title: How to get connectionString from EF Core 2.0 DbContext
body: <p>In EF6 works this code:</p>
  
  <pre><code>    public string GetConnectionString(DbContext ctx)
      {
          ObjectContext _objectContext = ((IObjectContextAdapter)ctx).ObjectContext;
          if (_objectContext?.Connection != null)
          {
              EntityConnection entityConnection = _objectContext.Connection as EntityConnection;
              return entityConnection?.StoreConnection?.ConnectionString;
          }
          return null;
      }
  </code></pre>
  
  <p>How to do it in EF Core 2.0 ?</p>