PowerShell Calendar Popup - winforms

Question

I am trying to use the PowerShell script from http://technet.microsoft.com/en-us/library/ff730942.aspx
After choosing a date and hitting enter, the variable $dtmDate has no data. Please help. Is it possible to add an OK/Cancel button?
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
$objForm = New-Object Windows.Forms.Form
$objForm.Text = "Select a Date"
$objForm.Size = New-Object Drawing.Size #(243,200)
$objForm.StartPosition = "CenterScreen"
$objForm.KeyPreview = $True
$objForm.Add_KeyDown({
if ($_.KeyCode -eq "Enter")
{
$dtmDate=$objCalendar.SelectionStart
$objForm.Close()
}
})
$objForm.Add_KeyDown({
if ($_.KeyCode -eq "Escape")
{
$objForm.Close()
}
})
$objCalendar = New-Object System.Windows.Forms.MonthCalendar
$objCalendar.ShowTodayCircle = $False
$objCalendar.MaxSelectionCount = 1
$objForm.Controls.Add($objCalendar)
$objForm.Topmost = $True
$objForm.Add_Shown({$objForm.Activate()})
[void] $objForm.ShowDialog()
if ($dtmDate)
{
Write-Host "Date selected: $dtmDate"
}

Answer 1

$dtmDate has no value in the context of your if statement because that code isn't being executed on your enter keypress... the block in the context of Add_KeyDown is. Try executing something like this instead:
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
$dtmDate = $null
# I've moved your Date printing logic into this function that can be called elsewhere.
Function Do-Work
{
if ($dtmDate -ne $null)
{
Write-Host "Date selected: $dtmDate"
}
}
$objForm = New-Object Windows.Forms.Form
$objForm.Text = "Select a Date"
$objForm.Size = New-Object Drawing.Size #(243,200)
$objForm.StartPosition = "CenterScreen"
$objForm.KeyPreview = $True
$objForm.Add_KeyDown({
if ($_.KeyCode -eq "Enter")
{
$dtmDate = $objCalendar.SelectionStart
$objForm.Close()
Do-Work
}
})
$objForm.Add_KeyDown({
if ($_.KeyCode -eq "Escape")
{
$objForm.Close()
}
})
$objCalendar = New-Object System.Windows.Forms.MonthCalendar
$objCalendar.ShowTodayCircle = $False
$objCalendar.MaxSelectionCount = 1
$objForm.Controls.Add($objCalendar)
$objForm.Topmost = $True
$objForm.Add_Shown({$objForm.Activate()})
[void] $objForm.ShowDialog()
The new function Do-Work is defined outside of the scope of Add_KeyDown, but since we call it there it will get executed on your Enter keypresses.

Answer 2

[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
New-Variable dtmDate -Option AllScope
$dtmDate = $null
$objForm = New-Object Windows.Forms.Form
$objForm.Text = "Select a Date"
$objForm.Size = New-Object Drawing.Size #(190,190)
$objForm.StartPosition = "CenterScreen"
$objForm.KeyPreview = $True
$objForm.Add_KeyDown(
{
if ($_.KeyCode -eq "Enter")
{
$dtmDate=$objCalendar.SelectionStart
$objForm.Close()
}
})
$objForm.Add_KeyDown(
{
if ($_.KeyCode -eq "Escape") {$objForm.Close()}
})
$objCalendar = New-Object System.Windows.Forms.MonthCalendar
$objCalendar.ShowTodayCircle = $False
$objCalendar.MaxSelectionCount = 1
$objForm.Controls.Add($objCalendar)
$objForm.Topmost = $True
$objForm.Add_Shown({$objForm.Activate()})
[void] $objForm.ShowDialog()
if ($dtmDate) {Write-Host "Date selected: $dtmDate" -ForegroundColor Green}
The line "New-Variable dtmDate -Option AllScope" allows the variable to be brought outside of the form scope, so you can use it further in your script.
I left out the creation of a function for the write host. If you want to do it the proper way, create a function of the entire script block.
The above script will work in the way you want it to. It's working for me!

Answer 3

You have to add:
New-Variable dtmDate -Option AllScope