Zhixian's Tech Blog


Can not load type MembershipPasswordAttribute using ASP.NET (Mono)

Filed under: web application development — Tags: , , , — Zhixian @ 08:33:01 am

Note: This blog post does not provide a solution.


Recently, I was trying to build a ASP.NET MVC project using Mono on my Ubuntu machine.
It did not end well.

While building the login page, I got this error message.

Could not load type ‘System.Web.Security.MembershipPasswordAttribute’ from assembly ‘System.Web, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’.

Error 500 - Google Chrome_201

The offending code is:

test.mvc.web - Views-Home-Index.cshtml - MonoDevelop_202

As it turns PasswordFor is not the only helper extension that will trigger this error.
TextBoxFor have the same issue as well.

Why this happens

As it turns out, the Mono 4.5 that I am using at this time of writing does not have this implemented yet.

You can view here (http://go-mono.com/status/status.aspx?reference=4.5&profile=4.5&assembly=System.Web).

Mono System.Web in 4.5 vs MS.NET 4.5 - Google Chrome_203


No good solution to this issue currently.

One possible workaround is not to use the HTML Helper extensions.



How to install Mono on Ubuntu (Part 2 of 2)

Filed under: development — Tags: , , , , , — Zhixian @ 00:06:12 am

This is continuation of my previous blog post How to install Mono on Ubuntu.
This part focus on testing the installation to make sure that you have the minimal to compile C# source code and to run ASP.NET web applications.


  1. You have installed Apache HTTP Server
  2. You have followed the installation instructions in the previous blog post.
  3. You know how to create folder and files in Ubuntu.
  4. You know how to start a terminal session and run commands in it.
  5. You know how to navigate to other directories using terminal session.

Summary Steps

  1. Compiling and Running helloworld
  2. Create a Apache virtual host

Compiling and Running helloworld

Create a folder to hold your source code. For example, I use “dotnet”.


Inside this folder, create a file call helloworld.cs.


Edit the contents of this file and replace it with the following:

// Hello1.cs
public class Hello1
   public static void Main()
      System.Console.WriteLine("Hello, World!");

After saving the file, start a new terminal session and navigate to the directory where you saved the file.

zhixian@SARA: ~-Projects-dotnet_136

The command to run the compiler for C# in Mono is mcs. Compile helloworld.cs by entering the following at the command-line:

mcs helloworld.cs

After running this command, you should see that you have a file call helloworld.exe in your project directory.

zhixian@SARA: ~-Projects-dotnet_137

To test run your application, enter the following command at the command-line.


zhixian@SARA: ~-Projects-dotnet_138

You should see the words “Hello, World!” after you run the command.

Create a Apache virtual host

Now that we are sure the compiler for C# works, we will test if mod_mono can run ASP.NET applications.
What we are going to do at this section is to create a virtual host on Apache to host our ASP.NET application.


  1. Define ASP.NET application
  2. Configure Apache virtual host

Define ASP.NET application

We are going to create our test application in this section.

Create a folder to hold the contents of your ASP.NET web application.
In my case, I choose to put my file in a directory call zxtech.


Inside this folder, create a file call test.aspx.


Edit test.aspx and replace the contents with the following:

<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
    <title>ASP Test Page</title>
        <form id="form1" runat="server">
          <asp:label id="lbl1" runat="server">ASP Test Page</asp:label>

test.aspx (~-Yandex.Disk-Websites-zxtech) - gedit_142

Save the file.
After saving the file, note the full path to the folder (press <CTRL>-L or press the button next to the Location buttons.)

You will need this information when configuring Apache virtual host.


Configure Apache virtual host

Ok. Here’s where things starts to get a little sticky.
At your terminal session, navigate to Apache HTTP server’s sites directory (its /etc/apache2/sites-available/ by default) by entering the following command at the command-line:

cd /etc/apache2/sites-available/

zhixian@SARA: -etc-apache2-sites-available_143

By default, there should be 2 files in the folder, 000-default.conf and default-ssl.conf.
Make a copy of 000-default.conf for your virtual host (I am picking dev.zxtech.web as my virtual host name) by running the following command:

sudo cp ./000-default.conf ./dev.zxtech.web.conf

zhixian@SARA: -etc-apache2-sites-available_144

After the file is copied, edit the file.
Because the file is in folder owned by the superuser, you need to run the following command to edit the file:

gksudo gedit ./dev.zxtech.web.conf &

zhixian@SARA: -etc-apache2-sites-available_145

After you opened the file, you should see the following:

dev.zxtech.web.conf (-etc-apache2-sites-available) - gedit (as superuser)_146

Things to edit on this file:

  1. ServerName
  2. ServerAdmin (optional)
  3. DocumentRoot (optional)

ServerName refers to the your virtual host name that you will be using. In the below screen shot, this will be dev.zxtech.web.

ServerAdmin refers to an e-mail address that will be used when people needs to contact the server administator.

DocumentRoot refers to the folder where you store your ASP.NET application files. This will be the location of the folder that that you have noted in the previous section. In the below screen shot, this will be /home/zhixian/Yandex.Disk/Websites/zxtech.

After update, the file should look something like the below.

-dev.zxtech.web.conf (-etc-apache2-sites-available) - gedit (as superuser)_147

Things to add on this file:

  1. DirectoryIndex
  2. MonoAutoApplication
  3. AddHandler
  4. MonoServerPath
  5. MonoDebug
  6. MonoSetEnv
  7. MonoApplications
  8. Apache directory configuration
  9. Apache location configuration

DirectoryIndex refers to the default documents that will be use if user navigate to the folder without specifying a specific filename.

MonoAutoApplication refers to using a scheme in mod_mono that allows accounts on a machine to deploy ASP.NET pages without requiring to do any configuration. I prefer to do manual configuration, and so am disabling it here.

AddHandler designates files with specified file extensions to be process by mod_mono.

MonoServerPath allows you to specify the version of Mono runtime to use.
In the below screen shot, we are using the latest mono-server 4 which is equivalent to using ASP.NET 4.0.

MonoSetEnv is use to set an environment variable for use with the Mono run time used to execute the web application.
In the screen shot below, I defined MONO_IOMAP.
MONO_IOMAP is defined to take care of case-sensitivity issues. You can read more about it here.

MonoApplications is use to tell mod_mono that the ASP.NET application exists at the root directory of the web site (/) and this root directory maps (:) to the folder /home/zhixian/Yandex.Disk/Websites/zxtech (hence “/:/home/zhixian/Yandex.Disk/Websites/zxtech”)

Aside from the above Mono configuration, you may need to add an Apache directory configuration section especially if you are are hosting the web application files outside of Apache’s default DocumentRoot location which is /var/www/

 <Directory /home/zhixian/Yandex.Disk/Websites/zxtech>
 Options Indexes FollowSymLinks
 AllowOverride None
 Require all granted

You will also need to add an Apache location configuration section.

 <Location "/">
 Order allow,deny
 Allow from all
 MonoSetServerAlias dev.zxtech.web
 SetHandler mono
 SetOutputFilter DEFLATE
 SetEnvIfNoCase Request_URI "\.(?:gif|jpe?g|png)$" no-gzip dont-vary
 <IfModule mod_deflate.c>
 AddOutputFilterByType DEFLATE text/html text/plain text/xml text/javascript

After you added the sections, your configuration file should look like the below.

dev.zxtech.web.conf (-etc-apache2-sites-available) - gedit (as superuser)_153

After defining the configuration file, you can enable the website.

sudo a2ensite dev.zxtech.web.conf

zhixian@SARA: -etc-apache2-sites-available_151

The last step to get our virtual name hosting working is to edit our hosts located at /etc/hosts

zhixian@SARA: ~_150

In your text editor, add a line dev.zxtech.web

hosts (-etc) - gedit (as superuser)_154

After this is done, you can navigate to http://dev.zxtech.web/test.aspx to test your sample web application.
You should see:

ASP Test Page - Firefox Developer Edition_155


A nice tutorial to C# can be found here (http://msdn.microsoft.com/en-us/library/aa288463%28v=vs.71%29.aspx)



Filed under: web application development — Tags: , , , , , , — Zhixian @ 22:47:08 pm

When working in ASP.NET, your web site that had been working fine might suddenly give you the below screen:


You are most likely to be receiving this error message because the application pool had stopped.


Your web site should start up again after you start the application pool.


Web site after application pool was started.



ASP.NET application restarts on every request (Part 2)

Filed under: web application development — Tags: , , , — Zhixian @ 11:43:12 am

This blog post is an continuation to my previous blog post on the same topic.

In my previous post, I mentioned that I did not reach a definitive conclusion as to what could have cause the application restarts on every request.
As it turns out while working on a module in my project, I chance across another scenario which may cause the same effect.

Just to provide some background, my project was running on ASP.NET framework 4.0  (running on IIS 7.5 in integrated managed pipeline mode).
Development machine was a Windows 7 (x64).

The scenario that I’m talking about is that I had mixed a x86 DLL into the bin folder of the project.

And wham! The issue of application restarts came back again.

I did not find out whether its that particular x86 DLL in question or will the same thing occur for all x86 DLLs (I’m leaning towards all).
My hypothesis that is that I’m running the application off .NET framework 4 on a x64 machine and mixing x86 DLLs with such a configuration will trigger the application restarts on every request.


  1. Replace the x86 DLL with a x64 version of the DLL
    This is the best solution.
  2. In the Advanced Settings of the AppPool use by the project in IIS, set the Enable 32-bit Applications flag to True.
    This works but will cause your application to have some performance issues (ie. slow down the application; running in 32bit vs 64bit).


ASP.NET application restarts on every request

Filed under: web application development — Tags: , , , — Zhixian @ 09:00:12 am

Lately I have been struggling with a very strange issue in one of my ASP.NET projects.

For some strange reason, the application would perform a recompilation on every request.
Having the recompilation means that the application needs to be restarted.
What this effectively means, is that the application will not be snappy as it should be as it will be going through the application life-cycle.

Interestingly, the shutdown reason provided by System.Web.Hosting.HostingEnvironment.ShutdownReason is BuildManagerChange.
Unfortunately, what MSDN has to say about this is:

The compilation system shut the application domain.
The BuildManagerChange member is introduced in the .NET Framework version 3.5.

What’s worse for me is that this topic of BuildManagerChange appears to be relatively uncharted territory.
Either no one has come across this issue or I’m one of the first developers to come across this issue or I’m using the wrong keywords to find resources regarding this topic.

To cut the long story short, I finally come to the conclusion that this is an infrastructure issue, specifically with IISEXPRESS 8.0 which is a bit of a disappointment because I really like developing using IISEXPRESS.
This conclusion was reached by virtue that the problem disappears when I:

  1. Use IIS (7.5, the default for my WIndows 7 machine)
  2. Use the web development server instead of IISEXPRESS
  3. Use IISEXPRESS 7.5 (inconclusive!)

I could not reach to a happy conclusion with point 3. The reason being that when you install IISEXPRESS 8.0, it will effective replace IISEXPRESS 7.5
So when I say “use IISEXPRESS 7.5”, it implies that I’m using a different machine. Since it’s a different machine, there would be tons of probable variables that may result the application in working. Hence, inconclusive.

But point 1 and 2 are good enough reasons for me to lay the blame at IISEXPRESS 8.0
So if you are encountering application restarts for no apparent reason on IISEXPRESS, try it with IIS 7.5

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