With Add-Type and $executioncontext you can add special varibles that have tied values.<\/p>\n
I made $random, and $now <\/p>\n
add-type @”
using System;
using System.Management.Automation;
public class RandomVariable : PSVariable
{
Random r;
public RandomVariable ()
: base(“Random”, 0, ScopedItemOptions.ReadOnly | ScopedItemOptions.AllScope)
{r = new Random();}<\/p>\n
public override object Value
{
get
{
return r.Next();
}
}
}
“@
$executioncontext.SessionState.PSVariable.Set((new-object RandomVariable))<\/p>\n
add-type @”
using System;
using System.Management.Automation;
public class NowVariable : PSVariable
{
public NowVariable ()
: base(“Now”, 0, ScopedItemOptions.ReadOnly | ScopedItemOptions.AllScope)
{}
public override object Value
{
get
{
return DateTime.Now;
}
}
}
“@
$executioncontext.SessionState.PSVariable.Set((new-object NowVariable))<\/p>\n
Results is,
PS C:\\tmp> $Random
229309908
PS C:\\tmp> $Random
1759972224
PS C:\\tmp> $Now
Thursday, 26 March 2009 3:20:29 PM<\/p>\n
I got this from Lee, where you can bind the behaviour to ScriptBlocks instead of C#, making it even easier to use. See attached <\/p>\n
It has in it,
get
{
if(getter != null) { return getter.Invoke(); }
else { return null; }
}<\/p>\n
Which is a simple way to cross over to PowerShell from C#
And you can use it like so,
PS C:\\temp> New-ScriptVariable.ps1 GLOBAL:today { (Get-Date).DayOfWeek }
PS C:\\temp> $today
Wednesday<\/p>\n
Cheers,
Ibrahim Abdul Rahim [MSFT]<\/p>\n