.Net

Exception across App Domains

Pedro Rainho — Tue, 24 Mar 2009 07:35:36 GMT

Recently I had a very strange exception and took me some time to figure out what was the problem. So lets imagine that I want to execute a piece of code in a different app domain, lets call it “NewDomain”, and that NewDomain throws a custom exception “MyException”.

The code of MyException is this:

[Serializable]
public class MyException : ApplicationException
{
    public MyException()
        : base()
    {
    }

    public MyException(string message)
        : base(message)
    {
        myCustomMessage = "Dear user you got an exception: " + message;
    }

    public MyException(string message, Exception innerException)
        :
        base(message, innerException)
    {
        myCustomMessage = "Dear user you got an exception: " + message;
    }

    public override string Message
    {
        get
        {
            return myCustomMessage;
        }
    }

    private string myCustomMessage;
}

If this exception is thrown across app domains you will get this nice exception:

The constructor to deserialize an object of type 'MyException’ was not found.

Server stack trace:

at System.Runtime.Serialization.ObjectManager.CompleteISerializableObject(Object obj, SerializationInfo info, StreamingContext context)

at System.Runtime.Serialization.ObjectManager.FixupSpecialObject(ObjectHolder holder)

at System.Runtime.Serialization.ObjectManager.DoFixups()

at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)

at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)

at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.DeserializeObject(MemoryStream stm)

at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.DeserializeMessageParts(MemoryStream stm)

at System.Runtime.Remoting.Messaging.SmuggledMethodReturnMessage.FixupForNewAppDomain()

at System.Runtime.Remoting.Channels.CrossAppDomainSink.SyncProcessMessage(IMessage reqMsg)

…

I didn’t know what the problem was at the beginning, because my class was marked with the attribute Serializable so what was the real problem???

The problem happens because I was transmitting the exception object across a stream. And across streams mark the class as Serializable is not enough.

So the solution is actually simple.

I need to add a protected constructor with the following signature

protected MyException(SerializationInfo info, StreamingContext context)

My MyException class needs to implement ISerializable, the class System.Exception already implements it
I need to implement the method

GetObjectData(SerializationInfo info, StreamingContext context)

Attribute the method with the following attribute

[SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]

I need all of this because the constructor is called during deserialization to reconstitute the exception object transmitted over a stream, and I need the method GetObjectData because I need to serialize my fields.

So, MyException class will lock like this:

[Serializable]
public class MyException : ApplicationException
{
    public MyException()
        : base()
    {
    }

    public MyException(string message)
        : base(message)
    {
        myCustomMessage = "Dear user you got an exception: " + message;
    }

    public MyException(string message, Exception innerException)
        :
        base(message, innerException)
    {
        myCustomMessage = "Dear user you got an exception: " + message;
    }

    protected MyException(SerializationInfo info, StreamingContext context)
        : base(info, context)
    {
        myCustomMessage = info.GetString("myCustomMessage");
    }

    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter = true)]
    public override void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        info.AddValue("myCustomMessage", myCustomMessage);

        base.GetObjectData(info, context);
    }

    public override string Message
    {
        get
        {
            return myCustomMessage;
        }
    }

    private string myCustomMessage;
}

Like I wrote I just had to implement a constructor to deserialize my fields and a method to serialize them.

Load and unload assemblies

Pedro Rainho — Sun, 15 Mar 2009 17:59:14 GMT

Last week, I had a problem that probably some .Net developer had faced. The problem consists in load and unload an assembly?.

Can I do that??? Well, I can’t do it in a simple way. One of the things that Assembly doesn’t support in unload, check this post to see why.

So, like I wrote, last week I was developing a new feature for a software factory and that feature consisted in get all references and do something else.

My recipe does something like this:

Get project assembly
Copy the assembly DLL to a location
Get all assembly references
Generate a file

Do number 1 is simple.

Do number 2 is also simple, but has a problem.

Do number 3 is also simple, but has a problem.

Do number 4 is simple.

I’m going to explain first problem number 3 then problem 2

The problem with number 3 it’s because I load a assembly and they I get referenced assemblies. To get referenced assemblies I just do:

Assembly assembly = Assembly.LoadFrom(@"c:\myAssembly.dll");
AssemblyName[] references = assembly.GetReferencedAssemblies();

This piece of code has a problem, since I’m loading the assembly and they get referenced assemblies the file myAssembly.dll is now locked this means that the next time I try to run number 2 I will get an exception and the file will not ne copied. And this is why I had problem number 2.

Now, how can I load the assembly and then unload that assembly so the file won’t be locked???

I came across some solutions.

One of the possible solutions is just copy the assembly to something unique like {GUID}.DLL and then load that {GUID}.DLL, and do everything I need to do, this way I won’t lock my file.
1. Problem: I will have the assembly {GUID}.DLL loaded (in memory) every time, and can’t delete file {GUID}.DLL, because it’s locked. And finally I can’t unload unless I close Visual Studio.
Why don’t I just load the assembly into an array of bytes and then load the assembly, like this:
```
Assembly assembly = Assembly.Load(File.ReadAllBytes(@"c:\myAssembly.dll"));
```
1. Problem: I can do this and my file will not be locked but that array of bytes will be in memory and my visual studio memory will grow every time I run that recipe. That memory will be released only when I close the Visual Studio.
I can load the assembly in a new AppDomain and then unload the AppDomain.
1. Problem: tThis was a strange problem and I don’t know why but I load the assembly in a new AppDomain and that assembly become part of the new AppDomain and the AppDomain.Current. This was strange. Don’t know if I was doing something wrong. Now since the Assembly is loaded in AppDomain.Current I wasn’t able to copy the file, because it was locked.
The last solution I came across to load the assembly and unload it. This solution Consists in create a new AppDomain and then use method DoCallBack:

Here it is the source code:

AppDomainSetup setup = new AppDomainSetup();
setup.ApplicationBase = ApplicationBasePath;

AppDomain newDomainReferences = AppDomain.CreateDomain("AppDomain", null, setup);

CallBackAssemblyReferences call = new CallBackAssemblyReferences(newDomainReferences, filepath);
newDomainReferences.DoCallBack(new CrossAppDomainDelegate(call.LoadAssemblyReferences));
AssemblyName[] assName = (AssemblyName[])newDomainReferences.GetData("AssemblyReferences");

AppDomain.Unload(newDomainReferences);

This solution enables me to do a callback in a different domain. My class CallBackAssemblyReferences just does this:

[Serializable]
internal class CallBackAssemblyReferences
{
    #region Members Variables
    private string assemblyFile;
    private AppDomain domain;
    #endregion

    #region Public Implementation
    public CallBackAssemblyReferences()
    {

    }
    public CallBackAssemblyReferences(AppDomain domain, string assemblyFile)
    {
        this.assemblyFile = assemblyFile;
        this.domain = domain;
    }

    public void LoadAssemblyReferences()
    {
        Assembly assembly = this.domain.Load(AssemblyName.GetAssemblyName(this.assemblyFile));

        domain.SetData("AssemblyReferences", assembly.GetReferencedAssemblies());
    }
    #endregion
}

This class has a constructor that receives the new domain I’m working on and the path to the assembly I want to load.

public CallBackAssemblyReferences(AppDomain domain, string assemblyFile)

Then I just have my callback method WITH NO PARAMETERS.

public void LoadAssemblyReferences()

This is the method that will be called when I do

newDomainReferences.DoCallBack(new CrossAppDomainDelegate(call.LoadAssemblyReferences));

The callback method only loads the assembly in the new domain and then sets data in the new domain. These data are the assembly references.

When the DoCallBack returns I just had to do

AssemblyName[] assName = (AssemblyName[])newDomainReferences.GetData("AssemblyReferences");

To get the references I had saved.

Finally I just unload the AppDomain.

Now I can run my recipe every time I need without lock the file and without decrease visual studio performance.

Moq.me

Pedro Rainho — Sun, 08 Mar 2009 10:42:10 GMT

Currently when I need do unit tests the mock framework that I’m currently using Is the Rhino Mocks.

But today after read a post, I found a new mock framework, named Moq.me. This framework was made by kzu.

kzu is one of the guys behind Clarius.

I know Clarius because I develop software factories and they have this toolkit, that I had tried, named Clarius Software Factory Toolkit and it’s a “software factory to do other software factories”. They also have the Clarius Visual T4(aka T4 Editor).

Now I have download Moq.me and will test it very very soon :)

Error during install of SQL Server 2008

Pedro Rainho — Mon, 23 Feb 2009 19:54:59 GMT

If you ever have this error:

“The file C:\Windows\Microsoft.NET\Framework\version_number\mscorlib.tlb could not be loaded. An attempt to repair this condition failed because the file could not be found. Please reinstall this program.”

During the install of SQL Server 2005 or SQL Server 2008 here is the solution. Link

My list of podcasts

Pedro Rainho — Thu, 19 Feb 2009 17:00:53 GMT

Today I’ve decided to share here my list of podcasts.

Here is the list:

Alt.NET Podcast by Mike Moore
ASP.NET Podcast by Wallace B. McClure
Deep Fried Bytes by Keith Elder & Chris Woodruff
Digital Planet by BBC World Service
Hansel Minutes by Scott Hanselman
Herding Code
.Net Rocks! by Carl Franklin
Polymorphic Podcast by Craig Shoemaker
Sparkling Client by Monica Mork and Erik Mork
StevePavlina.com by Steve Pavlina
ThoughtWorks - IT Matters Podcast
TWiT.TV
The Web 2.0 Show by Josh Owens and Adam Stacoviak
TSF - Mundo Digital

Hope someone add some comments with some url to other podcasts.

Can any one use the site “http://www.precoscombustiveis.dgge.pt/” without having errors??? Part 3

Pedro Rainho — Wed, 18 Feb 2009 10:35:40 GMT

While I was using the site I found a NEW kind of error

I typed “Paço d’arcos” in the search box. For those who don’t know Paço d’arcos Is near Oeiras.

And this friendly site searches for Paço d’arcos and shows a maps positioned near “Santa Maria da Feira” that is in north of Portugal, it’s like I search for “New york” and map pointed my to north pole… I don’t know if I should be impressed or sad how my money is being spent.

I done my homework and search in google maps just to see if Paço d’arcos is in fact near Oeiras and it is :)

Does any one ever test this site before go online ????

Can any one use the site “http://www.precoscombustiveis.dgge.pt/” without having errors??? Part 2

Pedro Rainho — Wed, 18 Feb 2009 10:21:12 GMT

While TRYING to navigate the site I saw errors after errors. but this error is new:

Why are the site trying to create folders while I'm navigating???? that is a nice question

Can any one use the site “http://www.precoscombustiveis.dgge.pt/” without having errors???

Pedro Rainho — Wed, 18 Feb 2009 10:08:24 GMT

Here in Portugal the governors decided to spend public money doing a site that, most of the time, doesn’t work. At least that is my opinion.

I only had spent in the site no more that 3-4 minutes and found some curious errors. I decide to share one of the error that I found.

Here is the screen shoots and how to reproduce one of the bug.

I select “Castelo Branco” and the I choose “Seleccionar todos os municipios deste distrito”, and what happens…

I love this error I can imagine users that are not programmers trying to understand this error message :) the message is sooooo expressive :).

This is where our governors spend our money…

But let’s check the error message just for seeing if it says something usefull. hooo and by the way I’ve formatted the message in the messagebox it’s more easy to read :)


Server Error in '/' Application.        

The ConnectionString property has not been initialized. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.       



Exception Details: System.InvalidOperationException: The ConnectionString property has not been initialized.       



Source Error:       




    
        
                           
             Line 11:     CMD = New OdbcCommand  Line 12:     CMD.Connection = CN  Line 13: 		CN.Open()

Line 14:     

Line 15:     If Request("mh") = "" OrElse Request("mh") = "1" Then
            
        
    



Source File: D:\Inetpub\wwwroot\DGEGPOSTOS2008\include\mapaPTDB.aspx    Line: 13       



Stack Trace:       




    
        
                           
             [InvalidOperationException: The ConnectionString property has not been initialized.]     
System.Data.Odbc.OdbcConnection.Open() +741    
 ASP.mapaPTCB_aspx.LeZonas() in D:\Inetpub\wwwroot\DGEGPOSTOS2008\include\mapaPTDB.aspx:13     
ASP.mapaPTCB_aspx.__Render__control1(HtmlTextWriter __output, Control parameterContainer) in D:\Inetpub\wwwroot\DGEGPOSTOS2008\include\mapaPTCB.aspx:5     
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +27     
System.Web.UI.Control.Render(HtmlTextWriter writer) +7     
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +243     
System.Web.UI.Page.ProcessRequestMain() +1926
            
        
    

       


       

Version Information: Microsoft .NET Framework Version:1.1.4322.2032; ASP.NET Version:1.1.4322.2032 
 
 
Interesting message especially the part that says OdbcCommand. What are they using as data bases… are they using MS Access as there data base or a CSV text file ????… that is a really nice question.

The other thing that I see is that there site is located in D:\Inetpub\wwwroot\DGEGPOSTOS2008\include hummm and the have a file called mapaPTDB.aspx that has a error on line 13 probably a missing a text file :)

Continuing with the error I see a message “The ConnectionString property has not been initialized.” hummm a public site sponsored by public money and some one forget to initialize correctly the connection string…

Continuing analyzing the error I see .NET Framework Version 1.1.4322.2032; ASP.NET Version 1.1.4322.2022… hummm analyzing these versions they also probably forget to apply Framework 1.1 SP1

I’m impressed how the governor invest my and others money.

Software Factory – Guidance Migration from Visual Studio 2005 to Visual Studio 2008

Pedro Rainho — Fri, 06 Feb 2009 09:28:32 GMT

Before begin I have to give some credit to my friend Rodrigo Guerreiro because he helped me with this PROBLEM.

First I can say that I wasn’t able to find ANY information in internet about migration. Don’t know if I was looking in the wrong sites but i wasn’t able to find any information.

Now this post reflect what I did in order to create 2 MSI’s files that can be installed in Visual Studio 2005 and Visual Studio 2008. (One MSI to install in VS2005 and another to install in VS2008)

Notice that I didn’t had to migrate my solution to VS2008 in order to create a MSI that installs a factory in VS2008

These was my steps:

Go to the solution folder and, in my case, there was a folder with the project setup. What I did was copy that folder and rename it from XXXSetup to XXXSetup2008.
Inside the folder XXXSetup2008 I rename the file XXXSetup.vdproj to XXXSetup2008.vdproj
Then I edit file XXXSetup2008.vdproj (With notepad :)) and every place I had XXXSetup I rename it to XXXsetup2008 (Very Careful with this point because you can mess up with the project and start from the begining). In my case I just had to do this renames:
1. "ProjectName" = "8:XXXSetup" para "ProjectName" = "8:XXXSetup2008"
2. "OutputFilename" = "8:Release\\XXXSetup.msi" para "OutputFilename" = "8:Release\\XXXSetup2008.msi"
After this I open the solution in VS2005 and added the project XXXSetup2008.vdproj to my solution
With the project XXXSetup2008 selected.
1. In the solution explorer choose “Custom Actions Editor” icon
  1. A window will open with the following custom actions
    -- GuidancePackage[Install], [commit], [roolback], [uninstall]
  3. Click in every single one and on the properties window change it from /Hive=8.0 /Configuration="[TARGETDIR]xxx.xml" to /Hive=9.0 /Configuration="[TARGETDIR]xxx.xml"
Again with the project XXXSetup2008 selected
1. In the solution explorer choose “Launch Conditions Editor” icon
2. A window will open with the following Launch Conditions:
  1. Search Target Machine
  2. Launch Conditions
3. click in every single option (CSharp, RunTime, VS, .NetFramework, C# Language, Guidance Automation Extensions, VS.Net) and in the properties you will have to change every single place you have 8 (VS2005) change it to 9 (VS2008).
5. Here it is what you need to change:
  1. In CSharp change it from:
    SOFTWARE\Microsoft\VisualStudio\8.0\InstalledProducts\Microsoft Visual C#
    To:
    SOFTWARE\Microsoft\VisualStudio\9.0\InstalledProducts\Microsoft Visual C#
  2. In RunTime change it from:
    SOFTWARE\Microsoft\VisualStudio\8.0\InstalledProducts\RecipeManagerPackage
    To:
    SOFTWARE\Microsoft\VisualStudio\9.0\InstalledProducts\RecipeManagerPackage
  3. In VS.Net change it from:
    SOFTWARE\Microsoft\VisualStudio\8.0\Setup\VS
    To:
    SOFTWARE\Microsoft\VisualStudio\9.0\Setup\VS
  4. In VS.Net change it from::
    Visual Studio .NET 8.0 is not installed. Do you want to see information of the product? Click Yes to be directed to a web page, click No to exit.
    To:
    Visual Studio .NET 9.0 is not installed. Do you want to see information of the product? Click Yes to be directed to a web page, click No to exit.

Now Compile and create the MSI’s. The next step is test the Factory in a VS 2008 :) Hope I was able to help. Sure helped me.

How to get all projects that exists in a Visual Studio Solution

Pedro Rainho — Thu, 05 Feb 2009 12:36:40 GMT

Recently during a software factory development I had a problem, how can I get all projects that exists in a visual studio solution.

The only solution that I found was this:

public static Project[] GetAllSolutionProjects(Solution solution)
{
    if (solution == null)
    {
        return null;
    }

    List<Project> solutionProjects = new List<Project>();

    foreach (Project project in solution.Projects)
    {
        if (project.Object is Project)
        {
            solutionProjects.Add(project.Object as Project);
        }
        else
        {
            Project[] projects = GetAllVsProjects(project.ProjectItems);

            if (projects != null && projects.Length > 0)
            {
                solutionProjects.AddRange(projects);
            }
        }
    }

    return solutionProjects.ToArray();
}

private static Project[] GetAllVsProjects(ProjectItems items)
{
    if (items == null)
    {
        return null;
    }

    List<Project> solutionProjects = new List<Project>();

    foreach (ProjectItem item in items)
    {
        if (IsProject(item.Kind))
        {
            solutionProjects.Add(item.Object as Project);
        }
        else if (item.SubProject != null)
        {
            if (IsProject(item.SubProject.Kind))
            {
                solutionProjects.Add(item.SubProject as Project);
            }
            else
            {
                Project[] subprojects = GetAllVsProjects(item.SubProject.ProjectItems);

                if (subprojects != null && subprojects.Length > 0)
                {
                    solutionProjects.AddRange(subprojects);
                }
            }
        }
        else
        {
            Project[] projects = GetAllVsProjects(item.ProjectItems);

            if (projects != null && projects.Length > 0)
            {
                solutionProjects.AddRange(projects);
            }
        }
    }

    return solutionProjects.ToArray();
}


public static bool IsProject(Guid projectKind)
{
    //Visual Basic {F184B08F-C81C-45F6-A57F-5ABD9991F28F}
    //Visual C# {FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}
    //Visual C++ {8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}
    //Visual J# {E6FDF86B-F3D1-11D4-8576-0002A516ECE8}
    //Web Project {E24C65DC-7377-472b-9ABA-BC803B73C61A}

    return IsWebProject(projectKind) || 
        IsVisualJSharpProject(projectKind) || 
        IsVisualCPlusPlusProject(projectKind) ||
        IsVisualCSharpProject(projectKind) ||
        IsVisualBasicProject(projectKind);
}

public static bool IsProject(string projectKind)
{
    if(string.IsNullOrEmpty(projectKind))
    {
        return false;
    }

    return IsProject(new Guid(projectKind));
}

public static bool IsWebProject(Guid projectKind)
{
    return projectKind.CompareTo(new Guid("{E24C65DC-7377-472b-9ABA-BC803B73C61A}")) == 0;
}

public static bool IsVisualJSharpProject(Guid projectKind)
{
    return projectKind.CompareTo(new Guid("{E6FDF86B-F3D1-11D4-8576-0002A516ECE8}")) == 0;
}

public static bool IsVisualCPlusPlusProject(Guid projectKind)
{
    return projectKind.CompareTo(new Guid("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}")) == 0;
}

public static bool IsVisualCSharpProject(Guid projectKind)
{
    return projectKind.CompareTo(new Guid("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}")) == 0;
}

public static bool IsVisualBasicProject(Guid projectKind)
{
    return projectKind.CompareTo(new Guid("{F184B08F-C81C-45F6-A57F-5ABD9991F28F}")) == 0;
}

Can any one tell me if is there a simple solution to get all projects in a VS solution, because this seems to me too much code just to get all projects. Is there another way???

The projects I want are: Visual Basic, Visual C#, Visual C++, Visual J# and Web Project. I was only able to do this watching to the project kind property.

Is there another way???