ParseChildrenAttribute-Konstruktor (Boolean, String)

Initialisiert eine neue Instanz der ParseChildrenAttribute-Klasse mithilfe des childrenAsProperties-Parameters und des defaultProperty-Parameters.

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

Syntax

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

Dim instance As New ParseChildrenAttribute(childrenAsProperties, defaultProperty)

public ParseChildrenAttribute (
    bool childrenAsProperties,
    string defaultProperty
)

public:
ParseChildrenAttribute (
    bool childrenAsProperties, 
    String^ defaultProperty
)

public ParseChildrenAttribute (
    boolean childrenAsProperties, 
    String defaultProperty
)

public function ParseChildrenAttribute (
    childrenAsProperties : boolean, 
    defaultProperty : String
)

Parameter

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

defaultProperty
Eine Zeichenfolge, die eine Auflistungseigenschaft des Serversteuerelements definiert, in dem geschachtelter Inhalt standardmäßig analysiert wird.

Hinweise

Wenn childrenAsProperties den Wert false aufweist, werden die Elemente als Steuerelemente analysiert.

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 eines benutzerdefinierten Serversteuerelements mit dem Namen CollectionPropertyControl festgelegt wird. Mithilfe von ParseChildrenAttribute wird die ChildrenAsProperties-Eigenschaft auf true festgelegt, und die DefaultProperty-Eigenschaft wird auf die Employee-Klasse festgelegt.

' Use the ParseChildren attribute to set the ChildrenAsProperties
' and DefaultProperty properties. Using this constructor, the
' control parses all child controls as properties and must define
' a public property named Employees, which it declares as
' an ArrayList. Nested (child) elements must correspond to
' child elements of the Employees property or to other
' properties of the control.   
<ParseChildren(True, "Employees")> _
<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

// Use the ParseChildren attribute to set the ChildrenAsProperties
// and DefaultProperty properties. Using this constructor, the
// control parses all child controls as properties and must define
// a public property named Employees, which it declares as
// an ArrayList. Nested (child) elements must correspond to
// child elements of the Employees property or to other
// properties of the control.  
[ParseChildren(true, "Employees")]
[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);
      
   }
}

// Use the ParseChildren attribute to set the ChildrenAsProperties
// and DefaultProperty properties. Using this constructor, the
// control parses all child controls as properties and must define
// a public property named Employees, which it declares as
// an ArrayList. Nested (child) elements must correspond to
// child elements of the Employees property or to other
// properties of the control.   
/** @attribute ParseChildren(true, "Employees")
 */
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.

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

    Dim sb As New StringBuilder()
    sb.Append("The DefaultProperty property is " & p.DefaultProperty.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">
        <AspSample:Employee Name="Employee 1" 
                            Title="Title 1" 
                            Alias="Alias 1" />
        <AspSample:Employee Name="Employee 2" 
                            Title="Title 2" 
                            Alias="Alias 2" />
      </AspSample:CollectionPropertyControl>
    </div>
    </form>
</body>
</html>

<%@ Page Language="C#" Debug="true" %>
<%@ 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)
  {
    
    // Verify attribute values.
    ParseChildrenAttribute p = 
      (ParseChildrenAttribute)Attribute.GetCustomAttribute(typeof(CollectionPropertyControl),
      typeof(ParseChildrenAttribute));

    StringBuilder sb = new StringBuilder();
    sb.Append("The DefaultProperty property is " + p.DefaultProperty.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">
        <AspSample:Employee Name="Employee 1" 
                            Title="Title 1" 
                            Alias="Alias 1" />
        <AspSample:Employee Name="Employee 2" 
                            Title="Title 2" 
                            Alias="Alias 2" />
      </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
Default

Last updated on 2007-08-20

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