Setting up my ipv4 through manually input in the textbox (Ex 10.11.3.120)

Question

Since this is my first time to create a application which can change ip address i have here sample codes the problem is my address not changing still its old ip address. in my code i just declare string only to test if its working. my OS is windows 8.

private void button1_Click_1(object sender, EventArgs e)
{
    //example of ip 10.11.3.120
    //click the button it change to ip 10.11.3.120
    setIP();
}

private void setIP()
{
    ManagementClassobjMC = newManagementClass("Win32_NetworkAdapterConfiguration");
    ManagementObjectCollectionobjMOC = objMC.GetInstances();

    foreach (ManagementObjectobjMOinobjMOC)
    {
        if ((bool)objMO["IPEnabled"])
        {
            try
            {
                ManagementBaseObjectsetIP;
                ManagementBaseObjectnewIP =
                objMO.GetMethodParameters("EnableStatic");
                stringip_address = "10.11.3.120";
                stringsubnet_mask = "255.255.255.0";
                newIP["IPAddress"] = newstring[]{ ip_address};
                newIP["SubnetMask"] = newstring[]{ subnet_mask};

                setIP = objMO.InvokeMethod("EnableStatic", newIP, null);

            }
            catch (Exceptionex)
            {
                MessageBox.Show(ex.ToString());
            }


        }
    }
}