Add-DynamicParam.ps1

<#
.SYNOPSIS
Adds a dynamic parameter to a script, within a DynamicParam block.

.DESCRIPTION
Adding dynamic parameters is a complex process, this attempts to simplify that.

.INPUTS
System.Object[] a list of possible values for this parameter to validate against.

.FUNCTIONALITY
PowerShell

.EXAMPLE
DynamicParam { Add-DynamicParam.ps1 Path string -Mandatory; $DynamicParams } Process { Import-Variables.ps1 $PSBoundParameters; ... }
#>

#Requires -Version 3
[Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseProcessBlockForPipelineCommand','',
Justification='This script uses $input within an End block.')]
[CmdletBinding()][OutputType([void])] Param(
# The name of the parameter.
[Parameter(Position=0,Mandatory=$true)][string] $Name,
# The data type of the parameter.
[Parameter(Position=1)][type] $Type,
# The position of the parameter when not specifying the parameter names.
[int] $Position = -2147483648,
# The name of the set of parameters this parameter belongs to.
[string[]] $ParameterSetName = '__AllParameterSets',
# Alternate names for the parameter.
[string[]] $Alias,
<#
The valid number of values for a parameter that accepts a collection.
A range can be specified with a list of two integers.
#>
[Alias('Count')][ValidateCount(1,2)][int[]] $ValidateCount,
# Valid root drive(s) for parameters that accept paths.
[string[]] $ValidateDrive,
<#
The valid length for a string parameter.
A range can be specified with a list of two integers.
#>
[Alias('Length')][ValidateCount(1,2)][int[]] $ValidateLength,
# The valid regular expression pattern to match for a string parameter.
[Alias('Match','Pattern')][string] $ValidatePattern,
# The valid range of values for a numeric parameter.
[Alias('Range')][ValidateCount(2,2)][int[]] $ValidateRange,
<#
A script block to validate a parameter's value.
Any true result will validate the value, any false result will reject it.
#>
[ScriptBlock] $ValidateScript,
<#
A set of valid values for the parameter.
This will enable tab-completion.
#>
[Parameter(ValueFromPipeline=$true)][Alias('Values')][object[]] $ValidateSet,
# Requires parameter to be non-null.
[switch] $NotNull,
# Requires parameter to be non-null and non-empty.
[switch] $NotNullOrEmpty,
# Requires the parameter value to be Trusted data.
[switch] $TrustedData,
# Requires a path parameter to be on a User drive.
[switch] $UserDrive,
# Indicates a required parameter.
[Alias('Required')][switch] $Mandatory,
# Indicates a parameter that can accept values from the pipeline.
[Alias('Pipeline')][switch] $ValueFromPipeline,
<#
Indicates a parameter that can accept values from the pipeline by matching the property name of pipeline objects to the
parameter name or alias.
#>
[Alias('PipelineProperties','PipeName')][switch] $ValueFromPipelineByPropertyName,
# Indicates that the parameter will include any following positional parameters.
[Alias('RemainingArgs')][switch] $ValueFromRemainingArguments
)
End
{
	$DynamicParams = Get-Variable DynamicParams -Scope 1 -ErrorAction Ignore
	if($null -eq $DynamicParams)
	{
		$DynamicParams = New-Object Management.Automation.RuntimeDefinedParameterDictionary
		$DynamicParams = New-Variable DynamicParams $DynamicParams -Scope 1 -PassThru
	}
	$atts = New-Object Collections.ObjectModel.Collection[System.Attribute]
	foreach($set in $ParameterSetName)
	{
		$att = New-Object Management.Automation.ParameterAttribute -Property @{
			Position                        = $Position
			ParameterSetName                = $ParameterSetName
			Mandatory                       = $Mandatory
			ValueFromPipeline               = $ValueFromPipeline
			ValueFromPipelineByPropertyName = $ValueFromPipelineByPropertyName
			ValueFromRemainingArguments     = $ValueFromRemainingArguments
		}
		$atts.Add($att)
	}
	if($Alias) {$atts.Add((New-Object Management.Automation.AliasAttribute $Alias))}
	if($NotNull) {$atts.Add((New-Object Management.Automation.ValidateNotNullAttribute))}
	if($NotNullOrEmpty) {$atts.Add((New-Object Management.Automation.ValidateNotNullOrEmptyAttribute))}
	if($ValidateCount)
	{
		if($ValidateCount.Length -eq 1) {$ValidateCount += $ValidateCount[0]}
		$atts.Add((New-Object Management.Automation.ValidateCountAttribute $ValidateCount))
	}
	if($ValidateDrive) {$atts.Add((New-Object Management.Automation.ValidateDriveAttribute $ValidateDrive))}
	if($ValidateLength)
	{
		if($ValidateLength.Length -eq 1) {$ValidateLength += $ValidateLength[0]}
		$atts.Add((New-Object Management.Automation.ValidateLengthAttribute $ValidateLength))
	}
	if($ValidatePattern) {$atts.Add((New-Object Management.Automation.ValidatePatternAttribute $ValidatePattern))}
	if($ValidateRange) {$atts.Add((New-Object Management.Automation.ValidateRangeAttribute $ValidateRange))}
	if($ValidateScript) {$atts.Add((New-Object Management.Automation.ValidateScriptAttribute $ValidateScript))}
	if($input) {$ValidateSet = $input}
	if($ValidateSet) {$atts.Add((New-Object Management.Automation.ValidateSetAttribute $ValidateSet))}
	if($TrustedData) {$atts.Add((New-Object Management.Automation.ValidateTrustedDataAttribute))}
	if($UserDrive) {$atts.Add((New-Object Management.Automation.ValidateUserDriveAttribute))}
	$param = New-Object Management.Automation.RuntimeDefinedParameter ($Name,$Type,$atts)
	$DynamicParams.Value.Add($Name,$param)
}