How to output data to GUI textbox using workflow/parallel? - winforms

Question

I am trying to output the result of the ping command to a textbox (windows forms GUI) using workflow/parallel and the message appears
"This type of assignment is not supported. Only variable names (i.e.: $variable) may be used as the target of an assignment statement."
picture
How can this issue be resolved?
Add-Type -assembly System.Windows.Forms
workflow parallelPing {
parallel {
$text1_box.Text = ping "google.com"
$text2_box.Text = ping "8.8.8.8"
$text3_box.Text = ping "stackoverflow.com"
}
}
$gui1 = New-Object System.Windows.Forms.Form
$gui1.Width = 1000
$gui1.Height = 700
$gui1.AutoSize = $false
$text1_box = New-Object System.Windows.Forms.TextBox
$text1_box.Location = New-Object System.Drawing.Point(10,20)
$text1_box.Multiline = $true
$text1_box.Width = 540
$text1_box.Height = 100
$gui1.Controls.Add($text1_box)
$text2_box = New-Object System.Windows.Forms.TextBox
$text2_box.Location = New-Object System.Drawing.Point(10,130)
$text2_box.Multiline = $true
$text2_box.Width = 540
$text2_box.Height = 100
$gui1.Controls.Add($text2_box)
$text3_box = New-Object System.Windows.Forms.TextBox
$text3_box.Location = New-Object System.Drawing.Point(10,240)
$text3_box.Multiline = $true
$text3_box.Width = 540
$text3_box.Height = 100
$gui1.Controls.Add($text3_box)
$getPing = New-Object System.Windows.Forms.Button
$getPing.Location = New-Object System.Drawing.Point(560,110)
$getPing.Width = 170
$getPing.Height = 90
$getPing.Text = '&Ping'
$getPing.Add_Click({parallelPing})
$gui1.Controls.Add($getPing)
$gui1.ShowDialog()

Answer 1

Since you are trying to assign the variable in the parallel block, use $workflow to access the workflow scope.
$workflow:Text1_box.text =
See this link for more details.

Answer 2

This works
$getPing = New-Object System.Windows.Forms.Button
$getPing.Location = New-Object System.Drawing.Point(560,110)
$getPing.Width = 170
$getPing.Height = 90
$getPing.Text = '&Ping'
$getPing.Add_Click({pingInfo})
$gui1.Controls.Add($getPing)
workflow parallelPing {
parallel {
$workflow:a1 = ping "google.com"
$workflow:a2 = ping "8.8.8.8"
$workflow:a3 = ping "stackoverflow.com"
}
$pingResult = #($a1, $a2, $a3)
return $pingResult
}
function pingInfo{
$text1_box.Lines = (parallelPing)[0]
$text2_box.Lines = (parallelPing)[1]
$text3_box.Lines = (parallelPing)[2]
}
$gui1.ShowDialog()
Thanks!