Tag Archives: tips and trix

Beta testing and error handling

Here is a simple snippet that you can run to output all exceptions in a script.

$ErrorActionPreference = "SilentlyContinue"

IWillProduceAnError

#----------------------------------------------------------------
# Debug function, dumps all errors in $Error variable to file
#----------------------------------------------------------------

Function Dump-Errors(){
    Param(
        [Parameter(Position=0, Mandatory = $True)]
        [String]$Logfile
    )
    $Error | Add-Content $Logfile
    $Error.Clear()
}

Dump-Errors -logfile "c:\temp\script.log"

If you look at the code, the cmdlet “IWillProduceAnError” is most likely not recognized and will produce an exception.
However, you have the $ErrorActionPreference set to SilentlyContinue so nothing will show for the user.

This is where the dump-errors function will help you catch errors you would otherwise never see.

Place the function in your code and make sure the last line to run is the function.
It will output all exceptions in the $Error variable to a file. You can then later collect the file from the users you know are beta testing and use the Try/Catch statements to correct your code. Combine this with the Powershell auto updater in silent mode and the user will never know you updated the code.

Windows forms, tips and trix – Buttons

Ever written a GUI to your application? Ever think there are alot of unnecessary lines?
Here is a smart way to add basic buttons without too many lines.

function CreateButton{
  param(
    $name,
    $text,
    $size,
    $location,
    $onclick,
    $Form
  )
  $name = New-Object System.Windows.Forms.Button
  $name.Text = "$text"
  $name.Location = "$location"
  $name.Size = "$size"
  $name.add_Click($onclick)
  $Form.Controls.Add($name)
}

This requires a specific type of code to be run on click. We declare a variable as code within curlybrackets as shown below. In this case we use System.Windows.Forms.SaveFileDialog and save a richtextbox named $consolewindow.

$SaveButton_Click = {
  $SaveFileDialog = New-Object System.Windows.Forms.SaveFileDialog
  $SaveFileDialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
  $SaveFileDialog.ShowDialog()
  $ConsoleWindow.Text | Out-File $SaveFileDialog.FileName
  $SaveFileDialog.Dispose()
}

To add a button with this information we need to create a main form and the console window with the code below.

[Void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

# Main form settings
$Form = New-Object System.Windows.Forms.Form
$Form.ClientSize = "1000,620"
$Form.DesktopLocation = "100,100"
$Form.MaximizeBox = $False
$Form.ShowIcon = $False
$Form.FormBorderStyle = "FixedSingle"
$Form.Name = "Example"
$Form.Text = "Example"

# Console window settings
$ConsoleWindow = New-Object System.Windows.Forms.RichTextBox
$ConsoleWindow.Size = "1000,250"
$ConsoleWindow.Location = "0,320"
#$ConsoleWindow.ReadOnly = $True #commented out for manual input.
$ConsoleWindow.BackColor = "Black"
$ConsoleWindow.ForeColor = "White"
$Form.Controls.Add($Consolewindow)

I’ve added a few extra rows just to make it look good for the example.
Now let’s create a button

CreateButton -name "SaveButton" -text "Save to file" -size "100,30" -location "50,50" -form $form -onclick $SaveButton_Click

Then we load the forms window

$Form.ShowDialog()

 

Normally you might not have a use for this function but when creating dynamic buttons you could have a use for it. To create a range of buttons from an array, use something like this.

$x = 0
$y = 0
for($i=0; $i -lt 20;$i++){
  CreateButton -name $Buttons[$i] -text $Buttons[$i] -size "100,30" -location "$x,$y" -form $form -onclick $Button_Click[$i]
  $x += 100
  if($x -gt "900"){$y += 30;$x = 0}
}

This example takes the first 20 from an array and puts them on the main form in a orderly fashion as to not overcrowd the main window. The example has no practical use, but you could extract nestled objects and create dynamic buttons with a bit of work.

The full script would look like this:
Note that i’m using the same function for all buttons.

function CreateButton{
  param(
    $name,
    $text,
    $size,
    $location,
    $onclick,
    $Form
  )
  $name = New-Object System.Windows.Forms.Button
  $name.Text = "$text"
  $name.Location = "$location"
  $name.Size = "$size"
  $name.add_Click($onclick)
  $Form.Controls.Add($name)
}
$SaveButton_Click = {
  $SaveFileDialog = New-Object System.Windows.Forms.SaveFileDialog
  $SaveFileDialog.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
  $SaveFileDialog.ShowDialog()
  $ConsoleWindow.Text | Out-File $SaveFileDialog.FileName
  $SaveFileDialog.Dispose()
}
[Void][Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")

# Main form settings
$Form = New-Object System.Windows.Forms.Form
$Form.ClientSize = "1000,620"
$Form.DesktopLocation = "100,100"
$Form.MaximizeBox = $False
$Form.ShowIcon = $False
$Form.FormBorderStyle = "FixedSingle"
$Form.Name = "Example"
$Form.Text = "Example"

# Console window settings
$ConsoleWindow = New-Object System.Windows.Forms.RichTextBox
$ConsoleWindow.Size = "1000,250"
$ConsoleWindow.Location = "0,320"
#$ConsoleWindow.ReadOnly = $True #commented out for manual input.
$ConsoleWindow.BackColor = "Black"
$ConsoleWindow.ForeColor = "White"
$Form.Controls.Add($Consolewindow)

$Buttons = @("1".."26")
$x = 0
$y = 0
for($i=0; $i -lt 20;$i++){
  if($buttons[$i] -eq $null){break}
  CreateButton -name $Buttons[$i] -text $Buttons[$i] -size "100,30" -location "$x,$y" -form $form -onclick $SaveButton_Click
  $x += 100
  if($x -gt "900"){$y += 30;$x = 0}
}

$Form.ShowDialog()