How to a file in a different drive called by dll?

I’m working on my first dockerfile from Visual Studio 2022. This is an .net core 2.1 MVC project. I started with the dockerfile created by VS. The image and container were created fine, except the runtime error System.IO.FileNotFoundException: Could not find file xxx. Here’s the dockerfile:

FROM AS base

FROM AS build
COPY . .
COPY /bin/Release/netcoreapp2.1/Library.dll .
COPY [“List.csproj”, “.”]
RUN dotnet restore “./List.csproj”
COPY . .
WORKDIR “/src/.”
RUN dotnet build “List.csproj” -c Release -o /app/build

FROM build AS publish
RUN dotnet publish “List.csproj” -c Release -o /app/publish /p:UseAppHost=false

FROM base AS final
COPY /Conn/Conn.xml /app/Conn/Conn.xml
COPY --from=publish /app/publish .
ENTRYPOINT [“dotnet”, “List.dll”]

The problem seems to be with this line:
COPY /Conn/Conn.xml /app/Conn/Conn.xml

The actually file c:\Conn\Conn.xml is called by a dll. I copied \Conn\Conn.xml to my project folder to avoid the docker build error. And the container has /app/Conn/Conn.xml. But obviously /app is not c:.

How can I solve the problems? Thanks.