Switch Gateway with C# code

using System;
using System.Management;

namespace WindowsFormsApplication_CS
{
    class NetworkManagement
    {
        /// <summary>
        /// Set's a new IP Address and it's Submask of the local machine
        /// </summary>
        /// <param name="ip_address">The IP Address</param>
        /// <param name="subnet_mask">The Submask IP Address</param>
        /// <remarks>Requires a reference to the System.Management namespace</remarks>
        public void setIP(string ip_address, string subnet_mask)
        {
            ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection objMOC = objMC.GetInstances();

            foreach (ManagementObject objMO in objMOC)
            {
                if ((bool)objMO["IPEnabled"])
                {
                    try
                    {
                        ManagementBaseObject setIP;
                        ManagementBaseObject newIP =
                            objMO.GetMethodParameters("EnableStatic");

                        newIP["IPAddress"] = new string[] { ip_address };
                        newIP["SubnetMask"] = new string[] { subnet_mask };

                        setIP = objMO.InvokeMethod("EnableStatic", newIP, null);
                    }
                    catch (Exception)
                    {
                        throw;
                    }


                }
            }
        }
        /// <summary>
        /// Set's a new Gateway address of the local machine
        /// </summary>
        /// <param name="gateway">The Gateway IP Address</param>
        /// <remarks>Requires a reference to the System.Management namespace</remarks>
        public void setGateway(string gateway)
        {
            ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection objMOC = objMC.GetInstances();

            foreach (ManagementObject objMO in objMOC)
            {
                if ((bool)objMO["IPEnabled"])
                {
                    try
                    {
                        ManagementBaseObject setGateway;
                        ManagementBaseObject newGateway =
                            objMO.GetMethodParameters("SetGateways");

                        newGateway["DefaultIPGateway"] = new string[] { gateway };
                        newGateway["GatewayCostMetric"] = new int[] { 1 };

                        setGateway = objMO.InvokeMethod("SetGateways", newGateway, null);
                    }
                    catch (Exception)
                    {
                        throw;
                    }
                }
            }
        }
        /// <summary>
        /// Set's the DNS Server of the local machine
        /// </summary>
        /// <param name="NIC">NIC address</param>
        /// <param name="DNS">DNS server address</param>
        /// <remarks>Requires a reference to the System.Management namespace</remarks>
        public void setDNS(string NIC, string DNS)
        {
            ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection objMOC = objMC.GetInstances();

            foreach (ManagementObject objMO in objMOC)
            {
                if ((bool)objMO["IPEnabled"])
                {
                    if (objMO["Caption"].Equals(NIC))
                    {
                        try
                        {
                            ManagementBaseObject newDNS =
                                objMO.GetMethodParameters("SetDNSServerSearchOrder");
                            newDNS["DNSServerSearchOrder"] = DNS.Split(',');
                            ManagementBaseObject setDNS =
                                objMO.InvokeMethod("SetDNSServerSearchOrder", newDNS, null);
                        }
                        catch (Exception)
                        {
                            throw;
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Set's WINS of the local machine
        /// </summary>
        /// <param name="NIC">NIC Address</param>
        /// <param name="priWINS">Primary WINS server address</param>
        /// <param name="secWINS">Secondary WINS server address</param>
        /// <remarks>Requires a reference to the System.Management namespace</remarks>
        public void setWINS(string NIC, string priWINS, string secWINS)
        {
            ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
            ManagementObjectCollection objMOC = objMC.GetInstances();

            foreach (ManagementObject objMO in objMOC)
            {
                if ((bool)objMO["IPEnabled"])
                {
                    if (objMO["Caption"].Equals(NIC))
                    {
                        try
                        {
                            ManagementBaseObject setWINS;
                            ManagementBaseObject wins =
                            objMO.GetMethodParameters("SetWINSServer");
                            wins.SetPropertyValue("WINSPrimaryServer", priWINS);
                            wins.SetPropertyValue("WINSSecondaryServer", secWINS);

                            setWINS = objMO.InvokeMethod("SetWINSServer", wins, null);
                        }
                        catch (Exception)
                        {
                            throw;
                        }
                    }
                }
            }
        }
    }
}