Added support for Exclusive flag parameter which ensures the a value is the EXCLUSIVE value in a given key.

DscResources/MSFT_RegistryResource/MSFT_RegistryResource.psm1

@@ -118,6 +118,20 @@ function Get-TargetResource
         {
             $registryResource['Ensure'] = 'Present'
         }
+
+        $valueNames = Get-RegistryKeyValueNames -RegistryKey $registryKey
+        $otherValueNames = @($valueNames | Where-Object {$_ -ne $ValueName})
+
+        if ($otherValueNames.Count -gt 0)
+        {
+            Write-Verbose -Message ($script:localizedData.Exclusive_IsNotExclusive -f $Key, $ValueName)
+            $registryResource['Exclusive'] = $false
+        }
+        elseif ($valueNames -eq $valueName)
+        {
+            Write-Verbose -Message ($script:localizedData.Exclusive_IsExclusive -f $Key, $ValueName)
+            $registryResource['Exclusive'] = $true
+        }
     }
 
     Write-Verbose -Message ($script:localizedData.GetTargetResourceEndMessage -f $Key)
@@ -206,7 +220,10 @@ function Set-TargetResource
         $Hex = $false,
 
         [Boolean]
-        $Force = $false
+        $Force = $false,
+
+        [Boolean]
+        $Exclusive = $false
     )
 
     Write-Verbose -Message ($script:localizedData.SetTargetResourceStartMessage -f $Key)
@@ -259,6 +276,20 @@ function Set-TargetResource
                 # Retrieve the name of the registry key
                 $registryKeyName = Get-RegistryKeyName -RegistryKey $registryKey
 
+                # Retrieve other registry key value names.
+                $valueNames = Get-RegistryKeyValueNames -RegistryKey $registryKey
+
+                if ($Exclusive)
+                {
+                    $otherValueNames = $valueNames | Where-Object {$_ -ne $ValueName}
+
+                    foreach ($name in $otherValueNames)
+                    {
+                        Write-Verbose -Message ($script:localizedData.Exclusive_RemovingRegistryValueName -f $Key, $Name)
+                        $null = Remove-ItemProperty -Path $Key -Name $name -Force
+                    }
+                }
+
                 # Check if the registry key value exists
                 if ($null -eq $actualRegistryKeyValue)
                 {
@@ -332,6 +363,20 @@ function Set-TargetResource
                     $null = Remove-Item -Path $Key -Recurse -Force
                 }
             }
+            else
+            {
+                if ($Exclusive)
+                {
+                    # Retrieve other registry key value names.
+                    $valueNames = Get-RegistryKeyValueNames -RegistryKey $registryKey
+
+                    foreach ($name in $valueNames)
+                    {
+                        Write-Verbose -Message ($script:localizedData.Exclusive_RemovingRegistryValueName -f $Key, $Name)
+                        $null = Remove-ItemProperty -Path $Key -Name $name -Force
+                    }
+                }
+            }
         }
     }
 
@@ -410,7 +455,10 @@ function Test-TargetResource
         $Hex = $false,
 
         [Boolean]
-        $Force = $false
+        $Force = $false,
+
+        [Boolean]
+        $Exclusive = $false
     )
 
     Write-Verbose -Message ($script:localizedData.TestTargetResourceStartMessage -f $Key)
@@ -512,6 +560,27 @@ function Test-TargetResource
         }
     }
 
+    if ($Exclusive)
+    {
+        # Need to get the actual registry key value since Get-TargetResource returns
+        $registryKey = Get-RegistryKey -RegistryKeyPath $Key
+
+        # Retrieve other registry key value names.
+        $valueNames = Get-RegistryKeyValueNames -RegistryKey $registryKey
+
+        $otherValueNames = @($valueNames | Where-Object {$_ -ne $ValueName})
+
+        if ($otherValueNames.Count -gt 0)
+        {
+            Write-Verbose -Message ($script:localizedData.Exclusive_TESTIsNotExclusive -f $key, $ValueName)
+            $registryResourceInDesiredState = $false
+        }
+        else
+        {
+            Write-Verbose -Message ($script:localizedData.Exclusive_TESTIsExclusive -f $key, $ValueName)
+        }
+    }
+
     Write-Verbose -Message ($script:localizedData.TestTargetResourceEndMessage -f $Key)
 
     return $registryResourceInDesiredState
@@ -793,6 +862,28 @@ function Get-RegistryKeyValueDisplayName
     return $registryKeyValueDisplayName
 }
 
+<#
+    .SYNOPSIS
+        Retrieves all the values in a Registry Key.
+
+    .PARAMETER RegistryKey
+        The registry key to retrieve the values from.
+#>
+function Get-RegistryKeyValueNames
+{
+    [OutputType([Object[]])]
+    [CmdletBinding()]
+    param
+    (
+        [Parameter(Mandatory = $true)]
+        [Microsoft.Win32.RegistryKey]
+        $RegistryKey
+    )
+
+    $registryKeyValue = $RegistryKey.GetValueNames()
+    return ,$registryKeyValue
+}
+
 <#
     .SYNOPSIS
         Retrieves the registry key value with the specified name from the specified registry key.

DscResources/MSFT_RegistryResource/MSFT_RegistryResource.schema.mof

@@ -8,4 +8,5 @@ class MSFT_RegistryResource : OMI_BaseResource
   [Write, Description("Specifies whether or not the registry key or value should exist. To add or modify a registry key or value, set this property to Present. To remove a registry key or value, set the property to Absent."), ValueMap{"Present", "Absent"},Values{"Present", "Absent"}] String Ensure;
   [Write, Description("Specifies whether or not the specified DWord or QWord registry key data is provided in a hexadecimal format. Not valid for types other than DWord and QWord. The default value is $false.")] Boolean Hex;
   [Write, Description("Specifies whether or not to overwrite the specified registry key value if it already has a value or whether or not to delete a registry key that has subkeys. The default value is $false.")] Boolean Force;
+  [Write, Description("Specifies whether the ValueName specified should be made to be the ONLY value in the Key (recreation of **delval functionality)")] Boolean Exclusive;
 };

DscResources/MSFT_RegistryResource/en-US/MSFT_RegistryResource.strings.psd1

@@ -35,4 +35,10 @@ ConvertFrom-StringData @'
     InvalidRegistryDrive = The registry drive {0} is invalid. Please update the Key parameter to include a valid registry drive.
     InvalidRegistryDriveAbbreviation = The registry drive abbreviation {0} is invalid. Please update the Key parameter to include a valid registry drive.
     RegistryDriveCouldNotBeMounted = The registry drive with the abbreviation {0} could not be mounted.
+
+    Exclusive_RemovingRegistryValueName = Enforcing Exclusive Flag by removing Value Name ({1}) from key ({0}).
+    Exclusive_IsExclusive = ValueName ({1}) IS EXCLUSIVE within key ({0}).
+    Exclusive_IsNotExclusive = ValueName ({1}) IS NOT EXCLUSIVE within key ({0}).
+    Exclusive_TESTIsExclusive = ValueName ({1}) IS EXCLUSIVE within Key ({0}).
+    Exclusive_TESTIsNotExclusive = The ValueName ({1}) IS NOT EXCLUSIVE within Key ({0}).
 '@

README.md

@@ -235,6 +235,7 @@ None
 * **[String] ValueType** _(Write)_: The type the specified registry key value should have. { *String* | Binary | DWord | QWord | MultiString | ExpandString }
 * **[Boolean] Hex** _(Write)_: Specifies whether or not the specified DWord or QWord registry key data is provided in a hexadecimal format. Not valid for types other than DWord and QWord. The default value is $false.
 * **[Boolean] Force** _(Write)_: Specifies whether or not to overwrite the specified registry key value if it already has a value or whether or not to delete a registry key that has subkeys. The default value is $false.
+* **[Boolean] Exclusive** _(Write)_: Specifies whether the specified value should be made to be the ONLY value in a Key (support for **delvals). The default value is $false.
 
 #### Read-Only Properties from Get-TargetResource
 

Tests/Integration/MSFT_RegistryResource.EndToEnd.Tests.ps1

@@ -40,6 +40,7 @@ try
 
             # Force is specified as true for both of these configurations
             $script:confgurationFilePathKeyAndNameOnly = Join-Path -Path $PSScriptRoot -ChildPath 'MSFT_RegistryResource_KeyAndNameOnly.config.ps1'
+            $script:confgurationFilePathKeyAndNameOnlyExclusive = Join-Path -Path $PSScriptRoot -ChildPath 'MSFT_RegistryResource_KeyAndNameOnly_Exclusive.config.ps1'
             $script:confgurationFilePathWithDataAndType = Join-Path -Path $PSScriptRoot -ChildPath 'MSFT_RegistryResource_WithDataAndType.config.ps1'
         }
 
@@ -316,6 +317,79 @@ try
             }
         }
 
+        Context 'Enforce Exclusivity using Flag Specifying ValueName' {
+            $configurationName = 'EnforceExclusivity'
+
+            New-ItemProperty -Path $script:testRegistryKeyPath -Name "Test" -Value 1
+            New-ItemProperty -Path $script:testRegistryKeyPath -Name "Test2" -Value 1
+
+            $registryParameters = @{
+                Key = $script:testRegistryKeyPath
+                Ensure = 'Present'
+                ValueName = 'Test_Exclusive'
+                Exclusive = $true
+                Force = $true
+            }
+
+            It 'Should compile and run configuration' {
+                { 
+                    . $script:confgurationFilePathKeyAndNameOnlyExclusive -ConfigurationName $configurationName
+                    & $configurationName -OutputPath $TestDrive @registryParameters
+                    Start-DscConfiguration -Path $TestDrive -ErrorAction 'Stop' -Wait -Force
+                } | Should Not Throw
+            }
+
+            It 'Should be able to call Get-DscConfiguration without throwing' {
+                { Get-DscConfiguration -ErrorAction 'Stop' } | Should Not Throw
+            }
+
+            $registryKeyValues = Get-ItemProperty -Path $registryParameters.Key -Name Test1, Test2 -ErrorAction SilentlyContinue
+
+            It 'Should have removed all the registry key value names' {
+                $registryKeyValues | Should Be $null
+            }
+
+            It 'Should return true from Test-TargetResource with the same parameters' {
+                MSFT_RegistryResource\Test-TargetResource @registryParameters | Should Be $true
+            }
+        }
+
+        Context 'Enforce Exclusivity using Flag Specifying Empty ValueName' {
+            $configurationName = 'EnforceExclusivity'
+
+            New-ItemProperty -Path $script:testRegistryKeyPath -Name "Test" -Value 1
+            New-ItemProperty -Path $script:testRegistryKeyPath -Name "Test2" -Value 1
+
+            $registryParameters = @{
+                Key = $script:testRegistryKeyPath
+                Ensure = 'Present'
+                ValueName = ''
+                Exclusive = $true
+            }
+
+            It 'Should compile and run configuration' {
+                { 
+                    . $script:confgurationFilePathKeyAndNameOnlyExclusive -ConfigurationName $configurationName
+                    & $configurationName -OutputPath $TestDrive @registryParameters
+                    Start-DscConfiguration -Path $TestDrive -ErrorAction 'Stop' -Wait -Force
+                } | Should Not Throw
+            }
+
+            It 'Should be able to call Get-DscConfiguration without throwing' {
+                { Get-DscConfiguration -ErrorAction 'Stop' } | Should Not Throw
+            }
+
+            $registryKeyValues = Get-ItemProperty -Path $registryParameters.Key -Name * -ErrorAction 'SilentlyContinue' | Where-Object {$_.Name -ne "Test_Exclusive"}
+
+            It 'Should have removed all the registry key value names' {
+                $registryKeyValues | Should Be $null
+            }
+
+            It 'Should return true from Test-TargetResource with the same parameters' {
+                MSFT_RegistryResource\Test-TargetResource @registryParameters | Should Be $true
+            }
+        }
+
         Context 'Remove a registry key' {
             $configurationName = 'RemoveRegistryKey'
 

Tests/Integration/MSFT_RegistryResource_KeyAndNameOnly_Exclusive.config.ps1

@@ -0,0 +1,48 @@
+param
+(
+    [Parameter(Mandatory = $true)]
+    [String]
+    $ConfigurationName
+)
+
+Configuration $ConfigurationName
+{
+    param
+    (
+        [Parameter(Mandatory = $true)]
+        [ValidateNotNullOrEmpty()]
+        [String]
+        $Key,
+
+        [ValidateSet('Present', 'Absent')]
+        [String]
+        $Ensure = 'Present',
+
+        [Parameter(Mandatory = $true)]
+        [String]
+        [AllowEmptyString()]
+        $ValueName,
+
+        [Parameter()]
+        [Boolean]
+        $Exclusive=$false,
+
+        [Parameter()]
+        [Boolean]
+        $Force=$true
+    )
+
+    Import-DscResource -ModuleName 'PSDscResources'
+
+    Node localhost
+    {
+        Registry Registry1
+        {
+            Key = $Key
+            Ensure = $Ensure
+            ValueName = $ValueName
+            Force = $Force
+            Exclusive = $Exclusive
+        }
+    }
+}