public/Get-VSASDTicketCustomFields.ps1

function Get-VSASDTicketCustomFields {
    <#
    .Synopsis
       Returns the value of a custom field in a service desk ticket.
    .DESCRIPTION
       Returns the value of a custom field in a service desk ticket.
       Takes either persistent or non-persistent connection information.
    .PARAMETER VSAConnection
        Specifies existing non-persistent VSAConnection.
    .PARAMETER URISuffix
        Specifies URI suffix if it differs from the default.
    .PARAMETER ServiceDeskId
        Specifies id of service desk
    .PARAMETER Filter
        Specifies REST API Filter.
    .PARAMETER Paging
        Specifies REST API Paging.
    .PARAMETER Sort
        Specifies REST API Sorting.
    .EXAMPLE
       Get-VSASDTicketCustomFields -ServiceDeskTicketId 3434343 -CustomFieldId 32323232
    .EXAMPLE
       Get-VSASDTicketCustomFields -VSAConnection $connection -ServiceDeskTicketId 3434343 -CustomFieldId 32323232
    .INPUTS
       Accepts piped non-persistent VSAConnection
    .OUTPUTS
       Array of items that represent custom fields of service desk ticket
    #>


    [CmdletBinding()]
    param ( 
        [parameter(Mandatory = $true, 
            ValueFromPipelineByPropertyName = $true,
            ParameterSetName = 'NonPersistent')]
        [VSAConnection] $VSAConnection,
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'NonPersistent')]
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'Persistent')]
        [ValidateNotNullOrEmpty()] 
        [string] $URISuffix = 'api/v1.0/automation/servicedesktickets/{0}/customfields/{1}',
        [ValidateNotNullOrEmpty()]
        [parameter(ParameterSetName = 'Persistent', Mandatory=$true, ValueFromPipelineByPropertyName=$true)]
        [parameter(ParameterSetName = 'NonPersistent', Mandatory=$true, ValueFromPipelineByPropertyName=$true)]
        [ValidateNotNullOrEmpty()] 
        [string] $ServiceDeskTicketId,
        [parameter(ParameterSetName = 'Persistent', Mandatory=$true, ValueFromPipelineByPropertyName=$true)]
        [parameter(ParameterSetName = 'NonPersistent', Mandatory=$true, ValueFromPipelineByPropertyName=$true)]
        [ValidateNotNullOrEmpty()] 
        [string] $CustomFieldId,         
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Filter,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Paging,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Sort
    )

    $URISuffix = $URISuffix -f $ServiceDeskTicketId, $CustomFieldId

    [hashtable]$Params =@{
        URISuffix = $URISuffix
    }

    if($VSAConnection) {$Params.Add('VSAConnection', $VSAConnection)}
    if($Filter)        {$Params.Add('Filter', $Filter)}
    if($Paging)        {$Params.Add('Paging', $Paging)}
    if($Sort)          {$Params.Add('Sort', $Sort)}

    return Get-VSAItems @Params
}

Export-ModuleMember -Function Get-VSASDTicketCustomFields