creating a PSScriptProperty

Hello assorted powershell legends!

I've been tinkering with powershell on my own and never though to post here,
until Thomas Lee suggested it.
Current problem: i can't find any way to create a ScriptBlock object from a
C# app.
I can create a command that is a script... but can't get an actual
"ScriptBlock" object.

code example below:

System.Management.Automation.ScriptBlock sc;

//help! do some magic here to instantiate my scriptblock...
//e.g.
//sc = new ScriptBlock(@"{""Hello""}"); //this doesn't work.
//perhaps i need to use:
//System.Management.Automation.CommandInvocationIntrinsics.NewScriptBlock
//but haven't worked out how that works yet...

PSScriptProperty psc = new PSScriptProperty("NewScriptBlock",sc);

//now i can add the script property to a PSObject's properties collection
//and invoke it...

ps1.Properties.Add(psc);

MessageBox.Show(ps1.Properties["NewScriptBlock"].Value);

....cheers
this is with RC1 by the way
lb

...:: secretGeek.net :: TimeSnapper.com ::..

I think there are better ways, but one method might be to use
invoke-expression.
It will return a scriptblock if you provide a string. Should be possible to
transform this code it into C#.

PS> $scriptblock = invoke-expression "{write-output 'hello, world!'}"
PS> $scriptblock | gm
TypeName: System.Management.Automation.ScriptBlock
PS> . $scriptblock
hello, world!

--
greetings
dreeschkind

"secretGeek" wrote:

> Hello assorted powershell legends!
>
> I've been tinkering with powershell on my own and never though to post here,
> until Thomas Lee suggested it.
> Current problem: i can't find any way to create a ScriptBlock object from a
> C# app.
> I can create a command that is a script... but can't get an actual
> "ScriptBlock" object.
>
> code example below:
>
> System.Management.Automation.ScriptBlock sc;
>
> //help! do some magic here to instantiate my scriptblock...
> //e.g.
> //sc = new ScriptBlock(@"{""Hello""}"); //this doesn't work.
> //perhaps i need to use:
> //System.Management.Automation.CommandInvocationIntrinsics.NewScriptBlock
> //but haven't worked out how that works yet...
>
> PSScriptProperty psc = new PSScriptProperty("NewScriptBlock",sc);
>
> //now i can add the script property to a PSObject's properties collection
> //and invoke it...
>
> ps1.Properties.Add(psc);
>
> MessageBox.Show(ps1.Properties["NewScriptBlock"].Value);
>
> ...cheers
> this is with RC1 by the way
> lb
>
> ..:: secretGeek.net :: TimeSnapper.com ::..

ScriptBlock does not have a public constructor available. If you are
developing a cmdlet then you can accept this as a parameter.

--
Narayanan Lakshmanan [MSFT]
Windows PowerShell Development
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.


"dreeschkind" <dreeschkind@discussions.microsoft.com> wrote in message
news:F594C86B-0AB4-4287-AB8E-A0F61EF6B4A8@microsoft.com...
>I think there are better ways, but one method might be to use
> invoke-expression.
> It will return a scriptblock if you provide a string. Should be possible
> to
> transform this code it into C#.
>
> PS> $scriptblock = invoke-expression "{write-output 'hello, world!'}"
> PS> $scriptblock | gm
> TypeName: System.Management.Automation.ScriptBlock
> PS> . $scriptblock
> hello, world!
>
> --
> greetings
> dreeschkind
>
> "secretGeek" wrote:
>
>> Hello assorted powershell legends!
>>
>> I've been tinkering with powershell on my own and never though to post
>> here,
>> until Thomas Lee suggested it.
>> Current problem: i can't find any way to create a ScriptBlock object from
>> a
>> C# app.
>> I can create a command that is a script... but can't get an actual
>> "ScriptBlock" object.
>>
>> code example below:
>>
>> System.Management.Automation.ScriptBlock sc;
>>
>> //help! do some magic here to instantiate my scriptblock...
>> //e.g.
>> //sc = new ScriptBlock(@"{""Hello""}"); //this doesn't work.
>> //perhaps i need to use:
>> //System.Management.Automation.CommandInvocationIntrinsics.NewScriptBlock
>> //but haven't worked out how that works yet...
>>
>> PSScriptProperty psc = new PSScriptProperty("NewScriptBlock",sc);
>>
>> //now i can add the script property to a PSObject's properties collection
>> //and invoke it...
>>
>> ps1.Properties.Add(psc);
>>
>> MessageBox.Show(ps1.Properties["NewScriptBlock"].Value);
>>
>> ...cheers
>> this is with RC1 by the way
>> lb
>>
>> ..:: secretGeek.net :: TimeSnapper.com ::..

Thanks Narayanan.
Yes, I see that ScriptBlock doesn't have a public constructor.
I'm not developing a cmdLet in this case -- i'm trying to write C# code that
will add a Property to a PSObject, and the type of Property I want to add is
a ScriptProperty.
ScriptProperties look very cool, as they giv you a real flexibility there.
So i just want to add a simple script property.
If I grab a ScriptBlock (object) from an existing ScriptProperty, then I can
use it for my new ScriptProperty (with whatever name I want) but I haven';t
worked out how to set my own script inside the script block.
I figure there must be some object that "emits" ScriptBlocks -- ie, acts as
a ScriptBlock factory -- and somewhere I'd have a chance to specify the body
of the script itself... but I can't find any such class, yet.


"Narayanan Lakshmanan [MSFT]" wrote:

> ScriptBlock does not have a public constructor available. If you are
> developing a cmdlet then you can accept this as a parameter.
>
> --
> Narayanan Lakshmanan [MSFT]
> Windows PowerShell Development
> Microsoft Corporation
> This posting is provided "AS IS" with no warranties, and confers no rights.
>
>
> "dreeschkind" <dreeschkind@discussions.microsoft.com> wrote in message
> news:F594C86B-0AB4-4287-AB8E-A0F61EF6B4A8@microsoft.com...
> >I think there are better ways, but one method might be to use
> > invoke-expression.
> > It will return a scriptblock if you provide a string. Should be possible
> > to
> > transform this code it into C#.
> >
> > PS> $scriptblock = invoke-expression "{write-output 'hello, world!'}"
> > PS> $scriptblock | gm
> > TypeName: System.Management.Automation.ScriptBlock
> > PS> . $scriptblock
> > hello, world!
> >
> > --
> > greetings
> > dreeschkind
> >
> > "secretGeek" wrote:
> >
> >> Hello assorted powershell legends!
> >>
> >> I've been tinkering with powershell on my own and never though to post
> >> here,
> >> until Thomas Lee suggested it.
> >> Current problem: i can't find any way to create a ScriptBlock object from
> >> a
> >> C# app.
> >> I can create a command that is a script... but can't get an actual
> >> "ScriptBlock" object.
> >>
> >> code example below:
> >>
> >> System.Management.Automation.ScriptBlock sc;
> >>
> >> //help! do some magic here to instantiate my scriptblock...
> >> //e.g.
> >> //sc = new ScriptBlock(@"{""Hello""}"); //this doesn't work.
> >> //perhaps i need to use:
> >> //System.Management.Automation.CommandInvocationIntrinsics.NewScriptBlock
> >> //but haven't worked out how that works yet...
> >>
> >> PSScriptProperty psc = new PSScriptProperty("NewScriptBlock",sc);
> >>
> >> //now i can add the script property to a PSObject's properties collection
> >> //and invoke it...
> >>
> >> ps1.Properties.Add(psc);
> >>
> >> MessageBox.Show(ps1.Properties["NewScriptBlock"].Value);
> >>
> >> ...cheers
> >> this is with RC1 by the way
> >> lb
> >>
> >> ..:: secretGeek.net :: TimeSnapper.com ::..
>
>

Well the factory you expect is also not available. PSCmdlet has a member
"InvokeCommand" which returns an object of type CommandInvocationIntrinsics.
This has a method NewScriptBlock which compiles a string into a ScriptBlock
object. But neither PSCmdlet or CommandInvocationIntrinsics have any public
constructor available and NewScriptBlock isn't a static function either. But
in case you want to achieve the same from a cmdlet, then its doable.

--
Narayanan Lakshmanan [MSFT]
Windows PowerShell Development
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.


"secretGeek" <secretGeek@discussions.microsoft.com> wrote in message
news:E07DF5A5-0127-4EE1-B6DA-F427CBDCC576@microsoft.com...
> Thanks Narayanan.
> Yes, I see that ScriptBlock doesn't have a public constructor.
> I'm not developing a cmdLet in this case -- i'm trying to write C# code
> that
> will add a Property to a PSObject, and the type of Property I want to add
> is
> a ScriptProperty.
> ScriptProperties look very cool, as they giv you a real flexibility there.
> So i just want to add a simple script property.
> If I grab a ScriptBlock (object) from an existing ScriptProperty, then I
> can
> use it for my new ScriptProperty (with whatever name I want) but I
> haven';t
> worked out how to set my own script inside the script block.
> I figure there must be some object that "emits" ScriptBlocks -- ie, acts
> as
> a ScriptBlock factory -- and somewhere I'd have a chance to specify the
> body
> of the script itself... but I can't find any such class, yet.
>
>
> "Narayanan Lakshmanan [MSFT]" wrote:
>
>> ScriptBlock does not have a public constructor available. If you are
>> developing a cmdlet then you can accept this as a parameter.
>>
>> --
>> Narayanan Lakshmanan [MSFT]
>> Windows PowerShell Development
>> Microsoft Corporation
>> This posting is provided "AS IS" with no warranties, and confers no
>> rights.
>>
>>
>> "dreeschkind" <dreeschkind@discussions.microsoft.com> wrote in message
>> news:F594C86B-0AB4-4287-AB8E-A0F61EF6B4A8@microsoft.com...
>> >I think there are better ways, but one method might be to use
>> > invoke-expression.
>> > It will return a scriptblock if you provide a string. Should be
>> > possible
>> > to
>> > transform this code it into C#.
>> >
>> > PS> $scriptblock = invoke-expression "{write-output 'hello, world!'}"
>> > PS> $scriptblock | gm
>> > TypeName: System.Management.Automation.ScriptBlock
>> > PS> . $scriptblock
>> > hello, world!
>> >
>> > --
>> > greetings
>> > dreeschkind
>> >
>> > "secretGeek" wrote:
>> >
>> >> Hello assorted powershell legends!
>> >>
>> >> I've been tinkering with powershell on my own and never though to post
>> >> here,
>> >> until Thomas Lee suggested it.
>> >> Current problem: i can't find any way to create a ScriptBlock object
>> >> from
>> >> a
>> >> C# app.
>> >> I can create a command that is a script... but can't get an actual
>> >> "ScriptBlock" object.
>> >>
>> >> code example below:
>> >>
>> >> System.Management.Automation.ScriptBlock sc;
>> >>
>> >> //help! do some magic here to instantiate my scriptblock...
>> >> //e.g.
>> >> //sc = new ScriptBlock(@"{""Hello""}"); //this doesn't work.
>> >> //perhaps i need to use:
>> >> //System.Management.Automation.CommandInvocationIntrinsics.NewScriptBlock
>> >> //but haven't worked out how that works yet...
>> >>
>> >> PSScriptProperty psc = new PSScriptProperty("NewScriptBlock",sc);
>> >>
>> >> //now i can add the script property to a PSObject's properties
>> >> collection
>> >> //and invoke it...
>> >>
>> >> ps1.Properties.Add(psc);
>> >>
>> >> MessageBox.Show(ps1.Properties["NewScriptBlock"].Value);
>> >>
>> >> ...cheers
>> >> this is with RC1 by the way
>> >> lb
>> >>
>> >> ..:: secretGeek.net :: TimeSnapper.com ::..
>>
>>

whats your context?
though a factory might not be avalible, there is nothing stopping you
in C# from creating your own pipeline and running a string of
powershell text that does the same thing. I do that all the time for
various things in powershell analyzer.

Karl
for everything i often have to make a choice.. can i, or should i try
to do this with the native powershell dotnet objects, or should i just
pass in a string to a pipeline object and get powershell to do it for
me. Some times its a hard call to make.