I was looking at a WPF/Powershell article MS Powershell blog WPF & PowerShell – Part 1 ( Hello World & Welcome to the Week of WPF )

When ever I try the 3rd Example

# Create a runspace to run Hello World


$rs = [Management.Automation.Runspaces.RunspaceFactory]::CreateRunspace()


$rs.ApartmentState, $rs.ThreadOptions = “STA”, “ReuseThread”


$rs.Open()


# Reference the WPF assemblies


$psCmd = {Add-Type}.GetPowerShell()


$psCmd.SetRunspace($rs)


$psCmd.AddParameter("AssemblyName", "PresentationCore").Invoke()


$psCmd.Command.Clear()


$psCmd = $psCmd.AddCommand("Add-Type")


$psCmd.AddParameter("AssemblyName", "PresentationFramework").Invoke()


$psCmd.Command.Clear()


$psCmd = $psCmd.AddCommand("Add-Type")


$psCmd.AddParameter("AssemblyName", "WindowsBase").Invoke()


$sb = $executionContext.InvokeCommand.NewScriptBlock(


(Join-Path $pwd "HelloWorld.ps1")


)


$psCmd = $sb.GetPowerShell()


$psCmd.SetRunspace($rs)


$null = $psCmd.BeginInvoke()


I get an error...


Method invocation failed because [System.Management.Automation.PowerShell] doesn't contain a method named 'SetRunspace'



I ran a $psCmd | gm



and there isn't a method called 'SetRunspace'.



What gives???

APIs change, even when something is in CTP.

Before: $psCmd.Command.Clear()
Now: $psCmd.Commands.Clear()

Before: $psCmd.SetRunspace($rs)
Now: $psCmd.Set_Runspace($rs)

Try the above changes.

I understand that things change but...

And that leads in to my next question. How would I have "Discovered" this change?

$psCmd |gm

doesn't expose that method.

I mean shouldn't past blog posts be annotated. Otherwise you have a lot of searchable mis-information.

This change is covered here:
http://blogs.msdn.com/powershell/ar...guide.aspx

Get-Member does expose the method. You just have to know to ask for it:

12:1:3 |(132)|P:\ PS>$psCMD | gm


TypeName: System.Management.Automation.PowerShell

Name MemberType
---- ----------
InvocationStateChanged Event
AddArgument Method
AddCommand Method
AddParameter Method
AddParameters Method
AddScript Method
BeginInvoke Method
BeginStop Method
CreateNestedPowerShell Method
Dispose Method
EndStop Method
Equals Method
GetHashCode Method
GetType Method
Invoke Method
Stop Method
ToString Method
Commands Property
InstanceId Property
InvocationStateInfo Property
IsNested Property
Runspace Property
RunspacePool Property
Streams Property

Notice the Commands property. Remember that everything in PS is an object. So the property of an object is itself an object:

12:2:17 |(133)|P:\ PS>$psCMD.Commands | gm


TypeName: System.Management.Automation.PSCommand

Name MemberType
---- ----------
AddArgument Method
AddCommand Method
AddParameter Method
AddScript Method
Clear Method
Clone Method
Equals Method
GetHashCode Method
GetType Method
ToString Method
Commands Property

So there is the Clear method.

@EBGreen,

Yes, the Clear() method is still there, but it would have been a bit more difficult to find the changes to the Get/Set Runspace members.