怎样实例化strSql,该怎么解决

怎样实例化strSql
public DataSet GetList(int FTypeID)
  {
  StringBuilder strSql = new StringBuilder();
  strSql.Append("select * ");
  strSql.Append(" FROM TProductsType where FTypeID=@FTypeID");
  return DBHelper.Query(strSql.ToString());
  }
总是说没有声明标量变量@FTypeID
怎样把strSql实例化

[解决办法]
改改 
strSql.Append( string.Format(" FROM TProductsType where FTypeID={0}",FTypeID));