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Classe ControlPersister

Fornisce metodi per rendere persistenti i controlli server Web in fase di progettazione.

Spazio dei nomi: System.Web.UI.Design
Assembly: System.Design (in system.design.dll)

public sealed class ControlPersister
public final class ControlPersister
public final class ControlPersister

La classe T:System.Web.UI.Design.ControlPersister fornisce i metodi che rendono persistenti un controllo Control o un'implementazione dell'interfaccia ITemplate come stringa di codice aspx. L'implementazione di questi metodi viene guidata da attributi di metadati quali DefaultValueAttribute, PersistenceModeAttribute e DesignerSerializationVisibilityAttribute.

NotaNota

La finestra di progettazione della pagina Web Form non supporta il metodo ResetPropertyName esposto facoltativamente dai controlli di tipo Microsoft Windows Form per la persistenza delle proprietà.

Per creare un oggetto T:System.Web.UI.Control o un'interfaccia ITemplate analizzando una stringa di dati di persistenza di un controllo o modello, utilizzare i metodi della classe ControlParser.

using System;
using System.Drawing;
using System.Drawing.Design;
using System.Web.UI;
using System.Web.UI.Design;
using System.Web.UI.WebControls;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Windows.Forms;
using System.Windows.Forms.Design;

namespace ControlParserPersisterDesignerControl_CS
{
    // Web control designer provides an interface 
    //   to use the ControlPersister and ControlParser.
    // The DesignerActionListCollection must run under "FullTrust",
    //   so you must also require your designer to run under "FullTrust".
    [System.Security.Permissions.PermissionSetAttribute(
        System.Security.Permissions.SecurityAction.InheritanceDemand, 
        Name = "FullTrust")]
    [System.Security.Permissions.PermissionSetAttribute(
        System.Security.Permissions.SecurityAction.Demand, 
        Name = "FullTrust")]
    public class ControlParserPersisterDesigner :
        System.Web.UI.Design.ControlDesigner
    {
        private DesignerActionListCollection _actLists = null;

        public ControlParserPersisterDesigner()
            : base()
        {}

        // Creates designer menu commands to persist
        // a control and to load a persisted control.
        public override DesignerActionListCollection ActionLists
        {
            get
            {
                if (_actLists == null)
                {
                    _actLists = new DesignerActionListCollection();
                    _actLists.AddRange(base.ActionLists);
                    _actLists.Add(new ParserActionList(this));
                }
                return _actLists;
            }
        }

        // A custom class for the DesignerActionList
        private class ParserActionList : DesignerActionList
        {
            private ControlParserPersisterDesigner _parent;
            private DesignerActionItemCollection _items;

            public ParserActionList(ControlParserPersisterDesigner parent) : 
                base(parent.Component)
            {
                _parent = parent;
            }

            public override DesignerActionItemCollection GetSortedActionItems()
            {
                if (_items == null)
                {
                    // Create the collection
                    _items = new DesignerActionItemCollection();

                    _items.Add(new DesignerActionMethodItem(this, "saveControl", "Parse and Save Control...", true));
                    _items.Add(new DesignerActionMethodItem(this, "loadPersistedControl", "Load Persisted Control...", true));
                }
                return _items;
            }

            // Displays a list of controls in the project, if any,
            // and displays the HTML markup for the selected control.       
            private void saveControl()
            {
                // Get the collection of components in the current 
                // design mode document.
                ComponentCollection documentComponents =
                    this.Component.Site.Container.Components;

                // Filter the components to those that derive from the 
                // System.Web.UI.Control class.

                // Create an IComponent array of the maximum possible length needed.
                IComponent[] filterArray = new IComponent[documentComponents.Count];

                // Count the total qualifying components.
                int total = 0;
                for (int i = 0; i < documentComponents.Count; i++)
                {
                    // If the component derives from System.Web.UI.Control, 
                    // copy a reference to the control to the filterArray 
                    // array and increment the control count.
                    if (typeof(System.Web.UI.Control).IsAssignableFrom(
                        documentComponents[i].GetType()))
                    {
                        if (((System.Web.UI.Control)documentComponents[i]).UniqueID
                            != null)
                        {
                            filterArray[total] = documentComponents[i];
                            total++;
                        }
                    }
                }

                if (total == 0)
                    throw new Exception(
                        "Document contains no System.Web.UI.Control components.");

                // Move the components that derive from System.Web.UI.Control to a 
                // new array of the correct size.
                System.Web.UI.Control[] controlArray =
                    new System.Web.UI.Control[total];
                for (int i = 0; i < total; i++)
                    controlArray[i] = (System.Web.UI.Control)filterArray[i];

                // Create a ControlSelectionForm to select a control.
                ControlSelectionForm selectionForm =
                    new ControlSelectionForm(controlArray);

                // Display the form.
                if (selectionForm.ShowDialog() != DialogResult.OK)
                    return;

                // Validate the selection.
                if (selectionForm.controlList.SelectedIndex == -1)
                    throw new Exception("You must select a control to persist.");

                // Parse the selected control into a persistence string.
                string persistedData = ControlPersister.PersistControl(
                    controlArray[selectionForm.controlList.SelectedIndex]);

                // Display the persistence string in a text box.
                StringDisplayForm displayForm =
                    new StringDisplayForm(persistedData);
                displayForm.ShowDialog();
            }

            // Displays a textbox form to receive an HTML 
            // string that represents a control, and creates
            // a toolbox item for the control, if not already
            // present in the selected toolbox category.
            private void loadPersistedControl()
            {
                // Display a StringInputForm to obtain a persisted control string.
                StringInputForm inputForm = new StringInputForm();

                if (inputForm.ShowDialog() != DialogResult.OK)
                    return;
                if (inputForm.TBox.Text.Length < 2)
                    return;

                // Obtain an IDesignerHost for the design-mode document.
                IDesignerHost host = (IDesignerHost)
                    this.Component.Site.GetService(typeof(IDesignerHost));

                // Create a Web control from the HTML markup.
                System.Web.UI.Control ctrl =
                    ControlParser.ParseControl(host, inputForm.TBox.Text.Trim());

                // Create a Web control toolbox item for the type of the control
                System.Web.UI.Design.WebControlToolboxItem item =
                    new System.Web.UI.Design.WebControlToolboxItem(ctrl.GetType());

                // Add the Web control toolbox item to the toolbox
                IToolboxService toolService = (IToolboxService)
                    this.Component.Site.GetService(typeof(IToolboxService));
                if (toolService != null)
                    toolService.AddToolboxItem(item);
                else
                    throw new Exception("IToolboxService was not found.");
            }
        }
    }

    // Simple text display control hosts the ControlParserPersisterDesigner.
    [DesignerAttribute(typeof(ControlParserPersisterDesigner),
         typeof(IDesigner))]
    public class ControlParserPersisterDesignerControl :
        System.Web.UI.WebControls.WebControl
    {
        private string _text;

        [Bindable(true),
            Category("Appearance"),
            DefaultValue("")]
        public string Text
        {
            get { return _text; }
            set { _text = value; }
        }

        public ControlParserPersisterDesignerControl()
            : base()
        {
            _text = "Right-click here to access control persistence " +
                "methods in design mode";
        }

        protected override void Render(HtmlTextWriter output)
        {
            output.Write(Text);
        }
    }

    // Provides a form with a list for selection.
    internal class ControlSelectionForm : Form
    {
        private System.Web.UI.Control[] controlArray;
        public System.Windows.Forms.ListBox controlList;

        public ControlSelectionForm(System.Web.UI.Control[] controlArray)
        {
            this.controlArray = controlArray;

            this.Size = new Size(400, 500);
            this.Text = "Control Selection Form";

            this.SuspendLayout();

            System.Windows.Forms.Label label1 =
                new System.Windows.Forms.Label();
            label1.Text = "Select a control to parse:";
            label1.Size = new Size(240, 20);
            label1.Location = new Point(10, 10);
            this.Controls.Add(label1);

            controlList = new System.Windows.Forms.ListBox();
            controlList.Size = new Size(370, 400);
            controlList.Location = new Point(10, 30);
            controlList.Anchor = AnchorStyles.Left | AnchorStyles.Top |
                AnchorStyles.Bottom | AnchorStyles.Right;
            this.Controls.Add(controlList);

            System.Windows.Forms.Button okButton =
                new System.Windows.Forms.Button();
            okButton.Text = "OK";
            okButton.Size = new Size(80, 24);
            okButton.Location =
                new Point(this.Width - 100, this.Height - 60);
            okButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
            okButton.DialogResult = DialogResult.OK;
            this.Controls.Add(okButton);

            System.Windows.Forms.Button cancelButton =
                new System.Windows.Forms.Button();
            cancelButton.Text = "Cancel";
            cancelButton.Size = new Size(80, 24);
            cancelButton.Location =
                new Point(this.Width - 200, this.Height - 60);
            cancelButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
            cancelButton.DialogResult = DialogResult.Cancel;
            this.Controls.Add(cancelButton);

            for (int i = 0; i < controlArray.Length; i++)
                controlList.Items.Add(controlArray[i].UniqueID);

            this.ResumeLayout();
        }
    }

    // Provides a form with a multiline text box display.
    internal class StringDisplayForm : Form
    {
        private System.Windows.Forms.TextBox tbox = 
            new System.Windows.Forms.TextBox();

        public System.Windows.Forms.TextBox TBox
        {
            get { return tbox; }
            set { tbox = value; }
        }

        public StringDisplayForm(string displayText)
        {
            this.Size = new Size(400, 300);
            this.Text = "Control Persistence String";

            this.SuspendLayout();
            TBox.Multiline = true;
            TBox.Size = new Size(this.Width - 40, this.Height - 90);
            TBox.Text = displayText;
            this.Controls.Add(TBox);

            System.Windows.Forms.Button okButton =
                new System.Windows.Forms.Button();
            okButton.Text = "OK";
            okButton.Size = new Size(80, 24);
            okButton.Location =
                new Point(this.Width - 100, this.Height - 60);
            okButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
            okButton.DialogResult = DialogResult.OK;
            this.Controls.Add(okButton);

            this.ResumeLayout();
        }
    }

    // Provides a form with a multiline text box for input.
    internal class StringInputForm : System.Windows.Forms.Form
    {
        private System.Windows.Forms.TextBox tbox = 
            new System.Windows.Forms.TextBox();

        public System.Windows.Forms.TextBox TBox
        {
            get { return tbox; }
        }

        public StringInputForm()
        {
            this.Size = new Size(400, 300);
            this.Text = "Input Control Persistence String";

            this.SuspendLayout();
            tbox = new System.Windows.Forms.TextBox();
            tbox.Multiline = true;
            tbox.Size = new Size(this.Width - 40, this.Height - 90);
            tbox.Text = "";
            this.Controls.Add(tbox);

            System.Windows.Forms.Button okButton =
                new System.Windows.Forms.Button();
            okButton.Text = "OK";
            okButton.Size = new Size(80, 24);
            okButton.Location =
                new Point(this.Width - 100, this.Height - 60);
            okButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
            okButton.DialogResult = DialogResult.OK;
            this.Controls.Add(okButton);

            System.Windows.Forms.Button cancelButton =
                new System.Windows.Forms.Button();
            cancelButton.Text = "Cancel";
            cancelButton.Size = new Size(80, 24);
            cancelButton.Location =
                new Point(this.Width - 200, this.Height - 60);
            cancelButton.Anchor = AnchorStyles.Bottom | AnchorStyles.Right;
            cancelButton.DialogResult = DialogResult.Cancel;
            this.Controls.Add(cancelButton);

            this.ResumeLayout();
        }
    }
}

System.Object
  System.Web.UI.Design.ControlPersister

I membri statici pubblici (Shared in Visual Basic) di questo tipo sono validi per le operazioni multithreading. I membri di istanza non sono garantiti come thread safe.

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 non supporta tutte le versioni di ciascuna piattaforma. Per un elenco delle versioni supportate, vedere Requisiti di sistema.

.NET Framework

Supportato in: 2.0 1.1 1.0
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