">Option2</option>
<option value="Option3">Option3</option>
<option value="Option4">Option4</option>
</aspSample:CustomHtmlSelectClearSelection>
</p>
<p>
<input
id="HtmlInputButton1"
runat="server"
type="button"
onserverclick="HtmlInputButton1_ServerClick"
value="Select"
name="HtmlInputButton1" />
</p>
<br />
<div id="Div1" runat="server"
style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" />
</form>
</body>
</html>
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomHtmlSelectClearSelection
Inherits System.Web.UI.HtmlControls.HtmlSelect
Protected Overrides Sub ClearSelection()
' For each item in the Items collection,
' set the Selected property to false.
Dim i As Integer
For i = 0 To Items.Count - 1
Items(i).Selected = False
Next i
End Sub
End Class
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomHtmlSelectClearSelection : System.Web.UI.HtmlControls.HtmlSelect
{
protected override void ClearSelection()
{
// For each item in the Items collection,
// set the Selected property to false.
for (int i=0; i < Items.Count; i++)
Items[i].Selected = false;
}
}
}
package Samples.AspNet.JSL.Controls;
public class CustomHtmlSelectClearSelection
extends System.Web.UI.HtmlControls.HtmlSelect
{
protected void ClearSelection()
{
// For each item in the Items collection,
// set the Selected property to false.
for (int i = 0; i < get_Items().get_Count(); i++) {
get_Items().get_Item(i).set_Selected(false);
}
} //ClearSelection
} //CustomHtmlSelectClearSelection
プラットフォーム
Windows 98,Windows Server 2000 SP4,Windows CE,Windows Millennium Edition,Windows Mobile for Pocket PC,Windows Mobile for Smartphone,Windows Server 2003,Windows XP Media Center Edition,Windows XP Professional x64 Edition,Windows XP SP2,Windows XP Starter Edition
Microsoft .NET Framework 3.0 は Windows Vista,Microsoft Windows XP SP2,および Windows Server 2003 SP1 でサポートされています。
バージョン情報
.NET Framework
サポート対象 : 3.0,2.0,1.1,1.0
参照
関連項目
HtmlSelect クラス
HtmlSelect メンバ
System.Web.UI.HtmlControls 名前空間
ListItemCollection
ListItem
Selected
Items