How do I indicate that a combo box has been populated with a selection?

Question

I am attempting to create a form in Powershell. It contains a ComboBox dropdown option that I am using as a required field. Until an option is selected, the continue button will be disabled. This is the code for the ComboBox and the button enabling:

$TSTypeBox.Name = "TSType"
$TSTypeBox.Location = New-Object System.Drawing.Point(116,100)
$TSTypeBox.Size = New-Object System.Drawing.Size(145,20)
$TSTypeBox.add_MouseHover($ShowHelp)
$TSTypeBox.DropDownStyle = "DropDownList"
Foreach ($item in ("1","2","3","4","5")) {
    $TSTypeBox.Items.Add($item) | Out-Null
    }
$TSTypeBox.SelectedItem = $TSLocation
$handler_TSTypeBox_SelectedIndexChanged= {
        If (($TSTypeBox.Text) -and ($ComputerNameBox.Text)) 
        {
            $OKButton.Enabled = 1
        }
        Else 
        {
            $OKButton.Enabled = 0
        }
    }
$TSTypeBox.add_SelectedIndexChanged($handler_TSTypeBox_SelectedIndexChanged)

This code in particular works as intended so I'm not worried about that. I am here about the $TSTypeBox.SelectedItem = $TSLocation line that I included. I have code elsewhere that pulls the IP address of the computer the program is being run on, which is then matched against an if/elseif/else statement to determine if the computer belongs to 1 or to 2, which are options that you can see were added to the ComboBox in the code above.

That if/else statement updated the $TSLocation variable which I then use to force the selection of one of the dropdown options in the ComboBox. This works as well, but unfortunately it does not enable the continue button as I would like. I had a hard time looking up issues about this because its super particular and I am probably doing this incorrectly (I have very little experience with Powershell scripting). If you have any additional questions about this please let me know. Thanks!

Answer 1

Ok, this might illustrate your problem.

Just because you set the SelectedItem value to something, doesn't mean the SelectedIndex changes

#
Add-Type -AssemblyName System.Windows.Forms -ErrorAction Stop
#
$TSLocation = '2'
#
$form = New-Object System.Windows.Forms.Form
$form.Text = "Test"
$form.MinimumSize = '430,495'
$form.MaximumSize = '430,545'
$form.StartPosition = 'CenterScreen'
#
# Add form objects
#
$TSTypeBox = New-Object System.Windows.Forms.ComboBox
$TSTypeBox.Name = "TSType"
$TSTypeBox.Location = '116,100'
$TSTypeBox.Size = '145,20'
$TSTypeBox.add_MouseHover($ShowHelp)
$TSTypeBox.DropDownStyle = "DropDownList"
Foreach ($item in ("1","2","3","4","5")) {
    $TSTypeBox.Items.Add($item) | Out-Null
    }

$ComputerNameBox = New-Object System.Windows.Forms.TextBox
$ComputerNameBox.Location = '120,20'
$ComputerNameBox.Size = '120,17'
$ComputerNameBox.Text = 'test'

$OutputBox = New-Object System.Windows.Forms.TextBox
$OutputBox.Location = '120,240'
$OutputBox.Size = '120,17'

$OkButton = New-Object System.Windows.Forms.Button
$OkButton.Location = '120,200'
$OkButton.Size = '54,24'
$OkButton.Text = 'OK'

$form.controls.AddRange(@($TSTypeBox,$OkButton,$ComputerNameBox,$OutputBox))
#
# Main Script goes here
#
$handler_TSTypeBox_SelectedIndexChanged= {
    $OutputBox.Text = "SelectedIndex is " + $TSTypeBox.SelectedIndex
        If (($TSTypeBox.Text) -and ($ComputerNameBox.Text)) 
        {
            $OKButton.Enabled = 1
        }
        Else 
        {
            $OKButton.Enabled = 0
        }
    }
$TSTypeBox.add_SelectedIndexChanged($handler_TSTypeBox_SelectedIndexChanged)

#
$TSTypeBox.SelectedIndex = $TSTypeBox.FindStringExact($TSLocation)
#
# Show form
$form.ShowDialog() | Out-Null
$form.Dispose()
# End

If in doubt, always best to simplify your script and add debug ,logging or output that shows what values are changing

Now that the problem is clear - this article points you in the right direction:

How do I set the selected item in a comboBox to match my string using C#?