Script to add items to Bundle

AddItemToBundle.cs

public static void AddItemToBundle(string bundleId, string itemId)
        {
            CoreServiceClient _CoreServiceClient = Utility.GetCoreServiceSettings();
            ReadOptions _readOption = new ReadOptions();
            VirtualFolderData bundle = (VirtualFolderData)_CoreServiceClient.Read(bundleId, _readOption);
            XmlDocument bundleConfiguration = new XmlDocument();
            bundleConfiguration.LoadXml(bundle.Configuration);

            XmlNameTable nameTable = new NameTable();
            nameTable = bundleConfiguration.NameTable;
            XmlNamespaceManager namespaceManager = new XmlNamespaceManager(nameTable);
            namespaceManager.AddNamespace("b", @"http://www.sdltridion.com/ContentManager/Bundle");
            namespaceManager.AddNamespace("xlink", @"http://www.w3.org/1999/xlink");

            XmlNode itemsElement = bundleConfiguration.SelectSingleNode("/b:Bundle/b:Items", namespaceManager);

            XmlElement itemElement = itemsElement.OwnerDocument.CreateElement("Item", @"http://www.sdltridion.com/ContentManager/Bundle");
            XmlAttribute xmlAttr = itemElement.OwnerDocument.CreateAttribute("xlink", "href", "http://www.w3.org/1999/xlink");
            xmlAttr.Value = itemId;
            XmlAttribute xmlAttr1 = itemElement.OwnerDocument.CreateAttribute("xlink", "type", "http://www.w3.org/1999/xlink");
            xmlAttr1.Value = "simple";
            itemElement.SetAttributeNode(xmlAttr);
            itemElement.SetAttributeNode(xmlAttr1);
            itemsElement.AppendChild(itemElement);
            bundle.Configuration = bundleConfiguration.InnerXml;
            _CoreServiceClient.Save(bundle, _readOption);
        }

AddItemToBundle.PS1

Function AddItemToBundle
 {
    [CmdletBinding()]
    Param (
            # Bundle ID
            [Parameter(Mandatory=$true)]
            [string]$BundleId,
		
	    # Item ID .
	    [Parameter(Mandatory=$true)]
	    [string]$ItemID
        )

    Begin
    {
    	$client = Get-TridionCoreServiceClient -Verbose:($PSBoundParameters['Verbose'] -eq $true);
	$readOptions = New-Object Tridion.ContentManager.CoreService.Client.ReadOptions;
    }
    
    Process
    {
        $bundle = Get-TridionItem -id $BundleId;

        $doc = New-Object System.Xml.XmlDocument;
        $doc.LoadXml($bundle.Configuration)

        $itemElem = $doc.CreateElement('Item', $BundleNamespace);
        $itemElem.SetAttribute('href', $XLinkNamespace, $itemId) | Out-Null;

        $rootElem = $doc.SelectSingleNode('/*/*');
        $rootElem.appendChild($itemElem) | Out-Null;

        $bundle.Configuration = $doc.InnerXml;
        $client.Save($bundle, $readOptions);
     }
    End
    {
    	Close-TridionCoreServiceClient $client;
    }

 }