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IWebEditable Interface

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

Namespace:  System.Web.UI.WebControls.WebParts
Assembly:  System.Web (in System.Web.dll)

'Declaration
Public Interface IWebEditable

The IWebEditable type exposes the following members.

  NameDescription
Public propertyWebBrowsableObjectGets a reference to the WebPart control, user control, or custom control that will be edited by EditorPart controls.
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  NameDescription
Public methodCreateEditorPartsReturns a collection of custom EditorPart controls associated with a server control that implements the IWebEditable interface.
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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.

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.


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

Namespace Samples.AspNet.VB.Controls
  <AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Class TextDisplayWebPart
    Inherits WebPart
    Private _contentText As String = Nothing
    Private _fontStyle As String = Nothing
    Private input As TextBox
    Private DisplayContent As Label
    Private lineBreak As Literal

    Public Overrides Function CreateEditorParts() _
                                As EditorPartCollection
      Dim editorArray As New ArrayList()
      Dim edPart as New TextDisplayEditorPart()
      edPart.ID = Me.ID & "_editorPart1"
      editorArray.Add(edPart)
      Dim editorParts As New EditorPartCollection(editorArray)
      Return editorParts

    End Function

    Public Overrides ReadOnly Property WebBrowsableObject() _
                                        As Object
      Get
        Return Me
      End Get
    End Property

    <Personalizable(), WebBrowsable()> _
    Public Property ContentText() As String
      Get
        Return _contentText
      End Get
      Set(ByVal value As String)
        _contentText = Value
      End Set
    End Property

    <Personalizable(), WebBrowsable()> _
    Public Property FontStyle() As String
      Get
        Return _fontStyle
      End Get
      Set(ByVal value As String)
        _fontStyle = Value
      End Set
    End Property

    Protected Overrides Sub CreateChildControls()
      Controls.Clear()
      DisplayContent = New Label()
      DisplayContent.BackColor = Color.LightBlue
      DisplayContent.Text = Me.ContentText
      If FontStyle Is Nothing Then
        FontStyle = "None"
      End If
      SetFontStyle(DisplayContent, FontStyle)
      Me.Controls.Add(DisplayContent)

      lineBreak = New Literal()
      lineBreak.Text = "<br />"
      Controls.Add(lineBreak)

      input = New TextBox()
      Me.Controls.Add(input)
      Dim update As New Button()
      update.Text = "Set Label Content"
      AddHandler update.Click, AddressOf Me.submit_Click
      Me.Controls.Add(update)

    End Sub

    Private Sub submit_Click(ByVal sender As Object, _
                             ByVal e As EventArgs)
      ' Update the label string.
      If input.Text <> String.Empty Then
        _contentText = input.Text + "<br />"
        input.Text = String.Empty
        DisplayContent.Text = Me.ContentText
      End If

    End Sub

    Private Sub SetFontStyle(ByVal label As Label, _
                             ByVal selectedStyle As String)
      If selectedStyle = "Bold" Then
        label.Font.Bold = True
        label.Font.Italic = False
        label.Font.Underline = False
      ElseIf selectedStyle = "Italic" Then
        label.Font.Italic = True
        label.Font.Bold = False
        label.Font.Underline = False
      ElseIf selectedStyle = "Underline" Then
        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
      End If

    End Sub

    ' Create a custom EditorPart to edit the WebPart control.
    <AspNetHostingPermission(SecurityAction.Demand, _
      Level:=AspNetHostingPermissionLevel.Minimal)> _
    Private Class TextDisplayEditorPart
      Inherits EditorPart
      Private _partContentFontStyle As DropDownList

      Public Overrides Function ApplyChanges() As Boolean
        Dim part As TextDisplayWebPart = CType(WebPartToEdit, _
                                               TextDisplayWebPart)
        ' Update the custom WebPart control with the font style.
        part.FontStyle = PartContentFontStyle.SelectedValue

        Return True

      End Function

      Public Overrides Sub SyncChanges()
        Dim part As TextDisplayWebPart = CType(WebPartToEdit, _
                                               TextDisplayWebPart)
        Dim currentStyle As String = part.FontStyle

        ' Select the current font style in the drop-down control.
        Dim item As ListItem
        For Each item In PartContentFontStyle.Items
          If item.Value = currentStyle Then
            item.Selected = True
            Exit For
          End If
        Next item

      End Sub

      Protected Overrides Sub 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)

      End Sub

      Protected Overrides Sub RenderContents(ByVal writer _
                                             As HtmlTextWriter)
        writer.Write("<b>Text Content Font Style</b>")
        writer.WriteBreak()
        writer.Write("Select a font style.")
        writer.WriteBreak()
        _partContentFontStyle.RenderControl(writer)
        writer.WriteBreak()

      End Sub

      ' Access the drop-down control through a property.
      Private ReadOnly Property PartContentFontStyle() As DropDownList
        Get
          EnsureChildControls()
          Return _partContentFontStyle
        End Get
      End Property

    End Class

  End Class

End Namespace


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.


<%@ page language="vb" %>
<%@ register TagPrefix="uc1" 
  TagName="DisplayModeUC" 
  Src="DisplayModeUCvb.ascx" %>
<%@ register tagprefix="aspSample" 
  Namespace="Samples.AspNet.VB.Controls" 
  Assembly="TextDisplayWebPartVB" %>

<!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.


<%@ control language="vb" classname="DisplayModeMenu"%>

<script runat="server">

 ' On initial load, fill the dropdown with display modes.
  Sub DisplayModeDropdown_Load(ByVal sender As Object, _
                               ByVal e As System.EventArgs)
    If Not IsPostBack Then
      Dim mgr As WebPartManager = _
        WebPartManager.GetCurrentWebPartManager(Page)
      Dim browseModeName As String = _
        WebPartManager.BrowseDisplayMode.Name
      ' Use a sorted list so the modes are sorted alphabetically.
      Dim itemArray As New SortedList(mgr.SupportedDisplayModes.Count)

      ' Add display modes only if they are supported on the page.
      Dim mode As WebPartDisplayMode
      For Each mode In mgr.SupportedDisplayModes
        Dim modeName As String = mode.Name
        itemArray.Add(modeName, modeName + " Mode")
      Next mode
      ' Fill the dropdown with the display mode names.
      Dim arrayItem As DictionaryEntry
      For Each arrayItem In itemArray
        Dim item As New ListItem(arrayItem.Value.ToString(), _
                                 arrayItem.Key.ToString())
        If item.Value = browseModeName Then
          item.Selected = True
        End If
        DisplayModeDropdown.Items.Add(item)
      Next arrayItem
    End If

  End Sub


' Change the page to the selected display mode.
  Sub DisplayModeDropdown_SelectedIndexChanged(ByVal sender As Object, _
                                               ByVal e As EventArgs)
    Dim mgr As WebPartManager = _
      WebPartManager.GetCurrentWebPartManager(Page)
    Dim selectedMode As String = DisplayModeDropdown.SelectedValue

    Dim mode As WebPartDisplayMode
    For Each mode In mgr.SupportedDisplayModes
      If selectedMode = mode.Name Then
        mgr.DisplayMode = mode
        Exit For
      End If
    Next mode

  End Sub

</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.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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