Windows PowerShell Tutorial 8 - Forms, Part 1

An introduction to creating Forms in PowerShell



  1. Regedit32
    For those of you familiar with Scripting languages you are probably used to using alternate applications like Visual Studio when you want to create GUIs for your scripts.

    There are a handful of other utilities for PowerShell too, which are a little cheaper to buy and still have the benefit of speeding up things like creating a GUI for your PowerShell script and Forms etcetera.

    Rather than spending money and having to learn how to use an additional tool, if you do not mind a little extra finger work, you can code your own GUI and Forms in PowerShell, and if you want you can even make use of Extensible Application Markup Language (XAML) language, and a handful of similar templates to help speed things up.

    Right now though, all that is more advanced, and beyond the focus of this introduction to creating a Form. Later, in other Tutorials I'll cover these advanced techniques, but for now let's get on with the basics.

    As PowerShell is centered around the .Net Framework you can make use of the [System.Windows.Forms] assembly to create a new object System.Windows.Forms.Form.

    As the [System.Windows.Forms] assembly is does not automatically load in PowerShell you need to add this assembly yourself by using the cmdlet Add-Type and the -AssemblyName parameter, then having done this create your new object.

    Note: You can also load the assembly using the following command:

    Code (PowerShell):
    [reflection.assembly]::LoadWithPartialName("System.Windows.Forms")


    Let's take a look at the simpler (and easier to remember) method combined with a basic script:

    Code (PowerShell):

    # Load the System.Windows.Forms assembly into PowerShell
    Add-Type -AssemblyName System.Windows.Forms

    # Create a new Form object and assign to the variable $Form
    $Form = New-Object System.Windows.Forms.Form

    #Initialize Form so it can be seen
    $Form.showDialog()
     
    If we open PowerShell or PowerShell ISE and run this basic script the following GUI form is generated:

    PS59.png

    Obviously, this form is of no practical use to us yet, but it is a platform we can use to start creating a more useful Form.

    Take a look at the following code block:

    Code (PowerShell):
    # Add description to the Form's titlebar
    $Form2.Text = "The Titlebar - Form"

    # Create a new Label object
    $Label = New-Object System.Windows.Forms.Label

    # Add some text to label
    $Label.Text = "Some random text to display"

    # Use AutoSize to guarantee label is correct size to contain text we add
    $Label.AutoSize = $true

    # Add Label to form
    $Form2.Controls.Add($Label)
    We can add this to our original Script to add a description to our Form's Title bar, and also add a new dimension to the form: the Label object, which we can use to add some text into the form.

    PS60.png
    • By using the .Text method with out $Form variable we are able to add a description to the Form's title bar.
    • We can create a new element in our form; the Label using the New-Object cmdlet to introduce the System.Windows.Forms.Label and this can be assigned to a variable.
    • Once we have assigned the Label to a variable we can then use the .Text method to add text to the label.
    • Given the text we add might be short or very long, its a good idea to make use of the AutoSize method to guarantee the label is large enough to hold whatever text we choose to enter for the label.
    • Now all you need to do is add the Label to our current Form using the Controls.add(<variable>).
    • The rest of the script is the initial building block you previously created.

    Starting to be a more useful form now, but for the fact the default font size is not too great for those of us who need glasses to read it, and do you actually like the font face, what if you want something a little different; perhaps to make the form a little nicer, or perhaps because a certain font face is easier to read for you.

    Not a problem, we can continue building on our code by adding some additional commands. For example:

    Code (PowerShell):
    # Choose a font face, font size, and style
    # Other styles include Bold, Italic, Underline and Strikeout
    # Note:  Fontface must be present on users computer
    $FontFace = New-Object System.Drawing.Font(
      "Comic Sans MS",20,[System.Drawing.FontStyle]::Regular
    )

    # Initialize the forms font
    $Form.Font = $FontFace

    # AutoSize ensures the Form size can contain the text
    $Form.AutoSize = $true

    # Allow user to resize too vs "GrowAndShrink" - user cannot resize
    $Form.AutoSizeMode = "GrowOnly"
    Now if we add this to our building block we get:

    PS61.png
    • This introduces a little more finger work!
    • First we need to create a new variable to store our Font information. You can call that variable whatever you like. Then you need to assign a new object to it which allows you to introduce System.Windows.Font(<Name>,<Size>,<Style>)
    • We then need to initialize our Forms font by assigning our new object to our $Form.Font(<object>)
    • As we are using a large font size, we include the AutoSize() for $Form to ensure the form automatically sizes to hold our text message in an easy to read format: $Form.AutoSize = $true
    • In addition I've added an additional option AutoSizeMode (which is not compulsory), but allows the Form to increase in size using an aspect ratio, e.g. Width x Depth: $Form.AutoSizeMode = "GrowOnly". You can control the Form size by adjusting its width only, by using "GrowAndShrink" instead.

      Using GrowAndShrink with above code would result in:

      PS62.png

    Apart from controlling these aspects of the Form, one can also take control of the Caption (i.e. Minimize, Maximize & Close buttons), as well as hide or show the SizeGrip which is what allows a user to adjust the size of the active window by dragging the bottom right corner. You can also control the opacity of the Form (i.e. whether you can see other windows beneath it and to what degree), and also determine what position on the Screen the Form will open to when activated. You can also control whether or not the activated Form will have an icon appear on the taskbar.

    To achieve all this we'll need to continue building on our Script code by adding some additional blocks of code, like below:

    Code (PowerShell):
    # Set Form State by controlling Window settings
    # Windows setting options: Minimized, Normal or Maximized
    # $false disables a particular Caption choice for the user
    $Form.MinimizeBox = $false
    $Form.MaximizeBox = $false
    $Form.WindowsState = "Normal"

    # Set whether user can see Form icon in taskbar
    # $false = not seen, $true = seen
    $Form.ShowInTaskbar = $false

    # Set whether user has access to the Size Grip for window
    # Options include Auto, Hide or Show
    $Form.SizeGripStyle = "Show"

    # Set what position Form opens in on users screen
    # Choices include:
    # CenterScreen, Manual, WindowsDefaultLocation,
    # WindowsDefaultBounds, CenterParent
    $Form.StartPosition = "CenterParent"          

    # Set the opacity level for window, i.e. how transparent it is
    # Range is from 0.0 (invisible) to 1.0 (100% opaque)
    $Form.Opacity = 0.6
    When added to our script we get:

    PS63.png
    • So in the above example by setting $Form.MinimizeBox and $Form.MaximizeBox to $false we are disabling them. If instead you assign $true to them the user will be able to use these buttons.
    • The $Form.WindowState can be assigned Minimized, Normal or Maximized which of course determines how the Form will open and display to the user.
    • In this example I set $Form.showInTaskbar to $false. This prevents the Forms icon appearing on the taskbar, but if you want that to appear there, assign $true instead.
    • The $Form.SizeGripStyle allows us to set one of three choices: Auto, Hide, or Show. By assigning Hide the grip icon normally located on the bottom right corner of our Form will not be viewed. The user can still adjust the size though, by hovering mouse to get the double-arrow.
    • The opacity can be set from 0.0 (invisible) to 1.0 which is 100% opaque (i.e. cannot be seen through)
    • The StartPosition can be one of several choices as illustrated in the code comments. In my case I used CenterParent which causes the Form to open in the top left corner, but if you wanted the Form to open in the actual center of the screen you'd go for $Form.StartPosition = "CenterScreen". Try the other choices, to determine which position you prefer. The position you settle on may in part be determined by your opacity setting.

    Now for the Form background itself. We can control this too and customize its look to our person preferences. Take a look at the following code snippet:

    Code (PowerShell):
    # Add a background color to form
    # You can use the Static color names found in System.Drawing.Color
    # Static Color example: "Blue"
    # Or you can use ARGB values (i.e. Alpha, Red, Green & Blue)
    # by using 4 pairs of letters from A to F to represent level of
    # Alpha, Red, Green & Blue in color
    # ARGB example: "#FFFFABCD"
    $Form5.BackColor = "#FFFFABCD"
    I won't be mean and ask you to guess the colour #FFFFABCD represents.

    Hint:
    think Sticky Notes.

    Now add this to our script and we get:

    PS64.png

    I won't go into it here, but suffice to say you could either convert this Script to an executable which you could place in your Startup folder, or create a new task to open the form at the desired time, and create your very own custom Sticky Notes.

    Now you are not just stuck with pretty colours. Why not use a picture instead:

    Code (PowerShell):
    # Replace BackGround with an image instead
    # Makes use of [System.Drawing.Image]
    # This allows you to create an image Object from a file
    # which can be used as a background to your form
    $BackgroundPicture = [System.Drawing.Image]::FromFile(
      # Image obtained Royalty Free from https://www.pexels.com/
      "$env:UserProfile\Pictures\catface.jpg"
    )

    # Set the image to be used
    $Form.BackgroundImage = $BackgroundPicture

    # Set Layout for image
    # Default = Tile which will tile the image
    # inside form as many times as it will fit
    # Choices include, None, Tile, Center, Stretch and Zoom
    $Form.BackgroundImageLayout = "None"

    # As we are using image, it is better to
    # set the Form size manually to fit the image size
    # Thus we do not use AutoSize (although you can if you want to)
    # Instead we use Width and Height to ensure a tidy fit for image
    # The cool thing is you can let the computer work that size out
    $Form.Width = $BackgroundPicture.Width
    $Form.Height = $BackgroundPicture.Height
    As you can see in the comments of this code block, there are a number of ways to manipulate an image and the form itself to help improve the final look of a Form should you choose to use a background image.
    • Initially we create our own variable ($BackgroundPicture in my case but you can name it what you like) to store an image on our computer.
    • Next we make use of [System.Drawing.Image]::FromFile(<path to file>\<filename>) to set a path to the image.
    • You then need to assign your variable: $Form.BackgroundImage = $BackgroundPicture
    • Next you'll want to determine the layout of your image. There are several choices as mentioned in the codes comments. I've chosen $Form.BackgroundImageLayout = "None" because I will be setting the Form to size itself to my image, and thus do not need to worry about tiling, stretching, or positioning the image.

      Note:
      If I did not choose any option here at all, the default behaviour would be for the image chosen to be tiled, hence given I do not want tiling, I had to choose an option!
    • You can set the Form's width and height to suit your image if you know the images dimensions, but rather than having to work all that out yourself, just let the computer do the work for you by using the .Width and .Height methods, e.g. $Form.Width = $BackgroundImage.Width
    • As I've introduced a background image, I need to consider the appearance of my Label which contains the text you are reading in the Form. I do not want it interfering with the image, so I set it to be transparent, by including this snippet: $Label.BackColor = "Transparent"
    So after adjusting our script to include these details:

    PS65.png

    And if we did not make that Label transparent we'd see:

    PS66.png

    Not so nice with a non transparent label!

    Well that concludes the introduction to creating your own GUI Forms in PowerShell.

    In Part 2 of this tutorial I'll take a look at how we add buttons, interactive text fields, Lists and the ability to drag and drop items into our Form.

    Till then happy PowerShelling !

    Regards,

    Regedit32
    Flam, Wolfie and Ian like this.