clear value of dynamic generated control issue.

public 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)gvAnswer.Rows[rowIndex].Cells[1].FindControl("txtAnswer"); drCurrentRow = dtCurrentTable.NewRow(); drCurrentRow["RowNumber"] = i + 1; drCurrentRow["Column1"] = box1.Text; 
                    rowIndex++;
                }
                //add new row to DataTable
               // dtCurrentTable.Rows.Add(drCurrentRow);
                //Store the current data to ViewState dtCurrentTable.Rows.Add(drCurrentRow); 
                ViewState["CurrentTable"] = dtCurrentTable;

                //Rebind the Grid with the current data
                gvAnswer.DataSource = dtCurrentTable;
                gvAnswer.DataBind();
            }
        }
        else
        {
            Response.Write("ViewState is null");
        }

        //Set Previous Data on Postbacks
        SetPreviousData();
    }

i have created dynamic text box at button click event.everytime i have called  AddNewRowToGrid() () to button click event.

now i have added 3 blank textbox.now i have enter value in 1st text box and click button .then new row have generated but 1st text box value was clearing.but i want to get that value...

u can see above highlighted code ...if any one have any idea let me know as earlier as possible.

Thanks,

Khushboo Nayak.