Json.net append json file - json

Question

I have the following code which uses Json.net:
class HistorianRecord
{
public string tagname { get; set; }
public string engunits { get; set; }
public string value { get; set; }
public string quality { get; set; }
public DateTime timestamp { get; set; }
}
private static void createJSONFile(DataTable dt)
{
var HistorianData = new List<HistorianRecord>();
foreach(DataRow row in dt.Rows)
{
HistorianData.Add(new HistorianRecord()
{
tagname = row["tagname"].ToString(),
engunits = row["engunits"].ToString(),
value = row["value"].ToString(),
quality = row["quality"].ToString(),
timestamp = DateTime.Parse(row["timestamp"].ToString())
});
}
var serializer = new JavaScriptSerializer();
var serializedResult = serializer.Serialize(HistorianData);
var deserializedResult = serializer.Deserialize<List<HistorianRecord>>(serializedResult);
File.WriteAllText(folderPath + fileName, JsonConvert.SerializeObject(deserializedResult));
}
Which produces the following JSON file, which I have shortened for this post as the are > 1000 rows in the datatable:
[
{
"tagname": "mytag1",
"engunits": "",
"value": "2",
"quality": "Good NonSpecific",
"timestamp": "2018-12-13T10:45:05Z"
},
{
"tagname": "myTag2",
"engunits": "",
"value": "0",
"quality": "Good NonSpecific",
"timestamp": "2018-12-13T10:45:00Z"
}
]
I would like to amend my code to so I can add some items at the beginning of the JSON file so it looks more like this:
[
{
"name": "ARandomName",
"content": [
{
"tagname": "mytag1",
"engunits": "",
"value": "2",
"quality": "Good NonSpecific",
"timestamp": "2018-12-13T10:45:05Z"
},
{
"tagname": "myTag2",
"engunits": "",
"value": "0",
"quality": "Good NonSpecific",
"timestamp": "2018-12-13T10:45:00Z"
}
]
}
]
This is so I can create some documents for a test MongoDB installation that I am investigating so all help is appreciated.

Answer 1

You simply can wrap your deserialized list of HistorianRecords in an anonymous object and reserialize it:
var anon = new
{
name = "ARandomName",
content = deserializedResult
};
string newJson = JsonConvert.SerializeObject(anon, Formatting.Indented);
Fiddle: https://dotnetfiddle.net/6kSvxS