PowerShell Parameter Sets

ParamSet.ps1

## Parameter Sets Examples


# Example #1

# Choose 1 or 2 out of 2
# order is not important

<# Combinations: 3 in total
1) A
2) B
3) A & B
#>


# Example #2

# Choose 1 or 2 or 3 out of 3
# order is not important

<# Combinations: 7 in total
1) A
2) B
3) C
4) A & B
5) A & C
6) B & C
7) A & B & C
#>


# Example #3

# Choose 1 or 2 out of 4
# but always need to have the 1st or 2nd, but can't have both 1st and 2nd
# order is not important

<# Combinations: 6 in total
1) A
2) B
3) A & C
4) A & D
5) B & C
6) B & D
#>


# Question: What does it mean that: order is not important
# Answer:   For example B & C is the same as C & B
#           so this is considered 1 combination out of the total (not two separate combinations)


# Now let's do the above with parameter sets in PowerShell


# Example #1

function Get-ParamSet1 {
<#
. SYNOPSIS
    Combinations: 3
    - Version
    - Role
    - Version & Role

    The function will always ask for at least one parameter,
    either the version or the role.
    The date is optional, even if you provide a date,
    the function will still ask for at least one of the other parameters, namely version or role
#>
[CmdletBinding(DefaultParameterSetName = 'Version')]
param (
    [Parameter(Mandatory,Position=0,ParameterSetName = 'Version')]
    [Parameter(Mandatory,Position=0,ParameterSetName = 'VersionAndRole')]
    [string]$Version,

    [Parameter(Mandatory,Position=1,ParameterSetName = 'Role')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'VersionAndRole')]
    [string]$Role,

    [datetime]$Date  # <-- optional parameter
)

# show the parameter set that was used
$PSCmdlet.ParameterSetName
}



# Example #2

function Get-ParamSet2 {
<#
. SYNOPSIS
    Combinations: 7
    - Version
    - Role
    - Group
    - Version & Role
    - Version & Group
    - Role & Group
    - Version & ROle & Group
#>
[CmdletBinding(DefaultParameterSetName = 'Version')]
param (
    [Parameter(Mandatory,Position=0,ParameterSetName = 'Version')]
    [Parameter(Mandatory,Position=0,ParameterSetName = 'VersionAndRole')]
    [Parameter(Mandatory,Position=0,ParameterSetName = 'VersionAndGroup')]
    [Parameter(Mandatory,Position=0,ParameterSetName = 'VersionAndRoleAndGroup')]
    [string]$Version,

    [Parameter(Mandatory,Position=1,ParameterSetName = 'Role')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'VersionAndRole')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'RoleAndGroup')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'VersionAndRoleAndGroup')]
    [string]$Role,

    [Parameter(Mandatory,Position=3,ParameterSetName = 'Group')]
    [Parameter(Mandatory,Position=3,ParameterSetName = 'VersionAndGroup')]
    [Parameter(Mandatory,Position=3,ParameterSetName = 'RoleAndGroup')]
    [Parameter(Mandatory,Position=3,ParameterSetName = 'VersionAndRoleAndGroup')]
    [string]$Group,

    [datetime]$Date
)

# show the parameter set that was used
$PSCmdlet.ParameterSetName
}



# Example #3

function Get-ParamSet3 {
<#
. SYNOPSIS
    Combinations: 6
    - Block
    - File
    - File & Int
    - File & Hash
    - Block & Int
    - Block & Hash
#>
[CmdletBinding(DefaultParameterSetName = 'Scriptblock')]
param (
    [Parameter(Mandatory,Position=0)]
    [string]$Name,

    [Parameter(Mandatory,Position=1,ParameterSetName = 'Scriptblock')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'BlockAndInt')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'BlockAndHash')]
    [scriptblock]$ScriptBlock,

    [Parameter(Mandatory,Position=1,ParameterSetName = 'Scriptfile')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'FileAndInt')]
    [Parameter(Mandatory,Position=1,ParameterSetName = 'FileAndHash')]
    [string]$ScriptFile,

    [Parameter(Mandatory,Position=2,ParameterSetName = 'BlockAndInt')]
    [Parameter(Mandatory,Position=2,ParameterSetName = 'FileAndInt')]
    [int]$Size,

    [Parameter(Mandatory,Position=2,ParameterSetName = 'BlockAndHash')]
    [Parameter(Mandatory,Position=2,ParameterSetName = 'FileAndHash')]
    [hashtable]$Hash,

    [datetime]$Date
)

# show the parameter set that was used
$PSCmdlet.ParameterSetName
}