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Literal.AddParsedSubObject(Object) Method

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Notifies the Literal control that an XML or HTML element was parsed and adds that element to the ControlCollection of the control.

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)

Parameters

obj
Object

An Object that represents the parsed element.

Exceptions

HttpException

obj is not of type LiteralControl.

Examples

The following code example demonstrates how to override the AddParsedSubObject method in a custom server control so that it always sets the Text property to the parsed object's Text property, if the parsed object is a Literal, and to an empty string otherwise.

<%@ 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 LiteralControl - AddParsedSubObject - C# Example</title>
       <script runat="server">
      void Button1_Click(Object sender, EventArgs e)
      {
         Literal1.Text = "Welcome to ASP.NET!";
      }
   </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom LiteralControl - AddParsedSubObject - C# Example</h3>
            
            <aspSample:CustomLiteralAddParsedSubObject 
              id="Literal1" 
              runat="server" 
              text="Literal Text" />

      <br /><br />

      <asp:Button 
        id="Button1"
        Text="Change"
        OnClick="Button1_Click"
        runat="server"/>
        
        </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 LiteralControl - AddParsedSubObject - VB.Net Example</title>
       <script runat="server">
      Sub Button1_Click(sender As Object, e As EventArgs)
      
         Literal1.Text = "Welcome to ASP.NET!"

      End Sub

   </script>
    </head>
    <body>
        <form id="Form1" method="post" runat="server">
            <h3>Custom LiteralControl - AddParsedSubObject - VB.Net Example</h3>
            
            <aspSample:CustomLiteralAddParsedSubObject id="Literal1" 
              runat="server" text="Literal Text" />

      <br /><br />

      <asp:Button id="Button1"
        Text="Change"
        OnClick="Button1_Click"
        runat="server"/>
        </form>
    </body>
</html>

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

namespace Samples.AspNet.CS.Controls
{
    [AspNetHostingPermission(SecurityAction.Demand, Level = AspNetHostingPermissionLevel.Minimal)]
    public sealed class CustomLiteralAddParsedSubObject : System.Web.UI.LiteralControl
    {
    protected override void AddParsedSubObject(object obj)
    {
      // If the server control contains any child controls.
      if (this.HasControls()) 
      {
        // Notify the base server control that an element, either XML or HTML, 
        // was parsed, and adds the element to the server control's 
        // ControlCollection object.
        base.AddParsedSubObject(obj);
      }
        // Else the server control doesn't contain any child controls.
      else 
      {
        // If the parsed element is a LiteralControl.
        if (obj is System.Web.UI.LiteralControl) 
        {
          // Set the server control's Text property to the parsed element's Text value.
          this.Text = ((System.Web.UI.LiteralControl)obj).Text;
        }
          // Else the parsed element is not a LiteralControl.
        else 
        {
          // If the server control has a value in the Text property.
          string currentText = this.Text;
          if (currentText.Length != 0) 
          {
            // Set the server control's Text property to an empty string.
            this.Text = System.String.Empty;

            // Notify the base server control that a new LiteralControl was parsed, 
            // and adds the element to the server control's ControlCollection object.
            base.AddParsedSubObject(new System.Web.UI.LiteralControl(currentText));
          }
          base.AddParsedSubObject(obj);
        }
      }
    }
  }
}

<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomLiteralAddParsedSubObject
    Inherits System.Web.UI.WebControls.Literal

    Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)

        ' If the server control contains any child controls.
        If Me.HasControls() Then

            ' Notify the base server control that an element, either XML or HTML, 
            ' was parsed, and adds the element to the server control's 
            ' ControlCollection object.
            MyBase.AddParsedSubObject(obj)
            ' Else the server control doesn't contain any child controls.
        Else
            ' If the parsed element is a LiteralControl.
            If TypeOf obj Is System.Web.UI.LiteralControl Then

                ' Set the server control's Text property to the parsed element's Text value.
                Me.Text = CType(obj, System.Web.UI.LiteralControl).Text

                ' Else the parsed element is not a LiteralControl.
            Else
                ' If the server control has a value in the Text property.
                Dim currentText As String = Me.Text
                If currentText.Length <> 0 Then

                    ' Set the server control's Text property to an empty string.
                    Me.Text = System.String.Empty

                    ' Notify the base server control that a new LiteralControl was parsed, 
                    ' and adds the element to the server control's ControlCollection object.
                    MyBase.AddParsedSubObject(New System.Web.UI.LiteralControl(currentText))
                End If
                MyBase.AddParsedSubObject(obj)
            End If
        End If
    End Sub
End Class

Applies to

See also