Entity Framework 6 and SQL Server Compact 4.0 – “Proper” private desktop deployment

About a year after I published the blog post Entity Framework 6 & SQL Server Compact 4 (2)–Easy Private Desktop Deployment it has occurred to me that the solution proposed in that blog post is far from perfect – my apologies! The suggestions for location of the database file etc. are still valid points, however.

TL;DR – Use my new NuGet package for Private Desktop deployment with SQL Server Compact 4.0 and Entity Framework 6, and make sure that:
- The binding redirect is set to: oldVersion="4.0.0.0-4.0.0.1"
- Prefer32Bit project option is disabled

The goal

First, let’s clarify what the goal behind “private desktop deployment” with SQL Server Compact is:

The goal is to be able to drop a folder of files on any PC and just run  a .NET application that includes a self-contained relational database and a sophisticated ORM over that database.

This goal is achievable with SQL Server Compact 4.0 and Entity Framework 6, as long as the PC in question has .NET Framework 4.0 installed.

The issues

First, let us look at the issues with the approach in the above blog post:
1: This approach uses the Microsoft.SqlServer.Compact package, which explicitly uses the non-private assembly version of System.Data.SqlServerCe.dll (which is 4.0.0.0). And it assumes that your project targets AnyCPU. This means that if you have SQL Server Compact installed in GAC, then the version from there will be picked up. That will work fine, as long as you have the exact same build of SQL Server Compact in both GAC and your application folder. But this leads us to issue number 2!
2: The EntityFramework.SqlServerCompact package does not depend explicitly on a release version of the Microsoft.SqlServer.Compact NuGet package and will pick up build 8854, which is 4.0 SP1 CTP1, instead of build 8876, which is 4.0 SP1 proper. (I wish that the 8854 builds were no longer visible on NuGet) – I am working on a fix for this, which is planned for EF 6.1.2. So the chances of not having the same version in GAC and locally are relatively big, and this will cause an error to be thrown, preventing your app from working:
Possible file version mismatch detected between ADO.NET Provider and native binaries of SQL Server Compact which could result in an incorrect functionality.

Manual fix

If you would like to ensure that your desktop application (console, Windows Forms or WPF) app can run anywhere use proper private deployment, follow these steps (in outline):

1: Install EntityFramework.SqlServerCompact

2: Copy files from Private folder in C:\Program Files (x86) to the project folder (as described in my Private deployment with LINQ to SQL blog post)

3: Make project x86 only (or at least remove the “Prefer 32 bit” option if you include all unmanaged dll files 

4: Disable post build event (via Project Properties/Build events tab) to prevent the 4.0.0.0 dll from being deployed

5: Modify app.config

a) add assembly redirect, as the EntityFramework.SqlServerCompact.dll references version 4.0.0.0, and we want to use 4.0.0.1:

<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="System.Data.SqlServerCe" publicKeyToken="89845dcd8080cc91" culture="neutral"/>
<bindingRedirect oldVersion="4.0.0.0-4.0.0.1" newVersion="4.0.0.1"/>
</dependentAssembly>
</assemblyBinding>
</runtime>

b) With version 4.0.0.0 => 4.0.0.1 in DbProviderFactories section:

 

“Automatic” fix

I have published a NuGet package EntityFramework.SqlServerCompact.PrivateDeployment  that performs most of the actions above, specifically 1, 2 (via a clever package that performs a build step), 3 (via an additional command in install.ps1), 4, and partly 5 (for some reason NuGet generates an incorrect bindingRedirect, so it must be fixed manually). Currently in pre-release, please provide feedback!

This package includes both the EntityFramework.SqlServerCompact provider for EF 6.1.1 and the SQL Server Compact 4.0 files for private deployment. I intend to update the package with the upcoming version 6.1.2 release of Entity Framework.