public abstract class OutBase<T>
  {
    public abstract T Find(string s);
    public abstract void Insert(T t);
  }

 public class OutExcel : OutBase<Excel.Range>
  {
    public Excel.Application XlApp { get; private set; }
    public Excel.Workbook XlWorkBook { get; private set; }
    public Excel.Worksheet XlWorkSheet { get; private set; }
    private object _misValue = Missing.Value;
    private string _excelFileName = string.Empty;

    public OutExcel(string excelFileName)
    {
      _excelFileName = excelFileName;
      OpenApp();
    }

    ~OutExcel()
    {
      CloseApp();
    }

    public override Excel.Range Find(string s)
    {
      throw new NotImplementedException();
    }

    public override void Insert(Excel.Range t)
    {
      throw new NotImplementedException();
    }
  }

    public abstract class Goods
    {
      public OutExcel Output { get; }
      public string Proposal { get; }

      public Goods(OutExcel output, string proposal)
      {
        Output = output;
        Proposal = proposal;
      }

      public abstract void SearchProposal();

      public override abstract string ToString();
    }

  public class TableGood : Goods
  {

    public TableGood(OutExcel output, string proposal, string tableName): base(output, proposal)
    {
    }

    public override void SearchProposal()
    {
      throw new NotImplementedException();
    }

    public override string ToString()
    {
      throw new NotImplementedException();
    }
  }