如何使 Sqlite 在 Windows 10 中工作

Question

There is a classic application where Microsoft is used.Entity Framework Core.Sqlite, trying to publish an application through Windows 10 deployment and throws an exception: DllNotFoundException: Unable to load DLL "e_sqlite3": the specified module could not be found. (Exception from HRESULT: 0x8007007E)

Tried adding e_sqlite3 library to " Windows application packaging Project", in end face with the exception: SQLite Error 14: 'unable to open database file' with EF Core code first

I tried different solutions found on the Internet, but not one I did not fit.

Development environment: Windows 10, Visual Studio 2017, Microsoft.EntityFrameworkCore.Sqlite 2.2.1.0 and Microsoft.Data.Sqlite 2.2.1.0

Answer 1

Here's how I solved both issues.

The first issue is that the native e_sqlite3.dll files are not copied to the Package project's output. The Package project has MSBuild logic in Microsoft.DesktopBridge.targets that is calling the GetCopyToOutputDirectoryItems target of each of its referenced projects (eg a WPF project). Since the e_sqlite3.dll files are being included in the referenced project by way of a NuGet package, the way in which they are being included doesn't cause them to be picked up by the GetCopyToOutputDirectoryItems target. I've worked around this by adding the following code to my WPF project:

  <Target Name="IncludeNativeBinariesAsOutput" BeforeTargets="GetCopyToOutputDirectoryItems">
    <ItemGroup>
      <Content Include="$(OutputPath)\x64\e_sqlite3.dll">
        <Link>x64\e_sqlite3.dll</Link>
        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
      </Content>
      <Content Include="$(OutputPath)\x86\e_sqlite3.dll">
        <Link>x86\e_sqlite3.dll</Link>
        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
      </Content>
    </ItemGroup>

    <AssignTargetPath Files="@(Content)" RootFolder="$(MSBuildProjectDirectory)">
      <Output TaskParameter="AssignedFiles" ItemName="ContentWithTargetPath" />
    </AssignTargetPath>
  </Target>

The next issue is with the "unable to open database file" error after the necessary native files are where they need to be. I'm thinking this is because it's trying to create the project in a location that is not supported by a Windows Package project. I've handled this by setting a special value that that SqliteConnection looks for to construct a path for the database file. I just added this line to my App constructor class before doing any database operations.

AppDomain.CurrentDomain.SetData("DataDirectory", ApplicationData.Current.LocalFolder.Path);