ParseChildrenAttribute Construtores

Definição

Namespace:

System.Web.UI

Assembly:

System.Web.dll

Inicializa uma nova instância da classe ParseChildrenAttribute.

Sobrecargas

ParseChildrenAttribute()	Inicializa uma nova instância da classe ParseChildrenAttribute.
ParseChildrenAttribute(Boolean)	Inicializa uma nova instância da classe ParseChildrenAttribute usando a propriedade ChildrenAsProperties para determinar se os elementos que estão contidos em um controle de servidor são analisados como propriedades do controle do servidor.
ParseChildrenAttribute(Type)	Inicializa uma nova instância da classe ParseChildrenAttribute usando a propriedade ChildControlType para determinar quais elementos contidos em um controle de servidor são analisados como controles.
ParseChildrenAttribute(Boolean, String)	Inicializa uma nova instância da classe ParseChildrenAttribute usando os parâmetros childrenAsProperties e defaultProperty.

ParseChildrenAttribute()

Inicializa uma nova instância da classe ParseChildrenAttribute.

public:
 ParseChildrenAttribute();

public ParseChildrenAttribute ();

Public Sub New ()

Comentários

Uma nova instância da ParseChildrenAttribute classe é criada com a ChildrenAsProperties propriedade definida como false.

Confira também

• ChildrenAsProperties

ParseChildrenAttribute(Boolean)

Inicializa uma nova instância da classe ParseChildrenAttribute usando a propriedade ChildrenAsProperties para determinar se os elementos que estão contidos em um controle de servidor são analisados como propriedades do controle do servidor.

public:
 ParseChildrenAttribute(bool childrenAsProperties);

public ParseChildrenAttribute (bool childrenAsProperties);

new System.Web.UI.ParseChildrenAttribute : bool -> System.Web.UI.ParseChildrenAttribute

Public Sub New (childrenAsProperties As Boolean)

Parâmetros

childrenAsProperties

Boolean

true para analisar os elementos como propriedades do controle do servidor; caso contrário, false.

Exemplos

O exemplo de código nesta seção contém duas partes. O primeiro exemplo de código demonstra como definir propriedades para a ParseChildrenAttribute classe. O segundo exemplo de código demonstra como usar classes em uma página de ASP.NET.

O exemplo de código a seguir demonstra como definir o ParseChildrenAttribute objeto para um controle de servidor personalizado chamado CollectionPropertyControl. Quando o ParseChildrenAttribute valor for declarado antes da definição da CollectionPropertyControlclasse, a ParseChildrenAttribute propriedade será definida ChildrenAsProperties como true.

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);
      }
   }
}

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


        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

        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

    ' 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
    End Class
End Namespace ' ParseChildrenSampleVB_2

O exemplo de código a seguir demonstra como usar as classes e Employee as CollectionPropertyControl classes em uma página de ASP.NET. Uma instância da Employee classe é adicionada declarativamente e outra é adicionada programaticamente.

<%@ 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 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="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>

Comentários

Se childrenAsProperties for false, os elementos contidos no controle do servidor são analisados como um controle. false é o padrão para ParseChildrenAttribute.

Confira também

• ChildrenAsProperties

ParseChildrenAttribute(Type)

Inicializa uma nova instância da classe ParseChildrenAttribute usando a propriedade ChildControlType para determinar quais elementos contidos em um controle de servidor são analisados como controles.

public:
 ParseChildrenAttribute(Type ^ childControlType);

public ParseChildrenAttribute (Type childControlType);

new System.Web.UI.ParseChildrenAttribute : Type -> System.Web.UI.ParseChildrenAttribute

Public Sub New (childControlType As Type)

Parâmetros

childControlType

Type

O tipo de controle a analisar como uma propriedade.

Exceções

ArgumentNullException

childControlType é null.

Confira também

• ParseChildrenAttribute(Boolean, String)

ParseChildrenAttribute(Boolean, String)

Inicializa uma nova instância da classe ParseChildrenAttribute usando os parâmetros childrenAsProperties e defaultProperty.

public:
 ParseChildrenAttribute(bool childrenAsProperties, System::String ^ defaultProperty);

public ParseChildrenAttribute (bool childrenAsProperties, string defaultProperty);

new System.Web.UI.ParseChildrenAttribute : bool * string -> System.Web.UI.ParseChildrenAttribute

Public Sub New (childrenAsProperties As Boolean, defaultProperty As String)

Parâmetros

childrenAsProperties

Boolean

true para analisar os elementos como propriedades do controle do servidor; caso contrário, false.

defaultProperty

String

Uma cadeia de caracteres que define uma propriedade de coleção do controle do servidor na qual o conteúdo aninhado é analisado por padrão.

Exemplos

O exemplo de código nesta seção contém duas partes. O primeiro exemplo de código demonstra como definir propriedades para a ParseChildrenAttribute classe. O segundo exemplo de código demonstra como usar classes em uma página de ASP.NET.

O exemplo de código a seguir demonstra como definir o ParseChildrenAttribute objeto de um controle de servidor personalizado chamado CollectionPropertyControl. Define ParseChildrenAttribute a ChildrenAsProperties propriedade true como e a DefaultProperty propriedade para a Employee classe.

// 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.   
<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
End Class

O exemplo de código a seguir demonstra como usar as classes e Employee as CollectionPropertyControl classes em uma página de ASP.NET.

<%@ 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 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="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>

Comentários

Se childrenAsProperties for false, os elementos são analisados como controles.

Confira também

• ChildrenAsProperties
• Default