Creating Generic Functions in PowerShell for Dynamic Menus

As PowerShell users, we’ve all been there – we create a function that seems perfect at the time, but later realize it could be more versatile and generic. In my previous post, I shared a function on how to use PowerShell to create an interactive dynamic menu. However, upon further reflection, I realized that the function could be more flexible by allowing users to change the query without modifying the function itself. In this follow-up post, we’ll explore how to create generic functions in PowerShell for dynamic menus.

The original function had two mandatory parameters: -ListItem and -GetItem. The first parameter retrieves data using a specific query, while the second parameter specifies the task to perform on the selected object. To make the function more generic, we’ll pass the query and task as separate strings instead of hardcoding them within the function. This approach allows users to easily modify the query without affecting the function’s code.

Here’s the updated function signature:

Set-Menu -ListItem $MyQuery -GetItem $MyTask

Now, let’s dive into how this function works. The first parameter, -ListItem, is the query that retrieves data. This can be any valid PowerShell command that returns a list of objects. For example, to retrieve a list of virtual machines (VMs), we can use the following query:

(Get-VM | Sort-Object)

To retrieve a list of datastores, we can use a similar query with a slight variation:

(Get-Datastore | Where {$_.Type -eq ‘VMFS’} | Sort-Object -Descending FreeSpaceGB)

The second parameter, -GetItem, specifies the task to perform on the selected object. This can be any valid PowerShell command that operates on a single object. For instance, if we want to retrieve a specific VM, we can set -GetItem to “Get-VM”. However, this parameter could also be used for more complex tasks like removing a VM or updating its settings.

To use the function, simply pass in the query and task as separate strings, followed by the list of items and their selected state:

Set-Menu -ListItem “((Get-VM | Sort-Object) -contains $($Context.SelectedItem))” -GetItem “Get-VM” -List $MyQuery -Get $MyTask

In this example, we’re retrieving a list of VMs using the previous query and then checking if the selected item is contained within that list. If it is, we perform the task specified by -GetItem, which in this case is “Get-VM”.

The beauty of this approach is that users can modify the query and task without affecting the function’s code. This makes the function more versatile and adaptable to different use cases. For instance, if you want to retrieve a list of datastores instead of VMs, simply change the $MyQuery variable to the appropriate query.

In conclusion, creating generic functions in PowerShell for dynamic menus allows users to modify the query and task without affecting the function’s code. This approach makes the function more versatile and adaptable to different use cases. By following these steps, you can create more powerful and flexible functions that can be used in a variety of situations.

I hope this follow-up post has provided valuable insights into creating generic functions for dynamic menus in PowerShell. As always, I welcome your comments and feedback. Please feel free to share your own experiences and tips on how to create more versatile functions in PowerShell.