Powershell Form Buttons only working on last tab - forms

Question

I'm trying to make a form that will enable/disable devices that can wake up Windows machine. The idea being that you move the devices your want enabled from one listbox to another, for each machine. I have Powershell forms tabs dynamically generated for each machine, along with "Add", "Remove", "Ok", and "Cancel" buttons on each tab. But whenever I run the code with real machines the "Add" & "Remove" buttons only move the selected devices on the last tab, not the first two. "Ok" & "Cancel" buttons work as intended on all tabs.
I'm suspecting something isn't getting uniquely assigned to each pair of "Add"/"Remove" buttons during the Foreach-Object loop, leaving only the last tab in the loop working, but I can't figure out what I'm missing.
Full Code:
$_ComputerList = #("Computer01","Computer02","Computer03")
$_HashComputerTable = #{}
$_HashFormTabTable = #{}
$_HashDevices = #{}
$_PotentialItems = #()
$_EnabledItems = #()
Foreach ($_Computer in $_ComputerList) {
$_HashComputerTable[$_Computer] = #(
$_PotentialDevicesList = [System.Collections.ArrayList]#(Invoke-Command -ComputerName $_Computer -ScriptBlock {powercfg /DEVICEQUERY wake_programmable} | Where {$_ -ne ""})
$_EnabledDevicesList = [System.Collections.ArrayList]#(Invoke-Command -ComputerName $_Computer -ScriptBlock {powercfg /devicequery wake_armed} | Where {$_ -ne ""} )
$_PotentialDevicesList = [System.Collections.ArrayList]#(Compare-Object -ReferenceObject $_PotentialDevicesList -DifferenceObject $_EnabledDevicesList | Select -ExpandProperty InputObject)
New-Object -TypeName PSObject -Property #{
PotentialDevices = $_PotentialDevicesList
EnabledDevices = $_EnabledDevicesList
}
)
}
Add-Type -AssemblyName System.Windows.Forms
[System.Windows.Forms.Application]::EnableVisualStyles()
$Form = New-Object system.Windows.Forms.Form
$FormSizeWidth = 985
$FormSizeHeight = 560
$Form.MinimumSize = "$FormSizeWidth,$FormSizeHeight"
$Form.MaximumSize = "$FormSizeWidth,$FormSizeHeight"
#$Form.ClientSize = "$FormSizeWidth,$FormSizeHeight"
$Form.FormBorderStyle = 'Fixed3D'
$Form.MaximizeBox = $false
$Form.text = "Form"
$Form.TopMost = $false
$TabBox = New-object System.Windows.Forms.TabControl
$TabBox.DataBindings.DefaultDataSourceUpdateMode = 0
$TabBox.Location = New-Object System.Drawing.size(5,5)
$TabBox.Name = "tabControl"
$TabBox.Width = $FormSizeWidth - 27
$TabBox.Height = $FormSizeHeight - 57
$TabBox.Anchor = "Top, Bottom, Left, Right"
$Form.Controls.Add($TabBox)
Foreach ($_Computer in $_ComputerList){
$_HashFormTabTable[$_Computer] = New-Object -TypeName PSObject -Property #{
Tab = New-Object System.Windows.Forms.TabPage
PotentialBox = New-Object system.Windows.Forms.ListBox
EnabledBox = New-Object system.Windows.Forms.ListBox
PotentialLabel = New-Object system.Windows.Forms.Label
EnabledLabel = New-Object system.Windows.Forms.Label
AddButton = New-Object system.Windows.Forms.Button
RemoveButton = New-Object system.Windows.Forms.Button
}
####Tab
$_HashFormTabTable[$_Computer].Tab.DataBindings.DefaultDataSourceUpdateMode = 0
$_HashFormTabTable[$_Computer].Tab.UseVisualStyleBackColor = $True
$_HashFormTabTable[$_Computer].Tab.Name = "$_Computer"
$_HashFormTabTable[$_Computer].Tab.Text = "$_Computer"
$TabBox.Controls.Add($_HashFormTabTable[$_Computer].Tab)
####PotentialBox
$_HashFormTabTable[$_Computer].PotentialBox.location = New-Object System.Drawing.Point(10,30)
$_HashFormTabTable[$_Computer].PotentialBox.Font = New-Object System.Drawing.Font("Lucida Console",10,[System.Drawing.FontStyle]::Regular)
$_HashFormTabTable[$_Computer].PotentialBox.text = "PotentialBox_" + "$_Computer"
$_HashFormTabTable[$_Computer].PotentialBox.width = 395
$_HashFormTabTable[$_Computer].PotentialBox.height = 440
$_HashFormTabTable[$_Computer].PotentialBox.SelectionMode = 'MultiExtended'
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].PotentialBox)
####EnabledBox
$_HashFormTabTable[$_Computer].EnabledBox.location = New-Object System.Drawing.Point(540,30)
$_HashFormTabTable[$_Computer].EnabledBox.Font = New-Object System.Drawing.Font("Lucida Console",10,[System.Drawing.FontStyle]::Regular)
$_HashFormTabTable[$_Computer].EnabledBox.text = "EnabledBox_" + "$_Computer"
$_HashFormTabTable[$_Computer].EnabledBox.width = 395
$_HashFormTabTable[$_Computer].EnabledBox.height = 440
$_HashFormTabTable[$_Computer].EnabledBox.SelectionMode = 'MultiExtended'
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].EnabledBox)
####PotentialLabel
$_HashFormTabTable[$_Computer].PotentialLabel.location = New-Object System.Drawing.Point(19,10)
$_HashFormTabTable[$_Computer].PotentialLabel.text = "Potential to Wake Device"
$_HashFormTabTable[$_Computer].PotentialLabel.AutoSize = $true
$_HashFormTabTable[$_Computer].PotentialLabel.width = 25
$_HashFormTabTable[$_Computer].PotentialLabel.height = 10
$_HashFormTabTable[$_Computer].PotentialLabel.Font = 'Microsoft Sans Serif,10'
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].PotentialLabel)
####EnabledLabel
$_HashFormTabTable[$_Computer].EnabledLabel.location = New-Object System.Drawing.Point(575,10)
$_HashFormTabTable[$_Computer].EnabledLabel.text = "Enabled to Wake Device"
$_HashFormTabTable[$_Computer].EnabledLabel.AutoSize = $true
$_HashFormTabTable[$_Computer].EnabledLabel.width = 25
$_HashFormTabTable[$_Computer].EnabledLabel.height = 10
$_HashFormTabTable[$_Computer].EnabledLabel.Font = 'Microsoft Sans Serif,10'
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].EnabledLabel)
####AddButton
$_HashFormTabTable[$_Computer].AddButton.Name = "AddButton_$_Computer"
$_HashFormTabTable[$_Computer].AddButton.location = New-Object System.Drawing.Point(440,140)
$_HashFormTabTable[$_Computer].AddButton.text = "-->"
$_HashFormTabTable[$_Computer].AddButton.width = 70
$_HashFormTabTable[$_Computer].AddButton.height = 30
$_HashFormTabTable[$_Computer].AddButton.Font = 'Microsoft Sans Serif,10'
$_HashFormTabTable[$_Computer].AddButton.Add_Click({
$_PotentialItems = #($_HashFormTabTable[$_Computer].PotentialBox.SelectedItems)
$_PotentialItems | Foreach{
$_HashFormTabTable[$_Computer].EnabledBox.Items.Add($_)
$_HashFormTabTable[$_Computer].PotentialBox.Items.Remove($_)
}
})
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].AddButton)
####RemoveButton
$_HashFormTabTable[$_Computer].RemoveButton.Name = "RemoveButton_$_Computer"
$_HashFormTabTable[$_Computer].RemoveButton.location = New-Object System.Drawing.Point(440,185)
$_HashFormTabTable[$_Computer].RemoveButton.text = "<--"
$_HashFormTabTable[$_Computer].RemoveButton.width = 70
$_HashFormTabTable[$_Computer].RemoveButton.height = 30
$_HashFormTabTable[$_Computer].RemoveButton.Font = 'Microsoft Sans Serif,10'
$_HashFormTabTable[$_Computer].RemoveButton.Add_Click({
$_EnabledItems = #($_HashFormTabTable[$_Computer].EnabledBox.SelectedItems)
$_EnabledItems | Foreach{
$_HashFormTabTable[$_Computer].PotentialBox.Items.Add($_)
$_HashFormTabTable[$_Computer].EnabledBox.Items.Remove($_)
}
})
$_HashFormTabTable[$_Computer].Tab.Controls.Add($_HashFormTabTable[$_Computer].RemoveButton)
####OkButton
$OkButton = New-Object system.Windows.Forms.Button
$OkButton.location = New-Object System.Drawing.Point(440,230)
$OkButton.text = "Ok"
$OkButton.width = 70
$OkButton.height = 30
$OkButton.Font = 'Microsoft Sans Serif,10'
$OkButton.Add_Click({OkClick})
$_HashFormTabTable[$_Computer].Tab.Controls.Add($OkButton)
####CancelButton
$CancelButton = New-Object system.Windows.Forms.Button
$CancelButton.location = New-Object System.Drawing.Point(440,275)
$CancelButton.text = "Cancel"
$CancelButton.width = 70
$CancelButton.height = 30
$CancelButton.Font = 'Microsoft Sans Serif,10'
$CancelButton.Add_Click({CancelClick})
$_HashFormTabTable[$_Computer].Tab.Controls.Add($CancelButton)
}
function OkClick {
Foreach ($_Computer in $_ComputerList) {
$_HashDevices[$_Computer] = New-Object -TypeName PSObject -Property #{
PotentialDevices = #($_HashFormTabTable[$_Computer].PotentialBox.items)
EnabledDevices = #($_HashFormTabTable[$_Computer].EnabledBox.items)
}
}
$Form.Close()
}
function CancelClick {
$Form.Close()
}
Foreach ($_Computer in $_ComputerList){
$_HashComputerTable[$_Computer].PotentialDevices | Foreach {if ($_ -ne $null) {[void] $_HashFormTabTable[$_Computer].PotentialBox.Items.Add($_)}}
$_HashComputerTable[$_Computer].EnabledDevices | Foreach {if ($_ -ne $null) {[void] $_HashFormTabTable[$_Computer].EnabledBox.Items.Add($_)}}
}
[void]$Form.ShowDialog()

Answer 1

I learned a new PowerShell method a couple of days ago - GetNewClosure() - , and so far this is the 3rd question since then that I've answered which uses it :-).
First off, I've simplified your code a bit, because you don't need to store references to all your controls in a global array. I've then also added a call to GetNewClosure() onto your callback scriptblocks.
The (simplified) code is then:
Add-Type -AssemblyName System.Windows.Forms
[System.Windows.Forms.Application]::EnableVisualStyles()
$Form = New-Object system.Windows.Forms.Form
$Form.Width = 985
$Form.Height = 560
$TabBox = New-object System.Windows.Forms.TabControl
$TabBox.Location = New-Object System.Drawing.size(5,5)
$TabBox.Dock = "Fill"
$Form.Controls.Add($TabBox)
foreach ($item in #("page1", "page2", "page3") )
{
#### tab page
$tabPage = New-Object System.Windows.Forms.TabPage
$tabPage.DataBindings.DefaultDataSourceUpdateMode = 0
$tabPage.Text = $item
$tabBox.Controls.Add($tabPage)
#### disabled listbox
$disabledList = New-Object system.Windows.Forms.ListBox
$disabledList.location = New-Object System.Drawing.Point(10,30)
$disabledList.width = 395
$disabledList.height = 440
$disabledList.SelectionMode = 'MultiExtended'
#( "aaa", "bbb" ) | % { $disabledList.Items.Add($_) }
$tabPage.Controls.Add($disabledList)
#### enabled listbox
$enabledList = New-Object system.Windows.Forms.ListBox
$enabledList.location = New-Object System.Drawing.Point(540,30)
$enabledList.width = 395
$enabledList.height = 440
$enabledList.SelectionMode = 'MultiExtended'
#( "ccc", "ddd" ) | % { $enabledList.Items.Add($_) }
$tabPage.Controls.Add($enabledList)
#### add button
$addButton = New-Object system.Windows.Forms.Button
$addButton.location = New-Object System.Drawing.Point(440,140)
$addButton.text = "-->"
$addButton.width = 70
$addButton.height = 30
$tabPage.Controls.Add($addButton)
$addButton.Add_Click(
{
#( $disabledList.SelectedItems ) | Foreach {
$enabledList.Items.Add($_)
$disabledList.Items.Remove($_)
}
}.GetNewClosure()
)
#### remove button
$removeButton = New-Object system.Windows.Forms.Button
$removeButton.location = New-Object System.Drawing.Point(440,185)
$removeButton.text = "<--"
$removeButton.width = 70
$removeButton.height = 30
$removeButton.Add_Click(
{
#( $enabledList.SelectedItems ) | Foreach {
$disabledList.Items.Add($_)
$enabledList.Items.Remove($_)
}
}.GetNewClosure()
)
$tabPage.Controls.Add($removeButton)
####OkButton
$OkButton = New-Object system.Windows.Forms.Button
$OkButton.location = New-Object System.Drawing.Point(440,230)
$OkButton.text = "Ok"
$OkButton.width = 70
$OkButton.height = 30
$OkButton.Add_Click({OkClick})
$tabPage.Controls.Add($OkButton)
####CancelButton
$CancelButton = New-Object system.Windows.Forms.Button
$CancelButton.location = New-Object System.Drawing.Point(440,275)
$CancelButton.text = "Cancel"
$CancelButton.width = 70
$CancelButton.height = 30
$CancelButton.Font = 'Microsoft Sans Serif,10'
$CancelButton.Add_Click({CancelClick})
$tabPage.Controls.Add($CancelButton)
}
function OkClick {
$Form.Close()
}
function CancelClick {
$Form.Close()
}
[void]$Form.ShowDialog()
In short, your original callbacks were evaluating the expression $_HashFormTabTable[$_Computer].PotentialBox, for example, at the time the callback executed, not when the callback scriptblock was created.
Note that PowerShell retains the last value of an iterator variable when a foreach loop exits - e.g.
PS> foreach ($x in #("aaa", "bbb", "ccc") ) {}
PS> $x
ccc
so when any of your callbacks were executing, they were all getting the last item in the $_HashFormTabTable array because the value of $_Computer was the last value iterated over in the for loop.
Compare the behaviour of this script, for example:
$callbacks = #();
foreach( $item in #( "aaa", "bbb", "ccc" ) )
{
$callbacks += { write-host "callback = '$item'" }
}
write-host "item = '$item'";
foreach( $callback in $callbacks )
{
$callback.Invoke()
}
which outputs
item = 'ccc'
callback = 'ccc'
callback = 'ccc'
callback = 'ccc'
with this one:
$callbacks = #();
foreach( $item in #( "aaa", "bbb", "ccc" ) )
{
$callbacks += { write-host "callback = '$item'" }.GetNewClosure()
}
write-host "item = '$item'"
foreach( $callback in $callbacks )
{
$callback.Invoke()
}
which outputs:
item = 'ccc'
callback = 'aaa'
callback = 'bbb'
callback = 'ccc'
Hope this helps.