.net - 如何根据客户端架构动态加载x86/x64版本的SQLite3.DLL？

Question

我正在尝试在运行时动态加载适当的 x86/x64 版本的 SQLite3.DLL，以便与 Devart.SQLite.DLL 一起使用。我无法控制事先将适当版本的 DLL 安装到应用程序根目录，因此我必须以某种方式尝试从应用程序根目录的/x86 或/x64 子目录中获取正确的版本。

关于如何实现这个的任何想法？诚然，我完全迷失在这里。到目前为止我的代码是:

Public Sub New()
    LoadAssembly("sqlite3.dll", True)
End Sub

Private Function GetAssemblyPath(ByVal assembly As String, ByVal version As String) As String
    Return Path.GetDirectoryName(Reflection.Assembly.GetExecutingAssembly().Location) & "\" & version & "\" & assembly
End Function ' GetAssemblyName

<Runtime.InteropServices.DllImportAttribute("kernel32.dll", EntryPoint:="LoadLibraryW")> _
Public Shared Function LoadLibraryW(<Runtime.InteropServices.InAttribute()> <Runtime.InteropServices.MarshalAsAttribute(Runtime.InteropServices.UnmanagedType.LPWStr)> lpLibFileName As String) As IntPtr
End Function

Private Sub LoadAssembly(ByVal myAssembly As String, Optional ByVal doLoadLibrary As Boolean = False)
    Dim an As AssemblyName
    Dim filename As String
    Dim version As String

    If UIntPtr.Size = 8 Then version = "x64" Else version = "x86"
    filename = GetAssemblyPath(myAssembly, version)

    Try
        If doLoadLibrary Then
            HostLog.WriteEntry(filename, EventLogEntryType.Information)
            Dim ptr As IntPtr = LoadLibraryW(filename)
            HostLog.WriteEntry(ptr.ToString(), EventLogEntryType.Information)
        Else
            an = AssemblyName.GetAssemblyName(filename)
            AppDomain.CurrentDomain.Load(an)
        End If
    Catch ex As Exception
        HostLog.WriteEntry(ex.Message, EventLogEntryType.Error)
    End Try
End Sub ' LoadAssembly

编辑如评论中所述，我未能指定在尝试加载 sqlite3.dll 时收到的实际错误。事实证明，我的 App.Config 中缺少以下内容:

<system.data>
  <DbProviderFactories>
    <remove invariant="Devart.Data.SQLite" />
    <add name="dotConnect for SQLite" 
       invariant="Devart.Data.SQLite" 
       description="Devart dotConnect for SQLite" 
       type="Devart.Data.SQLite.SQLiteProviderFactory, Devart.Data.SQLite, Version=4.2.122.0, Culture=neutral, PublicKeyToken=09af7300eec23701" />
  </DbProviderFactories>
</system.data>

将此添加到 App.Config 后，我之前的代码示例按预期工作。感谢大家的帮助。

Answer 1

您可以创建一个具有两个实现的接口(interface)。一个 x86 实现和一个 x64 实现。可以说 [DllImport("x86version.dll")]Bob(string s); 也可以说 [DllImport("x64version.dll")]Bob(string s);

例子:

public interface ISQLite
{
    public void Foo();
}

public class SQLite32 : ISQLite
{
   [DllImport("x86/SQLite3.dll")]
    private void foo();
   public void Foo()
   {
       foo();
   }
}

public class SQLite64 : ISQLite
{
   [DllImport("x64/SQLite3.dll")]
    private void foo();
   public void Foo()
   {
      foo();
   }
}

public static class SQLiteLoader
{
   public static ISQLite GetSQLite()
   {
       if(System.Environment.Is64BitOperatingSystem)
          return new SQLite64();
       else
          return new SQLite32();
   }
}