Literal.AddParsedSubObject(Object) Metodo

Riferimento

Definizione

Spazio dei nomi:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Importante

Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.

Notifica al controllo Literal che un elemento XML or HTML è stato analizzato e aggiunge l'elemento all'oggetto ControlCollection del controllo.

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)

Parametri

obj: Object

Oggetto Object che rappresenta l'elemento sottoposto ad analisi.

Eccezioni

HttpException

obj non è di tipo LiteralControl.

Esempio

Nell'esempio di codice seguente viene illustrato come eseguire l'override del AddParsedSubObject metodo in un controllo server personalizzato in modo che venga sempre impostata la Text proprietà sulla proprietà dell'oggetto Text analizzato, se l'oggetto analizzato è un oggetto e su un Literaloggetto vuoto string in caso contrario.

<%@ 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

Si applica a

Vedi anche

Panoramica del controllo server Web letterale

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