HtmlInputButton.OnPreRender メソッドとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

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HtmlInputButton.OnPreRender メソッド

OnPreRender イベントを発生させ、ポストバックを生成するためのクライアントスクリプトを登録します。

名前空間: System.Web.UI.HtmlControls
アセンブリ: System.Web (system.web.dll 内)
構文

Visual Basic (宣言)

Protected Friend Overrides
 Sub OnPreRender ( _
    e As EventArgs _
)

Visual Basic (使用法)

Dim e As EventArgs

Me.OnPreRender(e)

protected internal override void OnPreRender
 (
    EventArgs e
)

C++

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

protected void OnPreRender (
    EventArgs e
)

JScript

protected internal override function
 OnPreRender (
    e : EventArgs
)

パラメータ

e: イベントデータを格納している EventArgs。

解説

OnPreRender メソッドは Control.OnPreRender メソッドをオーバーライドします。OnPreRender は、主に、コントロール開発者が使用します。

使用例

OnPreRender メソッドをオーバーライドして、HtmlInputButton カスタムコントロールを常に太字で表示する方法を次のコード例に示します。

Visual Basic

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls"
 Assembly="Samples.AspNet.VB"
 %>
<%@ Page Language="VB" AutoEventWireup="True"
 %>
<HTML>
  <HEAD>
    <title>Custom HtmlInputButton - OnPreRender - Visual Basic Example</title>
    <script runat="server">
      Sub Page_Load(sender As Object,
 e As EventArgs)
        HtmlInputButton1.Attributes.Add("onclick",
 "alert('Hello client-side world.');")
      End Sub

      Sub HtmlInputButton1_ServerClick(sender As
 Object, e As EventArgs)
        Div1.InnerHtml = "Hello server-side world."
      End Sub
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post"
 runat="server">
      <h3>Custom HtmlInputButton - OnPreRender - Visual Basic Example</h3>

      <aspSample:CustomHtmlInputButtonOnPreRender
        id="HtmlInputButton1"
        runat="server"
        type="button"
        onserverclick="HtmlInputButton1_ServerClick"
        value="Html Input Button"
        name="HtmlInputButton1">&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls"
 Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom HtmlInputButton - OnPreRender - C# Example</title>
    <script runat="server">
      void Page_Load(Object sender, EventArgs e)
      {
        HtmlInputButton1.Attributes.Add("onclick","alert('Hello client-side
 world.');");
      }

      void HtmlInputButton1_ServerClick(Object sender, EventArgs
 e)
      {
        Div1.InnerHtml = "Hello server-side world.";
      }
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputButton - OnPreRender - C# Example</h3>

      <aspSample:CustomHtmlInputButtonOnPreRender
        id="HtmlInputButton1"
        runat="server"
        type="button"
        onserverclick="HtmlInputButton1_ServerClick"
        value="Html Input Button"
        name="HtmlInputButton1">&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls"
 Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
  <HEAD>
    <title>Custom HtmlInputButton - OnPreRender - VJ# Example</title>
    <script runat="server">
    void Page_Load(Object sender, EventArgs e)
    {
        HtmlInputButton1.get_Attributes().Add("onclick",
            "alert('Hello client-side world.');");
    } //Page_Load

    void HtmlInputButton1_ServerClick(Object sender, EventArgs
 e)
    {
        Div1.set_InnerHtml("Hello server-side world.");
    } //HtmlInputButton1_ServerClick
    </script>
  </HEAD>
  <body>
    <form id="Form1" method="post" runat="server">
      <h3>Custom HtmlInputButton - OnPreRender - VJ# Example</h3>

      <aspSample:CustomHtmlInputButtonOnPreRender
        id="HtmlInputButton1"
        runat="server"
        type="button"
        onserverclick="HtmlInputButton1_ServerClick"
        value="Html Input Button"
        name="HtmlInputButton1">&nbsp;&nbsp;

      <DIV id="Div1" runat="server"
        style="DISPLAY: inline; WIDTH: 256px; HEIGHT: 15px"
        ms_positioning="FlowLayout" />
    </form>
  </body>
</HTML>

Visual Basic

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)>
 _
    Public NotInheritable Class
 CustomHtmlInputButtonOnPreRender
        Inherits System.Web.UI.HtmlControls.HtmlInputButton

        Protected Overrides Sub
 OnPreRender(ByVal e As System.EventArgs)

            ' Call the base class's OnPreRender method.
            MyBase.OnPreRender(e)

            ' Always display the HtmlInputButton with bold text.
            Me.Style.Add("font-weight",
 "bold")
        End Sub
    End Class

End Namespace

using System.Web;
using System.Security.Permissions;

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlInputButtonOnPreRender
 : System.Web.UI.HtmlControls.HtmlInputButton
    {
        protected override void OnPreRender(System.EventArgs
 e)
        {
            // Call the base class's OnPreRender method.
            base.OnPreRender(e);

            // Always display the HtmlInputButton with bold text.
            this.Style.Add("font-weight", "bold");
        }
    }
}

package Samples.AspNet.JSL.Controls;

public class CustomHtmlInputButtonOnPreRender
    extends System.Web.UI.HtmlControls.HtmlInputButton
{
    protected void OnPreRender(System.EventArgs
 e)
    {
        // Call the base OnPreRender method.
        super.OnPreRender(e);
        // Always display the HtmlButton with bold text.
        this.get_Style().Add("font-weight", "bold");
    } //OnPreRender
} //CustomHtmlInputButtonOnPreRender