Read JSON data from DataTable column and append value for each key using C# in ASP.Net

Hi narasiman,

Check this example. Now please take its reference and correct your code.

HTML

<asp:GridView ID="gvDetails" runat="server" />

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dtFarmerFarmReports = new DataTable();
        dtFarmerFarmReports.Columns.AddRange(new DataColumn[3] { 
            new DataColumn("Id", typeof(int)), new DataColumn("Name", typeof(string)), new DataColumn("Questions", typeof(string)) });
        dtFarmerFarmReports.Rows.Add(1, "OLAM ", "{\"Produto prefer\":\"Algodão\",\"Plantou algodão\":\"Sim\"}");
        dtFarmerFarmReports.Rows.Add(2, "OLAM ", "{\"Produto prefer\":\"Feijão Buer\",\"Plantou algodão\":\"Não\"}");
        dtFarmerFarmReports.Rows.Add(3, "OLAM ", "{\"Produto prefer\":\"Buer\",\"Plantou algodão\":\"Jao\"}");

        DataTable dtQuestionText = new DataTable();
        dtQuestionText.Columns.AddRange(new DataColumn[4] { 
            new DataColumn("Id", typeof(int)), new DataColumn("Name"), new DataColumn("QuestionText"), new DataColumn("QuestionValue") });
        foreach (DataRow row in dtFarmerFarmReports.Rows)
        {
            var dict = JsonConvert.DeserializeObject<Dictionary<string, string>>(row["Questions"].ToString());
            foreach (var items in dict)
            {
                dtQuestionText.Rows.Add(Convert.ToInt32(row["Id"]), row["Name"].ToString(), items.Key, items.Value);
            }
        }

        DataTable dtDynamicColumn = new DataTable();
        dtDynamicColumn.Columns.AddRange(new DataColumn[] { new DataColumn("Id", typeof(int)), new DataColumn("Name") });
        var distinctColumn = dtQuestionText.AsEnumerable().Select(x => x.Field<string>("QuestionText")).Distinct().ToList();
        for (int i = 0; i < distinctColumn.Count; i++)
        {
            dtDynamicColumn.Columns.Add(distinctColumn[i], typeof(string));
        }

        for (int i = 0; i < dtQuestionText.Rows.Count; i++)
        {
            dtDynamicColumn.Rows.Add();
            dtDynamicColumn.Rows[i][0] = Convert.ToInt32(dtQuestionText.Rows[i]["Id"]);
            dtDynamicColumn.Rows[i][1] = dtQuestionText.Rows[i]["Name"].ToString();
            DataTable selected = dtQuestionText.Select("Id=" + Convert.ToInt32(dtQuestionText.Rows[i]["Id"])).CopyToDataTable();
            for (int j = 0; j < selected.Rows.Count; j++)
            {
                if (selected.Rows[j][2].ToString().ToLower() == dtDynamicColumn.Columns[2].ToString().ToLower())
                {
                    dtDynamicColumn.Rows[i][2] = selected.Rows[j][3].ToString();
                }
                else if (selected.Rows[j][2].ToString().ToLower() == dtDynamicColumn.Columns[3].ToString().ToLower())
                {
                    dtDynamicColumn.Rows[i][3] = selected.Rows[j][3].ToString();
                }
            }
        }
        dtDynamicColumn = dtDynamicColumn.DefaultView.ToTable(true);
        gvDetails.DataSource = dtDynamicColumn;
        gvDetails.DataBind();
    }
}

Screenshot