SQLite dll for x86/x64 architectures

Question

I am developing a program in VB.net, and using System.Data.SQLite Precompiled Binaries for .NET, However It is not working for x64 Architectures, and I am getting the classic culture problem and not loading correct file.

System.BadImageFormatException: 
Could not load file or assembly 'System.Data.SQLite, Version=1.0.65.0, Culture=neutral,
 PublicKeyToken=db937bc2d44ff139' or one of its dependencies. An attempt was made to load a program with an incorrect format.
File name: 'System.Data.SQLite,
 Version=1.0.65.0,
 Culture=neutral, 
 PublicKeyToken=db937bc2d44ff139'

Is there a way to use only one dll, maybe:

1. Add some directives like #IFDEF (x86 include some part of code) or else x64 code
2. Join dlls to make only one.
3. Reference this dll in VB.net

Do you think is other better Idea, as I would like to make only one compilation, not one for x32 and other for x64.

For instance (32 bits):

Private Shared Sub OpenConection(ByRef Conn As SQLite.SQLiteConnection)
    Conn = New SQLite.SQLiteConnection("Data Source=" & System.Environment.CurrentDirectory & "\database.db")
    Conn.Open()
End Sub

Private Shared Sub CloseConection(ByRef Conn As SQLite.SQLiteConnection)
    Conn.Close()
    Conn.Dispose()
    Conn = Nothing
End Sub

Public Shared Function ReturnSelect(ByVal DataTAbleName As String, ByVal sQuery As String, ByVal sWhere As String) As Data.DataTable
    Dim lDT As New DataTable
    Dim lTA As New SQLite.SQLiteDataAdapter
    If DataTAbleName Is Nothing Then Return New DataTable(DataTAbleName)
    Try
        OpenConection(conexion)
        lTA = New SQLite.SQLiteDataAdapter("SELECT " & sQuery & " FROM  " & DataTAbleName & IIf(sWhere <> String.Empty, " WHERE ", "") & sWhere, conexion)
        lTA.Fill(lDT)
    Catch ex As Exception
        Throw ex
    Finally
        CloseConection(conexion)
        lTA.Dispose()
        lTA = Nothing
    End Try
    Return lDT
End Function

How to change that to work on 64 bit architecture? Maybe including both 32 and 64 dll's and in functions do something like

Try
    Instance = Me
    'Check If Homidom Run in 32 or 64 bits
    If IntPtr.Size = 8 Then _OsPlatForm = "64" Else _OsPlatForm = "32"
    'continue code

Catch ex As Exception
    ' ex.Message
End Try

Answer 1

There are various options for using SQLite from a .NET assembly. Your first step is to move to something newer than the ancient 1.0.65 version. Current versions can be downloaded from here: http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki or via the SQLite NuGet packages.

If you need to be able to run under both 32-bit and 64-bit, one option is to use the native library pre-loading option, where you distribute the native binaries in separate directories, so that it looks like this:

• \App.exe (optional, managed-only application executable assembly)
• \App.dll (optional, managed-only application library assembly)
• \System.Data.SQLite.dll (required, managed-only core assembly)
• \System.Data.SQLite.Linq.dll (optional, managed-only LINQ assembly)
• \x86\SQLite.Interop.dll (required, x86 native interop assembly)
• \x64\SQLite.Interop.dll (required, x64 native interop assembly)

Another option is to build two versions of your app, and in each version you reference the appropriate mixed-mode assembly. You'd then end up with two versions, but they're a bit simpler to deal with since you don't need the extra subdirectory and native *.Interop.dlls.

In these cases you'd need no code differences or optional compilation between 32-bit and 64-bit. Installing from the different NuGet packages will probably get you started most easily.

A final option is to go for the managed-only clone called C#-SQLite: https://code.google.com/p/csharp-sqlite/. It's a port of the SQLite engine to managed C#, so the whole thing runs as AnyCPU and the bitness is not an issue.

Answer 2

I had the same problem few year ago and for me the best solution is:

• download the latest version of the library
• in your bin path put only the System.Data.SQLite.dll and eventually System.Data.SQLite.Linq.dll
• put the x86 SQLite.Interop.dll library into c:\Windows\SysWOW64
• put the x64 SQLite.Interop.dll library into c:\Windows\System32
• compile your project as Any CPU referencing only System.Data.SQLite (the dll into your bin path)
• enjoy

In this way the .NET framework will automatically load the correct (x86 vs x64) library during the runtime without registering anything in GAC or similar.

Hope this helps.