ParseChildrenAttribute Конструкторы

Определение

Пространство имен:

System.Web.UI

Сборка:

System.Web.dll

Инициализирует новый экземпляр класса ParseChildrenAttribute.

Перегрузки

ParseChildrenAttribute()	Инициализирует новый экземпляр класса ParseChildrenAttribute.
ParseChildrenAttribute(Boolean)	Инициализирует новый экземпляр класса ParseChildrenAttribute, используя свойство ChildrenAsProperties, чтобы определить, анализируются ли элементы, находящиеся в серверном элементе управления, как свойства серверного элемента управления.
ParseChildrenAttribute(Type)	Инициализирует новый экземпляр класса ParseChildrenAttribute, используя свойство ChildControlType, чтобы определить, какие элементы, находящиеся в серверном элементе управления, анализируются как элементы управления.
ParseChildrenAttribute(Boolean, String)	Инициализирует новый экземпляр класса ParseChildrenAttribute, используя параметры childrenAsProperties и defaultProperty.

ParseChildrenAttribute()

Инициализирует новый экземпляр класса ParseChildrenAttribute.

public:
 ParseChildrenAttribute();

public ParseChildrenAttribute ();

Public Sub New ()

Комментарии

Создается новый экземпляр ParseChildrenAttribute класса со свойством ChildrenAsProperties , которое имеет значение false.

См. также раздел

• ChildrenAsProperties

ParseChildrenAttribute(Boolean)

Инициализирует новый экземпляр класса ParseChildrenAttribute, используя свойство ChildrenAsProperties, чтобы определить, анализируются ли элементы, находящиеся в серверном элементе управления, как свойства серверного элемента управления.

public:
 ParseChildrenAttribute(bool childrenAsProperties);

public ParseChildrenAttribute (bool childrenAsProperties);

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

Public Sub New (childrenAsProperties As Boolean)

Параметры

childrenAsProperties

Boolean

true, чтобы анализировать элементы управления как свойства серверного элемента управления, в противном случае — false.

Примеры

Пример кода в этом разделе содержит две части. В первом примере кода показано, как задать свойства для ParseChildrenAttribute класса . Во втором примере кода показано, как использовать классы на странице ASP.NET.

В следующем примере кода показано, как задать объект для пользовательского ParseChildrenAttribute серверного элемента управления с именем CollectionPropertyControl. ParseChildrenAttribute Если класс объявляется перед классом, определяющим ParseChildrenAttributeCollectionPropertyControl, присваивает свойству ChildrenAsProperties значение 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

В следующем примере кода показано, как использовать классы CollectionPropertyControl и Employee на странице ASP.NET. Один экземпляр Employee класса добавляется декларативно, а другой — программным способом.

<%@ 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>

Комментарии

Если childrenAsProperties имеет значение false, элементы, содержащиеся в серверном элементе управления, анализируются как элемент управления . false является значением по умолчанию для ParseChildrenAttribute.

См. также раздел

• ChildrenAsProperties

ParseChildrenAttribute(Type)

Инициализирует новый экземпляр класса ParseChildrenAttribute, используя свойство ChildControlType, чтобы определить, какие элементы, находящиеся в серверном элементе управления, анализируются как элементы управления.

public:
 ParseChildrenAttribute(Type ^ childControlType);

public ParseChildrenAttribute (Type childControlType);

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

Public Sub New (childControlType As Type)

Параметры

childControlType

Type

Тип элемента управления, анализируемый как свойство.

Исключения

ArgumentNullException

childControlType имеет значение null.

См. также раздел

• ParseChildrenAttribute(Boolean, String)

ParseChildrenAttribute(Boolean, String)

Инициализирует новый экземпляр класса ParseChildrenAttribute, используя параметры childrenAsProperties и 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)

Параметры

childrenAsProperties

Boolean

true, чтобы анализировать элементы управления как свойства серверного элемента управления, в противном случае — false.

defaultProperty

String

Строка, определяющая свойство коллекции серверного элемента управления, в которой вложенное содержимое анализируется по умолчанию.

Примеры

Пример кода в этом разделе содержит две части. В первом примере кода показано, как задать свойства для ParseChildrenAttribute класса . Во втором примере кода показано, как использовать классы на странице ASP.NET.

В следующем примере кода показано, как задать ParseChildrenAttribute объект пользовательского серверного элемента управления с именем CollectionPropertyControl. Задает ParseChildrenAttribute свойству ChildrenAsProperties значение , true а свойству DefaultPropertyEmployee — класс .

// 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

В следующем примере кода показано, как использовать классы CollectionPropertyControl и Employee на странице 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>

Комментарии

Если childrenAsProperties имеет значение false, элементы анализируются как элементы управления.

См. также раздел

• ChildrenAsProperties
• Default