There is a PowerShell cmdlet Invoke-MgSubscribeGroup that I want to call this way:

Invoke-MgSubscribeGroup -GroupId da2d17a7-64a5-43e5-9d95-7b70333dd78c 
                        @{ UserId = "ed3d927d-7999-459f-955d-2afc272bd4d4" }

(Split into multiple lines for better readability)

When calling it, I get en error message:

A positional parameter cannot be found that accepts argument "System.Collections.Hashtable".

Since I'm not that deep into PowerShell I must have some false understanding of how to pass a hashtable, or I have misunderstood the documentation that says:

...To create the parameters described below, construct a hash table containing the appropriate properties...

My question

What is the correct syntax to call the Invoke-MgSubscribeGroup cmdlet and pass the user ID?

CodePudding user response：

To elaborate on your own answer:

PowerShell's syntax diagrams - available locally via Invoke-MgSubscribeGroup -? or Get-Command -Syntax Invoke-MgSubscribeGroup - contain all the relevant information.

That said, they're not easy to read, especially locally, and there's room for future improvement.

Quoting from Invoke-MgSubscribeGroup's documentation:

Invoke-MgSubscribeGroup
      -GroupId <String>
      # ...

Invoke-MgSubscribeGroup
      -InputObject <IGroupsIdentity>
      # ...

• Each (partial) quote represents a distinct parameter set, i.e. a unique combination of parameters representing a distinct feature group.

• That -GroupId and -InputObject are in different parameter sets and are exclusive to each, tells you that you cannot use them both in a given invocation (they way you mistakenly tried), i.e., that they are mutually exclusive.

• Additionally, given that the parameter names -GroupId and -InputObject are not enclosed in [...] means that you can only pass named, not positional arguments to them - that is, you must precede an argument to bind to these parameters with the parameter name; e.g, -GroupId foo rather than just foo.

• By convention, a parameter named -InputObject is typically used to represent values that can be supplied via the pipeline, as evidenced by the parameter's description stating Accept pipeline input: True - locally, you can see this with either Get-Help -Full Invoke-MgSubscribeGroup or - parameter-specifically - with Get-Help Invoke-MgSubscribeGroup -Parameter InputObject

  • Often, multiple input objects can only (meaningfully) be supplied via the pipeline; that is, -InputObject is often a mere implementation detail whose purpose is to facilitate pipeline input - see GitHub issue #4242.

  • GitHub issue #4135 proposes making syntax diagrams directly reflect which parameters accept pipeline input.

What complicates matters with respect to Invoke-MgSubscribeGroup's documentation, specifically (which seems to be very sparse in general):

• The help topic contains no examples (which you could normally request locally with Get-Help -Examples Invoke-MgSubscribeGroup)

• The data type of the -InputObject parameter, <IGroupsIdentity> (Microsoft.Graph.PowerShell.Models.IGroupsIdentity) doesn't seem to have its own documentation; it is only described in the "Notes" section of the help topic, as accepting a hashtable (@{ ... }), along with a list of the supported entries (keys and value types).

All that said: you could have passed your hashtable via the pipeline, as follows:

@{ 
  UserId = 'ed3d927d-7999-459f-955d-2afc272bd4d4'
  GroupId = 'da2d17a7-64a5-43e5-9d95-7b70333dd78c'
} | Invoke-MgSubscribeGroup

The advantage of this approach over passing an argument to -InputObject is that it would allow you to pass multiple hashtables to act on.

CodePudding user response：

After further investigating and reading the documentation again and again, I've found the correct syntax:

Invoke-MgSubscribeGroup -InputObject @{ 
    UserId = "ed3d927d-7999-459f-955d-2afc272bd4d4"; 
    GroupId = "da2d17a7-64a5-43e5-9d95-7b70333dd78c" }

(Split into multiple lines for better readability)

I now face permission issues, but this is out-of-scope for this question, since I've asked for the correct syntax only.