code throw execption

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

private void binddata()
{
    try
    {
        string connstring = @"Data Source=LENOVO-41B3F2CE\SQLEXPRESS;Initial Catalog=IMS;Integrated Security=True;Pooling=False";
        string query = "SELECT * FROM ['ISB VAS Nodes$']";
        SqlDataAdapter da = new SqlDataAdapter(query, connstring);
        DataTable dt = new DataTable();
        da.Fill(dt);
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
    catch (Exception)
    {
    
    }
}

protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
    GridView1.EditIndex = e.NewEditIndex;
    binddata();
}

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    GridViewRow row = GridView1.Rows[e.RowIndex];

    TextBox TextBoxEditID = (TextBox)row.FindControl("TextBoxEditID");
    TextBox TextBoxEditRackName = (TextBox)row.FindControl("TextBoxEditRackName");
    TextBox TextBoxEditqty = (TextBox)row.FindControl("TextBoxEditqty");
    TextBox TextBoxEdittype = (TextBox)row.FindControl("TextBoxEdittype");
    TextBox TextBoxEditdesc = (TextBox)row.FindControl("TextBoxEditdesc");
    TextBox TextBoxEditmodel = (TextBox)row.FindControl("TextBoxEditmodel");
    TextBox TextBoxEditsn = (TextBox)row.FindControl("TextBoxEditsn");
    TextBox TextBoxEditassettag = (TextBox)row.FindControl("TextBoxEditassettag");
    TextBox TextBoxEditcity = (TextBox)row.FindControl("TextBoxEditcity");
    TextBox TextBoxEditNodeName = (TextBox)row.FindControl("TextBoxEditNodename");
    TextBox TextBoxEditIPAddress = (TextBox)row.FindControl("TextBoxEditIPAddress");
    TextBox TextBoxEditFloatIP = (TextBox)row.FindControl("TextBoxEditFloatIP");
    TextBox TextBoxEditProcessors = (TextBox)row.FindControl("TextBoxEditProcessors");
    TextBox TextBoxEditRAM = (TextBox)row.FindControl("TextBoxEditRAM");
    TextBox TextBoxEditHardDisks = (TextBox)row.FindControl("TextBoxEditHarddisks");
    TextBox TextBoxEditRAIDManager = (TextBox)row.FindControl("TextBoxEditRAIDManager");



    //int productID = Int32.Parse(GridView1.DataKeys[e.RowIndex].Value.ToString());

    string ID = TextBoxEditID.Text;
    string Name = TextBoxEditRackName.Text;
    string qty = TextBoxEditqty.Text;
    string type = TextBoxEdittype.Text;
    string desc = TextBoxEditdesc.Text;
    string model = TextBoxEditmodel.Text;
    string sn = TextBoxEditsn.Text;
    string tag = TextBoxEditassettag.Text;
    string cty = TextBoxEditcity.Text;
    string node = TextBoxEditNodeName.Text;
    string ip = TextBoxEditIPAddress.Text;
    string fip = TextBoxEditFloatIP.Text;
    string pro = TextBoxEditProcessors.Text;
    string ram = TextBoxEditRAM.Text;
    string hd = TextBoxEditHardDisks.Text;
    string rmana = TextBoxEditRAIDManager.Text;

    Update(ID, Name, qty, type, desc, model, sn, tag, cty, node, ip, fip, pro, ram, hd, rmana);
}

private void Update(string ID, string Name, string qty, string type, string desc, string model, string sn, string tag, string cty, string node, string ip, string fip, string pro, string ram, string hd, string rmana)
{
    try
    {
        string constr = @"Data Source=LENOVO-41B3F2CE\SQLEXPRESS;Initial Catalog=inventory;Integrated Security=True;Pooling=False";
        string query = "UPDATE ['ISB VAS Nodes$'] SET RackName = @Name, QTY = @qty, Type = @type, [Desc] = @desc, Model = @model, SN = @sn, AssetTag = @tag, City = @cty, NodeName = @node, IPAddress = @ip, FloatIP = @fip, Processors = @pro, RAM = @ram, HardDisks = @hd, RAIDManager = @rmana WHERE ID = @ID";


        SqlConnection con = new SqlConnection(constr);
        SqlCommand com = new SqlCommand(query, con);


        com.Parameters.Add("@Name", SqlDbType.VarChar).Value = Name;
        com.Parameters.Add("@qty", SqlDbType.VarChar).Value = qty;
        com.Parameters.Add("@type", SqlDbType.VarChar).Value = type;
        com.Parameters.Add("@desc", SqlDbType.VarChar).Value = desc;
        com.Parameters.Add("@model", SqlDbType.VarChar).Value = model;
        com.Parameters.Add("@sn", SqlDbType.VarChar).Value = sn;
        com.Parameters.Add("@tag", SqlDbType.VarChar).Value = tag;
        com.Parameters.Add("@cty", SqlDbType.VarChar).Value = cty;
        com.Parameters.Add("@node", SqlDbType.VarChar).Value = node;
        com.Parameters.Add("@ip", SqlDbType.VarChar).Value = ip;
        com.Parameters.Add("@fip", SqlDbType.VarChar).Value = fip;
        com.Parameters.Add("@pro", SqlDbType.VarChar).Value = pro;
        com.Parameters.Add("@ram", SqlDbType.VarChar).Value = ram;
        com.Parameters.Add("@hd", SqlDbType.VarChar).Value = hd;
        com.Parameters.Add("@rmana", SqlDbType.VarChar).Value = rmana;
        com.Parameters.Add("@ID", SqlDbType.VarChar).Value = ID;


        con.Open();
        com.ExecuteNonQuery();
        con.Close();


        GridView1.EditIndex = -1;
        binddata();
    }
    catch (Exception ex)
    {
        throw ex; // give error at this point
    }
}