Hide, Show, Minimize, Maximize, etc window from Powershell.

Set-WindowState.ps1

function Set-WindowState {
    <#
    .SYNOPSIS
    Set the state of a window.

    .DESCRIPTION
    Set the state of a window using the `ShowWindowAsync` function from `user32.dll`.

    .PARAMETER InputObject
    The process object(s) to set the state of. Can be piped from `Get-Process`.

    .PARAMETER State
    The state to set the window to. Default is 'SHOW'.

    .PARAMETER SuppressErrors
    Suppress errors when the main window handle is '0'.

    .PARAMETER SetForegroundWindow
    Set the window to the foreground

    .PARAMETER ThresholdHours
    The number of hours to keep the window handle in memory. Default is 24.

    .EXAMPLE
    Get-Process notepad | Set-WindowState -State HIDE -SuppressErrors

    .EXAMPLE
    Get-Process notepad | Set-WindowState -State SHOW -SuppressErrors

    .LINK
    https://gist.github.com/lalibi/3762289efc5805f8cfcf

    .NOTES
    Original idea from https://gist.github.com/Nora-Ballard/11240204
    #>

    [CmdletBinding(DefaultParameterSetName = 'InputObject')]
    param(
        [Parameter(Position = 0, Mandatory = $true, ValueFromPipeline = $true)]
        [Object[]] $InputObject,

        [Parameter(Position = 1)]
        [ValidateSet(
            'FORCEMINIMIZE', 'HIDE', 'MAXIMIZE', 'MINIMIZE', 'RESTORE',
            'SHOW', 'SHOWDEFAULT', 'SHOWMAXIMIZED', 'SHOWMINIMIZED',
            'SHOWMINNOACTIVE', 'SHOWNA', 'SHOWNOACTIVATE', 'SHOWNORMAL'
        )]
        [string] $State = 'SHOW',
        [switch] $SuppressErrors = $false,
        [switch] $SetForegroundWindow = $false,
        [int] $ThresholdHours = 24
    )

    Begin {
        $WindowStates = @{
            'FORCEMINIMIZE'      = 11
            'HIDE'               = 0
            'MAXIMIZE'           = 3
            'MINIMIZE'           = 6
            'RESTORE'            = 9
            'SHOW'               = 5
            'SHOWDEFAULT'        = 10
            'SHOWMAXIMIZED'      = 3
            'SHOWMINIMIZED'      = 2
            'SHOWMINNOACTIVE'    = 7
            'SHOWNA'             = 8
            'SHOWNOACTIVATE'     = 4
            'SHOWNORMAL'         = 1
        }

        $Win32ShowWindowAsync = Add-Type -MemberDefinition @'
[DllImport("user32.dll")]
public static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
[DllImport("user32.dll", SetLastError = true)]
public static extern bool SetForegroundWindow(IntPtr hWnd);
'@ -Name "Win32ShowWindowAsync" -Namespace Win32Functions -PassThru

        $handlesFilePath = "$env:APPDATA\WindowHandles.json"

        $global:MainWindowHandles = @{}

        if (Test-Path $handlesFilePath) {
            $json = Get-Content $handlesFilePath -Raw
            $data = $json | ConvertFrom-Json
            $currentTime = Get-Date

            foreach ($key in $data.PSObject.Properties.Name) {
                $handleData = $data.$key

                if ($handleData -and $handleData.Timestamp) {
                    try {
                        $timestamp = [datetime] $handleData.Timestamp
                        if ($currentTime - $timestamp -lt (New-TimeSpan -Hours $ThresholdHours)) {
                            $global:MainWindowHandles[[int] $key] = $handleData
                        }
                    } catch {
                        Write-Verbose "Skipping invalid timestamp for handle $key"
                    }
                } else {
                    Write-Verbose "Skipping entry for handle $key due to missing data"
                }
            }
        }
    }

    Process {
        foreach ($process in $InputObject) {
            $handle = $process.MainWindowHandle

            if ($handle -eq 0 -and $global:MainWindowHandles.ContainsKey($process.Id)) {
                $handle = [int] $global:MainWindowHandles[$process.Id].Handle
            }

            if ($handle -eq 0) {
                if (-not $SuppressErrors) {
                    Write-Error "Main Window handle is '0'"
                } else {
                    Write-Verbose ("Skipping '{0}' with id '{1}', because Main Window handle is '0'" -f $process.ProcessName, $process.Id)
                }

                continue
            }

            Write-Verbose ("Processing '{0}' with id '{1}' and handle '{2}'" -f $process.ProcessName, $process.Id, $handle)

            $global:MainWindowHandles[$process.Id] = @{
                Handle = $handle.ToString()
                Timestamp = (Get-Date).ToString("o")
            }

            $Win32ShowWindowAsync::ShowWindowAsync($handle, $WindowStates[$State]) | Out-Null

            if ($SetForegroundWindow) {
                $Win32ShowWindowAsync::SetForegroundWindow($handle) | Out-Null
            }

            Write-Verbose ("» Set Window State '{1}' on '{0}'" -f $handle, $State)
        }
    }

    End {
        $data = [ordered] @{}

        foreach ($key in $global:MainWindowHandles.Keys) {
            if ($global:MainWindowHandles[$key].Handle -ne 0) {
                $data["$key"] = $global:MainWindowHandles[$key]
            }
        }

        $json = $data | ConvertTo-Json

        Set-Content -Path $handlesFilePath -Value $json
    }
}

MainWindowHandles are now stored in a .json file, in "$env:APPDATA\WindowHandles.json", and restored them every time the script is run. At this point there is no automatic way to clear this file, only manually.

.json now includes a timestamp for each entry and invalidates them, if a threshold is reached (default is 24 hours).

Wow, two years later, you still added a feature. That's awesome!

And I just realized I didn't respond, sorry about that lol.