show value in textbox into gridview asp.net

 protected void Button2_Click(object sender, EventArgs e)
    {
        if (TextBox1.Text == "")
        {
            ScriptManager.RegisterStartupScript(this, this.GetType(), "script", "alert('PR no can not be blank');", true);
        }
        else
        {
            string unit = "", prno = ""; int qty = 0, accsl = 0; string remark = ""; decimal price = 0;
            for (int i = 0; i <= GridView1.Rows.Count - 1; i++)
            {
                GridViewRow row = GridView1.Rows[i];
                CheckBox Chbox = (CheckBox)row.FindControl("chb1");
                if (Chbox.Checked == true)
                {
                    select++;
                }
            }

            if (select == 0)
            {
                ScriptManager.RegisterStartupScript(this, this.GetType(), "script", "alert('select checkbox for insert)');", true);
                return;
            }

            for (int i = 0; i <= GridView1.Rows.Count - 1; i++)
            {
                GridViewRow row = GridView1.Rows[i];
                CheckBox Chbox = (CheckBox)row.FindControl("chb1");
                if (Chbox.Checked == true)
                {
                    for (int j = 1; j < GridView1.Rows[i].Cells.Count; j++)
                    {

                        prno = TextBox1.Text;
                        //accsl = int.Parse(Label2.Text);
                        if (j == 1) qty = Convert.ToInt32(GridView1.Rows[i].Cells[j].Text);
                        if (j == 2) price = Convert.ToDecimal(GridView1.Rows[i].Cells[j].Text);
                        if (j == 3) unit = GridView1.Rows[i].Cells[j].Text;
                        if (j == 4) remark = GridView1.Rows[i].Cells[j].Text;
                        if (j == 5) accsl = Convert.ToInt32(GridView1.Rows[i].Cells[j].Text);
                    }
                    InsertData(prno, qty,price, unit, remark, accsl);
                    ScriptManager.RegisterStartupScript(this, this.GetType(), "script", "alert('Success fully added (PR...)');", true);

                }
            }
            TextBox1.Enabled = true;
            Button2.Visible = false;
        }
    }