New-DynamicParameter

New-DynamicParameter.ps1

function New-DynamicParameter {
    <#
    .SYNOPSIS
        Create a new dynamic parameter object for use with a dynamicparam block.
    .DESCRIPTION
        New-DynamicParameter allows simplified creation of runtime (dynamic) parameters.
    .EXAMPLE
        New-DynamicParameter Name -DefaultValue "Test" -ParameterType "String" -Mandatory -ValidateSet "Test", "Live"
    .EXAMPLE
        New-DynamicParameter Name -ValueFromPipelineByPropertyName
    .EXAMPLE
        New-DynamicParameter Name -ValidateRange 1, 2
    .NOTES
        Change log:
            24/10/2014 - Chris Dent - Added support for ValidatePattern options and ValidateSet case sensitivity.
            22/10/2014 - Chris Dent - First release.
    #>

    [CmdletBinding()]
    [OutputType([System.Management.Automation.RuntimeDefinedParameter])]
    param (
        # The name of the parameter to create.
        [Parameter(Mandatory = $true)]
        [Alias('Name')]
        [String]$ParameterName,

        [Object]$DefaultValue,

        # The .NET type of this parameter. 
        [Type]$ParameterType = "Object",

        # Set the mandatory flag for this parameter.
        [Switch]$Mandatory,

        # Define a position for the parameter.
        [Int32]$Position = -2147483648,

        # The parameter can be filled from the input pipeline.
        [Switch]$ValueFromPipeline,

        # The parameter can be filled from a specific property in the input pipeline.
        [Switch]$ValueFromPipelineByPropertyName,

        # Assign the parameter to a specific parameter set.
        [String]$ParameterSetName = "__AllParameterSets",

        # Disallow null or empty values for the parameter if the parameter is specified.
        [Switch]$ValidateNotNullOrEmpty,

        # Test the parameter value using a regular expression.
        [RegEx]$ValidatePattern,

        # Regular expression options which dictate the behaviour of ValidatePattern.
        [Text.RegularExpressions.RegexOptions]$ValidatePatternOptions = [Text.RegularExpressions.RegexOptions]::IgnoreCase,

        # A minimum and maximum value to compare the argument to.
        [Object[]]$ValidateRange,

        # Test the parameter value using a script.
        [ScriptBlock]$ValidateScript,

        # Test the parameter value against a set of values.
        [Object[]]$ValidateSet,

        # ValidateSet can be configured to be case sensitive by setting this parameter to $false. The default behaviour for ValidateSet ignores case.
        [Boolean]$ValidateSetIgnoreCase = $true
    )

    $AttributeCollection = @()

    $ParameterAttribute = New-Object Management.Automation.ParameterAttribute
    $ParameterAttribute.Mandatory = $Mandatory
    $ParameterAttribute.Position = $Position
    $ParameterAttribute.ValueFromPipeline = $ValueFromPipeline
    $ParameterAttribute.ValueFromPipelineByPropertyName = $ValueFromPipelineByPropertyName

    $AttributeCollection += $ParameterAttribute

    if ($psboundparameters.ContainsKey('ValidateNotNullOrEmpty')) {
        $AttributeCollection += New-Object Management.Automation.ValidateNotNullOrEmptyAttribute
    }
    if ($psboundparameters.ContainsKey('ValidatePattern')) {
        $ValidatePatternAttribute = New-Object Management.Automation.ValidatePatternAttribute($ValidatePattern.ToString())
        $ValidatePatternAttribute.Options = $ValidatePatternOptions

        $AttributeCollection += $ValidatePatternAttribute
    }
    if ($psboundparameters.ContainsKey('ValidateRange')) {
        $AttributeCollection += New-Object Management.Automation.ValidateRangeAttribute($ValidateRange)
    }
    if ($psboundparameters.ContainsKey('ValidateScript')) {
        $AttributeCollection += New-Object Management.Automation.ValidateScriptAttribute($ValidateScript)
    }
    if ($psboundparameters.ContainsKey('ValidateSet')) {
        $ValidateSetAttribute = New-Object Management.Automation.ValidateSetAttribute($ValidateSet)
        $ValidateSetAttribute.IgnoreCase = $ValidateSetIgnoreCase

        $AttributeCollection += $ValidateSetAttribute
    }

    $Parameter = New-Object Management.Automation.RuntimeDefinedParameter($ParameterName, $ParameterType, $AttributeCollection)
    if ($psboundparameters.ContainsKey('DefaultValue')) {
        $Parameter.Value = $DefaultValue
    }
    return $Parameter
}