通过

TextBox.AddParsedSubObject(Object) 方法

  • 参考

定义

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

重写以便只允许文本控件作为 Text 属性添加。

protected:
 override void AddParsedSubObject(System::Object ^ obj);
protected override void AddParsedSubObject (object obj);
override this.AddParsedSubObject : obj -> unit
Protected Overrides Sub AddParsedSubObject (obj As Object)

参数

obj
Object

一个 Object，表示已经过分析的元素。

例外

HttpException

obj 的类型不是 LiteralControl。

示例

下面的代码示例演示如何在自定义服务器控件中重写 AddParsedSubObject 方法，以便在分析的对象Text是Literal控件时，它始终将 属性设置为Text分析对象的 属性，否则会引发异常。

重要

此示例具有一个接受用户输入的文本框，这是一个潜在的安全威胁。 默认情况下，ASP.NET 网页验证用户输入是否不包含脚本或 HTML 元素。 有关详细信息，请参阅脚本侵入概述。

<%@ 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 TextBox - AddParsedSubObject - C# Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - AddParsedSubObject - C# Example</h3>
            
            <aspSample:CustomTextBoxAddParsedSubObject 
              id="TextBox1" 
              runat="server">Hello World!
            </aspSample:CustomTextBoxAddParsedSubObject>
            
        </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">
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head>
        <title>Custom TextBox - AddParsedSubObject - VB.NET Example</title>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom TextBox - AddParsedSubObject - VB.NET Example</h3>
            
            <aspSample:CustomTextBoxAddParsedSubObject id="TextBox1" 
             runat="server">Hello World!</aspSample:CustomTextBoxAddParsedSubObject>
        </form>
    </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
  public sealed class CustomTextBoxAddParsedSubObject : System.Web.UI.WebControls.TextBox
  {
    protected override void AddParsedSubObject(object obj)
    {
      // If the object is a LiteralControl, then set this control's Text property.
      if (obj is System.Web.UI.LiteralControl) 
      {
        this.Text = ((System.Web.UI.LiteralControl)obj).Text;
      }
      else 
      {
        throw new System.Web.HttpException("You cannot have a child control of type " + obj.GetType().Name.ToString());
      }
    }
  }
}

Imports System.Web
Imports System.Security.Permissions

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

        Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)

            ' If the object is a LiteralControl, then set this control's Text property.
            If TypeOf obj Is System.Web.UI.LiteralControl Then
                Me.Text = CType(obj, System.Web.UI.LiteralControl).Text
            Else
                Throw New System.Web.HttpException("You cannot have children controls of type " + obj.GetType().Name.ToString())
            End If
        End Sub
    End Class
End Namespace

适用于

另请参阅