HtmlSelect.ClearSelection メソッド
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

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。

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" %> <HTML> <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> <p> <DIV id="Div1" runat="server" style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" ms_positioning="FlowLayout" /> </p> </form> </body> </HTML>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %> <%@ Page Language="C#" AutoEventWireup="True" %> <HTML> <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> <p> <DIV id="Div1" runat="server" style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" ms_positioning="FlowLayout" /> </p> </form> </body> </HTML>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %> <%@ Page Language="VJ#" AutoEventWireup="True" %> <HTML> <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> <p> <DIV id="Div1" runat="server" style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px" ms_positioning="FlowLayout" /> </p> </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

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
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