How to set keyboard focus to a TextBox in Powershell - powershell

Question

I'm looking to find out how to automatically set the keyboard focus to a text box in powershell.
I have a script that asks the user to select an option from a dropdown menu, then based on that selection, they have to input certain parameters. That all works fine.
For ease of use, I'd like the focus of the keyboard to shift to the input box each time a new one is shown, so the user doesn't have to keep clicking on it to enter some text.
My code so far :
function inputBox($parameter)
{
$objForm = New-Object System.Windows.Forms.Form
$objForm.Text = $parameter
$objForm.Size = New-Object System.Drawing.Size(300,200)
$objForm.StartPosition = "CenterScreen"
$objForm.KeyPreview = $True
$objForm.Add_KeyDown({if ($_.KeyCode -eq "Enter")
{$paramValue=$objTextBox.Text;$objForm.Close()}})
$objForm.Add_KeyDown({if ($_.KeyCode -eq "Escape")
{$objForm.Close()}})
$OKButton = New-Object System.Windows.Forms.Button
$OKButton.Location = New-Object System.Drawing.Size(75,90)
$OKButton.Size = New-Object System.Drawing.Size(75,25)
$OKButton.Text = "OK"
$OKButton.Add_Click({$paramValue=$objTextBox.Text;$objForm.Close()})
$objForm.Controls.Add($OKButton)
$objLabel = New-Object System.Windows.Forms.Label
$objLabel.Location = New-Object System.Drawing.Size(10,20)
$objLabel.Size = New-Object System.Drawing.Size(280,20)
$objLabel.Text = $parameter
$objForm.Controls.Add($objLabel)
$objTextBox = New-Object System.Windows.Forms.TextBox
$objTextBox.Location = New-Object System.Drawing.Size(10,40)
$objTextBox.Size = New-Object System.Drawing.Size(260,20)
$objForm.KeyPreview = $True
$objForm.Controls.Add($objTextBox)
$objForm.Topmost = $True
$objForm.Add_Shown({$objForm.Activate()})
[void] $objForm.ShowDialog()
return $paramValue
Any ideas?
Thanks!

Answer 1

Following your code, where I can find a dropdown menu, to give focus to textbox when form is shown I've done:
$objForm.Add_Shown({$objForm.Activate(); $objTextBox.focus()})

Answer 2

Try the Select method in case Focus() doesn't work:
if($textbox.CanFocus)
{
$textbox.Focus()
}
else
{
$textbox.Select()
}

Answer 3

Works great, but I needed to make the paramValue variable script global (the scope inside the Add_Click routine is not the script scope and the paramValue setting is lost). Using $Global:paramValue worked for me.

Answer 4

This is an alternative to the answers of #CB and #Shay Levy (none of them worked for me):
$objForm.Add_Shown( { $objTextBox.Select() })

Answer 5

I'd like to add two additional alternative solutions to this problem.
Just move your $objTextBox creation code in first position above $OKButton.
The Code always initializes and prioritizes top to bottom. With this little change it will select your TextBox first.
And for a second solution add a TabIndex to prioritize manually.
$objTextBox.TabIndex = 0
$OKButton.TabIndex = 1
Lower numbers are prioritized and are focused first.

Answer 6

The code that works with the original post and FOCUS is:
if ( $objTextBox.CanFocus )
{
$objTextBox.Focus()
}
else
{
$objTextBox.Select()
}