Creating A DotNetNuke Module using ASP.NET AJAX

(This only applies to DotNetNuke 4.5.0 or higher) (The AJAX sample code can be downloaded at this link)

This article will cover the ASP.NET AJAX implementation in the DotNetNuke Framework.

The DotNetNuke Framework cannot assume that the web server it is running on has ASP.NET AJAX installed. In order to handle this a new class was created in DotNetNuke.Framework.AJAX which provides methods that developers can use to leverage AJAX in their solutions.

Setting Dependencies

One option in developing a DotNetNuke ASP.NET AJAX module is indicating the System.Web.UI.ScriptManager dependency in the module configuration setting:

Modules can optionally specify a semi-colon delimited list of Dependencies which their module requires (for example, indicate System.Web.UI.ScriptManager when your module requires that the site have ASP.NET AJAX installed and enabled). Then, during the installation of the module, if the environment does not support a specific permission, a message will be displayed to the user and the module will not be installed.

IsInstalled and RegisterScriptManager()

If you want to use ASP.NET AJAX functionality only when it is available, you can decide not to use the Dependency and use the IsInstalled flag and the IsEnabled setting.

The IsInstalled flag indicates whether AJAX is available in the environment and the IsEnabled setting must be used by developers to tell DotNetNuke that their module/skin is using AJAX on the page.

IsInstalled

The IsInstalled flag is simple to use and can be checked before any ASP.NET AJAX functionality is called. The function returns a Boolean value (true or false)

RegisterScriptManager()

AJAX needs to be registered very early in the page life cycle for it to be recognized, so DNN inserts the ScriptManager into the page dynamically. If modules loaded on the page use the RegisterScriptManager() method, DNN knows that the page requires AJAX. If no modules use RegisterScriptManager(), then DNN thinks that the page does not require AJAX - and at the Render stage it will REMOVE the ScriptManager from the page (since it thinks it is not necessary and does not need the extra overhead associated).

If DotNetNuke.Framework.AJAX.IsInstalled Then
DotNetNuke.Framework.AJAX.RegisterScriptManager()
End If

Supports Partial Rendering

The easiest way to deploy ASP.NET AJAX with DotNetNuke is to enable the Supports Partial Rendering flag in the definition for the module control (Host Menu > Module Definitions > Edit Module Definition > Edit Module Control).

Using this setting you only have to check DotNetNuke.Framework.AJAX.IsInstalled() if you have specific ASP.NET AJAX functionality that you will need to disable if ASP.NET AJAX is not available (see Creating Secure DotNetNuke ASP.NET AJAX Web Services for an example of when this is needed).

By default the Supports Partial Rendering flag is False for all controls. Only if the developer of the module explicitly sets the Supports Partial Rendering flag to True in their *.dnn installation manifest, or the Portal administrator checks the Supports Partial Rendering box, will it be wrapped by an Update Panel (and only if AJAX is installed ).

This functionality provides the simplest, most effective way for a module developer to create an application which works in the lowest common denominator environment - but is also able to take advantage of partial rendering when it is available.

The availability of this feature means that a module developer should seldom ever need to check DotNetNuke.Framework.AJAX.IsInstalled() or include an Update Panel in their module controls. Instead, the module developer only needs to set the Supports Partial Rendering flag in situations where it makes sense

However, if a control already contains JavaScript for dynamic behaviors, wrapping the control in an Update Panel has the potential to break the control's functionality.

Sample ASP.NET AJAX Application

The sample demonstrates ASP.NET AJAX support. All that was done was to enable the Supports Partial Rendering flag in the user control for the module.

The AJAX sample code can be downloaded at this link. (it will only work with DotNetNuke 4.5.0 or higher)

Imports DotNetNuke

Imports System.Collections.Generic

Namespace DotNetNuke.Modules

    Partial Class Ajax

        Inherits Entities.Modules.PortalModuleBase

        Dim CurrentPageIndex As Integer

        Protected Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

            If Not Page.IsPostBack Then

                ShowData(1)

            End If

        End Sub

        Private Sub ShowData(ByVal intCurrentPageIndex As Integer)

            Dim mySqlString As New StringBuilder()

            mySqlString.Append("SELECT FriendlyName, Description ")

            mySqlString.Append("FROM {databaseOwner}{objectQualifier}DesktopModules ")

            mySqlString.Append("ORDER BY FriendlyName")

            Dim colDesktopModules As New List(Of myDesktopModules)

            Using dr As IDataReader = _

                  CType(DataProvider.Instance().ExecuteSQL(mySqlString.ToString(), Nothing), IDataReader)

                While dr.Read

                    Dim objDesktopModules As New myDesktopModules()

                    objDesktopModules.FriendlyName = Convert.ToString(dr("FriendlyName"))

                    objDesktopModules.Description = Convert.ToString(dr("Description"))

                    colDesktopModules.Add(objDesktopModules)

                End While

            End Using

            Dim pagedData As New PagedDataSource()

            pagedData.DataSource = colDesktopModules

            pagedData.AllowPaging = True

            pagedData.PageSize = 10

            pagedData.CurrentPageIndex = intCurrentPageIndex - 1

            Me.lblTotalPages.Text = Convert.ToString(pagedData.PageCount)

            Me.lblCurrentPage.Text = Convert.ToString(pagedData.CurrentPageIndex + 1)

            If pagedData.IsFirstPage Then

                btnPrevious.Visible = False

            Else

                btnPrevious.Visible = True

            End If

            If pagedData.IsLastPage Then

                btnNext.Visible = False

            Else

                btnNext.Visible = True

            End If

            Me.GridView1.DataSource = pagedData

            Me.GridView1.DataBind()

        End Sub

        Protected Sub Next_Click(ByVal sender As Object, ByVal e As System.EventArgs)

            CurrentPageIndex = Convert.ToInt32(Me.lblCurrentPage.Text) + 1

            ShowData(CurrentPageIndex)

        End Sub

        Protected Sub btnPrevious_Click(ByVal sender As Object, ByVal e As System.EventArgs)

            CurrentPageIndex = Convert.ToInt32(Me.lblCurrentPage.Text) - 1

            ShowData(CurrentPageIndex)

        End Sub

    End Class

    Public Class myDesktopModules

        Dim _FriendlyName As String

        Dim _Description As String

        Public Property FriendlyName() As String

Get

                Return _FriendlyName

            End Get

            Set(ByVal value As String)

                _FriendlyName = value

            End Set

        End Property

        Public Property Description() As String

Get

                Return _Description

            End Get

            Set(ByVal value As String)

                _Description = value

            End Set

        End Property

    End Class

End Namespace