Author: Fabrice Sanga

You might be familiar with the Task Manager in Windows, which you rush to when a program window stops working abruptly and notifies you that its process is Not Responding. You then have no option other than clicking the button to End Task. By the name you guess, it manages tasks. It has many more features than inspecting and ending processes like monitoring system performance, starting tasks, etc.

The Process Inspector dialogue box is another reinvented wheel that inspects individual processes and provides an option to stop them. It is a simplified view of the Task Manager. However, it is a practical starter for making GUI applications in PowerShell while applying the Model-View-Controller (MVC) architecture.

Here is the link to the demo of the Process Inspector on YouTube. 🎞️

The project is a PowerShell module structured around three nested module scripts ProcessInspector.Model.psm1, ProcessInspector.View.psm1, and ProcessInspector.Controller.psm1 in the .\module subfolder provided that the paths are relative to the module base directory in PSModulePath.

ProcessInspector
│   ProcessInspector.psd1
│
└───module
    │   ProcessInspector.Controller.psm1
    │   ProcessInspector.Model.psm1
    │   ProcessInspector.View.psm1
    │
    └───script
            Get-ProcessInspectorUIAdapter.ps1
            ico.bmp
            New-ProcessInspectorUI.ps1
            Set-ProcessInspectorUIAdapterProperties.ps1

The module contains all the code related to the user interface, which is built using Windows Forms. It exports its only function New-ProcessInspector, referred to as a Factory Method that creates a new process inspector dialogue object that contains all the graphic elements.

PS> Import-Module ProcessInspector\module\ProcessInspector.View.psm1
PS> New-ProcessInspector | Get-Member -MemberType Script* | Select-Object Name,MemberType

Name                        MemberType
----                        ----------
Display                   ScriptMethod
Dispose                   ScriptMethod
OnProcessListDropDown     ScriptMethod
OnProcessSelected         ScriptMethod
OnRefreshTick             ScriptMethod
OnTerminateProcessClick   ScriptMethod
MemoryUsage             ScriptProperty
ProcessList             ScriptProperty
ProcessName             ScriptProperty
SortByName              ScriptProperty
TotalMemoryUsage        ScriptProperty

With the previous commands, we list the custom methods and properties of the Process Inspector UI object. It inherits its other members from the PSCustomObject type. You can unbind the parameter MemberType from Get-Member to get the complete list of members.

The created Process Inspector UI object encapsulates the bare WinForms user interface. The logic of the function New-ProcessInspector depends on the Adapter Design Pattern. The first script on which the View module depends, New-ProcessInspectorUI.ps1, returns the WinForms dialogue box object decorated with a timer and other note-properties that refer to graphic elements which state or behavior change. The commands below are executed from the PSModulePath.

PS> .\ProcessInspector\module\script\New-ProcessInspectorUI | Get-Member -MemberType NoteProperty | Select-Object Name

Name
----
ButtonToTerminateProcess
CheckBoxForSortByNameOption
ComboBoxForProcessName
LabelForMemoryUsage
LabelForTotalMemoryUsage
Timer

New-ProcessInspector returns an adapted view of the user interface form with the successive calls to Get-ProcessInspectorUIAdapter.ps1 and Set-ProcessInspectorUIAdapterProperties.ps1 scripts.

First, the controls convert to the values they contain:

• ComboBoxForProcessName converts to ProcessName and ProcessList,
• CheckBoxForSortByNameOption converts to SortByName,
• LabelForMemoryUsage converts to MemoryUsage,
• LabelForTotalMemoryUsage converts to TotalMemoryUsage.

Then, the controls and timer convert to a unified set of event listeners:

• ComboBoxForProcessName listens to OnProcessSelected() and OnProcessListDropDown(),
• ButtonToTerminateProcess listens to OnTerminateProcessClick(),
• Timer listens to OnRefreshTick().

The method Display() starts the timer and opens the dialogue box. The timer stops when the dialogue box closes. Dispose() releases resources.

Here is the link to the demo of the View on YouTube. 🎞️

The module is stateless and exports three simple functions. Their goal is to read data related to processes on the local system.

• Get-ProcessInstance gets a list of custom process objects. It only returns process names when it binds the parameter NoMemoryUsage switch for faster processing time when the user ticks the option to sort the list by names.
• Get-ProcessMemoryUsage returns the memory usage in megabytes (MB) of a specified process as computed in Task Manager. Here is the link to the comparison of values between the Task Manager and the Process Inspector on YouTube. 🎞️
• Get-TotalMemoryUsage returns the total memory usage of the local computer and displays it as a percentage value.

PS> Import-Module ProcessInspector\module\ProcessInspector.Model.psm1
PS> Get-ProcessInstance | Sort-Object MemoryUsage -Descending | Select-Object -First 10

Name                      MemoryUsage
----                      -----------
chrome                  1647558656.00
Code                    1311846400.00
MsMpEng                  360693760.00
msedge                   347893760.00
svchost                  206532608.00
StartMenuExperienceHost  176316416.00
dwm                      136261632.00
Video.UI                 132186112.00
explorer                 130179072.00
pwsh                     128028672.00

PS> Get-ProcessInstance -NoMemoryUsage | Select-Object -First 10

Name
----
AgentService
ApplicationFrameHost
app_updater
audiodg
backgroundTaskHost
chrome
client32
cmd
Code
CompPkgSrv

PS> Get-ProcessMemoryUsage chrome # in MB
1440.44

PS> Get-TotalMemoryUsage # in %
74.71

The Controller module is a Mediator between the View and the Model, both decoupled from each other. It exports three functions whose tasks are as follows:

• Reset-ProcessInspector: initializing the User Interface or resetting it,
• Show-ProcessInspector: displaying the Process Inspector dialog window,
• Stop-ProcessInspector: disposing of the resources.

Reset-ProcessInspector is where the event handlers are defined. The Controller performs only one Delete operation on the data when the OnTerminateProcessClick is raised. When the user clicks "Terminate Process", the selected process is deleted from the dropdown list and stopped from running on the local system.

Read operations happen when the user opens the dialogue to display the overall memory usage of the local system, when she clicks the combo box to list processes, and when she selects one to show its memory consumption.

At last, the ProcessInspector manifest indexes the Controller as the root module and exposes its functions.