Save dynamically created gridview row data in database in ASP.Net

Sir i have used this code, please check, is it right? 

 protected void Page_Load(object sender, EventArgs e)
    {
      
        if (!Page.IsPostBack)
        {
            SetInitialRow();
        }
    }

    private void SetInitialRow()
    {
        DataTable dt = new DataTable();
        DataRow dr = null;
        dt.Columns.Add(new DataColumn("RowNumber", typeof(string)));
        dt.Columns.Add(new DataColumn("Column1", typeof(string)));
        dt.Columns.Add(new DataColumn("Column2", typeof(string)));
        dt.Columns.Add(new DataColumn("Column3", typeof(string)));
        dr = dt.NewRow();
        dr["RowNumber"] = 1;
        dr["Column1"] = string.Empty;
        dr["Column2"] = string.Empty;
        dr["Column3"] = string.Empty;
        dt.Rows.Add(dr);

        //Store the DataTable in ViewState
        ViewState["CurrentTable"] = dt;

        Gridview1.DataSource = dt;
        Gridview1.DataBind();
    }
    private void AddNewRowToGrid()
    {
        int rowIndex = 0;

        if (ViewState["CurrentTable"] != null)
        {
            DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
            DataRow drCurrentRow = null;
            if (dtCurrentTable.Rows.Count > 0)
            {
                for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
                {
                    //extract the TextBox values
                    TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
                    TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
                    TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3");

                    drCurrentRow = dtCurrentTable.NewRow();
                    drCurrentRow["RowNumber"] = i + 1;

                    dtCurrentTable.Rows[i - 1]["Column1"] = box1.Text;
                    dtCurrentTable.Rows[i - 1]["Column2"] = box2.Text;
                    dtCurrentTable.Rows[i - 1]["Column3"] = box3.Text;

                    rowIndex++;
                }
                dtCurrentTable.Rows.Add(drCurrentRow);
                ViewState["CurrentTable"] = dtCurrentTable;

                Gridview1.DataSource = dtCurrentTable;
                Gridview1.DataBind();
            }
        }
        else
        {
            Response.Write("ViewState is null");
        }

        //Set Previous Data on Postbacks
        SetPreviousData();
    }
    private void SetPreviousData()
    {
        int rowIndex = 0;
        if (ViewState["CurrentTable"] != null)
        {
            DataTable dt = (DataTable)ViewState["CurrentTable"];
            if (dt.Rows.Count > 0)
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
                    TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
                    TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3");

                    box1.Text = dt.Rows[i]["Column1"].ToString();
                    box2.Text = dt.Rows[i]["Column2"].ToString();
                    box3.Text = dt.Rows[i]["Column3"].ToString();

                    rowIndex++;
                }
            }
        }
    }
   
    protected void ButtonAdd_Click(object sender, EventArgs e)
    {
        AddNewRowToGrid();
    }
    protected void ButtonSave_Click(object sender, EventArgs e)
    {
        int rowIndex = 0;
        StringCollection sc = new StringCollection();
        if (ViewState["CurrentTable"] != null)
        {
            DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
            if (dtCurrentTable.Rows.Count > 0)
            {
                for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
                {
                    //extract the TextBox values
                    TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1");
                    TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2");
                    TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3");

                    //get the values from the TextBoxes
                    //then add it to the collections with a comma "," as the delimited values
                    sc.Add(box1.Text + "," + box2.Text + "," + box3.Text);
                    rowIndex++;
                }
                //Call the method for executing inserts
                InsertRecords(sc);
            }
        }
    }

    private void InsertRecords(StringCollection sc)
    {
       // SqlConnection conn = new SqlConnection();
        StringBuilder sb = new StringBuilder(string.Empty);
        string[] splitItems = null;
        foreach (string item in sc)
        {

            const string sqlStatement = "INSERT INTO tbsample (name,class,school) VALUES";
            if (item.Contains(","))
            {
                splitItems = item.Split(",".ToCharArray());
                sb.AppendFormat("{0}('{1}','{2}','{3}'); ", sqlStatement, splitItems[0], splitItems[1], splitItems[2]);
            }

        }

        try
        {
            con.Open();
            SqlCommand cmd = new SqlCommand(sb.ToString(), con);
            cmd.CommandType = CommandType.Text;
            cmd.ExecuteNonQuery();

            //Display a popup which indicates that the record was successfully inserted
            Page.ClientScript.RegisterClientScriptBlock(typeof(Page), "Script", "alert('Records Successfuly Saved!');", true);

        }
        catch (Exception ex)
        {
            string msg = "Insert Error:";
            msg += ex.Message;
            throw new Exception(msg);

        }
        finally
        {
            con.Close();
        }
    }

Refer

Save and Retrieve Dynamic TextBox values in GridView to SQL Server Database