convert from SqlDataReader to JSON

Question

public string toJSON(SqlDataReader o)
{
    StringBuilder s = new StringBuilder();
    s.Append(\"[\");
    if (o.HasRows)
        while (o.Read())
            s.App         


        

Answer 1

If you want something that'll convert to arbitrary JSON, you could convert by serializing it into a Dictionary(Of string, object) thusly:

public IEnumerable<Dictionary<string, object>> Serialize(SqlDataReader reader)
{
    var results = new List<Dictionary<string, object>>();
    var cols = new List<string>();
    for (var i = 0; i < reader.FieldCount; i++) 
        cols.Add(reader.GetName(i));

    while (reader.Read()) 
        results.Add(SerializeRow(cols, reader));

    return results;
}
private Dictionary<string, object> SerializeRow(IEnumerable<string> cols, 
                                                SqlDataReader reader) {
    var result = new Dictionary<string, object>();
    foreach (var col in cols) 
        result.Add(col, reader[col]);
    return result;
}

And then use the NewtonSoft.Json JsonConvert object to get your JSON:

var r = Serialize(reader);
string json = JsonConvert.SerializeObject(r, Formatting.Indented);

UPDATE: If you just want to use built-in methods, and you happen to be using MVC, you can use the built in Json helper method on your newly serialized :

JsonResult Index(int id) {
    var r = Serialize(reader);
    return Json(r, JsonRequestBehavior.AllowGet);
}

Answer 2

Try this:

o = cmd.ExecuteReader();
var dataQuery = from d in o.Cast<DbDataRecord>()
                select new
                {
                    Id = (String)d["Id"],
                    CN = (String)d["CatName"],
                    Ord = (String)d["Ord"],
                    Icon = (String)d["Icon"]
                };
var data = dataQuery.ToArray();
JavaScriptSerializer serializer = new JavaScriptSerializer();
String jsonData = serializer.Serialize(data);

Answer 3

With Cinchoo ETL - an open source library, you can export SqlDataReader to JSON easily with few lines of code

string connectionstring = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=Northwind;Integrated Security=True";
StringBuilder sb = new StringBuilder();

using (var conn = new SqlConnection(connectionstring))
{
    conn.Open();
    var comm = new SqlCommand("SELECT top 2 * FROM Customers", conn);

    using (var parser = new ChoJSONWriter(sb))
        parser.Write(comm.ExecuteReader());
}

Console.WriteLine(sb.ToString());

Output:

[
 {
  "CustomerID": "ALFKI",
  "CompanyName": "Alfreds Futterkiste",
  "ContactName": "Maria Anders",
  "ContactTitle": "Sales Representative",
  "Address": "Obere Str. 57",
  "City": "Berlin",
  "Region": {},
  "PostalCode": "12209",
  "Country": "Germany",
  "Phone": "030-0074321",
  "Fax": "030-0076545"
 },
 {
  "CustomerID": "ANATR",
  "CompanyName": "Ana Trujillo Emparedados y helados",
  "ContactName": "Ana Trujillo",
  "ContactTitle": "Owner",
  "Address": "Avda. de la Constitución 2222",
  "City": "México D.F.",
  "Region": {},
  "PostalCode": "05021",
  "Country": "Mexico",
  "Phone": "(5) 555-4729",
  "Fax": "(5) 555-3745"
 }
]

Answer 4

This should do the job

private String sqlDatoToJson(SqlDataReader dataReader)
{
    var dataTable = new DataTable();
    dataTable.Load(dataReader);
    string JSONString = string.Empty;
    JSONString = JsonConvert.SerializeObject(dataTable);
    return JSONString;
}

Answer 5

This is to enhance Chandu's Linq answer that uses query syntax (from ... select ...). If you prefer Method Syntax, here is your answer.

drdr = cmd.ExecuteReader();
Record[] recs = drdr.Cast<DbDataRecord>().Select( data=>new Record{
            GraphID=(drdr.IsDBNull(0) ? "" : (string)data["LabelX"])
        , XAxis=(drdr.IsDBNull(1) ? "1999-09-09 00:00:00" : Convert.ToDateTime(data["XDate"]).ToString("yyyy-MM-dd HH:mm:ss"))
        , YVal=(drdr.IsDBNull(2) ? 0 : int.Parse(data["YFreq"].ToString()))
        }).ToArray();

MemoryStream mem = new MemoryStream();
DataContractJsonSerializer szr = new DataContractJsonSerializer(typeof(Record[]));
szr.WriteObject(mem, recs);
String jsonData = Encoding.UTF8.GetString(mem.ToArray(), 0, (int)mem.Length); 

Hope it helps somebody.

Answer 6

Further to Jonathan's Answer, I had a similar requirement in ASP.NET Core to convert the result of an SQLDataReader to a JSON string or a Result Object, so I created an extension method for it as :

 public static class MyExtensions
    {
        public async static Task<string> toJSON(this SqlDataReader reader)
        {            
            var results = await reader.GetSerialized();
            return JsonConvert.SerializeObject(results, Formatting.Indented);
        }
        public async static Task<IEnumerable<Dictionary<string, object>>> GetSerialized(this SqlDataReader reader)
        {
            var results = new List<Dictionary<string, object>>();
            var cols = new List<string>();
            for (var i = 0; i < reader.FieldCount; i++)
                cols.Add(reader.GetName(i));

            while (await reader.ReadAsync())
                results.Add(SerializeRow(cols, reader));

            return results;
        }
        private static Dictionary<string, object> SerializeRow(IEnumerable<string> cols,
                                                        SqlDataReader reader)
        {
            var result = new Dictionary<string, object>();
            foreach (var col in cols)
                result.Add(col, reader[col]);
            return result;
        }
    }

& used it as per my requirement as :

var result = await reader.GetSerialized(); //to get the result object

or

string strResult = await reader.toJSON(); //to get the result string

I created an async method because I had some other things to be done till the reading was finished from database.