递归地将多个 Datatable 层次结构序列化为 JSON 对象

Question

我想将多个相互关联的 DataTable 序列化为 JSON，并且可能会在映射表中设置额外的表。在这种情况下，我有 3 个数据表。

• 表 A 作为父表
• 表 B 作为表 A 的子表
• 表 C 作为表 B 的子表

JSON 输出应该是

{
    "TableA": [
        {
            "ID": "2490",
            "TYPE": "Electronic",
            "TableB": [
                {
                    "ID": "2490",
                    "ITEM": "XMT123",
                    "RECEIPT_NUM": "59",
                    "TableC": [
                        {
                            "ID": "2490",
                            "ITEM": "XMT123",
                            "QUANTITY": "164"
                        }
                    ]
                },
                {
                    "ID": "2491",
                    "ITEM": "XMT234",
                    "RECEIPT_NUM": "12",
                    "TableC": [
                        {
                            "ID": "2491",
                            "ITEM": "XMT234",
                            "QUANTITY": "92"
                        }
                    ]
                }
            ]
        },
        {
            "ID": "2491",
            "TYPE": "Electronic",
            "TableB": [
                {
                    "ID": "2491",
                    "ITEM": "XMT456",
                    "RECEIPT_NUM": "83",
                    "TableC": [
                        {
                            "ID": "2491",
                            "ITEM": "XMT456",
                            "QUANTITY": "261"
                        }
                    ]
                },
                {
                    "ID": "2492",
                    "ITEM": "XMT567",
                    "RECEIPT_NUM": "77",
                    "TableC": [
                        {
                            "ID": "2492",
                            "ITEM": "XMT567",
                            "QUANTITY": "70"
                        }
                    ]
                }
            ]
        }
    ]
}

我已经尝试过这样的代码，但它似乎不起作用

static void dataToJson(string connection_string, string query, string table_name)
{
    try
    {
        JArray jArray = new JArray();
        DataTable tbl = new DataTable();
        DataTable inner_tbl = new DataTable();
        SqlConnection conn = new SqlConnection(connection_string);
        conn.Open();
        var adapter = new SqlDataAdapter(query, conn); // query to get parent
        adapter.Fill(tbl);
        foreach (DataRow row in tbl.Rows)
        {
            JObject jo = new JObject();
            foreach (DataColumn col in tbl.Columns)
            {
                jo.Add(new JProperty(col.ColumnName.ToString(), row[col].ToString()));
            }
            jArray.Add(jo);

            query = "i have query to get child";
            dataToJson(connection_string, query, table_child);                  
        }
    }
    catch (Exception e)
    {
        WriteLog(e.Message, GetCurrentMethod(e));
    }
}

Answer 1

您必须在此递归方法中传递父级或返回子级。此外，如果所有表都在同一个数据库中，您不必每次都打开SqlConnection。
以下是传递父级的示例：

// Caller
JObject root = new JObject();
using (SqlConnection conn = new SqlConnection(connection_string))
{
    conn.Open();
    dataToJson(root, conn, query, "TableA");
}
Console.WriteLine(root.ToString());


static void dataToJson(JObject parent, SqlConnection conn, string query, string table_name)
{
    if (string.IsNullOrEmpty(table_name)) { return; }
    try
    {
        JArray jArray = new JArray();
        DataTable tbl = new DataTable();
        //DataTable inner_tbl = new DataTable();
        //SqlConnection conn = new SqlConnection(connection_string);
        //conn.Open();
        var adapter = new SqlDataAdapter(query, conn); // query to get parent
        adapter.Fill(tbl);
        foreach (DataRow row in tbl.Rows)
        {
            JObject jo = new JObject();
            foreach (DataColumn col in tbl.Columns)
            {
                jo.Add(new JProperty(col.ColumnName.ToString(), row[col].ToString()));
            }
            query = "i have query to get child";
            // Set the child table name to "table_child"
            dataToJson(jo, conn, query, table_child);  // Pass the JObject as the parent

            jArray.Add(jo); 
            parent.Add(new JProperty(table_name, jArray));
        }
    }
    catch (Exception e)
    {
        WriteLog(e.Message, GetCurrentMethod(e));
    }
}

顺便说一下，我不知道你是怎么得到子表的名字的，所以我用下面的字典来测试。

static Dictionary<string, string> table_hierarchy = new Dictionary<string, string>();
// Initialize
table_hierarchy.Add("TableA", "TableB");
table_hierarchy.Add("TableB", "TableC");
table_hierarchy.Add("TableC", "");