Develop Reference

Unable to find the requested Net Framework Data Provider

Its a very specific error message, but I can't find the problem.
I have a windows service that needs to communicate with a database, for that I do the following:
string provider = "Devart.Data.PostgreSql";
DbProviderFactory factory = DbProviderFactories.GetFactory(provider);
But it crashes, giving me this error:
System.ArgumentException: Unable to find the requested .Net Framework
Data Provider. It may not be installed. at
System.Data.Common.DbProviderFactories.GetFactory(String providerInvariantName)
I tried to move the Devart.Data.PostgreSql.dll to the bin folder, but the results are the same.
Then I checked my machine.config, and I have this:
<add name="dotConnect for PostgreSQL"
invariant="Devart.Data.PostgreSql"
description="Devart dotConnect for PostgreSQL"
type="Devart.Data.PostgreSql.PgSqlProviderFactory, Devart.Data.PostgreSql, Version=7.4.506.0, Culture=neutral, PublicKeyToken=09af7300eec23701" />
So it looks right, I didn't found any empty tags, found that in other SO posts, saying that removing those tags when empty could solve the problem, but I didnt had any.
So I don't know what is the problem.
I also created a console project, which uses the same .Net version, and with the exact code:
string provider = "Devart.Data.PostgreSql";
DbProviderFactory factory = DbProviderFactories.GetFactory(provider);
And it works. Does anyone knows what could it be?

Oracle .Net ManagedDataAccess Error: Could not load type 'OracleInternal.Common.ConfigBaseClass' from assembly

I have a project that works locally, on our dev server, and on our production server.
When I try to run it on the test server, I get the error below, and I don't know what to do about it beyond stare at my screen blankly. Hints? Process to trace the issue to its source?
I've installed the NuGet package for Oracle 12.2, etc.
Could not load type 'OracleInternal.Common.ConfigBaseClass' from
assembly 'Oracle.ManagedDataAccess, Version=4.121.2.0,
Culture=neutral, PublicKeyToken=89b483f429c47342'. 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.TypeLoadException: Could not load type
'OracleInternal.Common.ConfigBaseClass' from assembly
'Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral,
PublicKeyToken=89b483f429c47342'.
Source Error:
An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace below.
Stack Trace:
[TypeLoadException: Could not load type
'OracleInternal.Common.ConfigBaseClass' from assembly
'Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral,
PublicKeyToken=89b483f429c47342'.]
Oracle.ManagedDataAccess.EntityFramework.EntityFrameworkProviderSettings.Oracle.ManagedDataAccess.EntityFramework.EFProviderSettings.IEFProviderSettings.get_TracingEnabled()
+0 Oracle.ManagedDataAccess.EntityFramework.EFProviderSettings.InitializeProviderSettings()
+111 Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices..ctor()
+629 Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices..cctor()
+28
[TypeInitializationException: The type initializer for
'Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices'
threw an exception.]
Oracle.ManagedDataAccess.EntityFramework.EFOracleProviderServices.get_Instance()
+24
The Web.Config has the following blocks in it:
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<section name="oracle.manageddataaccess.client" type="OracleInternal.Common.ODPMSectionHandler, Oracle.ManagedDataAccess, Version=4.121.2.0, Culture=neutral, PublicKeyToken=89b483f429c47342" />
</configSections>
AND
<oracle.manageddataaccess.client>
<version number="*">
<dataSources>
<dataSource alias="PVMDataSource" descriptor="(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=pdxcludds108.pacificorp.us)(PORT=11086))(CONNECT_DATA=(SERVICE_NAME=DDS1086.PACIFICORP.US))) " />
</dataSources>
</version>
</oracle.manageddataaccess.client>
<connectionStrings>
<add name="OracleDbContext" providerName="Oracle.ManagedDataAccess.Client" connectionString="User Id=USERID;Password=WORKINGPASSWORD;Data Source=PVMDataSource" />
<add name="PVMEntities" connectionString="metadata=res://*/Models.PVMModel.csdl|res://*/Models.PVMModel.ssdl|res://*/Models.PVMModel.msl;provider=Oracle.ManagedDataAccess.Client;provider connection string="DATA SOURCE=pdxcludds108.pacificorp.us:11086/DDS1086.PACIFICORP.US;PASSWORD=XXXXXXX;PERSIST SECURITY INFO=True;USER ID=XXX"" providerName="System.Data.EntityClient" />
</connectionStrings>
NOTE: There are other projects working on this server, they're just using a different version of the Oracle client for .Net. None of the others is using only the Managed driver. I am looking for a way to dig into this error, some hint as to where that type is sourced and loaded from.

There is a conflict between Oracle.ManagedDataAccess from NuGet and the one that is installed (by Oracle client installation) on a server and that is registered in GAC.
Unregister Oracle.ManagedDataAccess from GAC and you will get rid of the error: Run command line and navigate to the directory:
{Oracle home}\product\{version}\client_64\ODP.NET\managed\x64
There you should find OraProvCfg.exe file. Run the following command to unregister Oracle.ManagedDataAccess from GAC:
OraProvCfg /action:ungac /providerPath:Oracle.ManagedDataAccess

You have to remove the Oracle.ManagedDataAccess assembly in your GAC (C:\Windows\Microsoft.NET\assembly...)
Use the command tool gacutil to remove the assembly:
C:\Program Files (x86)\Microsoft SDKs\Windows\YOUR_VERSION\bin\NETFX
4.6.1 Tools> gacutil /u Oracle.ManagedDataAccess

Was able to fix it by replacing references in the project to Oracle.ManagedDataAccess and Oracle.ManagedDataAccess.EntityFramework from those installed by the package manager to those installed by the oracle client installer. The versions are the same but the build number is different on those DLLs

As others said you need to remove Oracle.ManagedDataAccess from GAC.
I run {Oracle home}\product\12.1.0\dbhome_1\ODP.NET\managed\x64\unconfigure.bat and {Oracle home}\product\12.1.0\dbhome_1\ODP.NET\managed\x836\unconfigure.bat and it worked

We had the exact same problem as Dylan above. The issue appears to be with that specific Oracle version (4.121.2.0).
The solution was simple: Just go into Nuget and move up to the next version of your Nuget package for the Oracle.ManagedDataAccess.Client, 4.122.1.0.
Once we did that we could have mixed Oracle client or no-client environments or servers with or without the GAC Oracle installed, keep older apps that still use the GAC, and add new projects that use the Nuget packages. Its always a bad idea in these blogs to ask people to uninstall legacy stuff - like remove the Oracle dll in the GAC on a server - when you have environments with many legacy dependancies that still might reference it.

If removing the DLL from the GAC is not an option, consider getting the next version of oracle.managedData.access 12.2.1 and just put them on the server in the bin directory.
Afterwards you need to add an assemblyBinding to your web.config file.
This way you get arround pulling the 12.1.2 version from the GAC during runtime that will case the error.
You do not need to recompile your app against the new version.
<dependentAssembly>
<assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-12.1.2.0" newVersion="12.2.1.0" />
</dependentAssembly>

There is definitely something weird with this issue. I was developing an app on my local server which ran fine but got this error when I uploaded the app to our server. The server has oracle client installed. After looking at this thread I copied the two DLLs (Oracle.ManagedDataAccess.dll & Oracle.ManagedDataAccess.EntityFramework.dll) from within oracle client and replaced the versions in my app bin directory. That fixed the issue.

In my scenario, i have a console application consuming a class library database utility.
I had to reference the Oracle.ManagedDataAccess also on the console application so it can find the dll on runtime.
I don't know if this is the best approach, but worked for me.

good afternoon
I want to share how I solved this same error:
I started by starting visual studio 2019 cmd as administrator.
I ran the following command line in cmd: gacutil -u Oracle.ManagedDataAccess
Basically this command line will remove the Oracle reference from the GAC (Global Assembly Cache), this way it will only get the reference from the package that is in the project (which nuget installs) and not from the oracle client.

You need to install the Oracle Client drivers. The .NET packages don't contain them; they provide a translation from the managed world to the unmanaged. The drivers are in the unmanaged world and need to be installed properly.

Could not load file or assembly 'mysql.data,' version=6.7.4.0

I know that this problem has been encountered by many users here on SO but I cannot seem to find a permanent solution.
I keep encountering the error "could not load file or assembly 'mysql.data,' version=6.7.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d".
I am using Visual Studio 2012 Version 11.0.61030.00 Update 4. I have installed MySQL version 5.6.15.0 for Visual Studio. After installation, I notice that the machine.config file for both the 32 and 64 bit entries show Version=6.6.5.0 even though I have never installed a MySQL of that version.
I then check the project references for MySql.Data and MySql.Data.Entity and they are the correct version, i.e. 6.7.4.0 and copy local property set to true.
I even copy this to my App.config file:
<system.data>
<DbProviderFactories>
<clear />
<add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.7.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
</DbProviderFactories>
</system.data>
My application .NET 4.5 will run fine until I shut down my computer. If I work on my machine for 4 days without switching it off no problem.
After I shut down and restart my machine, the error comes up. I then try to manually change the machine.config settings to the version 6.7.4.0 but to no avail. I try to change the project configuration settings from any CPU to x86 but no solution.
When I encounter this, the only way I get to fix this is to uninstall MySQl and reinstall it again.
Is there a permanent solution to this problem? I have tried this MySQL connector 6.7.4 and Entity Framework 5 exceptions but like I say it seems a temporary solution.

I could be off on this but you could change the references specific version value to false.
Right click on the reference > Select Properties > Change the Specific version value

How can I deploy a .NET application that uses ODAC without installing the whole component to the user?

I have written a C# application that connects to an Oracle 10g database. Using Oracle Data Access Component 11.2 "ODAC", it works perfectly on my machine.
And now I want to deploy the application and install it in another "clean machine" that has the .NET Framework only! And I don't want to install the whole ODAC component to the user!
How could I do that? I have tried to include all the necessary DLL files to my bin folder, like:
oci.dll
ociw32.dll
Oracle.DataAccess.dll
orannzsbb11.dll
oraocci11.dll
oraociicus11.dll
OraOps11w.dll
msvcr71.dll
But still it didn't work. What should I do to solve this problem?

You don't need to install any Oracle client separately.
I installed the following in the same directory as the .exe:
Oracle.DataAccess.dll
oci.dll
OraOps11w.dll
oraociei11.dll
msvcr71.dll
Make sure your project references the same Oracle.DataAccess.dll that you are delivering.
This worked on a fresh pc which had never had oracle clients installed.
I avoided using TNSNAMES.ora by specifiying a connection string like this
connectionstring =
Data Source="(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=)(PORT=))" +
"(CONNECT_DATA=(SERVER = DEDICATED)(SERVICE_NAME = )))"
If you are using TNSNAMES.ora just cut and paste the connection details into a single line string.
see
What is the minimum client footprint required to connect C# to an Oracle database?
for more information.
ejm
For information on how to obtain the above dlls, see this tutorial: http://begeeben.wordpress.com/2012/08/01/accessing-oracle-database-without-installing-oracle-client/

Since this question was posted, the Oracle Managed Client is now available (provided by Oracle). I have been using it with no problems. Does not require hunting for DLL's or special configuration. Just add the package, modify configuration file, and you're set. NuGet Link and an article by Oracle about it..
Since this client is written entirely in .NET Managed code, it's architecture independent and there is no need for external DLL's, installing an Oracle Client, or anything like that.
You can install it in VS using Package Manager.
Install-Package Oracle.ManagedDataAccess
I've taken to putting this in the machine.config file (though it'll also work in web.config or app.config). I've found that this helps avoid conflicts with other drivers that may be installed:
<configuration>
<system.data>
<DbProviderFactories>
<remove invariant="Oracle.DataAccess.Client" />
<remove invariant="Oracle.ManagedDataAccess.Client" />
<add name="ODP.NET, Managed Driver"
invariant="Oracle.ManagedDataAccess.Client"
description="Oracle Data Provider for .NET, Managed Driver"
type="Oracle.ManagedDataAccess.Client.OracleClientFactory, Oracle.ManagedDataAccess, Version=4.121.1.0, Culture=neutral, PublicKeyToken=89b483f429c47342"/>
</DbProviderFactories>
</system.data>
<configuration>
Then for your connection string:
<add name="MyConnectionString" connectionString="Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=IPORNAMEOFHOST)(PORT=PORTNUM)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=ORACLESID)));User Id=ORACLEUSER;Password=ORACLEPASSWORD;" providerName="Oracle.ManagedDataAccess.Client"/>
IPORNAMEOFHOST= This is the IP address or DNS name of your server.
PORTNUM= This is the port number that Oracle is listening at. Typically 1521.
ORACLESID= The SID of the database you're trying to connect to.
ORACLEUSER= The username to use for the connection.
ORACLEPASSWORD= The password to use for the connection.

I'm not sure whether your concern is about having to install the Oracle client in addition to the ~50 MB ODAC install or just the standalone ODAC.
If the concern is about having to install the Oracle client and the ODAC, you can use the Oracle Instant Client? That's the smallest footprint method for installing the Oracle client. You'll also need the ODAC xcopy supplement.
If your concern is just the ODAC install, I don't think there is a smaller footprint available.

For NET Framework net462, net463, net47, net471, net472, net48
use the nuget package: Oracle.ManagedDataAccess
In c# project, add the next line:
<PackageReference Include="Oracle.ManagedDataAccess" Version="21.5.0" />
For netcore .NET net5.0/net6.0,netcoreapp3.0, netcoreapp3.1,netstandard2.1
use the package: Oracle.ManagedDataAccess.Core
<PackageReference Include="Oracle.ManagedDataAccess.Core" Version="3.21.50" />
If you are using TNS names (e.g ORCL in tnsnames.ora), the connection string is:
string oradb = $"Data Source=ORCL;User Id=hr;Password=hr;";
Also, you can use Easy Connect Naming Method;
string oradb = $"Data Source=192.168.1.70/{SERVICE_NAME};User Id=hr;Password=hr;";

Can't get sql server compact 3.5 / 4 to work with ASP .NET MVC 2

I'm using Visual Studio 2008 Pro.
I'm probably missing something very obvious here, but I've been trying to get the CTP for Sql Server compact 4 to work in my asp.net mvc application. I can find next to no instruction on how to set this up or a working example application. My goal is a private install so I can just include it in my web app without having to do sql server setup on my domain hosting. This is really just me shooting the breeze and trying to figure this out. I don't plan to host a market or anything with this.
So, I've copied all the dll's that install in the base 4.0 direction (c:\Program Files\Sql Server compact\v4.0) to a lib folder in my application. I've set the copy to output direction option to 'Copy if Newer'. I then reference the System.Data.SqlServerCE dll and set 'Copy Local' to True.
I created an sdf file via Sql Studio Express. An important note is that I did not see an option for creating a CE 4.0 version of this file, so it was created using CE 3.5. I create a few tables, add a few rows to those tables, copy the *.sdf file to my App_Data directory. It's worth mentioning that, from inside VS 2008, this file never appears in my project, but it does exist in the physical location of the App_Data directory. I'm not sure why this is.
Next, I just try making a basic connection to my sdf file via:
SqlCeConnection conn = new SqlCeConnection("DataSource=rpg.sdf");
This yields the error below:
Unable to load the native components of SQL Server Compact corresponding to the ADO.NET provider of version 8402. Install the correct version of SQL Server Compact. Refer to KB article 974247 for more details.
I figure from here, I'd just try getting Sql CE 3.5 to work. I upgrade my local installation of Sql CE 3.5 to sp2. I copy the dlls at the base location (c:\Program Files\Sql Server compact\v3.5), including removing and readding the version of the System.Data.SqlServerCE dll from my project references.
The curious thing here is when I right click and look at the properties of the referenced SqlServerCE dll, it always says it's version 4.0.0.1.
Guys, I really could use some direction here. I have searched stack overflow, the help docs, books online, and googled. I really haven't found anything that takes this from the very top for either CE 3.5 or 4.0 and tells me exactly what dll's to add, where to put them, how to reference them, how to add the .sdf file to my project, connect to it, and query from it. I did come across a few mentions of an IBuySpy portal sample app that was supposed to use Sql CE 3.5, but can't actually navigate the msdn download maze to get to it. Ideally, I want to setup a private deploy for CE 4.0.
I'm all ears. Suggestions, points, whatever would be highly appreciated. Thank you!
YES I DID SEE THE KB. IT DIDN'T HELP
See it here: http://support.microsoft.com/kb/974247
RESULTS FROM CORFLAG
Okay, tried that and these are my results:
C:\Development\Mvc2MessingAround\Mvc2MessingAround\bin\Lib>corflags System.Data.
SqlServerCe.dll
Microsoft (R) .NET Framework CorFlags Conversion Tool. Version 3.5.21022.8
Copyright (c) Microsoft Corporation. All rights reserved.
Version : v2.0.50727
CLR Header: 2.5
PE : PE32
CorFlags : 9
ILONLY : 1
32BIT : 0
Signed : 1
I would have sworn I installed the x86 version of both versions of Sql CE (3.5/4). The installer might have gotten confused somehow because my processor is 64bit capable, but i'm running Windows xp sp 3 32 bit. The results seem to indicate it's 64 bit. Is that the case?
ADDED DETAILS
To date the configurations below have been tried on 2 machines. Both are Windows xp sp3 32 bit with a 64 bit capable processor. The development environment on both is VS 2008 Pro. The results on machine 2 come after a fresh install of the Sql CE 4 Ctp.
CONFIGURATION #1
myapp\bin\
System.Data.SqlServerCe.dll
myapp\bin\private
amd64
x86
myapp\bin\private\x86
sqlceca40.dll
sqlcecompact40.dll
sqlceer40EN.dll
sqlceme40.dll
sqlceqp40.dll
sqlcese40.dll
myapp\bin\private\amd64
sqlceca40.dll
sqlcecompact40.dll
sqlceer40EN.dll
sqlceme40.dll
sqlceqp40.dll
sqlcese40.dll
Error:
An exception of type 'System.Data.SqlServerCe.SqlCeException' occurred in System.Data.SqlServerCe.DLL but was not handled in user code
Additional information: Unable to load the native components of SQL Server Compact corresponding to the ADO.NET provider of version 8402. Install the correct version of SQL Server Compact. Refer to KB article 974247 for more details.
Code:
SqlCeConnection conn = new SqlCeConnection();
CONFIGURATION 2
Same as #1, but with System.Data.SqlServerCE.Entity.dll at myapp\bin direction.
The page errors before hitting the code above. This is the message:
Could not load file or assembly 'System.Data.SqlServerCe.Entity' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.
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.BadImageFormatException: Could not load file or assembly 'System.Data.SqlServerCe.Entity' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.
I've checked the project settings in VS 2008 Pro and the .Net 3.5 framework is set as the target.
CONFIGURATION 3
Same as #1, except the System.Data.SqlServerCE.dll is referenced from the myapp\bin\private folder.
Results are the same as CONFIGURATION #1 (error message is 100% same and the error occurrs on the same line of code).
CORRECT CONFIGURATION
Per Erik's instructions (had I followed them more carefully), the setup should be
myapp\bin
x86
amd64
System.Data.SqlServerCE.dll
Reference the System.Data.SqlServerCE.dll directly from the bin folder for the code. My folly was thinking the Private folder needed to be included, but it doesn't. Do not put the System.Data.SqlServerCE.Entity.dll in the bin folder unless you are using a .net 4.0 solution. I don't think that dll works w/ 3.5.
Helpful link:
Link

SQL CE 3.5 does not work with ASP.NET, you must use 4.0 CTP.
Download from here.
Install the runtime.
Copy the following directory contents (including the x86 and amd64 folders) to the bin folder of your ASP.NET app:
C:\Program Files\Microsoft SQL Server Compact Edition\v4.0\Private
UPDATE: Use System.Data.SqlServerCe.dll from the Desktop folder to avoid Medium Trust issues
myapp\bin\
System.Data.SqlServerCe.dll
myapp\bin\x86
sqlceca40.dll
sqlcecompact40.dll
sqlceer40EN.dll
sqlceme40.dll
sqlceqp40.dll
sqlcese40.dll
myapp\bin\amd64
sqlceca40.dll
sqlcecompact40.dll
sqlceer40EN.dll
sqlceme40.dll
sqlceqp40.dll
sqlcese40.dll
Add a reference to the System.Data.SqlServerCe.dll file you just put in your /bin folder.
Place the SQL Compact sdf file in your App_Data folder.
Add connection string:
<connectionStrings>
<add name ="NorthWind"
connectionString="data source=|DataDirectory|\Nw40.sdf" />
</connectionStrings>
Connect! :-)
using System.Data.SqlServerCe;
protected void Page_Load(object sender, EventArgs e)
{
using (SqlCeConnection conn = new SqlCeConnection())
{
conn.ConnectionString = ConfigurationManager.ConnectionStrings["Northwind"].ConnectionString;
conn.Open();
using (SqlCeCommand cmd = new SqlCeCommand("SELECT TOP (1) [Category Name] FROM Categories", conn))
{
string valueFromDb = (string)cmd.ExecuteScalar();
Response.Write(string.Format("{0} Time {1}", valueFromDb, DateTime.Now.ToLongTimeString()));
}
}
}

If your using a connection string that uses a providerName and you haven't installed the SDK, then you also need to add this to you web.config (or app.config)
<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>
<system.data>
<DbProviderFactories>
<remove invariant="System.Data.SqlServerCe.4.0"/>
<add name="Microsoft SQL Server Compact Data Provider 4.0" invariant="System.Data.SqlServerCe.4.0" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=4.0.0.1, Culture=neutral, PublicKeyToken=89845dcd8080cc91"/>
</DbProviderFactories>
</system.data>
NOTE: the "remove" is needed in case you installed the SDK, as that will put this info in your machine.config

OK, here's a guess, since you're fishing for them.
Run corflags.exe on the assembly you copied to your references directory. What type of machine are you building for? If you're on a 64-bit machine and you're compiling to x64 or anyCpu, make sure that corflags tells you that your references are not 32-bit only references. Maybe it's "falling back" to an the wrong version in your GAC or something. If it tells you that the referenced assembly is 32-bit only, either compile your project as a 32-bit project or find a 64-bit version of the DLL?

If you are installing the SQL CE provider using NuGet, the simplest solution is to add a post-build step to copy these from the NuGet package NativeBinaries folder

The key for me was realizing that the version of System.Data.SqlServerCe.Entity.dll in the Private directory (C:\Program Files\Microsoft SQL Server Compact Edition\v4.0\Private) is 4.0.0.1, where the version beneath the Desktop directory (C:\Program Files\Microsoft SQL Server Compact Edition\v4.0\Desktop\System.Data.SqlServerCe.Entity) is 4.0.0.0. The version of System.Data.SqlServerCe.dll in the Private directory is 4.0.0.0.
I think it was a mistake on the part of Microsoft to distribute an updated SqlServerCe.Entity.dll without a corresponding update to SqlServer.dll.

I build an asp.net web api and hosted it on azure and faced some issues with sql server compact I fix it by:
first remove all system.data.sqlserverce.dll and any dll use it then
installed these tow packages :
Install-Package SqlServerCompact then rebuild
Install-Package EntityFramework.SqlServerCompact -Version 4.3.6 then rebuild
after I did it just worked fine for me + install any NuGet package that depends on system.data.sqlserverce.dll they all just work great
I hope this will help some one
reference