As with the hashtable, the Add method may be used to add a new value to a dictionary:

$dictionary.Add("Computer1", "192.168.10.222") 

If the key already exists, using Add will generate an error, as was the case with the hashtable.

In a dictionary, the Contains method behaves differently from the same method in the hashtable. When checking for the existence of a key, the ContainsKey method should be used as follows:

if (-not $dictionary.ContainsKey("Computer2")) { 
    $dictionary.Add("Computer2", "192.168.10.13") 
} 

The dictionary supports the addition of elements using dot-notation:

$dictionary.Computer3 = "192.168.10.134" 

The dictionary leverages PowerShell's type conversion for both the key and the value. For example, if a numeric key is used, it will be converted into a string. If an IP address is expressed as a string, it will be converted into an IPAddress object.

For example, consider the addition of the following element:

$dictionary.Add(1, 20) 

In this case, key 1 is converted into a string, and the value 20 is converted into an IP address. Inspecting the element afterward shows the following:

PS> $dictionary."1"

Address            : 20
AddressFamily      : InterNetwork
ScopeId            : 
IsIPv6Multicast    : False
IsIPv6LinkLocal    : False
IsIPv6SiteLocal    : False
IsIPv6Teredo       : False
IsIPv4MappedToIPv6 : False
IPAddressToString  : 20.0.0.0