C# 并非所有代码路径都返回值问题

我在一个类数据库中有这段代码

并非所有路径都返回值

任何帮助都将不胜感激

public static DataSet DELETE_PDT(String rowid)
{
    SqlConnection con = new SqlConnection();
    SqlCommand cmd = new SqlCommand("sp_DELETE_PDT", con);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.Add("@rowid", SqlDbType.Int).Value = rowid;

    con.ConnectionString = ConfigurationManager.ConnectionStrings["WMS"].ConnectionString;

    try
    {
        con.Open();
        cmd.ExecuteNonQuery();
        cmd.Dispose();
        con.Close();
    }
    catch (Exception ex)
    {
        throw new Exception("Error while deleting record. Please contact your System Administrator", ex);
    }
}

您的方法应该有一个返回值，因为您已将其声明为返回Dataset

例如

return new Dataset();

如果不想看到错误消息，请更改

public static DataSet DELETE_PDT(String rowid)
{
   // statements
}

到

更新1

根据您的评论，我将修改它以再次返回字符串值

public static string DELETE_PDT(String rowid)
{
    using (SqlConnection con = new SqlConnection())
    {
        con.ConnectionString = ConfigurationManager.ConnectionStrings["WMS"].ConnectionString;
        using (SqlCommand cmd = new SqlCommand("sp_DELETE_PDT", con))
        {
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("@rowid", SqlDbType.Int).Value = rowid;
            try
            {
                if (con.State == ConnectionState.Open)
                con.Close();
                con.Open();
                cmd.ExecuteNonQuery();
                return "Record has been deleted";
            }
            catch (Exception ex)
            {
                return "Error while deleting record. Please contact your System Administrator";
            }
        }
    }
}

---

您已经声明了返回数据集的方法。。。但你什么也不回。所以您需要返回DataSet的实例或更改方法签名。

您已声明该方法应返回DataSet，但它不会返回任何与该方法所做操作符合逻辑的内容。将签名更改为：

public static void DELETE_PDT(String rowid)

旁注：为了避免出现异常而留下未关闭的连接，可以使用。它确保无论发生什么情况，都始终释放命令和连接：

public static void DELETE_PDT(String rowid) {
  using (SqlConnection con = new SqlConnection()) {
    con.ConnectionString = ConfigurationManager.ConnectionStrings["WMS"].ConnectionString;
    using (SqlCommand cmd = new SqlCommand("sp_DELETE_PDT", con)) {
      cmd.CommandType = CommandType.StoredProcedure;
      cmd.Parameters.Add("@rowid", SqlDbType.Int).Value = rowid;
      try {
        con.Open();
        cmd.ExecuteNonQuery();
      } catch (Exception ex) {
        throw new Exception("Error while deleting record. Please contact your System Administrator", ex);
      }
    }
  }
}

---

我已经重构了你的代码；试试这个：

public static void DELETE_PDT(String rowid) {
    using(SqlConnection con = new SqlConnection()) {
        con.ConnectionString = ConfigurationManager.ConnectionStrings["WMS"].ConnectionString;
        using(SqlCommand cmd = new SqlCommand("sp_DELETE_PDT", con)) {
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("@rowid", SqlDbType.Int).Value = rowid;

            try
            {
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
            catch (Exception ex)
            {
                throw new Exception("Error while deleting record. Please contact your System Administrator", ex);
            }
        }
    }
}

---

我能把它改成什么？Thanks@jorame：将返回类型更改为void，即不返回任何内容，或实际返回一个数据集。再次感谢您John。John问题，我现在如何从主代码调用此方法？这是我之前的“DataBase.DELETE_PDTrowid；”@我也一样。您需要指定类名，因为该方法是静态的。DataBase.DELETE_PDTrowid；我想我明白了。我用了一个HiddenField作为rowid。让我试试John question，我正在从sp_DELETE_PDT返回一条消息。如何将其分配给主代码中的标签。我收到了这条消息。Text=DataBase.DELETE\u pdt并使用以下方法进行重新分解：

public static void DELETE_PDT(String rowid) {
    using(SqlConnection con = new SqlConnection()) {
        con.ConnectionString = ConfigurationManager.ConnectionStrings["WMS"].ConnectionString;
        using(SqlCommand cmd = new SqlCommand("sp_DELETE_PDT", con)) {
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("@rowid", SqlDbType.Int).Value = rowid;

            try
            {
                con.Open();
                cmd.ExecuteNonQuery();
                con.Close();
            }
            catch (Exception ex)
            {
                throw new Exception("Error while deleting record. Please contact your System Administrator", ex);
            }
        }
    }
}