Convert Datatable to JSON in ASP.net using C#

Introduction:

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for machines to parse and generate. JSON is a text format that is completely language independent.

JSON is built on two structures:

- A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.

- An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.

Fore more information visit http://en.wikipedia.org/wiki/JSON

There are the follwing ways to do this:-

Method 1:

public static string ConvertTableToJSON()

    {

        DataTable dtEmployee = new DataTable(); 

       

        dtEmployee.Columns.Add("EmpId", typeof(int));

        dtEmployee.Columns.Add("Name", typeof(string));

        dtEmployee.Columns.Add("Address", typeof(string));

        dtEmployee.Columns.Add("Date", typeof(DateTime));

        //

        // Here we add five DataRows.

        //

        dtEmployee.Rows.Add(25, "Rk", "Gurgaon", DateTime.Now);

        dtEmployee.Rows.Add(50, "Sachin", "Noida", DateTime.Now);

        dtEmployee.Rows.Add(10, "Nitin", "Noida", DateTime.Now);

        dtEmployee.Rows.Add(21, "Aditya", "Meerut", DateTime.Now);

        dtEmployee.Rows.Add(100, "Mohan", "Banglore", DateTime.Now);

        //gvEmployees.DataSource = dtEmployee;

        string[] jsonArray = new string[dtEmployee.Columns.Count];

        string headString = string.Empty;

        for (int i = 0; i < dtEmployee.Columns.Count; i++)

        {

            jsonArray[i] = dtEmployee.Columns[i].Caption; // Array for all columns

            headString += "'" + jsonArray[i] + "' : '" + jsonArray[i] + i.ToString() + "%" + "',";

        }

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

       

        StringBuilder sb = new StringBuilder();

        sb.Append("[");

        if (dtEmployee.Rows.Count > 0)

        {

            for (int i = 0; i < dtEmployee.Rows.Count; i++)

            {

                string tempString = headString;

                sb.Append("{");

                // To get each value from the datatable

                for (int j = 0; j < dtEmployee.Columns.Count; j++)

                {

                    tempString = tempString.Replace(dtEmployee.Columns[j] + j.ToString() + "%", dtEmployee.Rows[i][j].ToString());

                }

                sb.Append(tempString + "},");

            }

        }

        else

        {

            string tempString = headString;

            sb.Append("{");

            for (int j = 0; j < dtEmployee.Columns.Count; j++)

            {

                tempString = tempString.Replace(dtEmployee.Columns[j] + j.ToString() + "%", "-");

            }

            sb.Append(tempString + "},");

        }

        sb = new StringBuilder(sb.ToString().Substring(0, sb.ToString().Length - 1));

        sb.Append("]");       

        return sb.ToString(); // json formated output

    }

Output

Method 2: 

public string GetJson()

    {

        System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();

        List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();

        Dictionary<string, object> row = null;

        DataTable dtEmployee = new DataTable();

        dtEmployee.Columns.Add("EmpId", typeof(int));

        dtEmployee.Columns.Add("Name", typeof(string));

        dtEmployee.Columns.Add("Address", typeof(string));

        dtEmployee.Columns.Add("Date", typeof(DateTime));

        //

        // Here we add five DataRows.

        //

        dtEmployee.Rows.Add(25, "Rk", "Gurgaon", DateTime.Now);

        dtEmployee.Rows.Add(50, "Sachin", "Noida", DateTime.Now);

        dtEmployee.Rows.Add(10, "Nitin", "Noida", DateTime.Now);

        dtEmployee.Rows.Add(21, "Aditya", "Meerut", DateTime.Now);

        dtEmployee.Rows.Add(100, "Mohan", "Banglore", DateTime.Now);

        foreach (DataRow dr in dtEmployee.Rows)

        {

            row = new Dictionary<string, object>();

            foreach (DataColumn col in dtEmployee.Columns)

            {

                row.Add(col.ColumnName, dr[col]);

            }

            rows.Add(row);

        }

        return serializer.Serialize(rows);

    }    

Output

 

Download the source code click here ..

I hope this will help you.. :)