ControlBuilder-Klasse

Artikel
08/20/2007

Unterstützt den Seitenparser beim Erstellen eines Steuerelements und der darin enthaltenen untergeordneten Steuerelemente.

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

Syntax

'Declaration
Public Class ControlBuilder
'Usage
Dim instance As ControlBuilder

public class ControlBuilder

public ref class ControlBuilder

public class ControlBuilder

public class ControlBuilder

Hinweise

Standardmäßig wird jedes Steuerelement einer Seite einer ControlBuilder-Standardklasse zugeordnet. Bei der Analyse wird im ASP.NET-Seitenframework eine Struktur von ControlBuilder-Objekten entsprechend der Steuerelementstruktur für die Seite erstellt. Die ControlBuilder-Struktur wird dann zum Generieren von Seitencode verwendet, um die Steuerelementstruktur zu erstellen. Zusätzlich zu den untergeordneten Steuerelementen definiert der ControlBuilder die Art und Weise, wie der Inhalt innerhalb der Steuerelementtags analysiert wird. Sie können dieses Standardverhalten überschreiben, indem Sie eine eigene Generatorklasse für benutzerdefinierte Steuerelemente definieren. Dazu muss ein ControlBuilderAttribute-Attribut wie folgt auf die Steuerelementgeneratorklasse angewendet werden:

[ControlBuilderAttribute(typeof(ControlBuilderType))]

Beispiel

Im folgenden Codebeispiel wird ein Table-Steuerelement erstellt, dessen Attribute und Inhalt definiert werden, während die Tabelle erstellt wird. Die folgende Befehlszeile wird zum Erstellen der ausführbaren Datei verwendet.

[Visual Basic]

vbc /r:System.dll /r:System.Web.dll /r:System.Drawing.dll /t:library /out:myWebAppPath/Bin/vb_mycontrolbuilder.dll myControlBuilder.vb

[C#]

csc /t:library /out:myWebAppPath/Bin/cs_mycontrolbuilder.dll myControlBuilder.cs

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


Namespace CustomControls

    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public Class MyTableCell
        Inherits TableCell
        Implements INamingContainer
    End Class


    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public Class MyCell
        Inherits Control
        Implements INamingContainer
        ' Class Name: MyCell.
        ' Declares the class for the child controls to be included in the control collection.

        Private _id As String
        Private _value As String
        Private _backColor As Color

        Public Property CellID() As String
            Get
                Return _id
            End Get
            Set(ByVal value As String)
                _id = value
            End Set
        End Property

        Public Property Text() As String
            Get
                Return _value
            End Get
            Set(ByVal value As String)
                _value = value
            End Set
        End Property


        Public Property BackColor() As Color
            Get
                Return _backColor
            End Get
            Set(ByVal value As Color)
                _backColor = value
            End Set
        End Property
    End Class

    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
    Public Class MyControlBuilderVB
        Inherits ControlBuilder

        Public Overrides Function GetChildControlType(ByVal tagName As String, ByVal attribs As IDictionary) As Type

            ' Allows TableRow without "runat=server" attribute to be added to the collection.
            If (String.Compare(tagName, "mycell", True) = 0) Then
                Return GetType(MyCell)
            End If
            Return Nothing
        End Function

        ' Ignores literals between rows.
        Public Overrides Sub AppendLiteralString(ByVal s As String)
            ' Ignores literals between rows.
        End Sub

    End Class

    <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal), ControlBuilderAttribute(GetType(MyControlBuilderVB))> _
        Public Class MyVB_CustomControl
        Inherits Control
        Implements INamingContainer

        ' Class name: MyVB_CustomControl.
        ' Processes the element declarations within a control 
        ' declaration. This builds the actual control.

        ' Custom control to build programmatically.
        Private _table As Table

        Private _cellObjects As New Hashtable()

        ' Variables that must contain the control attributes as defined in the Web page.
        Private _rows As Integer
        Private _columns As Integer
        Private _title As String

        ' Rows property to be used as the attribute name in the Web page.     
        Public Property Rows() As Integer
            Get
                Return _rows
            End Get
            Set(ByVal value As Integer)
                _rows = value
            End Set
        End Property

        ' Columns property to be used as the attribute name in the Web page.

        Public Property Columns() As Integer
            Get
                Return _columns
            End Get
            Set(ByVal value As Integer)
                _columns = value
            End Set
        End Property

        ' Title property to be used as the attribute name in the Web page   
        Public Property Title() As String
            Get
                Return _title
            End Get
            Set(ByVal value As String)
                _title = value
            End Set
        End Property


        Protected Sub createNewRow(ByVal rowNumber As Integer)

            ' Creates a row and adds it to the table.
            Dim row As TableRow

            row = New TableRow()
            _table.Rows.Add(row)

            ' Creates a cell that contains text.
            Dim y As Integer
            For y = 0 To Columns - 1
                appendCell(row, rowNumber, y)
            Next y
        End Sub 'createNewRow


        Protected Sub appendCell(ByVal row As TableRow, ByVal rowNumber As Integer, ByVal cellNumber As Integer)
            Dim cell As TableCell
            Dim textbox As TextBox

            cell = New TableCell()

            textbox = New TextBox()

            cell.Controls.Add(textbox)

            textbox.ID = "r" + rowNumber.ToString() + "c" + cellNumber.ToString()

            ' Checks for the MyCell child object.
            If Not (_cellObjects(textbox.ID) Is Nothing) Then
                Dim cellLookup As MyCell
                cellLookup = CType(_cellObjects(textbox.ID), MyCell)

                textbox.Text = cellLookup.Text
                textbox.BackColor = cellLookup.BackColor

            Else
                textbox.Text = "Row: " + rowNumber.ToString() + " Cell: " + cellNumber.ToString()
            End If

            row.Cells.Add(cell)
        End Sub 'appendCell

        ' Called at runtime when a child object is added to the collection.
        Protected Overrides Sub AddParsedSubObject(ByVal obj As Object)

            Dim cell As MyCell = CType(obj, MyCell)
            If Not (cell Is Nothing) Then
                _cellObjects.Add(cell.CellID, cell)
            End If
        End Sub 'AddParsedSubObject


        Protected Overrides Sub OnPreRender(ByVal e As EventArgs)
            ' Sub name: OnPreRender.
            ' Carries out changes affecting the control state and renders the resulting UI.

            ' Increases the number of rows if needed.
            While _table.Rows.Count < Rows
                createNewRow(_table.Rows.Count)
            End While

            ' Checks that each row has the correct number of columns.
            Dim i As Integer
            For i = 0 To _table.Rows.Count - 1
                While _table.Rows(i).Cells.Count < Columns
                    appendCell(_table.Rows(i), i, _table.Rows(i).Cells.Count)
                End While

                While _table.Rows(i).Cells.Count > Columns
                    _table.Rows(i).Cells.RemoveAt((_table.Rows(i).Cells.Count - 1))
                End While
            Next i
        End Sub 'OnPreRender


        <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
        Protected Overrides Sub CreateChildControls()
            ' Sub name: CreateChildControls.
            ' Adds the Table and the text controls to the control collection. 


            Dim [text] As LiteralControl

            ' Initializes the text control using the Title property.
            [text] = New LiteralControl("<h5>" + Title + "</h5>")
            Controls.Add([text])


            _table = New Table()

            Controls.Add(_table)
        End Sub
    End Class

End Namespace

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

namespace CustomControls
{
    [AspNetHostingPermission(SecurityAction.Demand,
        Level = AspNetHostingPermissionLevel.Minimal)]
    public class MyTableCell : TableCell, INamingContainer { };

    [AspNetHostingPermission(SecurityAction.Demand,
        Level = AspNetHostingPermissionLevel.Minimal)]
    public class MyCell
    /*
     * Class name: MyCell.
     * Declares the class for the child controls to include in the control collection.
     */
    {
        string _id;
        string _value;
        Color _backColor;

        public string CellID
        {
            get
            { return _id; }
            set
            { _id = value; }
        }

        public string Text
        {
            get
            { return _value; }
            set
            { _value = value; }
        }

        public Color BackColor
        {
            get
            { return _backColor; }
            set
            { _backColor = value; }
        }
    };

    [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
    public class MyControlBuilder : ControlBuilder
    {

        public override Type GetChildControlType(string tagName, IDictionary attribs)
        {
            // Allows TableRow without "runat=server" attribute to be added to the collection.
            if (String.Compare(tagName, "mycell", true) == 0)
                return typeof(MyCell);
            return null;
        }

        public override void AppendLiteralString(string s)
        {
            // Ignores literals between rows.
        }

    }
    [AspNetHostingPermission(SecurityAction.Demand,
        Level = AspNetHostingPermissionLevel.Minimal)]
    [ControlBuilderAttribute(typeof(MyControlBuilder))]
    public class MyCS_CustomControl : Control, INamingContainer
    /*
     * Class name: MyCS_CustomControl.
     * Processes the element declarations within a control declaration. 
     * This builds the actual control.
     */
    {
        // Declares the custom control that must be built programmatically.
        Table _table;

        private String _title;
        private int _rows;
        private int _columns;

        Hashtable _cellObjects = new Hashtable();

        // Rows property to be used as the attribute name in the Web page.  
        public int Rows
        {
            get
            { return _rows; }
            set
            { _rows = value; }
        }

        // Columns property to be used as the attribute name in the Web page.
        public int Columns
        {
            get
            { return _columns; }
            set
            { _columns = value; }
        }

        // Title property to be used as the attribute name in the Web page.
        public string Title
        {
            get
            { return _title; }
            set
            { _title = value; }
        }

        protected void createNewRow(int rowNumber)
        {

            // Creates a row and adds it to the table.
            TableRow row;

            row = new TableRow();
            _table.Rows.Add(row);

            // Creates a cell that contains text.

            for (int y = 0; y < Columns; y++)
                appendCell(row, rowNumber, y);

        }

        protected void appendCell(TableRow row, int rowNumber, int cellNumber)
        {
            TableCell cell;
            TextBox textbox;

            cell = new TableCell();
            textbox = new TextBox();
            cell.Controls.Add(textbox);
            textbox.ID = "r" + rowNumber.ToString() + "c" + cellNumber.ToString();

            // Checks for the MyCell child object.
            if (_cellObjects[textbox.ID] != null)
            {
                MyCell cellLookup;
                cellLookup = (MyCell)_cellObjects[textbox.ID];

                textbox.Text = cellLookup.Text;
                textbox.BackColor = cellLookup.BackColor;
            }
            else
                textbox.Text = "Row: " + rowNumber.ToString() + " Cell: " +
                cellNumber.ToString();

            row.Cells.Add(cell);

        }

        // Called at runtime when a child object is added to the collection.  
        protected override void AddParsedSubObject(object obj)
        {
            MyCell cell = obj as MyCell;
            if (cell != null)
            {
                _cellObjects.Add(cell.CellID, cell);
            }

        }

        protected override void OnPreRender(EventArgs e)
        /*
         * Function name: OnPreRender.
         * Carries out changes affecting the control state and renders the resulting UI.
        */
        {

            // Increases the number of rows if needed.
            while (_table.Rows.Count < Rows)
            {
                createNewRow(_table.Rows.Count);
            }

            // Checks that each row has the correct number of columns.
            for (int i = 0; i < _table.Rows.Count; i++)
            {
                while (_table.Rows[i].Cells.Count < Columns)
                {
                    appendCell(_table.Rows[i], i, _table.Rows[i].Cells.Count);
                }

                while (_table.Rows[i].Cells.Count > Columns)
                {
                    _table.Rows[i].Cells.RemoveAt(_table.Rows[i].Cells.Count - 1);
                }
            }
        }

        protected override void CreateChildControls()
        /*
         * Function name: CreateChildControls.
         * Adds the Table and the text control to the control collection.
         */
        {
            LiteralControl text;

            // Initializes the text control using the Title property.
            text = new LiteralControl("<h5>" + Title + "</h5>");
            Controls.Add(text);

            _table = new Table();
            _table.BorderWidth = 2;
            Controls.Add(_table);
        }
    }
}

package CustomControls;
import System.*;
import System.Web.*;
import System.Web.UI.*;
import System.Web.UI.WebControls.*;
import System.Collections.*;
import System.Drawing.*;
import System.Security.Permissions.*;

/** @attribute AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
 */
public class MyTableCell extends TableCell implements INamingContainer
{
}

/** @attribute AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
 */
public class MyCell
{
    /*
        Class name: MyCell.
        Declares the class for the child controls to include in the control
        collection.
    */
    private String _id;
    private String _value;
    private Color _backColor;
    
    /** @property 
     */
    public String get_CellID()
    {
        return _id;
    } //get_CellID

    /** @property 
     */
    public void set_CellID(String value)
    {
        _id = value;
    } //set_CellID

    /** @property 
     */
    public String get_Text()
    {
        return _value;
    } //get_Text

    /** @property 
     */
    public void set_Text(String value)
    {
        _value = value;
    } //set_Text

    /** @property 
     */
    public Color get_BackColor()
    {
        return _backColor;
    } //get_BackColor

    /** @property 
     */
    public void set_BackColor(Color value)
    {
        _backColor = value;
    } //set_BackColor
} //MyCell

/** @attribute AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
 */
public class MyControlBuilder extends ControlBuilder
{
    public Type GetChildControlType(String tagName, IDictionary attribs)
    {
        // Allows TableRow without "runat=server" attribute to be added
        // to the collection.
        if (String.Compare(tagName, "mycell", true) == 0) {
            return MyCell.class.ToType();
        }
        return null;
    }

    public void AppendLiteralString(String s)
    {
        // Ignores literals between rows.
    }
}

/** @attribute ControlBuilderAttribute(MyControlBuilder.class)
 */
/** @attribute AspNetHostingPermission(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
 */
public class MyJSL_CustomControl extends Control implements INamingContainer
{
    /*
        Class name: MyJSL_CustomControl.
        Processes the element declarations within a control declaration. 
        This builds the actual control.
    */
    // Declares the custom control that must be built programmatically.
    private Table _table;
    private String _title;
    private int _rows;
    private int _columns;
    private Hashtable _cellObjects = new Hashtable();

    // Rows property to be used as the attribute name in the Web page.  
    /** @property 
     */
    public int get_Rows()
    {
        return _rows;
    }

    /** @property 
     */
    public void set_Rows(int value)
    {
        _rows = value;
    }

    // Columns property to be used as the attribute name in the Web page.
    /** @property 
     */
    public int get_Columns()
    {
        return _columns;
    }

    /** @property 
     */
    public void set_Columns(int value)
    {
        _columns = value;
    }

    // Title property to be used as the attribute name in the Web page.
    /** @property 
     */
    public String get_Title()
    {
        return _title;
    }

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

    protected void CreateNewRow(int rowNumber)
    {
        // Creates a row and adds it to the table.
        TableRow row;
        row = new TableRow();
        _table.get_Rows().Add(row);
        // Creates a cell that contains text.
        for (int y = 0; y < get_Columns(); y++) {
            AppendCell(row, rowNumber, y);
        }
    } //CreateNewRow

    protected void AppendCell(TableRow row, int rowNumber, int cellNumber)
    {
        TableCell cell;
        TextBox textbox;

        cell = new TableCell();
        textbox = new TextBox();
        cell.get_Controls().Add(textbox);
        textbox.set_ID("r" + ((Int32)rowNumber).ToString() + "c"
            + ((Int32)cellNumber).ToString());
        // Checks for the MyCell child object.
        if (_cellObjects.get_Item(textbox.get_ID()) != null) {
            MyCell cellLookup;
            cellLookup = (MyCell)_cellObjects.get_Item(textbox.get_ID());

            textbox.set_Text(cellLookup.get_Text());
            textbox.set_BackColor(cellLookup.get_BackColor());
        }
        else {
            textbox.set_Text("Row: " + ((Int32)rowNumber).ToString() + " Cell: "
                + ((Int32)cellNumber).ToString());
        }

        row.get_Cells().Add(cell);
    }

    // Called at runtime when a child object is added to the collection.  
    protected void AddParsedSubObject(Object obj)
    {
        MyCell cell = (MyCell)obj;
        if (cell != null) {
            _cellObjects.Add(cell.get_CellID(), cell);
        }
    }

    protected void OnPreRender(EventArgs e)
    {
        /*
            Function name: OnPreRender.
            Carries out changes affecting the control state and renders the
            resulting UI.
        */
        // Increases the number of rows if needed.
        while (_table.get_Rows().get_Count() < get_Rows()) {
            CreateNewRow(_table.get_Rows().get_Count());
        }
        // Checks that each row has the correct number of columns.
        for (int i = 0; i < _table.get_Rows().get_Count(); i++) {
            while (_table.get_Rows().get_Item(i).get_Cells().
                get_Count() < get_Columns()) {
                AppendCell(_table.get_Rows().get_Item(i), i,
                    _table.get_Rows().get_Item(i).get_Cells().get_Count());
            }

            while (_table.get_Rows().get_Item(i).get_Cells().get_Count() >
                get_Columns()) {
                _table.get_Rows().get_Item(i).get_Cells().RemoveAt(
                    _table.get_Rows().get_Item(i).get_Cells().get_Count() - 1);
            }
        }
    }

    protected void CreateChildControls()
    {
        /*
            Function name: CreateChildControls.
            Adds the Table and the text control to the control collection.
        */
        LiteralControl text;
        // Initializes the text control using the Title property.
        text = new LiteralControl("<h5>" + get_Title() + "</h5>");
        get_Controls().Add(text);

        _table = new Table();
        _table.set_BorderWidth(new Unit(2));
        get_Controls().Add(_table);
    }
}

Im folgenden Codebeispiel wird das vorherige benutzerdefinierte Steuerelement verwendet. Es wird insbesondere eine Tabelle erstellt, deren Attribute und Inhalt zur Laufzeit definiert werden. Beachten Sie, dass die in der @ Register-Direktive dargestellten Werte die vorherige Befehlszeile widerspiegeln.

<%@ Page Language="VB" %>
<%@ Register TagPrefix="AspNetSamples" Assembly="vb_mycontrolbuilder" Namespace="CustomControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ControlBuilder Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <AspNetSamples:MyVB_CustomControl id="Custom1" 
                                         title="Auto-Generated Table"
                                         columns="3"
                                         rows="3"  
                                         runat="server">
         <mycell cellid="r0c0" BackColor="red" text="red cell"></mycell>
         <mycell cellid="r2c2" BackColor="green" text="green cell"></mycell>
       </AspNetSamples:MyVB_CustomControl>
    </div>
    </form>
</body>
</html>

<%@ Page Language="C#" %>
<%@ Register TagPrefix="AspNetSamples" Assembly="cs_mycontrolbuilder" Namespace="CustomControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ControlBuilder Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <AspNetSamples:MyCS_CustomControl id="Custom1" 
                                         title="Auto-Generated Table"
                                         columns="3"
                                         rows="3"  
                                         runat="server">
         <mycell cellid="r0c0" BackColor="red" text="red cell"></mycell>
         <mycell cellid="r2c2" BackColor="green" text="green cell"></mycell>
       </AspNetSamples:MyCS_CustomControl>
    </div>
    </form>
</body>
</html>

<%@ Page Language="VJ#" %>
<%@ Register TagPrefix="AspNetSamples" Assembly="js_mycontrolbuilder" Namespace="CustomControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ControlBuilder Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <AspNetSamples:MyJSL_CustomControl id="Custom1" 
                                         title="Auto-Generated Table"
                                         columns="3"
                                         rows="3"  
                                         runat="server">
         <mycell cellid="r0c0" BackColor="red" text="red cell"></mycell>
         <mycell cellid="r2c2" BackColor="green" text="green cell"></mycell>
       </AspNetSamples:MyJSL_CustomControl>
    </div>
    </form>
</body>
</html>

.NET Framework-Sicherheit

AspNetHostingPermission für den Betrieb in einer Hostumgebung. Anforderungswert: LinkDemand, Berechtigungswert: Minimal.
AspNetHostingPermission für den Betrieb in einer Hostumgebung. Anforderungswert: InheritanceDemand, Berechtigungswert: Minimal.

Vererbungshierarchie

System.Object
System.Web.UI.ControlBuilder
Abgeleitete Klassen

Threadsicherheit

Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.

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

ControlBuilder-Member
System.Web.UI-Namespace
Control-Klasse
WebControl
Page
ControlBuilderAttribute
ParseChildrenAttribute
PersistChildrenAttribute
AddParsedSubObject

Freigeben über