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ControlBuilder, classe

Prend l'analyseur de page en charge en générant un contrôle et les contrôles enfants qu'il contient.

Espace de noms : System.Web.UI
Assembly : System.Web (dans system.web.dll)

public class ControlBuilder
public class ControlBuilder
public class ControlBuilder

Par défaut, tous les contrôles d'une page sont associés à une classe ControlBuilder par défaut. Pendant l'analyse, l'infrastructure de page ASP.NET construit une arborescence d'objets ControlBuilder qui correspond à l'arborescence des contrôles de la page. L'arborescence ControlBuilder est alors utilisée pour générer le code de la page et ainsi créer l'arborescence des contrôles. En plus de contrôles enfants, le ControlBuilder définit le comportement de l'analyse du contenu placé dans les balises d'un contrôle. Vous pouvez substituer ce comportement par défaut en définissant votre propre classe de générateurs de contrôles personnalisés. Pour ce faire, appliquez un attribut ControlBuilderAttribute à votre classe de générateurs de contrôles, de la manière suivante :

[ControlBuilderAttribute(typeof(ControlBuilderType))]

L'exemple de code suivant crée un contrôle Table dont les attributs et le contenu sont définis au moment de la génération de la table. Voici la ligne de commande à utiliser pour générer l'exécutable.

[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
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);
    }
}

L'exemple de code ci-dessous utilise le contrôle personnalisé précédent. En particulier, il génère une table dont les attributs et le contenu sont définis au moment de l'exécution. Remarquez que les valeurs montrées dans la directive @ Register reflètent la ligne de commande précédente.

<%@ 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>

  • AspNetHostingPermission  pour opérer dans un environnement hébergé. Valeur de demande : LinkDemand ; valeur d'autorisation : Minimal.
  • AspNetHostingPermission  pour opérer dans un environnement hébergé. Valeur de demande : InheritanceDemand ; valeur d'autorisation : Minimal.
System.Object
  System.Web.UI.ControlBuilder
     Classes dérivées
Les membres statiques publics (Shared en Visual Basic) de ce type sont thread-safe. Il n'est pas garanti que les membres d'instance soient thread-safe.

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

Le .NET Framework ne prend pas en charge toutes les versions de chaque plate-forme. Pour obtenir la liste des versions prises en charge, consultez Configuration requise.

.NET Framework

Prise en charge dans : 2.0, 1.1, 1.0

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