Updating user info but does not update and has no error - sql

Question

I'm trying to update multiple user info but it won't update. I have tried a lot of ways and all of them would execute, but they do not update the data, and yet throw no errors. Am I missing something?
Here is the code:
protected void Update_Click(object sender, EventArgs e)
{
using (SqlConnection sqlCon = new SqlConnection(connectionstring))
{
sqlCon.Open();
using (var sqlStt = sqlCon.CreateCommand())
{
sqlStt.CommandType = CommandType.Text;
sqlStt.CommandText = "UPDATE USERS SET LAST_NAME = #LAST_NAME, FIRST_NAME = #FIRST_NAME, BIRTHDATE = #BIRTHDATE, PHONE_NUM = #PHONE_NUM, EMAIL = #EMAIL WHERE USERNAME ='" + Session["USERNAME"] + "' ";
sqlStt.Parameters.AddWithValue("#LAST_NAME", Lname.Text);
sqlStt.Parameters.AddWithValue("#FIRST_NAME", Fname.Text);
sqlStt.Parameters.AddWithValue("#BIRTHDATE", Birthdate.Text);
sqlStt.Parameters.AddWithValue("#PHONE_NUM", Phone_num.Text);
sqlStt.Parameters.AddWithValue("#EMAIL", Email.Text);
sqlStt.ExecuteNonQuery();
}
sqlCon.Close();
Display_Info();
Disable_Field();
Notificationtext.Text = "Your account has been updated!";
}
}
void Disable_Field()
{
Lname.Enabled = false;
Fname.Enabled = false;
Birthdate.Enabled = false;
Phone_num.Enabled = false;
Email.Enabled = false;
}
void Display_Info()
{
using (SqlConnection sqlCon = new SqlConnection(connectionstring))
{
sqlCon.Open();
SqlCommand sqlCmd = new SqlCommand("SELECT LAST_NAME, FIRST_NAME, BIRTHDATE, PHONE_NUM, EMAIL FROM USERS WHERE USERNAME ='" + Session["USERNAME"] + "' ", sqlCon);
SqlDataReader reader;
reader = sqlCmd.ExecuteReader();
if (reader.Read())
{
Lname.Text = reader["LAST_NAME"].ToString();
Fname.Text = reader["FIRST_NAME"].ToString();
Birthdate.Text = reader["BIRTHDATE"].ToString();
Phone_num.Text = reader["PHONE_NUM"].ToString();
Email.Text = reader["EMAIL"].ToString();
}
sqlCon.Close();
}
}
I also wanted to display the update to the textbox then disable it. After I click update, the data before it was updated would display instead.