NHibernate.MappingException: No persister for:
XYZ.ProductName.Model.Customer

But this was working last time I compiled and I haven’t been writing database code. What could I have done?

The Problem

NHibernate cannot find your model. Did you move it? Maybe you were just doing some refactoring and you moved the models to a different namespace?

Check Your FluentConfiguration

First you should check your FluentConfiguration and make sure you’ve actually wired up the model that’s missing.

var automappingConfiguration = new MyAutomappingConfiguration();
Fluently.Configure()
                    .Database(SQLiteConfiguration.Standard.ConnectionString(connectionString).ShowSql())
                    .Mappings
                    (
                        m => m.AutoMappings.Add(AutoMap.AssemblyOf<Customer>(automappingConfiguration))
                    )
                    .BuildConfiguration();

Yep, there’s our Customer. So why can’t NHibernate find it?

Check Your AutomappingConfiguration

Next you should check your AutomappingConfiguration and make sure it’s pointing to the correct namespace.

public class MyAutomappingConfiguration : DefaultAutomappingConfiguration
{
	public override bool ShouldMap(Type type)
	{
		return type.Namespace == "XYZ.ProductName.SomeOtherProject.Models";
	}
}

Doh! I moved those models to a new namespace during some refactoring with Resharper. I better update the namespace in my AutomappingConfiguration.

—

Hopefully you’ve managed to help NHibernate find your models now.

Have fun coding!

An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection,
and InnerException for more details.

And the inner exception looked like this:

Could not create the driver from NHibernate.Driver.SQLite20Driver, NHibernate, Version=3.3.1.4000, Culture=neutral,
PublicKeyToken=aa95f207798dfdb4.

The Problem

Typically this error just means NHibernate cannot locate and load the SQLite DLL. This could be because you’re trying to load the 64-bit DLL under a 32-bit project or vice-versa. I noticed a lot of people were simply configuring their Visual Studio projects for x86 and referencing only the x86 SQLite DLL to solve this problem, but this is unnecessary. Below I’ll explain how to set this up properly.

The Solution

Basically the System.Data.SQLite DLL needs to be in the same directory as the NHibernate DLL. Typically, whichever Visual Studio project is set as the startup project (your main application interface) should have a reference to System.Data.SQLite. So just add the NuGet package to that project, as well as any test projects that may need access to the database as well.

The Long-winded Solution

Or if the above wasn’t clear enough…

Install FluentNHibernate

Firstly, you need to have FluentNHibernate installed and referenced in your project. For this, I would recommend installing NuGet.

After NuGet is installed, just grab the package using the GUI or run the Install-Package command from the NuGet prompt:

PM> Install-Package FluentNHibernate

You’ll reference FluentNHibernate from any project that uses it in the code, just like normal.

Configure FluentNHibernate

Make sure you’re building a valid NHibernate configuration in your code using Fluently.Configure() and that you’re using FluentNHibernate.Cfg.Db.SQLiteConfiguration.

Install SQLite

Using NuGet, grab the package using the GUI or run the Install-Package command from the NuGet prompt:

PM> Install-Package System.Data.SQLite

Make sure you’re installing System.Data.SQLite and NOT installing System.Data.SQLite.x86 or System.Data.SQLite.x64. The System.Data.SQLite package contains both the x86 and x64 versions of the DLL, which is what I would recommend if you want to compile your application for both 32-bit and 64-bit machines.

Reference SQLite

Add to reference to System.Data.SQLite to your primary application project (e.g. the startup project, the GUI, etc.). Also add a reference to any test projects that use the database, such as your NUnit tests.

You’re Done?

Does it work? If so, congrats! Happy coding!

It Didn’t Work

Ok, so if it didn’t work, you can try telling .NET which assembly to load.

Update Your App.config or Web.config

In your App.config or Web.config for your main application or any other projects that access the database, add the following:

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <qualifyAssembly partialName="System.Data.SQLite"
          fullName="System.Data.SQLite, Version=1.0.84.0,
          Culture=neutral, PublicKeyToken=db937bc2d44ff139"/>
    </assemblyBinding>
  </runtime>

The qualifyAssembly element specifies the full name of the assembly that should be dynamically loaded when a partial name is used; this should ensure the correct version is loaded at runtime.

Also, if you’re wondering how I got the PublicKeyToken for the DLL, check out my article on finding the public key token for a .NET DLL or assembly.

Finish Line

You’re all done! Now you can use FluentNHibernate and SQLite in both x86 and x64 mode. The correct DLL should be loaded based on your project/compiler settings.

Happy hacking!

Where are these utilities?

The two utilities you can use to get public key tokens are sn and gacutil. You can find either of them in the Visual Studio Command Prompt or the .NET Framework directory.

Visual Studio Command Prompt

To get to the Visual Studio Command Prompt, just hit the Start menu and type Visual Studio Command Prompt into the finder. If you have Visual Studio installed, you should be able to find this tool.

.NET Framework Directory

Alternatively, you can also run these tools from the .NET Framework directory. For .NET 4.0 or 4.5, you’ll find the tools here: C:\Windows\Microsoft.NET\Framework\v4.0.30319

Just navigate to that directory in cmd.exe or PowerShell.

Public Key Tokens with sn

Just run sn -T followed by your DLL or assembly. Here’s an example:

PS > sn -T "C:\dev\project_name\packages\System.Data.SQLite.1.0.84.0\lib\net45\System.Data.SQLite.dll"

Microsoft (R) .NET Framework Strong Name Utility  Version 3.5.30729.1
Copyright (c) Microsoft Corporation.  All rights reserved.

Public key token is db937bc2d44ff139

Public Key Tokens with gacutil

If the DLL is in the GAC, you can do the same thing with gacutil:

PS > gacutil -l System.Data.SQLite
Microsoft (R) .NET Global Assembly Cache Utility. Version 4.0.30319.1
Copyright (c) Microsoft Corporation. All rights reserved.

The Global Assembly Cache contains the following assemblies:
System.Data.SQLite, Version=1.0.84.0, Culture=neutral, PublicKeyToken=db937bc2d44ff139, processorArchitecture=AMD64

Number of items = 1

Now go get that token you were after!

The referenced assembly "StructureMap" could not be resolved because it has a dependency on
"System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" which is not in the
currently targeted framework ".NETFramework,Version=v4.0,Profile=Client". Please remove references
to assemblies not in the targeted framework or consider retargeting your project.

The Problem

If you take a closer look at the error, you’ll notice the targeted framework includes the text Profile=Client.

The .NET Framework 4 Client Profile is a subset of the .NET Framework 4 that is optimized for client applications; it restricts the set of referenced assemblies to only those that are interesting to a client application. For example, it won’t make System.Web available by default because it is not typically valuable to client apps.

So if you started building a Forms app (or WCF or WPF), Visual Studio might have defaulted you to target the .NET Framework 4 Client Profile instead of just .NET Framework 4. And now, it’s complaining because you want to add libraries that a client application doesn’t typically have any use for.

The Solution

Right-click the project that needs the reference added, click properties, and update the project to target .NET Framework 4 instead of the Client Profile.

Now get back to work!

The Problem

Not to worry! If you’re seeing the correct number of rows, you probably just have some visibility problems with the class being used.

In my case, I was trying to bind a list of proxies (List) like this:

private void BindProxyGrid(IList proxies)
{
    var proxiesBindingList = new BindingList(proxies);
    dgvProxies.DataSource = proxiesBindingList;
}

And my proxy class looked something like this:

public class Proxy
{
    public string Ip;
    public int Port;
}

The Solution

So why didn’t it work? Because the DataGridView requires properties and I was using public fields. Updating the class to use properties fixed the problem!

public class Proxy
{
    public string Ip { get; set; }
    public int Port { get; set; }
}

It works!

The Lesson Learned

If you’re using a BindingList with your DataGridView, you may need to adjust the visibility for any class members you want to display in the grid; for example, the DataGridView can’t access public fields or properties marked internal.

Happy coding!

The Problem

The line endings in the following file are not consistent. Do you want to normalize the line endings?

This probably means some of the developers have been editing our source code using a text-editor (instead of Visual Studio) and they had their line endings set to “Unix” or “Mac” instead of “Dos/Windows”. This isn’t a big deal, though it is annoying.

Vim: Convert All Files to Dos/Windows Line Endings

Since I don’t know which files have this problem, I decided to just normalize all the line endings. There are various ways to do this, but I chose to use vim since the documentation on this topic is excellent.

To convert from any mixture of CRLF endings and LF-only endings, to CRLF endings:

:set ffs=dos
:args **\*.cs
:argdo w

We’re basically asking vim to assume Dos/Windows line endings, having it open all *.cs files (C# code files), then having it write the line-ending changes.

Downsides

This does change every single file that was found, regardless of the original line endings. It’s best to do this as one commit in source control to avoid any confusion.

Alternatives

You can also use unix2dos to do this conversion or any scripting language (python, perl, powershell).

Some people also let their source control handle their line endings. Git can enforce these line endings by updating them for you if you prefer. However, at my office, we choose not to let our source control alter our code in any way; we prefer to do that ourselves.

Now get back to coding!

Creating a New Object

First let’s create an object using New-Object.

PS > $myObj = New-Object Object

Add a Property

Add a new property to the object by using Add-Member and specifying the member type NoteProperty.

PS > Add-Member -MemberType NoteProperty -InputObject $myObj -Name MyName -Value "Sean"
PS > $myObj.MyName
Sean

Add a Method

Add a new method to the object by using Add-Member and specifying the member type ScriptMethod. The value should be a script block, so put your code in curly braces.

When calling the method, don’t forget to use parentheses. When calling cmdlets in PowerShell you don’t use parentheses, so it’s easy to forget to do so here.

PS > Add-Member -MemberType ScriptMethod -InputObject $myObj -Name PrintName -Value { Write-Host "My name is" $this.MyName }
PS > $myObj.PrintName()
My name is Sean

Add a Method that Accepts Arguments

You can use a param statement to allow your method to accept arguments.

Don’t forget to follow each statement with a semicolon since we’re defining our method on a single line.

When passing the arguments you’ll need to comma-delimit them; again, this is in contrast to the space-delimited arguments you pass to cmdlets.

PS > Add-Member -MemberType ScriptMethod -InputObject $myObj -Name PrintNameAgeAndInterest -Value { param($age, $interest); Write-Host "My name is" $this.MyName "and I am $age years old. I like $interest!" }
PS > $myObj.PrintNameAgeAndInterest(23, 'programming')
My name is Sean and I am 23 years old. I like programming!

Creating Large Methods

You don’t have to create methods all on one line if you don’t want to. If you’re building a script–and you probably are–make sufficient use of white space to make your code easier to read. I personally use the ` (backtick) to continue my methods on the next line for readability. Here’s an example.

Add-Member -MemberType ScriptMethod -InputObject $myObj -Name Print1ThroughX -Value `
{
	param($x)
	for($i = 1; $i -le $x; $i++)
	{
		Write-Host $i
	}
}

And look, it works!

PS > $myObj.Print1ThroughX(10)
1
2
3
4
5
6
7
8
9
10

Overwriting Methods

What if you define a method, but you make a mistake?

PS > Add-Member -MemberType ScriptMethod -InputObject $myObj -Name OutputName -Value { Write-Hst "My name is" $this.MyName }
PS > $myObj.OutputName()
Exception calling "OutputName" with "0" argument(s): "The term 'Write-Hst' is not recognized as the name of a cmdlet,
 function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that t
he path is correct and try again."
At line:1 char:18
+ $myObj.OutputName <<<< ()
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ScriptMethodRuntimeException

Oh no! I misspelled Write-Host. No problem! Just use the -Force attribute to overwrite the method with the corrected version.

PS > Add-Member -Force -MemberType ScriptMethod -InputObject $myObj -Name OutputName -Value { Write-Host "My name is" $this.MyName }
PS > $myObj.OutputName()
My name is Sean

Have fun using objects in PowerShell!

Could not connect to the feed specified at '$the-server/app/nuget/v1/FeedService.svc'. Please verify the package
source (located in the Package Manager Settings) is valid and ensure your network connectivity.

The solution

This is a confirmed bug in NuGet 1.7, as seen in both this NuGet bug report (2066) and this TeamCity bug report (21011). To fix the problem you need to download a newer version of NuGet that contains the bug fix.

NuGet 1.8

As of this blog post NuGet 1.8 isn’t released, but it should be released soon; try updating your plugin to the latest stable version to see if your problem is resolved.

Update: NuGet 1.8 has been released! Upgrade using the Visual Studio Extension Manager or download it here!

Nightly builds

If the latest stable build doesn’t resolve your issue, you can download a nightly build from NuGet’s CI server.
1. Go to NuGet’s CI server
2. Click the link at the bottom to log in as a guest
3. Under the NuGet section you’ll see a couple of options (currently 1.8 and Default)
4. Mouse over the Artifacts link for whichever build you choose (I chose to download a 1.8 build), click VisualStudioAddIn and then NuGet.Tools.vsix
5. Your download should start; let it finish
6. Probably best to close any open Visual Studio instances
7. Run the vsix installer by double-clicking it

Your new NuGet extension should now be installed and your TeamCity feed URL should now work!

Enjoy NuGetting!

WebAdministration Errors

If you import the module using the 32-bit version of PowerShell, you might see the following.

PS > Import-Module WebAdministration
PS > Get-Website
Get-Website : Retrieving the COM class factory for component with CLSID {688EEEE5-6A7E-422F-B2E1-6AF00DC944A6} failed
  due to the following error: 80040154.
At line:1 char:12
+ Get-Website <<<<
    + CategoryInfo          : NotSpecified: (:) [Get-Website], COMException
    + FullyQualifiedErrorId : System.Runtime.InteropServices.COMException,Microsoft.IIs.PowerShell.Provider.GetWebsite
   Command

If you import the module using the 64-bit version of PowerShell, you might see this error.

PS > Import-Module WebAdministration
PS > Get-Website
format-default : Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))
    + CategoryInfo          : NotSpecified: (:) [format-default], COMException
    + FullyQualifiedErrorId : System.Runtime.InteropServices.COMException,Microsoft.PowerShell.Commands.FormatDefaultCommand

Solutions

Enable IIS Management Service

Firstly, you should make sure the IIS Management Service is enabled. To do so, follow these steps:
1. Click Start and then click Control Panel
2. In Control Panel, click Programs and then click Turn Windows features on or off.
3. In the Windows Features dialog box, verify that IIS Management Service is checked and then click OK

Try both 32-bit PowerShell and 64-bit PowerShell

If you're on a 64-bit platform, you have both the 32-bit and 64-bit versions of PowerShell installed. In my personal experience, using 64-bit PowerShell worked for me. However, people on various internet forums have claimed that the 32-bit version of PowerShell worked for them. Try running your script from both versions to see which one works for you.

64-bit PowerShell: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
32-bit PowerShell: C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe

Test Script

To test each version, try running these commands and make sure you don't get errors.

Import-Module WebAdministration
Get-Website

An Object To Use

For example purposes–in case you want to try any of these out right now–you can create a list of processes and use that as your object.

PS > $object = Get-Process

Feel free to use any object you want though.

Examining a Single Object

PS > # List all methods and properties
PS > $object | Get-Member

Examining the Properties of an Object

PS > # List properties
PS > $object | Get-Member -memberType property
PS > # A few more properties
PS > $object | Get-Member -memberType *property

Examining the Properties of an Array Object

PS > # Brief list of properties on an object or array
PS > $object | Select-Object *
PS > # List properties on each element in the array
PS > $object | Format-List *
PS > # Using -Force on Format-List can sometimes reveal hidden properties
PS > $object | Format-List * -Force

Examining the Methods of an Object

PS > # List methods
PS > $object | Get-Member -memberType method
PS > # List standard Methods
PS > $object | Get-Member -memberType *method | Where-Object { $_.Name -notlike '*_*' }
PS > # List static Methods
PS > $object | Get-Member -static -memberType *method

Recursively Examining an Object

This is really useful for objects that contain other objects or when you’re having a tough time figuring out how to drill down into an object to get the data you want.

PS > # Recursively examine the object to a depth of 5
PS > $object | Format-Custom * -Depth 5