Registry Test
{
   Key = "HKLM:\Software\Microsoft\7-Zip"
    # This is a KEY property so it has to be specified which makes it then odd to have to specify Member to Include as well.
    ValueName = "FastCompression"
    ValueData = 1
    ValueType = DWORD 
    # This just feels clunky because you would have to pass a valuename above because it's a key, but then you could specify other values as well? That would make it hard to troubleshoot.
    MembersToInclude = @(
        
        @{
            ValueName = "HighValue"
            ValueData = 1
            ValueType = DWORD
        }, 
        "AnotherValue" # So it should create another ValueName? Which ValueData etc.?
    )
    MembersToExclude = @(
        # Why should I need to specify all of this information, but if I don't it won't be consistent with above.
        @{
            ValueName = "Offset"
            ValueData = 1
            ValueType = DWORD
        }
        ,* # The Group Property doesn't accept wildcards, but this one would have to, it's the whole purpose of the change.
    )
}

Registry Test
{
    Key = "HKLM:\Software\Microsoft\7-Zip"
    ValueName = "FastCompression"
    ValueData = 1
    ValueType = DWORd
    Exclusive = $true # Could go with other names as well, but basically a property saying that this should be the only value in this key.
}

Registry Test
{
    Key = "HKLM:\Software\Microsoft\7-Zip"
    ValueName = "" # Even though Value Name is a Key, it can still be blank.  This has typically been used to remove a key.
    Exclusive = $true # Now this would wipe all values out of a key without erasing the key.
} 

Registry 7Zip_FastCompression
{
    Key = 'HKLM:\Software\Microsoft\7-Zip'
    ValueName = 'FastCompression'
    ValueData = 1
    ValueType = 'DWORD'
}

Registry 7Zip_HighValue
{
    Key = 'HKLM:\Software\Microsoft\7-Zip'
    ValueName = 'HighValue'
    ValueData = 1
    ValueType = 'DWORD'
}

Registry 7Zip_RemoveExcessValueNames
{
    Key = 'HKLM:\Software\Microsoft\7-Zip'
    ValueName = '' # Ideally without this property
    RemoveExcessValueNames = $true
    DependsOn = @(
        '[Registry]7Zip_FastCompression',
        '[Registry]7Zip_HighValue'
    )
}

<#
    $Key, $DependsOn, and $RemoveExcessValueNames are from the respective
    `[Registry]7Zip_RemoveExcessValueNames` property
#>

if ($DependsOn)
{
    $DependentResources = Get-DscConfiguration `
        | Where-Object { $DependsOn -contains $_.ResourceId.Split(':')[0] }

    if ($DependentResources.ResourceId.StartsWith('[Registry]') -contains $false)
    {
        Throw "When using RemoveExcessValueNames, all resources referenced in DependsOn must be Registry resources."
    }

    if (($DependentResources.key | Sort-Object -Unique).Count -ne 1)
    {
        Throw "When using RemoveExcessValueNames, Registry resources referenced in DependsOn must all have the same Key."
    }

    if ($DependentResources.key[0] -ne $Key)
    {
        Throw "When using RemoveExcessValueNames, Registry resources referenced in DependsOn must have the same key as this resource."
    }
}

$AllowedValueNames = $DependentResources.ValueName
$RegKey = Get-Item -LiteralPath $Key
$NotAllowedValues = $RegKey.Property `
    | Where-Object { $AllowedValueNames -notcontains $_ }

foreach ($Value in $NotAllowedValues)
{
    Remove-ItemProperty -LiteralPath $Key -Name $Value -Force
}

Registry Test_RemoveExcessValueNames
{
    Key = 'HKLM:\Software\Microsoft\7-Zip'
    ValueName = '' # Ideally without this property
    RemoveExcessValueNames = @(
        'FastCompression',
        'HighValue'
    )
    DependsOn = @(
        '[Registry]Test_FastCompression',
        '[Registry]Test_HighValue'
    )
}