I have a data table like below

Question column will contain the question in text format.

Json should be

{
    "Subject":"English",
    "xxxxxxx":"Subjective",
    "yyyyyyy":"Subjective",
    "zzzzzzz":"Objective",
    "sasasas":"Objective",
    "cvcvcvv":"Subjective"
}

I have tried like below. But this will not return above output.

var list = new List<string[]>();
foreach (DataRow row in dt_questions.Rows)
{
    string Subject   = row["Subject"].ToString();
    string Question= row["Question"].ToString();
    string Qtype= row["Qtype"].ToString();
    list.Add(new string[] { Subject, Question, Qtype});
}
var jsonSerialiser = new JavaScriptSerializer();
var json = jsonSerialiser.Serialize(list);

CodePudding user response：

Since the 'subject' should be used only once, you have to treat this outside the loop, and loop over the rest.
Then use a dictionary instead of a list:

var dt = new DataTable();
foreach(string c in "Subject,Question,Qtype".Split(','))
    dt.Columns.Add(c, typeof(string));
    
for(int i = 1; i<= 5;i  )
    dt.Rows.Add("English", $"Q{i}", (i==3 || i==4 ? "Objective" : "Subjective"));   

var dc = new Dictionary<string, string>();

dc.Add("Subject", dt.Rows[0].Field<string>("Subject"));

foreach(DataRow r in dt.Rows)
{
    dc.Add(r.Field<string>("Question"), r.Field<string>("QType"));
}

var jsonSerialiser = new JavaScriptSerializer();
var json = jsonSerialiser.Serialize(dc);

Or with Newtonsoft:

string json2 = Newtonsoft.Json.JsonConvert.SerializeObject(dc);