Checkbox changed with gridview data textboxs upload

Hello everyone click the chechbox event then in gridview data upload in form textbox upload.How can I do. My code is below. Can anyone help me please..

protected void chkcsec_CheckedChanged1(object sender, EventArgs e)
    {
        string deleting;
        string deleting1;
        string deleting2;
        string deleting3;
        string deleting4;
        foreach (GridViewRow row in GridView1.Rows)
        {

            CheckBox chk = (CheckBox)row.FindControl("chkcsec");
            if (chk != null && chk.Checked == true)
            {

                deleting= row.Cells[2].Text;
                deleting1= row.Cells[3].Text;
                deleting2= row.Cells[4].Text;
                deleting3 = row.Cells[5].Text;
                deleting4= row.Cells[6].Text;

                txtGuncelle.Visible = true;

                txtGuncelle.Text = silinecek;
                txtbaslik.Text = silinecek1;
                txtaciklama.Text = silinecek2;
                drpkategori.SelectedItem.Value = silinecek4;


            }


        }