Device.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

namespace PcnWeb.Models
{
    public partial class Device
	{
		public Device()
		{
			this.Ports = new List<Port>();
		}
		[Key]
		public int deviceRecId { get; set; }
		public int deviceLocRecId { get; set; }
		public int processAreaRecId { get; set; }
		public int systemRecId { get; set; }
		public int deviceDescRecId { get; set; }
		public int deviceIPTypeRecId { get; set; }
		public int speedRecId { get; set; }
		public int ipAddressRecId { get; set; }

		[Required, StringLength(64)]
		[Unique]
		public string Name { get; set; }		

		[StringLength(256)]
		public string Comment { get; set; }

		public virtual IPAddress IPAddress { get; set; }
		public virtual MasterBus MasterBus { get; set; }
		public virtual ICollection<Port> Ports { get; set; }
		public virtual DeviceDesc DeviceDesc { get; set; }
		public virtual DeviceIPType DeviceIPType { get; set; }
		public virtual DeviceLoc DeviceLoc { get; set; }
		public virtual ProcessArea ProcessArea { get; set; }
		public virtual NetworkSpeed NetworkSpeed { get; set; }
		public virtual ProcessSystem ProcessSystem { get; set; }
	}
}

Device_Create.cshtml

@model PcnWeb.Models.Device

@{
    ViewBag.Title = "Create  a Device";
}

<h2>Create</h2>

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>Device</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.deviceLocRecId, "DeviceLoc")
        </div>
        <div class="editor-field">
            @Html.DropDownList("deviceLocRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.deviceLocRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.processAreaRecId, "ProcessArea")
        </div>
        <div class="editor-field">
            @Html.DropDownList("processAreaRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.processAreaRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.systemRecId, "ProcessSystem")
        </div>
        <div class="editor-field">
            @Html.DropDownList("systemRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.systemRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.deviceDescRecId, "DeviceDesc")
        </div>
        <div class="editor-field">
            @Html.DropDownList("deviceDescRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.deviceDescRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.deviceIPTypeRecId, "DeviceIPType")
        </div>
        <div class="editor-field">
            @Html.DropDownList("deviceIPTypeRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.deviceIPTypeRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.speedRecId, "NetworkSpeed")
        </div>
        <div class="editor-field">
            @Html.DropDownList("speedRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.speedRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.ipAddressRecId, "IPAddress")
        </div>
        <div class="editor-field">
            @Html.DropDownList("ipAddressRecId", String.Empty)
            @Html.ValidationMessageFor(model => model.ipAddressRecId)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Name, "Name")
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Name)
            @Html.ValidationMessageFor(model => model.Name)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Comment, "Comment")
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Comment)
            @Html.ValidationMessageFor(model => model.Comment)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

IP_Address.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;

namespace PcnWeb.Models
{
    public class IP_Address
	{
		public IP_Address()
		{
			this.UPSs = new List<UPS>();
		}
		public virtual ICollection<UPS> UPSs { get; set; }
		public virtual ICollection<NetworkSwitch> NetworkSwitches { get; set; }
		public virtual ICollection<Device> Devices { get; set; }

		[Key]
		public int ipAddressRecId { get; set; }

		[Required]
		[NotMapped]
		[RegularExpression(@"(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)|DHCP", ErrorMessage = "IP Address must be in the form of four octets 0-255: 255.255.255.255 or DHCP")]
		public string IP_Address
		{
			get
			{
				if (ipOctet1 == null | ipOctet2 == null | ipOctet3 == null | ipOctet4 == null)
					return "DHCP";
				return ipOctet1 + "." + ipOctet2 + "." + ipOctet3 + "." + ipOctet4;
			}
			set
			{
				if (value == "DHCP")
				{
					ipOctet1 = null;
					ipOctet2 = null;
					ipOctet3 = null;
					ipOctet4 = null;
					return;
				}

				//@todo Parseing could throw a number of errors: ArgumentNullException, FormatException, Exception
				byte[] temp = System.Net.IPAddress.Parse(value).GetAddressBytes();
				ipOctet1 = temp[0];
				ipOctet2 = temp[1];
				ipOctet3 = temp[2];
				ipOctet4 = temp[3];
			}
		}
		[NotMapped] //@todo check if this is needed. Don't want an extra database entry.
		public long ipTotal
		{
			get
			{
				if (ipOctet1 == null || ipOctet2 == null || ipOctet3 == null || ipOctet4 == null)
					return 0;
				//(first octet * 2^24) + (second octet * 2^16) + (third octet * 2^8) + (fourth octet)
				return ((long)ipOctet1 * 16777216) + ((long)ipOctet2 * 65536) + ((long)ipOctet3 * 256) + (long)ipOctet4;
			}
		}

		public Nullable<int> ipOctet1 { get; set; }
		public Nullable<int> ipOctet2 { get; set; }
		public Nullable<int> ipOctet3 { get; set; }
		public Nullable<int> ipOctet4 { get; set; }


		[Required]
		[NotMapped]
		[RegularExpression(@"(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)|DHCP", ErrorMessage = "Subnet Mask must be in the form of four octets 0-255: 255.255.255.255 or DHCP")]
		public string Subnet_Mask
		{
			get
			{
				if (smOctet1 == null || smOctet2 == null || smOctet3 == null || smOctet4 == null)
					return "DHCP";
				return smOctet1 + "." + smOctet2 + "." + smOctet3 + "." + smOctet4;
			}
			set
			{
				if (value == "DHCP")
				{
					smOctet1 = null;
					smOctet2 = null;
					smOctet3 = null;
					smOctet4 = null;
					return;
				}

				//@todo Parseing could throw a number of errors: ArgumentNullException, FormatException, Exception
				byte[] temp = System.Net.IPAddress.Parse(value).GetAddressBytes();
				smOctet1 = temp[0];
				smOctet2 = temp[1];
				smOctet3 = temp[2];
				smOctet4 = temp[3];
			}
		}
		[NotMapped] //@todo check if this is needed. Don't want an extra database entry.
		public long smTotal
		{
			get
			{
				if (smOctet1 == null || smOctet2 == null || smOctet3 == null || smOctet4 == null)
					return 0;
				//(first octet * 2^24) + (second octet * 2^16) + (third octet * 2^8) + (fourth octet)
				return ((long)smOctet1 * 16777216) + ((long)smOctet2 * 65536) + ((long)smOctet3 * 256) + (long)smOctet4;
			}
		}

		public Nullable<int> smOctet1 { get; set; }
		public Nullable<int> smOctet2 { get; set; }
		public Nullable<int> smOctet3 { get; set; }
		public Nullable<int> smOctet4 { get; set; }
	}
}

IP_Address_Create.cshtml

@model PcnWeb.Models.IPAddress

@{
    ViewBag.Title = "Create  a IPAddress";
}

<h2>Create</h2>

<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>

@using (Html.BeginForm()) {
    @Html.ValidationSummary(true)
    <fieldset>
        <legend>IPAddress</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.IP_Address, "IP Address")
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.IP_Address)
            @Html.ValidationMessageFor(model => model.IP_Address)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Subnet_Mask, "Subnet Mask")
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Subnet_Mask)
            @Html.ValidationMessageFor(model => model.Subnet_Mask)
        </div>

        <p>
            <input type="submit" value="Create" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>