Create CSV file from Data Table in asp.net with c#

Step 1:  Write this code on Button click event   

        if (GridLoginStatus.Rows.Count != 0)

        {

          string strFilePath =

            ConfigurationManager.AppSettings["CSVFilePath"];   

            CreateCSVFile(dt, strFilePath);

            lblErrorMsg.Text = "Report Saved";

        }

        else

        {

            lblErrorMsg.Text = "No Data Captured";

        }

Step 2:  Add a function on the form

    public void CreateCSVFile(DataTable dt, string strFilePath)

    {

        // Create the CSV file to which grid data will be exported.

        StreamWriter sw = new StreamWriter(strFilePath, false);

        // First we will write the headers.

        int iColCount = dt.Columns.Count;

        for (int i = 0; i < iColCount; i++)

 {

            sw.Write(dt.Columns[i]);

            if (i < iColCount - 1)

            {

                sw.Write(",");

            }

        }

        sw.Write(sw.NewLine);

        // Now write all the rows.

        foreach (DataRow dr in dt.Rows)

        {

            for (int i = 0; i < iColCount; i++)

            {

                if (!Convert.IsDBNull(dr[i]))

                {

                    sw.Write(dr[i].ToString());

                }

                if (i < iColCount - 1)

                {

                    sw.Write(",");

                }

            }

            sw.Write(sw.NewLine);

        }

        sw.Close();

    }