As promised, I have published the slides from my TFS Overview presentation to the Louisville .NET Meetup group. 

I want to thank Ed Blankenship for providing me with a bunch of the slides I used.

Simple Answer

There are times you need to take an ASP.NET web application offline.  In general, the way to do so is place an App_Offline.htm file into the root of the web application.  The ASP.NET application looks for that with every request, if it see it then it will display that page vice the requested page.

My Problem

The one problem I have with this is that due to security at work, I need a system administrator to touch the web servers outside of the development network (even as the project lead, I’m not allowed to touch the production server).  Last week we had issues with the system due to some maintenance done on the database.  I wasn’t able to get a hold of the DBA to fix that problem and the on-call web administrator was not acting promptly enough to upload an App_Offline page I provided them.

So, for about five hours people were getting errors as soon as they logged into the system.  And wouldn’t you know this was a weekend that a lot of people decided to try to get things done.  Normally, almost nobody goes into the system during the weekend.

My Solution

With the events of last weekend, I decided that I needed to find a way to take the application offline for such problems without having to get the system administrator involved.  I did a lot of searching around the web and almost everything simply talked about the App_Offline solution.  The idea I came up with was to use a flag in the HTTP Application State to indicate whether the application was offline or not.  Then I would have the Application_BeginRequest event look at that, if the application was offline then direct to a page that told the user that the application was offline.  I describe this solution in detail below.

I would assume that you would add this solution to an existing web application, but for the purpose of this blog entry, I have created a new ASP.NET Web Application that I have called “ApplicationOfflineExample.”

ApplicationStateHelper Class

The first thing you will want to do with your application is add the ApplicationStateHelper class described below.  The purpose of this class is to provide helper methods for accessing the variables stored in the HTTP Application State.  The code for this class is as such:

Public NotInheritable Class ApplicationStateHelper  ''' <summary>  ''' Gets or sets a value indicating whether the application is offline.  ''' </summary>  ''' <value><c>True</c> if the application is offline; otherwise, <c>False</c>.</value>  ''' <revisions>  '''   <revision date="4/4/2009" author="CEG" version="1.00.00.000">Initial Development</revision>  ''' </revisions>  Public Shared Property ApplicationOffline() As Boolean    Get      If IsNothing(HttpContext.Current.Application.Item("ApplicationOffline")) = True _OrElse TypeOf HttpContext.Current.Application.Item("ApplicationOffline") Is Boolean = False Then        HttpContext.Current.Application.Add("ApplicationOffline", False)      End If      Return DirectCast(HttpContext.Current.Application.Item("ApplicationOffline"), Boolean)    End Get    Set(ByVal value As Boolean)      If IsNothing(HttpContext.Current.Application.Item("ApplicationOffline")) Then        HttpContext.Current.Application.Add("ApplicationOffline", value)      Else        HttpContext.Current.Application.Item("ApplicationOffline") = value      End If    End Set  End Property  ''' <summary>  ''' Gets or sets the application offline message.  ''' </summary>  ''' <value>The application offline message.</value>  ''' <revisions>  '''   <revision date="4/4/2009" author="Chad Green" version="1.00.00.000">Initial Development</revision>  ''' </revisions>  Public Shared Property ApplicationOfflineMessage() As String    Get      If IsNothing(HttpContext.Current.Application.Item("ApplicationOfflineMessage")) = True _OrElse TypeOf HttpContext.Current.Application.Item("ApplicationOfflineMessage") Is String = False Then        HttpContext.Current.Application.Add("ApplicationOfflineMessage", _"Application offline.  Try again later.")      End If      Return DirectCast(HttpContext.Current.Application.Item("ApplicationOfflineMessage"), String)    End Get    Set(ByVal value As String)      If IsNothing(HttpContext.Current.Application.Item("ApplicationOfflineMessage")) Then        HttpContext.Current.Application.Add("ApplicationOfflineMessage", value)      Else        HttpContext.Current.Application.Item("ApplicationOfflineMessage") = value      End If    End Set  End PropertyEnd Class

As you can see, we have two shared (static) property values.  The first one, ApplicationOffline, is a flag that indicates whether the application is offline or not.  The second, ApplicationOfflineMessage, stores the message that will be displayed to users when the application is offline.  The properties values are shared in order to provide quicker and easier access to the values throughout the web application.

Site Administration Web Page

In order to be able to set the offline status of the web application, I have added a web page, SiteAdministration.aspx, that provides the necessary capability.  The page contains several elements, including an indication as to the application’s offline status, a text box to specify the message displayed when the application is offline, and a button to switch the application offline status.  I have also added a Return Home link to make using this demo easier.

<html xmlns="http://www.w3.org/1999/xhtml" >  <head id="Head1" runat="server">    <title>Site Administration</title>  </head>  <body>    <form id="frmSiteAdministration" runat="server">      <p>The purpose of this page is to provide administration of the site.</p>      <hr />      <h1>Site Status</h1>      <p>The site is currently <asp:Label ID="lblSiteStatus"runat="server"Text="Online"Font-Bold="true"ForeColor="Black" />.</p>            <p>Offline Message: <asp:TextBox ID="txtOfflineMessage"runat="server"TextMode="MultiLine"Rows="5"Width="300" /></p>      <p><asp:Button ID="btnChangeSiteStatus" runat="server" Text="Take Site Offline" /></p>      <hr />      <p><a href="Default.aspx">Return Home</a></p>    </form>  </body></html>

In the code behind we have the following procedures.

Private Sub PrepareSiteStatusSection()    If ApplicationStateHelper.ApplicationOffline Then        lblSiteStatus.Text = "Offline"        lblSiteStatus.ForeColor = Drawing.Color.Red        btnChangeSiteStatus.Text = "Bring Site Back Online"    Else        lblSiteStatus.Text = "Online"        lblSiteStatus.ForeColor = Drawing.Color.Black        btnChangeSiteStatus.Text = "Take Site Offline"    End If    txtOfflineMessage.Text = ApplicationStateHelper.ApplicationOfflineMessageEnd Sub

The PrepareSiteStatusSection takes the application offline status information and populates the appropriate details on the page.  This method is used later when updating the page.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load    If Not Page.IsPostBack Then        PrepareSiteStatusSection()    End IfEnd Sub

Then we have the Page_Load method.  The only thing we are doing here is calling the PrepareSiteStatusSection method to populate Site Status section of the page.

Private Sub btnChangeSiteStatus_Click(ByVal sender As Object, _ByVal e As System.EventArgs) Handles btnChangeSiteStatus.Click  ApplicationStateHelper.ApplicationOffline = Not ApplicationStateHelper.ApplicationOffline  ApplicationStateHelper.ApplicationOfflineMessage = txtOfflineMessage.Text  PrepareSiteStatusSection()End Sub

Finally we have the button click event handler code that will either take the application offline or back online.

Application Offline Web Page

Next, we add a web page that will be used to inform users that the application is offline.

<html xmlns="http://www.w3.org/1999/xhtml" >  <head id="Head1" runat="server">    <title>Application Offline</title>  </head>  <body>    <form id="frmApplicationOffline" runat="server">      <asp:Label ID="lblOfflineMessage" runat="server" />    </form>  </body></html>

As you can see, this page is very simple and just includes a label that we’ll populate in the page’s load event seen below.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load  If Not Page.IsPostBack Then    lblOfflineMessage.Text = ApplicationStateHelper.ApplicationOfflineMessage  End IfEnd Sub

Global Application Class

Finally, we need to modify the Application_BeginRequest method in the Global Application Class (Global.asax).  If your application does not have such, make sure to add it now.  Then you want to add the If clause shown below to the Application_BeginRequest method.

Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)  If Request.Path <> "/SiteAdministration.aspx" AndAlso _Request.Path <> "/ApplicationOffline.aspx" Then    If ApplicationStateHelper.ApplicationOffline Then      Response.Redirect("ApplicationOffline.aspx")    End If  End IfEnd Sub

First thing we do is ensure that the application is not serving up the SiteAdminsitration or ApplicationOffline pages.  Obviously we want those to continue to work.  Next we are looking at the ApplicationOffline variable from the ApplicationStateHelper.  If it is set to the True, then we redirect to the ApplicationOffline page.

Results

Now, if you run the application everything will work.  Once you go to the Site Administration page and click the Take Site Offline button, users will no longer be able to access the application web pages other than the Site Administration page (which you would use some type of authorization method to only allow authorized users to the page).

The only caveat I have found so far is that if your application gets restarted for any reason, the offline flag will return to false allowing users to access the whole application.

Using the built-in blog entry tools in BlogEngine.net works just fine, but I have come to like Windows Live Writer better.  It just seems to make things just a little bit easier.  Here are some very simple instructions on how to get Windows Live Writer working for BlogEngine.net.

After you have downloaded Windows Live Writer, you will find it the Windows Live menu.  The first time you open it you will be presented with the dialog below prompting you to configure it.  Click the Next button.

Next you’ll be asked to specify which blog service you use.  As you can see, Live Writer is automatically configured for Windows Live Spaces and SharePoint blogs.  For BlogEngine.NET, you will want to select the “Other blog service” and click the Next button.

Now, you will need to provide your account information for your blog.

After clicking the Next button, Windows Live Writer will go out and ensure it can connect to your blog and make all the settings needed to post to the blog.

It takes about a minute for Windows Live Writer to configure itself.  Once it has you will be asked to provide a nickname for the blog.  This is used within Windows Live Writer to distinguish between the different blogs you have setup.

One other option you are given on the is screen is to send notifications of blog updates to your Windows Live profile.  This is another way of advertising your blog.

Clicking the Finish button will take you to the application and you can now create blog entries.

One of the great features of using Windows Live Writer is that it picks up your theme and shows you exactly how the post will look like.

The only issue I have found so far is that the “Set publish date” feature doesn’t seem to work.  If you need to specifically set the publish date, do so in the BlogEngine.net interface after having BlogEngine.net publish the entry.

UPDATE:  Received a twit from Brandon Turner (one of the Windows Live Writer developers) that the publish date problem should be fixed in BlogEngine.NET 1.5.

I’m a big fan of extension methods and I have been using them for since .NET 3.5 was released.  One of the things I have been thinking about doing for quite some time is to publish my library of extension methods I have built.  Today I’m proud to announce the initial release of my Extension Library project on CodePlex.

This library includes useful extensions to the following types:

• DataRow

• DataSet

• DateTime

• IDataReader

• Integer

• ListControl

• Object

• String

• WebControl

One of things I wanted, which is part of the reasons why it took me so long to get this project published, is full documentation.  You can download that here:  ExtensionLibrary.dll (31.00 kb)

One of the hardest parts of using the Visual Studio Code Analysis tool (or FXCop) is trying to figure out which rules to worry about.  Last year David Kean published the What rules do Microsoft have turned on internally? article.  This article provide some really good insight and let us know that Microsoft is realistic when it writes its own code.

According to the article, there are several reasons why rules would be turned off:

Since Visual Studio 2005 came out, I have been working on determining which rules to turn off.  Initially, I would keep everything on and then turn off a rule when I was getting violations that I simply didn’t want to worry about (for one reason or another).

Because of the way how things went this summer at work, I ended up having time to really go through and evaluate all of the rules.  The list below is the list of rules I have determined should be used when performing code analysis.  One other thing I did was also determine whether I wanted to consider a rule as an error or a warning.  The idea was to ensure that there are some rules that have a higher level or importance and the project shouldn’t even compile until those rules pass.

XML Documentation Comments are a great feature within .NET (although credit does go to Sun with their JavaDoc which XML comments are based off).  One thing that is missing is the ability to document the revisions to a code construct (types and type members).  As a class library matures and gets changed to meet changed/new requirements, it helps to know when and what was changed.

For the longest time I have been my own <revisions> tag with <revision> tags within.  The revision tag contains the following parameters:

date
The date the revision to the code construct was made.

author
Name of the author that made the revision.

version
The version of the assembly where the revision was made.

cc
Identifier of the change control item.

Example
”’ <summary>
”’ Returns the <see cref="Boolean">Boolean</see> value of the specified column.
”’ </summary>
”’ <param name="input">The <see cref="DataRow">DataRow</see> containing the desired data.</param>
”’ <param name="columnName">Name of the column to retrieve the desired data from.</param>
”’ <returns>The <see cref="Boolean">Boolean</see> value stored in the specified column.</returns>
”’ <remarks>If the specified column contains a null, the return value will be <c>False</c>.</remarks>
”’ <revisions>
”’   <revision date="11/2/2008" author="Chad Green" version="1.00.00.000">Initial Development</revision>
”’ </revisions>
<Extension()> Public Function GetBooleanValue(ByVal input As DataRow, _
                                                                   ByVal columnName As String) As Boolean
  Return GetBooleanValue(input, columnName, False)
End Function

Documentation Generation
Once you start using this tag, you’ll need to update the main_sandcastle.xsl file to include the revision information in your documentation.  The location of this file will depend on the presentation style you’re using.  For example, if you the vs2005 style the file will be located at C:\Program Files (x86)\Sandcastle\Presentation\vs2005\transforms\.  First, you’ll need to add the following to the "body" xsl template:

Then, you’ll need to add the following xsl template:

<xsl:template match="revisions">
  <xsl:call-template name="section">
    <xsl:with-param name="toggleSwitch" select="‘revisons’"/>
    <xsl:with-param name="title">Revisions</xsl:with-param>
    <xsl:with-param name="content">
      <div class="tableSection">
        <table width="100%" cellspacing="2" cellpadding="5" frame="lhs">
          <tr>
            <th>Date</th>
            <th>Author</th>
             <th>Version</th>
             <th>Description</th>
           </tr>
           <xsl:for-each select="revision">
             <tr>
               <td>
                 <xsl:value-of select="@date" />
               </td>
               <td>
                 <xsl:value-of select="@author" />
               </td>
               <td>
                 <xsl:value-of select="@version" />
               </td>
               <td>
                 <xsl:apply-templates />
               </td>
             </tr>
           </xsl:for-each>
         </table>
       </div>
     </xsl:with-param>
   </xsl:call-template>
</xsl:template>

Now when you generate your documentation, you will have something like this added to your documentation:

As I mentioned the other day, Visual Studio 2008 was released with some pretty serious performance issues.  Well, within the last couple of hours Microsoft released the promised hotfix to correct the problems.  According to the Microsoft Connect site, this hotfix addresses the following issues:

HTML Source view performance

· Source editor freezes for a few seconds when typing in a page with a custom control that has more than two levels of sub-properties.
· “View Code” right-click context menu command takes a long time to appear with web application projects.
· Visual Studio has very slow behavior when opening large HTML documents.
· Visual Studio has responsiveness issues when working with big HTML files with certain markup.
· The Tab/Shift-Tab (Indent/Un-indent) operation is slow with large HTML selections.

Design view performance

· Slow typing in design view with certain page markup configurations.

HTML editing

· Quotes are not inserted after Class or CssClass attribute even when the option is enabled.
· Visual Studio crashes when ServiceReference element points back to the current web page.

JavaScript editing

· When opening a JavaScript file, colorization of the client script is sometimes delayed several seconds.
· JavaScript Intellisense does not work if an empty string property is encountered before the current line of editing.

Web Site build performance

· Build is very slow when Bin folder contains large number of assemblies and .refresh files with web-site projects.

I have download and installed the hotfix and did a couple of things.  Things seem to look good, but I will not be able to really test out fixes until I get on my work machine.  But, I wanted to go ahead and let everyone know about the hotfix's availability.

You can get the hotfix here:  https://connect.microsoft.com/VisualStudio/Downloads/DownloadDetails.aspx?DownloadID=10826

One of the more annoying things I have found with Visual Studio 2008 is that the IsNothing command is not included in the VB.NET AutoComplete listbox.  Once you get use to the AutoComplete (doesn't really take long) you really hate it when something straight from the language is missing.

If you agree with me, go to Microsoft connect site and rate the feedback so they'll be more willing to work on the issue.  I submitted feedback to Microsoft via the Connect, so if you agree this should be fixed, please go to https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=327338 and rate it so Microsoft will be more willing to work on the issue.

As you can see, I’m using BlogEngine.NET to run this site. It’s a pretty cool application even if you don’t make any changes to it. As I found a couple of months ago, getting it installed on a web site hosted with GoDaddy was not as simple as it should be.

Well, now GoDaddy includes BlogEngine.NET with its offerings in the GoDaddy Hosting Connection. Simply click on a button to install the application and answer a couple of questions and GoDaddy fires off a process to install BlogEngine.NET on within hosting account.

But it appears that the install process forgot a very important step (at least when I did this). The App_Data folder is not given write permission which prevents you from making some setting changes. To correct this problem, do the following:

1. Log into your GoDaddy account
2. Under “My Products”, click “Hosting Account List”
3. You’ll be redirected to the Manage Hosting page, click the Open Control Panel option for the appropriate domain.
4. A new browser window will be opened to the GoDaddy Hosting Control Cneter.
5. From the Content menu, select File Manger.
6. Check the checkbox for the App_Data folder (which will enable the Permissions button).
7. Click on the Permissions button
8. Ensure that the Write option is checked

After that, everything should work just fine.

As you can see, I’m using BlogEngine.NET to run this site. It’s a pretty cool application even if you don’t make any changes to it. As I found a couple of months ago, getting it installed on a web site hosted with GoDaddy was not as simple as it should be.

Well, now GoDaddy includes BlogEngine.NET with its offerings in the GoDaddy Hosting Connection. Simply click on a button to install the application and answer a couple of questions and GoDaddy fires off a process to install BlogEngine.NET on within hosting account.

But it appears that the install process forgot a very important step (at least when I did this). The App_Data folder is not given write permission which prevents you from making some setting changes. To correct this problem, do the following:

1. Log into your GoDaddy account
2. Under “My Products”, click “Hosting Account List”
3. You’ll be redirected to the Manage Hosting page, click the Open Control Panel option for the appropriate domain.
4. A new browser window will be opened to the GoDaddy Hosting Control Cneter.
5. From the Content menu, select File Manger.
6. Check the checkbox for the App_Data folder (which will enable the Permissions button).
7. Click on the Permissions button
8. Ensure that the Write option is checked

After that, everything should work just fine.