[Winforms] Creating a Responsive Windows Form Using PowerShell With Runspaces

I recently wrote a PowerShell script that used the Windows Forms .NET assembly (Winforms) to create a graphical user interface. The form included a button that initiated a long-running task.

While the task was executing, I wanted to ensure the form remained responsive to user input, and I also wanted to update a status field on the form with the progress of the executing task.

Below is the code for the script that we’ve create.

Add-Type -AssemblyName System.Windows.Forms

# Long running task with runspace
function PoSHCounter {
    # Disable the button 
    $button.Enabled = $false

    for ($i = 10; $i -le 99; $i++) {
        $label.Text = $i
        Start-Sleep -Milliseconds 50
    }

    # Re-enable the button when the loop finishes.
    $button.Enabled = $true
}

# Create the form.
    $form                   = New-Object Windows.Forms.Form
    $form.ClientSize        = New-Object Drawing.Size(400, 200)
    $form.Text              = "Responsive Windows Form"
    $form.StartPosition     = "CenterScreen"
    $form.FormBorderStyle   = "FixedSingle"

# Create the button.
    $button             = New-Object Windows.Forms.Button
    $button.Location    = New-Object Drawing.Point(100, 20)
    $button.Width       = 180
    $button.Text        = "Start Counting"
    $button.Add_Click({PoSHCounter})

# Create the label.
    $label              = New-Object Windows.Forms.Label
    $label.Location     = New-Object Drawing.Point(125, 60)
    $label.Font         = New-Object System.Drawing.Font("Consolas",63,[System.Drawing.FontStyle]::Bold)
    $label.ForeColor    = [System.Drawing.Color]::DarkBlue
    $label.AutoSize     = $True
    $label.Text         = 10

# Add controls to the form.
    $form.Controls.AddRange(@($button, $label))

# Show the form.
    [Windows.Forms.Application]::Run($form)

Now, by default, any graphical interface created via PowerShell will run in a single-threaded apartment; which means that the application will be blocked, or become unresponsive, while it is waiting for a task to complete.

Responsive Windows Form with runspace

The best way of overcoming this restriction is to leverage .NET runspaces (each runspace provides a separate execution context for a PowerShell pipeline).

The following code provides a simplified example of how I used runspaces to manage the execution of a long running task.

The script creates a form with a button and a text label.
The button initiates a script block that counts to 99.
The button is intentionally disabled during this period.
The window remains responsive throughout, and the label is incrementally refreshed to show the value of the counter.

Add-Type -AssemblyName System.Windows.Forms
# Long running task with runspace
function PoSHCounter {
    # The main script block
    $scriptBlock = {
        # Disable the button 
        $sync.button.Enabled = $false
        
        for ($i = 10; $i -le 99; $i++) {
            $sync.label.Text = $i
            Start-Sleep -Milliseconds 50
        }
        # Re-enable the button when the loop finishes.
        $sync.button.Enabled = $true
    }

    # Create a PowerShell instance with the script block
    $psInstance = [PowerShell]::Create().AddScript($scriptBlock)
    
    # Create then open a new runspace
    $runspace = [RunspaceFactory]::CreateRunspace()
    $runspace.ApartmentState = "STA"
    $runspace.ThreadOptions = "ReuseThread"
    $runspace.Open()

    # Add shared data to the runspace
    $runspace.SessionStateProxy.SetVariable("sync", $sync)
    
    # Associate the PowerShell instance with the opened runspace
    $psInstance.Runspace = $runspace

    # Execute the script asynchronously using BeginInvoke() method
    $psInstance.BeginInvoke()
}

# Create the form.
    $form                   = New-Object Windows.Forms.Form
    $form.ClientSize        = New-Object Drawing.Size(400, 200)
    $form.Text              = "Responsive Windows Form"
    $form.StartPosition     = "CenterScreen"
    $form.FormBorderStyle   = "FixedSingle"

# Create the button.
    $button             = New-Object Windows.Forms.Button
    $button.Location    = New-Object Drawing.Point(100, 20)
    $button.Width       = 180
    $button.Text        = "Start Counting"
    $button.Add_Click({PoSHCounter})

# Create the label.
    $label              = New-Object Windows.Forms.Label
    $label.Location     = New-Object Drawing.Point(125, 60)
    $label.Font         = New-Object System.Drawing.Font("Consolas",63,[System.Drawing.FontStyle]::Bold)
    $label.ForeColor    = [System.Drawing.Color]::DarkBlue
    $label.AutoSize     = $True
    $label.Text         = 10

# For talking across runspaces (share info between runspaces)
    $sync           = [hashtable]::Synchronized(@{})
    $sync.runspace  = $runspace
    $sync.host      = $host
    $sync.form      = $form
    $sync.button    = $button
    $sync.label     = $label

# Add controls to the form.
    $form.Controls.AddRange(@($sync.button, $sync.label))

# Show the form.
    [Windows.Forms.Application]::Run($form)

As you can see in the above screenshot. This time, when the job is running ( in the background) the GUI can be moved normally.

In the next section, I’ve created some examples of using runspace to do some tasks in Windows.

PowerShell runspace examples

Example 1: Ping a host:

The script creates a form with a button and a textbox.
The button initiates a script block to ping a host
The button is intentionally disabled during this period.
The window remains responsive throughout, and the textbox shows the status.

Add-Type -AssemblyName System.Windows.Forms

# Long running task with runspace
function PoSHCounter {
    # The main script block
    $scriptBlock = {
        # Disable the button 
        $sync.button.Enabled = $false

        $sync.textbox.Text = "Pinging to the host..."
        $sync.textbox.AppendText([Environment]::NewLine)

        $sync.textbox.AppendText("Completed. Below are the results:")
        $sync.textbox.AppendText([Environment]::NewLine)

        $sync.textbox.AppendText((powershell -noprofile -Command "ping 127.0.0.1" | Out-String))

        # Re-enable the button when the loop finishes.
        $sync.button.Enabled = $true
    }

    # Create a PowerShell instance with the script block
    $psInstance = [PowerShell]::Create().AddScript($scriptBlock)
    
    # Create then open a new runspace
    $runspace = [RunspaceFactory]::CreateRunspace()
    $runspace.ApartmentState = "STA"
    $runspace.ThreadOptions = "ReuseThread"
    $runspace.Open()

    # Add shared data to the runspace
    $runspace.SessionStateProxy.SetVariable("sync", $sync)
    
    # Associate the PowerShell instance with the opened runspace
    $psInstance.Runspace = $runspace

    # Execute the script asynchronously using BeginInvoke() method
    $psInstance.BeginInvoke()
}

# Create the form.
    $form                   = New-Object Windows.Forms.Form
    $form.ClientSize        = New-Object Drawing.Size(772, 380)
    $form.Text              = "Responsive Windows Form"
    $form.StartPosition     = "CenterScreen"
    $form.FormBorderStyle   = "FixedSingle"

# Create the button.
    $button             = New-Object Windows.Forms.Button
    $button.Location    = New-Object Drawing.Point(20, 20)
    $button.BackColor   = [System.Drawing.Color]::Green
    $button.ForeColor   = [System.Drawing.Color]::White
    $button.Size        = New-Object System.Drawing.Size(150,40) 
    $button.Text        = "Start Pinging"
    $button.Add_Click({PoSHCounter})

# Create a textbox to display the output
    $textbox                      = New-Object system.Windows.Forms.TextBox
    $textbox.Multiline            = $true
    $textbox.Text                 = "Waiting for output..."
    $textbox.Font                 = New-Object System.Drawing.Font("Consolas",9,[System.Drawing.FontStyle]::Regular)
    $textbox.Size                 = New-Object System.Drawing.Size(728,270)
    $textbox.Location             = New-Object System.Drawing.Point(20,70)
    $textbox.BackColor            = "#1F1F1F"
    $textbox.ForeColor            = 'Cyan'

# For talking across runspaces (share info between runspaces)
    $sync           = [hashtable]::Synchronized(@{})
    $sync.runspace  = $runspace
    $sync.host      = $host
    $sync.form      = $form
    $sync.button    = $button
    $sync.label     = $label
    $sync.textbox   = $textbox

# Add controls to the form.
    $form.Controls.AddRange(@($sync.button, $sync.label, $sync.textbox))

# Show the form.
    [Windows.Forms.Application]::Run($form)

Example 2: Download a file using PowerShell

The script creates a form with a button and a textbox.
The button initiates a script block to download a file from the internet.
The button is intentionally disabled during this period.
The window remains responsive throughout, and the textbox shows the download status.

Add-Type -AssemblyName System.Windows.Forms

# Long running task with runspace
function PoSHCounter {
    # The main script block
    $scriptBlock = {
        # Disable the button 
        $sync.button.Enabled = $false

        $sync.textbox.Text = "Downloading..."
        $sync.textbox.AppendText([Environment]::NewLine)
        
        $source = 'http://ipv4.download.thinkbroadband.com/1MB.zip'
        $destination = 'D:\temp\1MB.zip'
        Invoke-WebRequest -Uri $source -OutFile $destination

        $sync.textbox.AppendText("Download completed")
        $sync.textbox.AppendText([Environment]::NewLine)
        $sync.textbox.AppendText("The downloaded file is saved to:" + "$(Get-ChildItem -Path D:\temp | Out-String)")

        # Re-enable the button when the loop finishes.
        $sync.button.Enabled = $true
    }

    # Create a PowerShell instance with the script block
    $psInstance = [PowerShell]::Create().AddScript($scriptBlock)
    
    # Create then open a new runspace
    $runspace = [RunspaceFactory]::CreateRunspace()
    $runspace.ApartmentState = "STA"
    $runspace.ThreadOptions = "ReuseThread"
    $runspace.Open()

    # Add shared data to the runspace
    $runspace.SessionStateProxy.SetVariable("sync", $sync)
    
    # Associate the PowerShell instance with the opened runspace
    $psInstance.Runspace = $runspace

    # Execute the script asynchronously using BeginInvoke() method
    $psInstance.BeginInvoke()
}

# Create the form.
    $form                   = New-Object Windows.Forms.Form
    $form.ClientSize        = New-Object Drawing.Size(772, 380)
    $form.Text              = "Responsive Windows Form"
    $form.StartPosition     = "CenterScreen"
    $form.FormBorderStyle   = "FixedSingle"

# Create the button.
    $button             = New-Object Windows.Forms.Button
    $button.Location    = New-Object Drawing.Point(20, 20)
    $button.BackColor   = [System.Drawing.Color]::Green
    $button.ForeColor   = [System.Drawing.Color]::White
    $button.Size        = New-Object System.Drawing.Size(150,40) 
    $button.Text        = "Start Pinging"
    $button.Add_Click({PoSHCounter})

# Create a textbox to display the output
    $textbox                      = New-Object system.Windows.Forms.TextBox
    $textbox.Multiline            = $true
    $textbox.Text                 = "Waiting for output..."
    $textbox.Font                 = New-Object System.Drawing.Font("Consolas",9,[System.Drawing.FontStyle]::Regular)
    $textbox.Size                 = New-Object System.Drawing.Size(728,270)
    $textbox.Location             = New-Object System.Drawing.Point(20,70)
    $textbox.BackColor            = "#1F1F1F"
    $textbox.ForeColor            = 'Cyan'
    
# For talking across runspaces (share info between runspaces)
    $sync           = [hashtable]::Synchronized(@{})
    $sync.runspace  = $runspace
    $sync.host      = $host
    $sync.form      = $form
    $sync.button    = $button
    $sync.label     = $label
    $sync.textbox   = $textbox

# Add controls to the form.
    $form.Controls.AddRange(@($sync.button, $sync.label, $sync.textbox))

# Show the form.
    [Windows.Forms.Application]::Run($form)

Example 3: Get the list of processes

The script creates a form with a button and a textbox.
The button initiates a script block to get the first five processes on a computer.
The button is intentionally disabled during this period.
The window remains responsive throughout, and the textbox shows the results.

Add-Type -AssemblyName System.Windows.Forms

# Long running task with runspace
function PoSHCounter {
    # The main script block
    $scriptBlock = {
        # Disable the button 
        $sync.button.Enabled = $false
        
        $sync.textbox.AppendText([Environment]::NewLine)
        $sync.textbox.AppendText((Get-Process | Select-Object -First 5 | Out-String))

        # Re-enable the button when the loop finishes.
        $sync.button.Enabled = $true
    }

    # Create a PowerShell instance with the script block
    $psInstance = [PowerShell]::Create().AddScript($scriptBlock)
    
    # Create then open a new runspace
    $runspace = [RunspaceFactory]::CreateRunspace()
    $runspace.ApartmentState = "STA"
    $runspace.ThreadOptions = "ReuseThread"
    $runspace.Open()

    # Add shared data to the runspace
    $runspace.SessionStateProxy.SetVariable("sync", $sync)
    
    # Associate the PowerShell instance with the opened runspace
    $psInstance.Runspace = $runspace

    # Execute the script asynchronously using BeginInvoke() method
    $psInstance.BeginInvoke()
}

# Create the form.
    $form                   = New-Object Windows.Forms.Form
    $form.ClientSize        = New-Object Drawing.Size(772, 380)
    $form.Text              = "Responsive Windows Form"
    $form.StartPosition     = "CenterScreen"
    $form.FormBorderStyle   = "FixedSingle"

# Create the button.
    $button             = New-Object Windows.Forms.Button
    $button.Location    = New-Object Drawing.Point(20, 20)
    $button.BackColor   = [System.Drawing.Color]::Green
    $button.ForeColor   = [System.Drawing.Color]::White
    $button.Size        = New-Object System.Drawing.Size(150,40) 
    $button.Text        = "Submit"
    $button.Add_Click({PoSHCounter})

# Create a textbox to display the output
    $textbox                      = New-Object system.Windows.Forms.TextBox
    $textbox.Multiline            = $true
    $textbox.Text                 = "Waiting for output..."
    $textbox.Font                 = New-Object System.Drawing.Font("Consolas",9,[System.Drawing.FontStyle]::Regular)
    $textbox.Size                 = New-Object System.Drawing.Size(728,270)
    $textbox.Location             = New-Object System.Drawing.Point(20,70)
    $textbox.BackColor            = "#1F1F1F"
    $textbox.ForeColor            = 'Cyan'

# For talking across runspaces (share info between runspaces)
    $sync           = [hashtable]::Synchronized(@{})
    $sync.runspace  = $runspace
    $sync.host      = $host
    $sync.form      = $form
    $sync.button    = $button
    $sync.label     = $label
    $sync.textbox   = $textbox

# Add controls to the form.
    $form.Controls.AddRange(@($sync.button, $sync.label, $sync.textbox))

# Show the form.
    [Windows.Forms.Application]::Run($form)