Database not updating .Why?

//update the customer selected from grid
/////////////////updation of data///////////
SqlConnection con5 = new SqlConnection();
SqlCommand cmd5 = new SqlCommand();
con5.ConnectionString = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database1.mdf;Integrated Security=True;User Instance=True";
cmd5.Connection = con5;
con5.Open();
cmd5.Parameters.AddWithValue("@customerno", TextBox1.Text);
cmd5.Parameters.AddWithValue("@fname", TextBox2.Text);
cmd5.Parameters.AddWithValue("@mname", TextBox3.Text);
cmd5.Parameters.AddWithValue("@lname", TextBox4.Text);
cmd5.Parameters.AddWithValue("@gender", DropDownList1.Text);
cmd5.Parameters.AddWithValue("@email", TextBox5.Text);
cmd5.Parameters.AddWithValue("@mobile1", TextBox6.Text);
cmd5.Parameters.AddWithValue("@mobile2", TextBox7.Text);
cmd5.Parameters.AddWithValue("@flat", TextBox8.Text);
cmd5.Parameters.AddWithValue("@wing", TextBox9.Text);
cmd5.Parameters.AddWithValue("@society", TextBox10.Text);
cmd5.Parameters.AddWithValue("@landmark", TextBox11.Text);
cmd5.Parameters.AddWithValue("@road", TextBox12.Text);
cmd5.Parameters.AddWithValue("@city", TextBox13.Text);
cmd5.Parameters.AddWithValue("@pincode", TextBox14.Text);
cmd5.CommandText = "Update customer set fname=@fname,mname=@mname,lname=@lname,gender=@gender,email=@email,mobile1=@mobile1,mobile2=@mobile2,flat=@flat,wing=@wing,society=@society,landmark=@landmark,road=@road,city=@city,pincode='"+TextBox14.Text +"' where customerno='"+TextBox1.Text+"'" ;
cmd5.ExecuteNonQuery();
string showHelloWorld = "alert('Done');";

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "msg", showHelloWorld, true);

TextBox1.Text = "";
TextBox2.Text = "";
TextBox3.Text = "";
TextBox4.Text = "";
TextBox5.Text = "";
TextBox6.Text = "";
TextBox7.Text = "";
TextBox8.Text = "";
TextBox9.Text = "";
TextBox10.Text = "";
TextBox11.Text = "";
TextBox12.Text = "";
TextBox13.Text = "";
TextBox14.Text = "";
//disabling the update and delete button on page load
Button3.Enabled = false;
Button4.Enabled = false;
/////////////////////////
//enabling the addnew button

///////////