PersistChildrenAttribute PersistChildrenAttribute PersistChildrenAttribute PersistChildrenAttribute Class

Definition

Definiert ein Attribut, das von ASP.NET-Serversteuerelementen verwendet wird, um zur Entwurfszeit anzugeben, ob die in einem Serversteuerelement enthaltenen, geschachtelten Inhalte Steuerelementen oder Eigenschaften des Serversteuerelements entsprechen.Defines an attribute that is used by ASP.NET server controls to indicate at design time whether nested content that is contained within a server control corresponds to controls or to properties of the server control. Diese Klasse kann nicht vererbt werden.This class cannot be inherited.

public ref class PersistChildrenAttribute sealed : Attribute
[System.AttributeUsage(System.AttributeTargets.Class)]
public sealed class PersistChildrenAttribute : Attribute
type PersistChildrenAttribute = class
    inherit Attribute
Public NotInheritable Class PersistChildrenAttribute
Inherits Attribute
Vererbung
PersistChildrenAttributePersistChildrenAttributePersistChildrenAttributePersistChildrenAttribute
Attribute

Beispiele

Das Codebeispiel in diesem Abschnitt enthält zwei Teile.The code example in this section contains two parts. Im ersten Codebeispiel wird veranschaulicht, wie die Metadaten eines benutzerdefinierten Steuer Elements so festgelegt werden, dass der zugehörige Inhalt zur Entwurfszeit als Eigenschaften des Steuer Elements beibehalten wird.The first code example demonstrates how to set the metadata of a custom control so that at design time, its nested content is persisted as properties of the control. Im zweiten Codebeispiel wird veranschaulicht, wie Klassen auf einer ASP.NET-Seite verwendet werden.The second code example demonstrates how to use classes in an ASP.NET page.

Im folgenden Codebeispiel wird veranschaulicht, wie das PersistChildrenAttribute -Attribut angewendet wird, sodass keines der nicht in einem benutzerdefinierten Steuerelemente eines benutzerdefinierten Server Steuer Elements als nicht gespeicherte Steuerelemente beibehalten wird.The following code example demonstrates how to apply the PersistChildrenAttribute attribute so that none of a custom server control's nested controls are persisted as nested controls. Für das benutzerdefinierte Server CollectionPropertyControl Steuerelement PersistChildrenAttribute mit dem Namen false ist das- Employee Attribut auf festgelegt, sodass die hinzugefügten Objekte als als Elemente gespeicherte Elemente beibehalten werden.The custom server control named CollectionPropertyControl has the PersistChildrenAttribute attribute set to false so that the Employee objects that are added are persisted as nested elements.

using System;
using System.Collections;
using System.Drawing;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Security.Permissions;

namespace PersistChildrenSamples
{
   // The child element class.
   [AspNetHostingPermission(SecurityAction.Demand, 
      Level=AspNetHostingPermissionLevel.Minimal)]
   public sealed class Employee
   {
      private String name;
      private String title;
      private String alias;

      public Employee():this ("","",""){}
      
      public Employee (String name, String title, String alias)
      {
         this.name = name;
         this.title = title;
         this.alias = alias;
      }
      public String Name
      {
         get
         {
            return name;
         }
         set
         {
            name = value;
         }
      }
      
      public String Title
      {
         get
         {
            return title;
         }
         set
         {
            title = value;
         }
      }
      
      public String Alias
      {
         get
         {
            return alias;
         }
         set
         {
            alias = value;
         }
      }
   }
   // Use the PersistChildren attribute to set the Persist
   // property to false so that none of this class's
   // child controls will be persisted as controls. They will
   // be persisted only as child elements of this class.
   // If you set the PersistChildren attribute to true, or if you
   // do not include this attribute when you create a control,
   // the child controls will be persisted as controls.   
   [PersistChildren(false)]
   [AspNetHostingPermission(SecurityAction.Demand, 
      Level=AspNetHostingPermissionLevel.Minimal)]
   public sealed class CollectionPropertyControl : Control
   {  
      private String header;
      private ArrayList employees = new ArrayList();
      
      public String Header
      {
         get
         {
            return header;
         }
         set
         {
            header = value;
         }
      }


      
      public ArrayList Employees
      {
         get 
         {
            return employees;
         }
      }
      // Override the CreateChildControls method to 
      // add child controls to the Employees property when this
      // custom control is requested from a page.
      protected override void CreateChildControls()
      {
         Label label = new Label();
         label.Text = Header;
         label.BackColor = Color.Beige;
         label.ForeColor = Color.Red;
         Controls.Add(label);
         Controls.Add(new LiteralControl("<BR> <BR>"));

         Table table = new Table();
         TableRow htr = new TableRow();

         TableHeaderCell hcell1 = new TableHeaderCell();    
         hcell1.Text = "Name";
         htr.Cells.Add(hcell1);

         TableHeaderCell hcell2 = new TableHeaderCell();
         hcell2.Text = "Title";
         htr.Cells.Add(hcell2);
         
         TableHeaderCell hcell3 = new TableHeaderCell();
         hcell3.Text = "Alias";
         htr.Cells.Add(hcell3);
         table.Rows.Add(htr);

         table.BorderWidth = 2;
         table.BackColor = Color.Beige;
         table.ForeColor = Color.Red;
         foreach (Employee employee in Employees)
         {
            TableRow tr = new TableRow();

            TableCell cell1 = new TableCell();
            cell1.Text = employee.Name;
            tr.Cells.Add(cell1);
            
            TableCell cell2 = new TableCell();
            cell2.Text = employee.Title;
            tr.Cells.Add(cell2);
            
            TableCell cell3 = new TableCell();
            cell3.Text = employee.Alias;
            tr.Cells.Add(cell3);
            
            table.Rows.Add(tr);
         }
         Controls.Add(table);
         
      }
   }
}
' Create a namespace that defines two classes, one a custom control, Employee,
' which is created for every instance of a child element with its name
' declared in a page associated with this namespace, the other, Employees,
' which contains these child elements.
Imports System.Collections
Imports System.Drawing
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Security.Permissions

Namespace PersistChildrenSampleVB

' Create a class that will be rendered as a child of the control
' that has the ParseChildren attribute applied to it.
 <AspNetHostingPermission(SecurityAction.Demand, _
   Level:=AspNetHostingPermissionLevel.Minimal)> _
 Public NotInheritable Class Employee
   Private _name As String
   Private _title As String
   Private _alias As String
   
   
   Public Sub New()
      Me.New("", "", "")
   End Sub

    
   Public Sub New(name As String, title As String, employeeAlias As String)
      Me._name = name
      Me._title = title
      Me._alias = employeeAlias
   End Sub
   
   Public Property Name() As String
      Get
         Return _name
      End Get
      Set
         _name = value
      End Set
   End Property
   
   
   Public Property Title() As String
      Get
         Return _title
      End Get
      Set
         _title = value
      End Set
   End Property
   
   
   Public Property [Alias]() As String
      Get
         Return _alias
      End Get
      Set
         _alias = value
      End Set
   End Property
End Class 'Employee

 ' Use the PersistChildren attribute to set the Persist
 ' property to false so that none of this class's
 ' child controls will be persisted as controls. They will
 ' be persisted only as child elements of this class.
 ' If you set the PersistChildren attribute to true, or if you
 ' do not include this attribute when you create a control,
 ' the child controls will be persisted as controls.
 <PersistChildren(False)>  _
 <AspNetHostingPermission(SecurityAction.Demand, _
   Level:=AspNetHostingPermissionLevel.Minimal)> _
 Public NotInheritable Class CollectionPropertyControl
   Inherits Control
   Private _header As String
   Private _employees As New ArrayList()
   
   
   Public Property Header() As String
      Get
         Return _header
      End Get
      Set
         _header = value
      End Set
   End Property
   
   
   
   
   Public ReadOnly Property Employees() As ArrayList
      Get
         Return _employees
      End Get
   End Property
   
   ' Override the CreateChildControls method to 
   ' add child controls to the Employees property when this
   ' custom control is requested from a page.
   Protected Overrides Sub CreateChildControls()
      Dim label As New Label()
      label.Text = Header
      label.BackColor = Color.Beige
      label.ForeColor = Color.Red
      Controls.Add(label)
      Controls.Add(New LiteralControl("<BR> <BR>"))
      
      Dim table As New Table()
      Dim htr As New TableRow()
      
      Dim hcell1 As New TableHeaderCell()
      hcell1.Text = "Name"
      htr.Cells.Add(hcell1)
      
      Dim hcell2 As New TableHeaderCell()
      hcell2.Text = "Title"
      htr.Cells.Add(hcell2)
      
      Dim hcell3 As New TableHeaderCell()
      hcell3.Text = "Alias"
      htr.Cells.Add(hcell3)
      table.Rows.Add(htr)
      
      table.BorderWidth = Unit.Pixel(2)
      table.BackColor = Color.Beige
      table.ForeColor = Color.Red
      Dim employee As Employee
      For Each employee In  Employees
         Dim tr As New TableRow()
         
         Dim cell1 As New TableCell()
         cell1.Text = employee.Name
         tr.Cells.Add(cell1)
         
         Dim cell2 As New TableCell()
         cell2.Text = employee.Title
         tr.Cells.Add(cell2)
         
         Dim cell3 As New TableCell()
         cell3.Text = employee.Alias
         tr.Cells.Add(cell3)
         
         table.Rows.Add(tr)
      Next employee
      Controls.Add(table)
   End Sub
 End Class 'CollectionPropertyControl
End Namespace ' PersistChildrenSampleVB

Im folgenden Codebeispiel wird veranschaulicht, wie die CollectionPropertyControl - Employee Klasse und die-Klasse auf einer ASP.NET-Seite verwendet werden.The following code example demonstrates how to use the CollectionPropertyControl and Employee classes in an ASP.NET page.

<%@ Page Language="C#" %>
<%@ Register TagPrefix="AspSample" Assembly="Samples.AspNet.CS.Controls" Namespace="PersistChildrenSamples" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
  
  protected void Page_Load(object sender, EventArgs e)
  {

    // Create two new employees and add them to the custom control.
    Employee e1 = new Employee("Employee 1", "Title 1", "Alias 1");
    Employee e2 = new Employee("Employee 2", "Title 2", "Alias 2");
    CollectionPropertyControl1.Employees.Add(e1);
    CollectionPropertyControl1.Employees.Add(e2);

    // Verify attribute values.
    PersistChildrenAttribute p =
      (PersistChildrenAttribute)Attribute.GetCustomAttribute(typeof(CollectionPropertyControl), 
      typeof(PersistChildrenAttribute));

    StringBuilder sb = new StringBuilder();
    sb.Append("The Persist property is " + p.Persist.ToString() + "<br />");
    sb.Append("The UseCustomPersistence property is " + p.UsesCustomPersistence.ToString() + "<br />");
    sb.Append("The IsDefault method returns " + p.IsDefaultAttribute().ToString());
    Message.Text = sb.ToString();
    
  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>PersistChildrenAttribute</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <asp:Label ID="Message"
                 runat="server"/>
      <AspSample:CollectionPropertyControl id="CollectionPropertyControl1" 
                                           runat="server">
      </AspSample:CollectionPropertyControl>
    </div>
    </form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Register TagPrefix="AspSample" Assembly="Samples.AspNet.VB.Controls" Namespace="PersistChildrenSampleVB" %>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
  
  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

    ' Create two new employees and add them to the custom control.
    Dim e1 As New Employee("Employee 1", "Title 1", "Alias 1")
    Dim e2 As New Employee("Employee 2", "Title 2", "Alias 2")
    CollectionPropertyControl1.Employees.Add(e1)
    CollectionPropertyControl1.Employees.Add(e2)

    ' Verify attribute values.
    Dim p As PersistChildrenAttribute = _
    Attribute.GetCustomAttribute(GetType(CollectionPropertyControl), _
    GetType(PersistChildrenAttribute))

    Dim sb As New StringBuilder()
    sb.Append("The Persist property is " & p.Persist.ToString() & "<br />")
    sb.Append("The UseCustomPersistence property is " & p.UsesCustomPersistence.ToString() & "<br />")
    sb.Append("The IsDefault method returns " & p.IsDefaultAttribute().ToString())
    Message.Text = sb.ToString()

  End Sub
  
</script>


<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>PersistChildrenAttribute</title>
</head>
<body>
    <form id="Form1" runat="server">
    <div>
      <asp:Label ID="Message"
                 runat="server"/>
      <AspSample:CollectionPropertyControl id="CollectionPropertyControl1" 
                                           runat="server">
      </AspSample:CollectionPropertyControl>
    </div>
    </form>
</body>
</html>

Hinweise

Der PersistChildrenAttribute wird in Verbindung ParseChildrenAttribute mit verwendet, um zu bestimmen, wie der Inhalt eines Steuer Elements interpretiert wird.The PersistChildrenAttribute is used in combination with the ParseChildrenAttribute to determine how nested content of a control is interpreted. Wenn PersistChildrenAttribute ist true und istParseChildrenAttribute , wird der geschachtelte Inhalt, der in einem ASP.NET-Server Steuerelement enthalten ist, als Steuerelemente beibehalten. falseIf PersistChildrenAttribute is true and ParseChildrenAttribute is false, the nested content contained within an ASP.NET server control is persisted as controls. Wenn PersistChildrenAttributeden Wert undParseChildrenAttribute den Wert hat,wirdderInhaltalsEigenschaftendesServerSteuerElementsbeibehalten.true falseIf PersistChildrenAttribute is false and ParseChildrenAttribute is true, the nested content is persisted as properties of the server control. Weitere Informationen zum Verwenden von Attributen finden Sie unter Attribute.For more information about using attributes, see Attributes.

Konstruktoren

PersistChildrenAttribute(Boolean) PersistChildrenAttribute(Boolean) PersistChildrenAttribute(Boolean) PersistChildrenAttribute(Boolean)

Initialisiert eine neue Instanz der PersistChildrenAttribute-Klasse, wobei mithilfe eines booleschen Werts angegeben wird, ob geschachtelte Inhalte als geschachtelte Steuerelemente beibehalten werden sollen.Initializes a new instance of the PersistChildrenAttribute class using a Boolean value indicating whether to persist nested content as nested controls.

PersistChildrenAttribute(Boolean, Boolean) PersistChildrenAttribute(Boolean, Boolean) PersistChildrenAttribute(Boolean, Boolean) PersistChildrenAttribute(Boolean, Boolean)

Initialisiert eine neue Instanz der PersistChildrenAttribute-Klasse unter Verwendung von zwei booleschen Werten.Initializes a new instance of the PersistChildrenAttribute class using two Boolean values. Ein Wert gibt an, ob geschachtelte Inhalte als geschachtelte Steuerelemente beibehalten werden; der andere gibt an, ob eine benutzerdefinierte Beibehaltungsmethode verwendet wird.One indicating whether to persist nested content as nested controls and the other indicating whether to use a custom persistence method.

Felder

Default Default Default Default

Gibt den standardmäßigen Attributzustand an.Indicates the default attribute state. Das Default-Feld ist schreibgeschützt.The Default field is read-only.

No No No No

Gibt an, dass geschachtelte Inhalte zur Entwurfszeit nicht als geschachtelte Steuerelemente beibehalten werden sollen.Indicates that nested content should not persist as nested controls at design time. Dieses Feld ist schreibgeschützt.This field is read-only.

Yes Yes Yes Yes

Gibt an, dass geschachtelte Inhalte zur Entwurfszeit als Steuerelemente beibehalten werden sollen.Indicates that nested content should persist as controls at design time. Das Yes-Feld ist schreibgeschützt.The Yes field is read-only.

Eigenschaften

Persist Persist Persist Persist

Ruft einen Wert ab, der angibt, ob die geschachtelten Inhalte zur Entwurfszeit als geschachtelte Steuerelemente beibehalten werden.Gets a value that indicates whether the nested content is persisted as nested controls at design time.

TypeId TypeId TypeId TypeId

Ruft bei Implementierung in einer abgeleiteten Klasse einen eindeutigen Bezeichner für dieses Attribute ab.When implemented in a derived class, gets a unique identifier for this Attribute.

(Inherited from Attribute)
UsesCustomPersistence UsesCustomPersistence UsesCustomPersistence UsesCustomPersistence

Ruft einen Wert ab, der angibt, ob das Serversteuerelement zur Entwurfszeit eine benutzerdefinierte Beibehaltung von geschachtelten Steuerelementen bereitstellt.Gets a value indicating whether the server control provides custom persistence of nested controls at design time.

Methoden

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Bestimmt, ob das angegebene Objekt mit dem aktuellen Objekt identisch ist.Determines whether the specified object is equal to the current object.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Fungiert als eine Hashfunktion für die PersistChildrenAttribute-Klasse.Serves as a hash function for the PersistChildrenAttribute class.

GetType() GetType() GetType() GetType()

Ruft den Type der aktuellen Instanz ab.Gets the Type of the current instance.

(Inherited from Object)
IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute() IsDefaultAttribute()

Gibt einen Wert zurück, der angibt, ob der Wert der aktuellen Instanz der PersistChildrenAttribute-Klasse der Standardwert der abgeleiteten Klasse ist.Returns a value indicating whether the value of the current instance of the PersistChildrenAttribute class is the default value of the derived class.

Match(Object) Match(Object) Match(Object) Match(Object)

Beim Überschreiben in einer abgeleiteten Klasse wird ein Wert zurückgegeben, der angibt, ob diese Instanz einem bestimmten Objekt entspricht.When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(Inherited from Attribute)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Erstellt eine flache Kopie des aktuellen Object.Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Gibt eine Zeichenfolge zurück, die das aktuelle Objekt darstellt.Returns a string that represents the current object.

(Inherited from Object)

Explizite Schnittstellenimplementierungen

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Ordnet eine Reihe von Namen einer entsprechenden Reihe von Dispatchbezeichnern zu.Maps a set of names to a corresponding set of dispatch identifiers.

(Inherited from Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Ruft die Typinformationen für ein Objekt ab, mit deren Hilfe die Typinformationen für eine Schnittstelle abgerufen werden können.Retrieves the type information for an object, which can be used to get the type information for an interface.

(Inherited from Attribute)
_Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32) _Attribute.GetTypeInfoCount(UInt32)

Ruft die Anzahl der Schnittstellen mit Typinformationen ab, die von einem Objekt bereitgestellt werden (0 oder 1).Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Stellt den Zugriff auf von einem Objekt verfügbar gemachte Eigenschaften und Methoden bereit.Provides access to properties and methods exposed by an object.

(Inherited from Attribute)

Gilt für:

Siehe auch