JobNo wont appear on the text box when imputed

Question

When I input JobNo. example 04542, it won't appear on the textbox when I click on add button. Please check if anything is missing.

 

Thanks for always coming to my aid.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace NSPM_Sales_Invoice
{
public partial class frmNewBill : Form
{
SqlConnection con = new SqlConnection(Properties.Settings.Default.NSPM_Sales_InvoiceCon);
SqlCommand cmd;
public frmNewBill()
{
InitializeComponent();
txtDeleteUpdate.Visible = false;
}
{
cmbDescription.Select();
cmbDescription.Items.Clear();
con.Open();
cmd = con.CreateCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Select ProName from tbl_Products order by ProName asc";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);
foreach (DataRow dr in dt.Rows)
{
cmbDescription.Items.Add(dr["ProName"].ToString());
}
con.Close();
dataGridView1.Columns[5].Visible = false;
dataGridView1.Columns[6].Visible = false;
}
private void btnAdd_Click(object sender, EventArgs e)
{
if (cmbDescription.Text == "")
{
MessageBox.Show("Description is Empty");
}
else if (txtQuantity.Text == "")
{
MessageBox.Show("Quantity is Empty");
}
else if (txtUnitPrice.Text == "")
{
MessageBox.Show("Unit Price is Empty");
}
else if (txtJobNo.Text == "")
{
MessageBox.Show("JobNo is Empty");
if (txtDeleteUpdate.Text == "")
{
int row = 0;
dataGridView1.Rows.Add();
row = dataGridView1.Rows.Count - 1;
dataGridView1["Description", row].Value = cmbDescription.Text;
dataGridView1["Quantity", row].Value = txtQuantity.Text;
dataGridView1["UnitPrice", row].Value = txtUnitPrice.Text;
dataGridView1["GoodValue", row].Value = txtGoodValue.Text;
dataGridView1["JobNo", row].Value = txtJobNo.Text;
dataGridView1["Date", row].Value = dateTimePicker1.Value.ToString("yyyy-MM-dd");
dataGridView1.Refresh();
cmbDescription.Focus();
if (dataGridView1.Rows.Count > 0)
{
dataGridView1.CurrentCell = dataGridView1.Rows[dataGridView1.Rows.Count - 1].Cells[1];
}
}
else
{
btnAdd.Text = "UPDATE";
int i = 0;
DataGridViewRow row = dataGridView1.Rows[i];
row.Cells[1].Value = cmbDescription.Text;
row.Cells[2].Value = txtQuantity.Text;
row.Cells[3].Value = txtUnitPrice.Text;
row.Cells[4].Value = txtGoodValue.Text;
row.Cells[5].Value = txtJobNo.Text;
btnAdd.Text = "ADD";
}
cleartextbox();
gridGoodValue();
}
}
private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
{
this.dataGridView1.Rows[e.RowIndex].Cells[0].Value = (e.RowIndex + 1).ToString();
}
int i;
private void dataGridView1_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
i = e.RowIndex;
DataGridViewRow row = dataGridView1.Rows[i];
cmbDescription.Text = row.Cells[1].Value.ToString();
txtQuantity.Text = row.Cells[2].Value.ToString();
txtUnitPrice.Text = row.Cells[3].Value.ToString();
txtGoodValue.Text = row.Cells[4].Value.ToString();
txtJobNo.Text = row.Cells[5].Value.ToString();
txtDeleteUpdate.Text = row.Cells[0].Value.ToString();
btnAdd.Text = "UPDATE";
}
private void btnDelete_Click(object sender, EventArgs e)
{
if (txtDeleteUpdate.Text == "")
{
MessageBox.Show("Select Product to Delete");
}
else
{
foreach (DataGridViewRow row in dataGridView1.SelectedRows)
{
if (!row.IsNewRow) dataGridView1.Rows.Remove(row);
}
}
btnAdd.Text = "ADD";
gridGoodValue();
cleartextbox();
}
public void cleartextbox()
{
cmbDescription.Text = "";
txtQuantity.Text = "";
txtUnitPrice.Text = "";
txtGoodValue.Text = "";
txtJobNo.Text = "";
txtDeleteUpdate.Text = "";
}
}