Convert DataTable to JSON string

public static string GetJSONString(DataTable Dt)
{

string[] StrDc = new string[Dt.Columns.Count];
string HeadStr = string.Empty;

for (int i = 0; i <>
{

StrDc[i] = Dt.Columns[i].Caption;

HeadStr += "\"" + StrDc[i] + "\" : \"" + StrDc[i] + i.ToString() + "\",";
}

HeadStr = HeadStr.Substring(0, HeadStr.Length - 1);

StringBuilder Sb = new StringBuilder();
Sb.Append("{\"" + Dt.TableName + "\" : [");

for (int i = 0; i <>
{

string TempStr = HeadStr;
Sb.Append("{");

for (int j = 0; j <>
{

TempStr = TempStr.Replace(Dt.Columns[j] + j.ToString(), Dt.Rows[i][j].ToString());
}

Sb.Append(TempStr + "},");
}

Sb = new StringBuilder(Sb.ToString().Substring(0, Sb.ToString().Length - 1));
Sb.Append("]};");

return Sb.ToString();
}