Question

I need to change the default port(1433) of SQL EXPRESS 2008 instance in c#.

Answer 1

You have to use the WMI provider that comes with SMO to do it. Add references to

Microsoft.SqlServer.ConnectionInfo
Microsoft.SqlServer.Management.Sdk.Sfc
Microsoft.SqlServer.Smo
Microsoft.SqlServer.SqlWmiManagement
Microsoft.SqlServer.WmiEnum

and a using for

using Microsoft.SqlServer.Management.Smo.Wmi;

Then the code is basically like this:

ManagedComputer c = new ManagedComputer();

//Get the SQL service and stop it if it's running
Service svc = c.Services["MSSQL$SQLEXPRESS"];
if (svc.ServiceState == ServiceState.Running)
{
    svc.Stop();
}

//Connect to the SQLEXPRESS instance and change the port
ServerInstance s = c.ServerInstances["MSSQL$SQLEXPRESS"];
ServerProtocol prot = s.ServerProtocols["Tcp"];
prot.IPAddresses[0].IPAddressProperties["TcpPort"].Value = "1433";

//Commit the changes
prot.Alter();

//Restart the service
svc.Start();

This assumes you have one IP address and not multiple addresses. If you have multiple you may need to modify the index into prot.IPAddresses[].