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ParseChildrenAttribute-Konstruktor (Boolean)

Initialisiert eine neue Instanz der ParseChildrenAttribute-Klasse, wobei mithilfe der ChildrenAsProperties-Eigenschaft bestimmt wird, ob die in einem Serversteuerelement enthaltenen Elemente als Eigenschaften des Serversteuerelements analysiert werden.

Namespace: System.Web.UI
Assembly: System.Web (in system.web.dll)

Syntax

'Declaration
Public Sub New ( _
    childrenAsProperties As Boolean _
)
'Usage
Dim childrenAsProperties As Boolean

Dim instance As New ParseChildrenAttribute(childrenAsProperties)

public ParseChildrenAttribute (
    bool childrenAsProperties
)

public:
ParseChildrenAttribute (
    bool childrenAsProperties
)

public ParseChildrenAttribute (
    boolean childrenAsProperties
)

public function ParseChildrenAttribute (
    childrenAsProperties : boolean
)

Parameter

  • childrenAsProperties
    true, wenn die Elemente des Serversteuerelements als Eigenschaften analysiert werden sollen, andernfalls false.

Hinweise

Wenn childrenAsProperties den Wert false aufweist, werden die im Serversteuerelement enthaltenen Elemente als Steuerelement analysiert. false ist der Standardwert für ParseChildrenAttribute.

Beispiel

Das Codebeispiel in diesem Abschnitt besteht aus zwei Teilen. Im ersten Teil wird das Festlegen von Eigenschaften für die ParseChildrenAttribute-Klasse veranschaulicht. Im zweiten Teil wird die Verwendung von Klassen in einer ASP.NET-Seite veranschaulicht.

Im folgenden Codebeispiel wird veranschaulicht, wie das ParseChildrenAttribute-Objekt für ein benutzerdefiniertes Serversteuerelement mit dem Namen CollectionPropertyControl festgelegt wird. Wenn ParseChildrenAttribute vor der Klasse deklariert wird, die CollectionPropertyControl definiert, legt ParseChildrenAttribute die ChildrenAsProperties-Eigenschaft auf true fest.

Imports System
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Security.Permissions

Namespace Samples.AspNet.VB.Controls

    ' 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 'New


        Public Sub New(ByVal name As String, ByVal title As String, ByVal employeeAlias As String)
            Me._name = name
            Me._title = title
            Me._alias = employeeAlias
        End Sub 'New

        Public Property Name() As String
            Get
                Return _name
            End Get
            Set(ByVal value As String)
                _name = Value
            End Set
        End Property


        Public Property Title() As String
            Get
                Return _title
            End Get
            Set(ByVal value As String)
                _title = Value
            End Set
        End Property


        Public Property [Alias]() As String
            Get
                Return _alias
            End Get
            Set(ByVal value As String)
                _alias = Value
            End Set
        End Property
    End Class 'Employee

    ' Use this Boolean version of the ParseChildrenAttribute constructor
    ' to set the ChildrenAsProperties property to true. Any properties of the
    ' the CollectionPropertyControl custom control will be used as parsable
    ' children.
    <ParseChildren(True)> _
    <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(ByVal value As String)
                _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 = System.Drawing.Color.Beige
            label.ForeColor = System.Drawing.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 = System.Drawing.Color.Beige
            table.ForeColor = System.Drawing.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 'CreateChildControls 
    End Class 'CollectionPropertyControl
End Namespace ' ParseChildrenSampleVB_2

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

namespace Samples.AspNet.CS.Controls
{
   // 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 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 this Boolean version of the ParseChildrenAttribute constructor
   // to set the ChildrenAsProperties property to true. Any properties of the
   // the CollectionPropertyControl custom control will be used as parsable
   // children.
   [ParseChildren(true)]
   [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 = System.Drawing.Color.Beige;
         label.ForeColor = System.Drawing.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 = System.Drawing.Color.Beige;
         table.ForeColor = System.Drawing.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);
         
      }
   }
}

package ParseChildrenSamples_2;
// 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.
import System.*;
import System.Collections.*;
import System.Web.*;
import System.Web.UI.*;
import System.Web.UI.WebControls.*;

// Create a class that will be rendered as a child of the control
// that has the ParseChildren attribute applied to it.
public class Employee
{
    private String name;
    private String title;
    private String alias;

    public Employee()
    {
        this("", "", "");
    } //Employee

    public Employee(String name, String title, String alias)
    {
        this.name = name;
        this.title = title;
        this.alias = alias;
    } //Employee

    /** @property 
     */
    public String get_Name()
    {
        return name;
    } //get_Name

    /** @property 
     */
    public void set_Name(String value)
    {
        name = value;
    } //set_Name

    /** @property 
     */
    public String get_Title()
    {
        return title;
    } //get_Title

    /** @property 
     */
    public void set_Title(String value)
    {
        title = value;
    } //set_Title

    /** @property *
     */
    public String get_Alias()
    {
        return alias;
    } //get_Alias

    /** @property 
     */
    public void set_Alias(String value)
    {
        alias = value;
    } //set_Alias
} //Employee

// Use this Boolean version of the ParseChildrenAttribute constructor
// to set the ChildrenAsProperties property to true. Any properties of the
// the CollectionPropertyControl custom control will be used as parsable
// children.
/** @attribute ParseChildren(true)
 */
public class CollectionPropertyControl extends Control
{
    private String header;
    private ArrayList employees = new ArrayList();

    /** @property 
     */
    public String get_Header()
    {
        return header;
    } //get_Header

    /** @property 
     */
    public void set_Header(String value)
    {
        header = value;
    } //set_Header

    /** @property 
     */
    public ArrayList get_Employees()
    {
        return employees;
    } //get_Employees

    // Override the CreateChildControls method to 
    // add child controls to the Employees property when this
    // custom control is requested from a page.
    protected void CreateChildControls()
    {
        Label label = new Label();
        label.set_Text(get_Header());
        label.set_BackColor(System.Drawing.Color.get_Beige());
        label.set_ForeColor(System.Drawing.Color.get_Red());
        get_Controls().Add(label);
        get_Controls().Add(new LiteralControl("<BR> <BR>"));

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

        TableHeaderCell hCell1 = new TableHeaderCell();
        hCell1.set_Text("Name");
        htr.get_Cells().Add(hCell1);

        TableHeaderCell hCell2 = new TableHeaderCell();
        hCell2.set_Text("Title");
        htr.get_Cells().Add(hCell2);

        TableHeaderCell hCell3 = new TableHeaderCell();
        hCell3.set_Text("Alias");
        htr.get_Cells().Add(hCell3);
        table.get_Rows().Add(htr);

        table.set_BorderWidth(new Unit(2));
        table.set_BackColor(System.Drawing.Color.get_Beige());
        table.set_ForeColor(System.Drawing.Color.get_Red());
        Employee employee = null;
        for (int iCtr = 0; iCtr < get_Employees().get_Count(); iCtr++) {
            employee = (Employee)get_Employees().get_Item(iCtr);
            TableRow tr = new TableRow();

            TableCell cell1 = new TableCell();
            cell1.set_Text(employee.get_Name());
            tr.get_Cells().Add(cell1);

            TableCell cell2 = new TableCell();
            cell2.set_Text(employee.get_Title());
            tr.get_Cells().Add(cell2);

            TableCell cell3 = new TableCell();
            cell3.set_Text(employee.get_Alias());
            tr.get_Cells().Add(cell3);

            table.get_Rows().Add(tr);
        }
        get_Controls().Add(table);
    } //CreateChildControls 
} //CollectionPropertyControl

Im folgenden Codebeispiel wird veranschaulicht, wie die CollectionPropertyControl-Klasse und die Employee-Klasse in einer ASP.NET-Seite verwendet werden. Eine Instanz der Employee-Klasse wird deklarativ, eine weitere programmgesteuert hinzugefügt.

<%@ Page Language="VB" %>
<%@ Register TagPrefix="AspSample" Assembly="Samples.AspNet.VB.Controls" Namespace="Samples.AspNet.VB.Controls" %>

<!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 a new employee object and add it to custom control.
    Dim e1 As New Employee("Employee 2", "Title 2", "Alias 2")
    CollectionPropertyControl1.Employees.Add(e1)

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

    Dim sb As New StringBuilder()
    sb.Append("The ChildControlType property is " & p.ChildControlType.ToString() & "<br>")
    sb.Append("The ChildrenAsProperties property is " & p.ChildrenAsProperties.ToString() & "<br>")
    sb.Append("The IsDefaultAttribute 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">
      <Employees>
        <AspSample:Employee Name="Employee 1" 
                            Title="Title 1" 
                            Alias="Alias 1" />
      </Employees>
      </AspSample:CollectionPropertyControl>
    </div>
    </form>
</body>
</html>

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

<!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 a new employee object and add it to the custom control.
    Employee e1 = new Employee("Employee 2", "Title 2", "Alias 2");
    CollectionPropertyControl1.Employees.Add(e1);

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

    StringBuilder sb = new StringBuilder();
    sb.Append("The ChildControlType property is " + p.ChildControlType.ToString() + "<br>");
    sb.Append("The ChildrenAsProperties property is " + p.ChildrenAsProperties.ToString() + "<br>");
    sb.Append("The IsDefaultAttribute method returns " + p.IsDefaultAttribute().ToString());
    Message.Text = sb.ToString();

  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ParseChildrenAttribute Example</title>
</head>
<body>
    <form runat="server">
    <div>
      <asp:Label ID="Message"
                 runat="server"/>
      <AspSample:CollectionPropertyControl id="CollectionPropertyControl1" 
                                           runat="server">
      <Employees>
        <AspSample:Employee Name="Employee 1" 
                            Title="Title 1" 
                            Alias="Alias 1" />
      </Employees>
      </AspSample:CollectionPropertyControl>    
    </div>
    </form>
</body>
</html>

Plattformen

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Versionsinformationen

.NET Framework

Unterstützt in: 2.0, 1.1, 1.0

Siehe auch

Referenz

ParseChildrenAttribute-Klasse
ParseChildrenAttribute-Member
System.Web.UI-Namespace
ChildrenAsProperties

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