Connection property has not been initialized Error (ExecuteNonQuery) - sql-server

Question

This question has been addressed all over the web and I tried a lot of things without success. The SQL EXPRESS service is setup to accept local system account but the problem still exists.
This is my connection string:
<add name="PhoneTemplateChange" providerName="System.Data.SqlClient" connectionString="Data Source=.\SQLEXPRESS;Database=PhoneTemplateChange;Integrated Security=SSPI" />
I created a class to do database operations in the constructor I have
_connectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["PhoneTemplateChange"].ConnectionString;
and a method in this class to insert data
public void AddNewChangeOrder(int operation, int targetExt)
{
using (SqlConnection con = new SqlConnection(_connectionString))
{
string sql = "INSERT into [dbo].ChangeOrder (operation, targetExt, dtrequested) VALUES (#operation, #targetExt, #dtrequested)";
using (SqlCommand cmd = new SqlCommand(sql))
{
try
{
cmd.Parameters.AddWithValue("#operation", operation);
cmd.Parameters.AddWithValue("#targetExt", targetExt);
cmd.Parameters.AddWithValue("dtrequested", DateTime.Now);
//con.CreateCommand();
con.Open();
//cmd.InitializeLifetimeService();
int rows = cmd.ExecuteNonQuery();
con.Close();
}
catch (SqlException e)
{
throw new Exception(e.Message);
}
}
}
I have played around with the connection string trying all different suggestions, also the commented code in the method above is what I tried to solve the problem. Still no luck!
I also changed the connection string I get two different exceptions this way
Database=PhoneTemplateChange
The above gives the exception in the title.
And the following gives the Exception "Cannot open Database PhoneTemplatechange.mdf requested by the login. Login failed for user 'mydomain\myusername'"
Database=PhoneTemplateChange.mdf
Any ideas?

Answer 1

You are missing the line of code where you specify that cmd uses con as it's connection. As a result the Command (cmd) has no connection, and con isn't associated with any command at all.
Add this line before executing:
cmd.Connection - con;
Alternatively (and better IMO) change your using statement as follows:
using (SqlCommand cmd = new SqlCommand(sql, con))