IWebEditable Interface

Definition

Namespace:

System.Web.UI.WebControls.WebParts

Assembly:

System.Web.dll

Provides an interface for developers to specify custom editing controls that are associated with a WebPart control.

C#

public interface IWebEditable

Derived

System.Web.UI.WebControls.WebParts.WebPart

Examples

The following code example demonstrates how to override the methods of the IWebEditable interface in a custom WebPart control, which then creates an instance of a custom EditorPart control when the WebPart control enters edit mode.

This example has four parts:

• The code for the custom class.

• The Web page that hosts the custom control.

• A user control that switches the page into edit mode.

• A description of how the example works in a browser.

The first part of the code example is the custom TextDisplayWebPart class. Notice that the class derives from the WebPart class and implements the IWebEditable interface, providing specific implementations for the CreateEditorParts method and the WebBrowsableObject property. Notice also that nested within the TextDisplayWebPart class is a private, custom TextDisplayEditorPart class that derives from the base EditorPart class. For the code example to run, you must compile this source code. You can compile it explicitly and put the resulting assembly in your Web site's Bin folder or the global assembly cache. Alternatively, you can put the source code in your site's App_Code folder, where it will be dynamically compiled at run time. For a walkthrough that demonstrates both methods of compiling, see Walkthrough: Developing and Using a Custom Web Server Control.

C#

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

namespace Samples.AspNet.CS.Controls
{
  [AspNetHostingPermission(SecurityAction.Demand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  [AspNetHostingPermission(SecurityAction.InheritanceDemand,
    Level = AspNetHostingPermissionLevel.Minimal)]
  public class TextDisplayWebPart : WebPart
  {
    private String _contentText = null;
    private String _fontStyle = null;
    TextBox input;
    Label DisplayContent;
    Literal lineBreak;

    public override EditorPartCollection CreateEditorParts()
    {
      ArrayList editorArray = new ArrayList();
      TextDisplayEditorPart edPart = new TextDisplayEditorPart();
      edPart.ID = this.ID + "_editorPart1";
      editorArray.Add(edPart);
      EditorPartCollection editorParts = 
        new EditorPartCollection(editorArray);
      return editorParts;
    }

    public override object WebBrowsableObject
    {
      get { return this; }
    }

    [Personalizable(), WebBrowsable]
    public String ContentText
    {
      get { return _contentText; }
      set { _contentText = value; }
    }

    [Personalizable(), WebBrowsable()]
    public String FontStyle
    {
      get { return _fontStyle; }
      set { _fontStyle = value; }
    }

    protected override void CreateChildControls()
    {
      Controls.Clear();
      DisplayContent = new Label();
      DisplayContent.BackColor = Color.LightBlue;
      DisplayContent.Text = this.ContentText;
      if (FontStyle == null)
        FontStyle = "None";
      SetFontStyle(DisplayContent, FontStyle);
      this.Controls.Add(DisplayContent);

      lineBreak = new Literal();
      lineBreak.Text = @"<br />";
      Controls.Add(lineBreak);

      input = new TextBox();
      this.Controls.Add(input);
      Button update = new Button();
      update.Text = "Set Label Content";
      update.Click += new EventHandler(this.submit_Click);
      this.Controls.Add(update);
    }

    private void submit_Click(object sender, EventArgs e)
    {
      // Update the label string.
      if (!string.IsNullOrEmpty(input.Text))
      {
        _contentText = input.Text + @"<br />";
        input.Text = String.Empty;
        DisplayContent.Text = this.ContentText;
      }
    }

    private void SetFontStyle(Label label, String selectedStyle)
    {
      if (selectedStyle == "Bold")
      {
        label.Font.Bold = true;
        label.Font.Italic = false;
        label.Font.Underline = false;
      }
      else if (selectedStyle == "Italic")
      {
        label.Font.Italic = true;
        label.Font.Bold = false;
        label.Font.Underline = false;
      }
      else if (selectedStyle == "Underline")
      {
        label.Font.Underline = true;
        label.Font.Bold = false;
        label.Font.Italic = false;
      }
      else
      {
        label.Font.Bold = false;
        label.Font.Italic = false;
        label.Font.Underline = false;
      }
    }

    // Create a custom EditorPart to edit the WebPart control.
    [AspNetHostingPermission(SecurityAction.Demand,
      Level = AspNetHostingPermissionLevel.Minimal)]
    private class TextDisplayEditorPart : EditorPart
    {
      DropDownList _partContentFontStyle;

      public override bool ApplyChanges()
      {
        TextDisplayWebPart part = 
          (TextDisplayWebPart)WebPartToEdit;
        // Update the custom WebPart control with the font style.
        part.FontStyle = PartContentFontStyle.SelectedValue;

        return true;
      }

      public override void SyncChanges()
      {
        TextDisplayWebPart part = 
          (TextDisplayWebPart)WebPartToEdit;
        String currentStyle = part.FontStyle;

        // Select the current font style in the drop-down control.
        foreach (ListItem item in PartContentFontStyle.Items)
        {
          if (item.Value == currentStyle)
          {
            item.Selected = true;
            break;
          }
        }
      }

      protected override void CreateChildControls()
      {
        Controls.Clear();

        // Add a set of font styles to the dropdown list.
        _partContentFontStyle = new DropDownList();
        _partContentFontStyle.Items.Add("Bold");
        _partContentFontStyle.Items.Add("Italic");
        _partContentFontStyle.Items.Add("Underline");
        _partContentFontStyle.Items.Add("None");

        Controls.Add(_partContentFontStyle);
      }

      protected override void RenderContents(HtmlTextWriter writer)
      {
        writer.Write("<b>Text Content Font Style</b>");
        writer.WriteBreak();
        writer.Write("Select a font style.");
        writer.WriteBreak();
        _partContentFontStyle.RenderControl(writer);
        writer.WriteBreak();
      }

      // Access the drop-down control through a property.
      private DropDownList PartContentFontStyle
      {
        get 
        {
          EnsureChildControls();
          return _partContentFontStyle;
        }
      }
    }
  }
}

The second part of the code example is a Web page that hosts the custom control. Notice that although an EditorZone control is declared in the markup of the page, the custom EditorPart control need not be referenced there, because it can be added programmatically at run time.

ASP.NET (C#)

<%@ page language="c#" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeUC" 
  Src="DisplayModeUCcs.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.CS.Controls" 
  Assembly="TextDisplayWebPartCS" %>

<!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>
      Text Display WebPart with EditorPart
    </title>
  </head>
  <body>
    <form id="form1" runat="server">
      <asp:webpartmanager id="WebPartManager1" runat="server" />
      <uc1:DisplayModeUC ID="DisplayModeUC1" runat="server" />
      <asp:webpartzone id="zone1" runat="server" 
        CloseVerb-Enabled="false">
        <zonetemplate>
          <aspSample:TextDisplayWebPart 
            runat="server"   
            id="textwebpart" 
            title = "Text Content WebPart" /> 
        </zonetemplate>
      </asp:webpartzone> 
      <asp:EditorZone ID="EditorZone1" runat="server" /> 
    </form>
  </body>
</html>

The third part of the code example is a user control that enables a user to switch the page into edit mode. Notice that the user control is referenced in the hosting Web page. For a full description of how to create this user control, see Walkthrough: Changing Display Modes on a Web Parts Page.

ASP.NET (C#)

<%@ control language="C#" classname="DisplayModeMenu"%>

<script runat="server">

  // On initial load, fill the dropdown with display modes.
  void DisplayModeDropdown_Load(object sender, System.EventArgs e)
  {
    if (!IsPostBack)
    {
      WebPartManager mgr = 
        WebPartManager.GetCurrentWebPartManager(Page);
      String browseModeName = WebPartManager.BrowseDisplayMode.Name;
      // Use a sorted list so the modes are sorted alphabetically.
      SortedList itemArray = 
        new SortedList(mgr.SupportedDisplayModes.Count);

      // Add display modes only if they are supported on the page.
      foreach (WebPartDisplayMode mode in mgr.SupportedDisplayModes)
      {
        String modeName = mode.Name;
        itemArray.Add(modeName, modeName + " Mode");      
      }
      // Fill the dropdown with the display mode names.
      foreach(DictionaryEntry arrayItem in itemArray)
      {
        ListItem item = new ListItem(arrayItem.Value.ToString(), 
          arrayItem.Key.ToString());
        if (item.Value == browseModeName)
          item.Selected = true;
        DisplayModeDropdown.Items.Add(item);
      }
    }
  }

  // Change the page to the selected display mode.
  void DisplayModeDropdown_SelectedIndexChanged(object sender, 
    EventArgs e)
  {
    WebPartManager mgr = WebPartManager.GetCurrentWebPartManager(Page);
    String selectedMode = DisplayModeDropdown.SelectedValue;

    foreach (WebPartDisplayMode mode in mgr.SupportedDisplayModes)
    {
      if (selectedMode == mode.Name)
      {
        mgr.DisplayMode = mode;
        break;
      }
    }
  }

</script>
<div>
  <asp:DropDownList ID="DisplayModeDropdown" 
    runat="server" 
    AutoPostBack="true" 
    OnLoad="DisplayModeDropdown_Load" 
    OnSelectedIndexChanged="DisplayModeDropdown_SelectedIndexChanged" />
</div>

To run the code example, load the hosting Web page in a browser, add some text to the text box, and click the Set Label Content button to update the label in the control. To switch the page into edit mode, select Edit from the drop-down list containing the display modes. To display the UI from the custom TextDisplayEditorPart control, click the verbs menu drop-down arrow on the TextDisplayWebPart control, and select Edit. In the editing UI, you can use the drop-down list containing the font styles to update the text style for the label in the TextDisplayWebPart control. You must click Browse Mode in the display modes drop-down list to return the page to normal view and confirm that the text in the label now has the font style you selected while in edit mode.

Remarks

The IWebEditable interface enables you to associate custom EditorPart controls with a server control--such as a WebPart control, a user control, or a custom server control. The EditorPart controls are contained with an EditorZone control, and this zone with its editing controls provides end users with a user interface (UI) for modifying properties, appearance, and behavior on the associated WebPart control.

The IWebEditable interface includes two exposed members. The WebBrowsableObject property provides a way for EditorPart controls to get a reference to the associated server control. The CreateEditorParts method is used to create an instance of each custom EditorPart control associated with a server control, and return them as a collection.

The IWebEditable interface is already implemented on the base WebPart class, although by default this implementation does not associate any custom EditorPart controls with the WebPart class. To associate a derived WebPart control with custom EditorPart controls, you can override the CreateEditorParts method.

Notes to Implementers

If you want to use server controls that are not WebPart controls in a Web Parts application (that is, if you add these controls to a WebPartZoneBase zone), and if you want to associate custom EditorPart controls with such server controls, you need to implement the IWebEditable interface. Derived WebPart controls should not implement the interface, because the base WebPart class already does so.

Properties

WebBrowsableObject

Gets a reference to the WebPart control, user control, or custom control that will be edited by EditorPart controls.

Methods

CreateEditorParts()

Returns a collection of custom EditorPart controls associated with a server control that implements the IWebEditable interface.

Applies to

See also

• EditorPart
• ASP.NET Web Parts Controls