EditableDesignerRegion Class

Represents an editable content region within the design-time markup for the associated control.

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

public class EditableDesignerRegion : DesignerRegion
public class EditableDesignerRegion extends DesignerRegion
public class EditableDesignerRegion extends DesignerRegion
Not applicable.

Use the EditableDesignerRegion class to help manage templates at design time. A ControlDesigner will use an instance of this class with its GetEditableDesignerRegionContent method to generate HTML markup of the region's content.

This example shows how to create a control with two clickable regions and an EditableDesignerRegion object with two views, or templates. Compile the project, then open the page in a visual designer and switch to design (WYSIWYG) view. There are two clickable views, View1 and View2. Click View1 and drag the CheckBox control from the lower part of the page into the empty designer region just below the clickable regions. Click View2 and drag the RadioButton control into the empty designer region. Click View1 again, and the region with the CheckBox reappears. Click View2 and the region with the RadioButton reappears. Switch back to source view to see how your changes are persisted in the HTML markup


Your project must have a reference to the System.Design.dll assembly.

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

namespace Samples.ASPNet.ControlDesigners_CS 
        ToolboxData("<{0}:MyMultiRegionControl runat=\"server\" width=\"200\"></{0}:MyMultiRegionControl>")
    public class MyMultiRegionControl : CompositeControl
        // Define the templates that represent 2 views on the control
        private ITemplate _view1;
        private ITemplate _view2;

        // Create persistable inner properties 
        // for the two editable views
        [PersistenceMode(PersistenceMode.InnerProperty), DefaultValue(null)]
        public virtual ITemplate View1
            get { return _view1; }
            set { _view1 = value; }
        [PersistenceMode(PersistenceMode.InnerProperty), DefaultValue(null)]
        public virtual ITemplate View2
            get { return _view2; }
            set { _view2 = value; }

        // The current view on the control; 0 = view1, 1 = view2
        private int _currentView = 0;
        public int CurrentView
            get { return _currentView; }
            set { _currentView = value; }

        // Create a simple table with a row of two clickable, 
        // readonly headers and a row with a single column, which 
        // is the 'container' to which we'll be adding controls.
        protected override void CreateChildControls()
            // Always start with a clean form

            // Create a table using the control's declarative properties
            Table t = new Table();
            t.CellSpacing = 1;
            t.BorderStyle = BorderStyle;
            t.Width = this.Width;
            t.Height = this.Height;

            // Create the header row
            TableRow tr = new TableRow();
            tr.HorizontalAlign = HorizontalAlign.Center;
            tr.BackColor = Color.LightBlue;

            // Create the first cell in the header row
            TableCell tc = new TableCell();
            tc.Text = "View1";
            tc.Width = new Unit("50%");

            // Create the second cell in the header row
            tc = new TableCell();
            tc.Text = "View 2";
            tc.Width = new Unit("50%");


            // Create the second row for content
            tr = new TableRow();
            tr.HorizontalAlign = HorizontalAlign.Center;

            // This cell represents our content 'container'
            tc = new TableCell();
            tc.ColumnSpan = 2;


            // Add the finished table to the Controls collection

    // Region-based control designer for the above web control, 
    // derived from CompositeControlDesigner.
    public class MyMultiRegionControlDesigner : CompositeControlDesigner 
        private MyMultiRegionControl myControl;

        public override void Initialize(IComponent component)
            myControl = (MyMultiRegionControl)component;

        // Make this control resizeable on the design surface
        public override bool AllowResize
                return true;

        // Use the base to create child controls, then add region markers
        protected override void CreateChildControls() {

            // Get a reference to the table, which is the first child control
            Table t = (Table)myControl.Controls[0];

            // Add design time markers for each of the three regions
            if (t != null)
                // View1
                t.Rows[0].Cells[0].Attributes[DesignerRegion.DesignerRegionAttributeName] = "0";
                // View2
                t.Rows[0].Cells[1].Attributes[DesignerRegion.DesignerRegionAttributeName] = "1";
                // Editable region
                t.Rows[1].Cells[0].Attributes[DesignerRegion.DesignerRegionAttributeName] = "2";

        // Handler for the Click event, which provides the region in the arguments.
        protected override void OnClick(DesignerRegionMouseEventArgs e)
            if (e.Region == null)

            // If the clicked region is not a header, return
            if (e.Region.Name.IndexOf("Header") != 0)

            // Switch the current view if required
            if (e.Region.Name.Substring(6, 1) != myControl.CurrentView.ToString())
                myControl.CurrentView = int.Parse(e.Region.Name.Substring(6, 1));

        // Create the regions and design-time markup. Called by the designer host.
        public override String GetDesignTimeHtml(DesignerRegionCollection regions) {
            // Create 3 regions: 2 clickable headers and an editable row
            regions.Add(new DesignerRegion(this, "Header0"));
            regions.Add(new DesignerRegion(this, "Header1"));

            // Create an editable region and add it to the regions
            EditableDesignerRegion editableRegion = 
                new EditableDesignerRegion(this, 
                    "Content" + myControl.CurrentView, false);

            // Set the highlight for the selected region
            regions[myControl.CurrentView].Highlight = true;

            // Use the base class to render the markup
            return base.GetDesignTimeHtml();

        // Get the content string for the selected region. Called by the designer host?
        public override string GetEditableDesignerRegionContent(EditableDesignerRegion region) 
            // Get a reference to the designer host
            IDesignerHost host = (IDesignerHost)Component.Site.GetService(typeof(IDesignerHost));
            if (host != null)
                ITemplate template = myControl.View1;
                if (region.Name == "Content1")
                    template = myControl.View2;

                // Persist the template in the design host
                if (template != null)
                    return ControlPersister.PersistTemplate(template, host);

            return String.Empty;

        // Create a template from the content string and  
        // put it in the selected view.
        public override void SetEditableDesignerRegionContent(EditableDesignerRegion region, string content)
            if (content == null)

            // Get a reference to the designer host
            IDesignerHost host = (IDesignerHost)Component.Site.GetService(typeof(IDesignerHost));
            if (host != null)
                // Create a template from the content string
                ITemplate template = ControlParser.ParseTemplate(host, content);

                if (template != null)
                    // Determine which region should get the template
                    // Either 'Content0' or 'Content1'
                    if (region.Name.EndsWith("0"))
                        myControl.View1 = template;
                    else if (region.Name.EndsWith("1"))
                        myControl.View2 = template;


<%@ Page Language="C#"  %>
<%@ Register TagPrefix="aspSample" 
    Namespace="Samples.ASPNet.ControlDesigners_CS" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Designers Page</title>
    <form id="form1" runat="server">

        <aspSample:MyMultiRegionControl ID="myCtl" Runat=Server Width=200 Height=75 BorderStyle=solid >
        </aspSample:MyMultiRegionControl><br />
        <asp:CheckBox ID="CheckBox1" runat="server" />
        <asp:RadioButton ID="RadioButton1" runat="server" />


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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