通过

HtmlTextArea.RenderAttributes(HtmlTextWriter) 方法

  • 参考

定义

命名空间:
System.Web.UI.HtmlControls
程序集:
System.Web.dll

将 HtmlTextArea 控件的属性呈现到指定的 HtmlTextWriter 对象。

protected:
 override void RenderAttributes(System::Web::UI::HtmlTextWriter ^ writer);
protected override void RenderAttributes (System.Web.UI.HtmlTextWriter writer);
override this.RenderAttributes : System.Web.UI.HtmlTextWriter -> unit
Protected Overrides Sub RenderAttributes (writer As HtmlTextWriter)

参数

writer
HtmlTextWriter

接收呈现内容的 HtmlTextWriter。

示例

下面的代码示例演示如何重写 RenderAttributes 自定义服务器控件中的方法，以便始终显示控件 HtmlTextArea 的特定标题文本。

<%@ 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">
<script runat="server">
  
  void Page_Load(Object sender, EventArgs e)
  {
    HtmlTextArea1.Value = "Hello HTML Text Area World.";
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlTextArea RenderAttributes Example</title>
  </head>

  <body>
    <form id="Form1" 
          method="post" 
          runat="server">

      <h3>Custom HtmlTextArea - RenderAttributes - C# Example</h3>

      <aspSample:CustomHtmlTextAreaRenderAttributes 
        id="HtmlTextArea1" 
        name="HtmlTextArea1" 
        runat="server" 
        rows="4" 
        cols="50" />
        
    </form>
  </body>
</html>

<%@ 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">
<script runat="server">

  Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    
    HtmlTextArea1.Value = "Hello HTML Text Area World."
    
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>Custom HtmlTextArea RenderAttributes Example</title>
  </head>

  <body>
    <form id="Form1" 
          method="post"
          runat="server">

      <h3>Custom HtmlTextArea RenderAttributes Example</h3>

      <aspSample:CustomHtmlTextAreaRenderAttributes 
        id="HtmlTextArea1" 
        name="HtmlTextArea1" 
        runat="server" 
        rows="4" 
        cols="50" />
        
    </form>
  </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomHtmlTextAreaRenderAttributes : System.Web.UI.HtmlControls.HtmlTextArea
    {
        protected override void RenderAttributes(System.Web.UI.HtmlTextWriter writer)
        {
            // Write out the Title attribute.
            writer.Write(" Title=\"Text from RenderAttributes.\"");
            
            // Call the base class's RenderAttributes method.
            base.RenderAttributes(writer);
        }
    }
}

Imports System.Web
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls
    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public NotInheritable Class CustomHtmlTextAreaRenderAttributes
        Inherits System.Web.UI.HtmlControls.HtmlTextArea

        Protected Overrides Sub RenderAttributes(ByVal writer As System.Web.UI.HtmlTextWriter)

            ' Write out the Title attribute.
            writer.Write(" Title=""Text from RenderAttributes.""")

            ' Call the base class's RenderAttributes method.
            MyBase.RenderAttributes(writer)
        End Sub
    End Class
End Namespace

注解

该方法 RenderAttributes 直接呈现 name 控件的属性 HtmlTextArea ，以确保其具有与属性相同的值 Control.UniqueID 。 呈现属性后，该方法 RenderAttributes 将调用基类 RenderAttributes 的方法。

该方法 RenderAttributes 主要用于控件开发人员扩展控件的功能 HtmlTextArea 。

适用于

另请参阅