Powershell Function Pipeline a Data Table

Question

I've got a function which outputs a data table result and would like to be able to make it useable in a pipeline result. I can read into the table to return just the mpname but it I would like to know if its possible to have both options? So for example
if the command is run separately it outputs the data table but if run in a pipeline is outputs just the string?
Any advice or suggestions greatly appreciated :)! Been scratching my head on this for a while...
function Get-MPPropertiesTest {
[CmdletBinding(DefaultParameterSetName="None")]
param
[Parameter(Position=0,Mandatory=$false,
HelpMessage='Select Management Pack',
ParameterSetName="Two"
[String]$ManagementPack
begin {
switch ($psCmdlet.ParameterSetName) {
"None" {$ManagementPack = 'Microsoft.Unix.Library'
$SqlQuery = "Select MPName, MPFriendlyName, MPVersion, MPXML
FROM
[dbo].[ManagementPack]
Where MPName = '$ManagementPack'"
"Two" {$SqlQuery = "Select MPName, MPFriendlyName, MPVersion, MPXML
FROM
[dbo].[ManagementPack]
Where MPName = '$ManagementPack'
process{
write-verbose "Beginning process"
Write-Verbose "Processing $ManagementPack"
$SqlConnection = New-Object System.Data.SqlClient.SqlConnection
$SqlConnection.ConnectionString = "Server = $SCOMSQLServer; Database = $SCOMDBName; Integrated Security = True"
$SqlConnection.Open()
$SqlCmd = New-Object System.Data.SqlClient.SqlCommand
$sqlcmd.CommandTimeout = 600000
$SqlCmd.Connection = $SqlConnection
$SqlCmd.CommandText = $SqlQuery
$result = $sqlcmd.ExecuteReader()
$resulttable = new-object “System.Data.DataTable”
$resulttable.Load($result)
$SqlConnection.Close()
End{
return $resulttable
Raf Delgado

Answer 1

A "Get-Process Notepad" returns the single option in the table which is also fine. What I'm trying to achieve is effectively the same as doing a get-process notepad | stop-process, how does the stop-process know to read the table for the variable
to use?
On my test function I can successfully do a pipe to an export-csv so it is piping, the return however shows the first line as "#TYPE System.Data.DataRow" which when piping to my other function. 
Raf Delgado
Get-Process notepad does not return a "table of text". It returns an object.
Get-Process notepad
Handles NPM(K) PM(K) WS(K) VM(M) CPU(s) Id ProcessName
88 7 1344 8008 92 0.03 5928 notepad
You may see a table of text on the console. But that's not all that has been returned. 
In this example, it's specifically a ComponentModel.Component object
$SomeVariable = Get-Process notepad
$SomeVariable.GetType()
IsPublic IsSerial Name BaseType
True False Process System.ComponentModel.Component
An object has properties, methods, and events:
$SomeVariable | Get-Member TypeName: System.Diagnostics.Process
Name MemberType Definition
Handles AliasProperty Handles = Handlecount
Name AliasProperty Name = ProcessName
NPM AliasProperty NPM = NonpagedSystemMemorySize
PM AliasProperty PM = PagedMemorySize
VM AliasProperty VM = VirtualMemorySize
WS AliasProperty WS = WorkingSet
Disposed Event System.EventHandler Disposed(System.Object, System.EventArgs)
ErrorDataReceived Event System.Diagnostics.DataReceivedEventHandler ErrorDataReceived(System.Object, System.Diagnostics.DataReceivedEventArgs)
Exited Event System.EventHandler Exited(System.Object, System.EventArgs)
OutputDataReceived Event System.Diagnostics.DataReceivedEventHandler OutputDataReceived(System.Object, System.Diagnostics.DataReceivedEventArgs)
BeginErrorReadLine Method void BeginErrorReadLine()
BeginOutputReadLine Method void BeginOutputReadLine()
CancelErrorRead Method void CancelErrorRead()
CancelOutputRead Method void CancelOutputRead()
Close Method void Close()
CloseMainWindow Method bool CloseMainWindow()
CreateObjRef Method System.Runtime.Remoting.ObjRef CreateObjRef(type requestedType)
Dispose Method void Dispose(), void IDisposable.Dispose()
Equals Method bool Equals(System.Object obj)
GetHashCode Method int GetHashCode()
GetLifetimeService Method System.Object GetLifetimeService()
GetType Method type GetType()
InitializeLifetimeService Method System.Object InitializeLifetimeService()
Kill Method void Kill()
Refresh Method void Refresh()
Start Method bool Start()
ToString Method string ToString()
WaitForExit Method bool WaitForExit(int milliseconds), void WaitForExit()
WaitForInputIdle Method bool WaitForInputIdle(int milliseconds), bool WaitForInputIdle()
__NounName NoteProperty System.String __NounName=Process
BasePriority Property int BasePriority {get;}
Container Property System.ComponentModel.IContainer Container {get;}
EnableRaisingEvents Property bool EnableRaisingEvents {get;set;}
ExitCode Property int ExitCode {get;}
ExitTime Property datetime ExitTime {get;}
Handle Property System.IntPtr Handle {get;}
HandleCount Property int HandleCount {get;}
HasExited Property bool HasExited {get;}
Id Property int Id {get;}
MachineName Property string MachineName {get;}
MainModule Property System.Diagnostics.ProcessModule MainModule {get;}
MainWindowHandle Property System.IntPtr MainWindowHandle {get;}
MainWindowTitle Property string MainWindowTitle {get;}
MaxWorkingSet Property System.IntPtr MaxWorkingSet {get;set;}
MinWorkingSet Property System.IntPtr MinWorkingSet {get;set;}
Modules Property System.Diagnostics.ProcessModuleCollection Modules {get;}
NonpagedSystemMemorySize Property int NonpagedSystemMemorySize {get;}
NonpagedSystemMemorySize64 Property long NonpagedSystemMemorySize64 {get;}
PagedMemorySize Property int PagedMemorySize {get;}
PagedMemorySize64 Property long PagedMemorySize64 {get;}
PagedSystemMemorySize Property int PagedSystemMemorySize {get;}
PagedSystemMemorySize64 Property long PagedSystemMemorySize64 {get;}
PeakPagedMemorySize Property int PeakPagedMemorySize {get;}
PeakPagedMemorySize64 Property long PeakPagedMemorySize64 {get;}
PeakVirtualMemorySize Property int PeakVirtualMemorySize {get;}
PeakVirtualMemorySize64 Property long PeakVirtualMemorySize64 {get;}
PeakWorkingSet Property int PeakWorkingSet {get;}
PeakWorkingSet64 Property long PeakWorkingSet64 {get;}
PriorityBoostEnabled Property bool PriorityBoostEnabled {get;set;}
PriorityClass Property System.Diagnostics.ProcessPriorityClass PriorityClass {get;set;}
PrivateMemorySize Property int PrivateMemorySize {get;}
PrivateMemorySize64 Property long PrivateMemorySize64 {get;}
PrivilegedProcessorTime Property timespan PrivilegedProcessorTime {get;}
ProcessName Property string ProcessName {get;}
ProcessorAffinity Property System.IntPtr ProcessorAffinity {get;set;}
Responding Property bool Responding {get;}
SessionId Property int SessionId {get;}
Site Property System.ComponentModel.ISite Site {get;set;}
StandardError Property System.IO.StreamReader StandardError {get;}
StandardInput Property System.IO.StreamWriter StandardInput {get;}
StandardOutput Property System.IO.StreamReader StandardOutput {get;}
StartInfo Property System.Diagnostics.ProcessStartInfo StartInfo {get;set;}
StartTime Property datetime StartTime {get;}
SynchronizingObject Property System.ComponentModel.ISynchronizeInvoke SynchronizingObject {get;set;}
Threads Property System.Diagnostics.ProcessThreadCollection Threads {get;}
TotalProcessorTime Property timespan TotalProcessorTime {get;}
UserProcessorTime Property timespan UserProcessorTime {get;}
VirtualMemorySize Property int VirtualMemorySize {get;}
VirtualMemorySize64 Property long VirtualMemorySize64 {get;}
WorkingSet Property int WorkingSet {get;}
WorkingSet64 Property long WorkingSet64 {get;}
PSConfiguration PropertySet PSConfiguration {Name, Id, PriorityClass, FileVersion}
PSResources PropertySet PSResources {Name, Id, Handlecount, WorkingSet, NonPagedMemorySize, PagedMemorySize, PrivateMemorySize, VirtualMemorySi...
Company ScriptProperty System.Object Company {get=$this.Mainmodule.FileVersionInfo.CompanyName;}
CPU ScriptProperty System.Object CPU {get=$this.TotalProcessorTime.TotalSeconds;}
Description ScriptProperty System.Object Description {get=$this.Mainmodule.FileVersionInfo.FileDescription;}
FileVersion ScriptProperty System.Object FileVersion {get=$this.Mainmodule.FileVersionInfo.FileVersion;}
Path ScriptProperty System.Object Path {get=$this.Mainmodule.FileName;}
Product ScriptProperty System.Object Product {get=$this.Mainmodule.FileVersionInfo.ProductName;}
ProductVersion ScriptProperty System.Object ProductVersion {get=$this.Mainmodule.FileVersionInfo.ProductVersion;}
In this example, you can close notepad by using the Kill method:
$SomeVariable.Kill()
When writing a function to use an object as input, you specify the input variable as an object type instead of [string]. For example:
function Kill-Process {
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true,
ValueFromPipeLine=$true,
ValueFromPipeLineByPropertyName=$true,
Position=0)]
[System.Diagnostics.Process]$Process
$Process.Kill()
So, now I can do this:
Get-Process notepad | Kill-Process
and that will close notepad.
How did that work?
In the Kill-Process function, I used
CmdletBinding - see this link for more details
I used
ValueFromPipeLineByPropertyName and ValueFromPipeLine - see this link for more details
I specified the object type I'm accepting as input.
This is exactly the same object type that's the Output of the Get-Process cmdlet. This is how a pipeline works in Powershell. It's not that a cmdlet parses text from a prior cmdlet. It looks for its required input from the pipeline if 'ValueFromPipeLine'
is specified.   
Sam Boutros, Senior Consultant, Software Logic, KOP, PA http://superwidgets.wordpress.com (Please take a moment to Vote as Helpful and/or Mark as Answer, where applicable) _________________________________________________________________________________
Powershell: Learn it before it's an emergency http://technet.microsoft.com/en-us/scriptcenter/powershell.aspx http://technet.microsoft.com/en-us/scriptcenter/dd793612.aspx
Thank you Sam! This is Perfect! Makes a lot more sense now.
So if I wanted to parse to a Datatable could I do something like the below?
function Get-ManagementPack {
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true,
ValueFromPipeLine=$true,
ValueFromPipeLineByPropertyName=$true,
Position=0)]
[System.Data.Datatable]$ManagementPack
$ManagementPack
Raf Delgado