Created a simple application that connects to PostgreSQL but when I containerized it using Docker i cant seem to start it and no port/s were shown when i ran the container. What seems to be the problem?

The application works without the Docker but when I containerize it, that's where the problem arises.

docker build is successful and when I use docker run

it gives me a container but when I check it using docker ps -a no ports where shown

This is what I did on docker terminal

and this is my code when connecting to PostgreSQL db

class Program
{
    static void Main(string[] args)
    {
        using (var connection = new NpgsqlConnection("Host=localhost;Username=postgres;Password=password;Database=user"))
        {
            connection.Open();
            connection.Execute("Insert into customer (name) values ('Mikolasola');");
            var value = connection.Query<string>("Select name from customer;");
            Console.WriteLine(value.First());
        }

        Console.Read();
    }
}

here's my docker file

FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS build-env
WORKDIR /app

COPY *.csproj ./
RUN dotnet restore

COPY . ./
RUN dotnet publish -c Release -o out

FROM mcr.microsoft.com/dotnet/core/aspnet:2.2
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "webapplication1.dll"]

Edit: Changed my Docker file to this and somehow I can get the port now

FROM microsoft/dotnet:2-sdk AS build-env
WORKDIR /app

COPY *.csproj ./
RUN dotnet restore

COPY . ./
RUN dotnet publish -c Release -r linux-x64 -o out

FROM microsoft/dotnet:2-runtime-deps
WORKDIR /app
COPY --from=build-env /app/out ./
ENTRYPOINT ["./webapplication1"]

But I can't run it. Here's the screenshot

Any help would be much appreciated. Thanks! PS: im a newbie