Here is another solution:

$env:HostIP = (
    Get-NetIPConfiguration |
    Where-Object {
        $_.IPv4DefaultGateway -ne $null -and
        $_.NetAdapter.Status -ne "Disconnected"
    }
).IPv4Address.IPAddress

You'll need Select-Object to achieve what you want.

The Select-Object cmdlet selects specified properties of an object or set of objects. It can also select unique objects, a specified number of objects, or objects in a specified position in an array.

When I want to get specific properties, I always run the command I want with fl * (alias for Format-List *) to get all the properties returned that exist. e.g:

PS C:\Windows\system32> Get-NetAdapter | Get-NetIPAddress | fl *


PrefixOrigin             : Dhcp
SuffixOrigin             : Dhcp
Type                     : Unicast
Store                    : ActiveStore
AddressFamily            : IPv4
AddressState             : Preferred
ifIndex                  : 14
Caption                  :
Description              :
ElementName              :
InstanceID               :
CommunicationStatus      :
DetailedStatus           :
HealthState              :
InstallDate              :
Name                     : ;:8:8:8;>:55;>55;55;
OperatingStatus          :
OperationalStatus        :
PrimaryStatus            :
Status                   :
StatusDescriptions       :
AvailableRequestedStates :
EnabledDefault           : 2
EnabledState             :
OtherEnabledState        :
RequestedState           : 12
TimeOfLastStateChange    :
TransitioningToState     : 12
CreationClassName        :
SystemCreationClassName  :
SystemName               :
NameFormat               :
OtherTypeDescription     :
ProtocolIFType           : 4096
ProtocolType             :
Address                  :
AddressOrigin            : 0
AddressType              :
IPv4Address              : 10.0.0.140
IPv6Address              :
IPVersionSupport         :
PrefixLength             : 24
SubnetMask               :
InterfaceAlias           : Ethernet
InterfaceIndex           : 14
IPAddress                : 10.0.0.140
PreferredLifetime        : 6.21:47:25
SkipAsSource             : False
ValidLifetime            : 6.21:47:25
PSComputerName           :
CimClass                 : ROOT/StandardCimv2:MSFT_NetIPAddress
CimInstanceProperties    : {Caption, Description, ElementName, InstanceID...}
CimSystemProperties      : Microsoft.Management.Infrastructure.CimSystemProperties

Then I know what properties fit my needs and I can select the ones I want. You can use:

Get-NetAdapter | Get-NetIPAddress | Select-Object InterfaceAlias, IPAddress | Format-Table

But keep in mind that the Format-Table is only used for you to view it. If you need to do something else with the returned properties, omit the Format-Table.

foreach(NetworkInterface ni in NetworkInterface.GetAllNetworkInterfaces())
{
   if(ni.NetworkInterfaceType == NetworkInterfaceType.Wireless80211 || ni.NetworkInterfaceType == NetworkInterfaceType.Ethernet)
   {
       Console.WriteLine(ni.Name);
       foreach (UnicastIPAddressInformation ip in ni.GetIPProperties().UnicastAddresses)
       {
           if (ip.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
           {
               Console.WriteLine(ip.Address.ToString());
           }
       }
   }  
}

This should get you what you want. ip.Address is an IPAddress, that you want.