DataTable与json互转，字段类型信息丢失问题初探

最近遇到个项目，需要用到DataTable类型对象与json字符串的互转，datatable中字段的类型容易丢失，倒腾了一下，算是把这个问题初步解决了（剩下的就是些特殊字符的处理问题~~）。建议感兴趣的同学研究下framework里面的System.Web.Script.Serialization程序集或者Newtonsoft.Json开源项目，里面有很多关于json的知识。

约定json传递的格式：{“totalCount”:"1000","fieldType":{"id":"GUID",“name”:"string","birth":"date"},"data":[{"id":"","name":"","birth":""},{},{},....{}]},

工具类中的方法：

public static string SerializeDataTable2(DataTable dt)
        {
            if (null == dt || 0 == dt.Columns.Count)
            {
                throw new Exception("invalid datatable!");
            }
            StringBuilder json = new StringBuilder();
            int totalCount = dt.Rows.Count;
            json.Append("{"totalCount":"" + totalCount + "",");

            json.Append(""fieldType":{");
            foreach (DataColumn dc in dt.Columns)
            {
                json.Append(""" + dc.ColumnName + "":"" + dc.DataType.ToString() + "",");
            }
            json.Remove(json.Length - 1, 1).Append("},"data":");

            JavaScriptSerializer serializer = new JavaScriptSerializer();
            serializer.MaxJsonLength = 2097152 * 10;
            List<Dictionary<string, object>> list = new List<Dictionary<string, object>>();
            foreach (DataRow dr in dt.Rows)
            {
                Dictionary<string, object> result = new Dictionary<string, object>();
                foreach (DataColumn dc in dt.Columns)
                {
                    result.Add(dc.ColumnName, dr[dc].ToString());
                }
                list.Add(result);
            }
            json.Append(serializer.Serialize(list)).Append("}");
            return json.ToString();
        }


        /*
         {"totalCount":"100","fieldType":{},"data":[{},{},...{}]}
         */
        public static DataTable DeSerializeToDataTable2(string json)
        {
            if (string.IsNullOrEmpty(json))
            {
                throw new Exception("invalid json string!");
            }
            DataTable dtb = new DataTable();


            try
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                Dictionary<string, object> dic = serializer.Deserialize<Dictionary<string, object>>(json);
                int totalCount = Convert.ToInt32(dic["totalCount"]);

                foreach (KeyValuePair<string, object> kv in dic["fieldType"] as Dictionary<string, object>)
                {
                    dtb.Columns.Add(new DataColumn(kv.Key, Type.GetType(kv.Value.ToString())));
                }

                foreach (Dictionary<string, object> drow in dic["data"] as ArrayList)
                {
                    DataRow row = dtb.NewRow();
                    foreach (string key in drow.Keys)
                    {
                        if (string.IsNullOrEmpty(drow[key].ToString()))
                        {
                            Type type = dtb.Columns[key].DataType;
                            if (type.Equals(typeof(string)))
                            {
                                row[key] = DBNull.Value;
                                continue;
                            }
                            if (type.Equals(typeof(int)))
                            {
                                row[key] = DBNull.Value;
                                continue;
                            }

                            if (type.Equals(typeof(decimal)))
                            {
                                row[key] = DBNull.Value;
                                continue;
                            }
                            if (type.Equals(typeof(DateTime)))
                            {
                                row[key] = DBNull.Value;
                                continue;
                            }
                            if (type.Equals(typeof(Guid)))
                            {
                                row[key] = DBNull.Value;
                                continue;
                            }

                            row[key] = type.Assembly.CreateInstance(dtb.Columns[key].DataType.ToString());
                            continue;
                        }
                        row[key] = drow[key];//添加列值
                    }
                    dtb.Rows.Add(row);//添加一行
                }

            }
            catch (Exception e)
            {
                throw e;
            }
            return dtb;
        }

亲测有效，欢迎拍砖。