Literal.AddParsedSubObject(Object) Method

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

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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

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