asked on

Add logging to form generated by powershell script.

I have a powershell script which includes a 'WriteToLog' function which basically just writes data to the output stream using the 'Write-Output' cmdlet. This used to work without any issue, however I have since introduced a custom form which is built by the script and displayed using the 'ShowDialog' cmdlet - once the form is displayed any calls to the 'WriteToLog' function do not seem to work any more?

Note: I have proven that the form is calling the 'WriteToLog' function successfully, but the 'Write-Output' is no longer working as expected. I reckon this is because the output is being sent to the output stream of the form and not the calling script but this is a complete guess.

So any ideas how I can dynamically get the output from a generated form in Powershell.

I assume this is because the

Jeremy Weisinger

Can you post the script and point out where it stops outputting (if possible)?

Blowfelt82

ASKER

Unfortunately the script is on a secure server and I have no way of copying the scripts - sorry to be so unhelpful! I will try and get a rough draft of the code up ASAP.

Blowfelt82

ASKER

Ok here is a very rough draft of the problem - at least recreates the problem I am facing:

  Function Log
  {
    [CmdletBinding()]
  
    Param ([Parameter(Mandatory=$true)][AllowEmptyString()][string]$LogMessage)
  
    Process{
      Write-Host "Writing to Log:"
      Write-Output  $LogMessage
    }
  }

    $objAForm           = New-Object System.Windows.Forms.Form
    $objBForm         = New-Object System.Windows.Forms.Form

  Function TestFunction()
  {
    Log "Test: In Function"
  }

  Function GenerateForm
  {

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

    # define WinForm object size variables

    $frmASizeHeight      = 180 
    $frmASizeWidth       = 250 
    $objATreeViewHeight  = 250 
    $objATreeViewWidth   = 250
    $objANextButtonX     = 127
    $objANextButtonY     = 115
    $objACancelButtonX   = 37
    $objACancelButtonY   = 115
    $objAButtonDimX      = 80
    $objAButtonDimY      = 24
    $returnValue        = 0

    # create a Windows Form object
  
    $objAForm.Text            = "FORM 1"
    $objAForm.Size            = New-Object System.Drawing.Size($frmASizeWidth, $frmASizeHeight) 
    $objAForm.KeyPreview      = $True
    $objAForm.ControlBox      = $True

    # Buttons

    $objACancelButton           = New-Object System.Windows.Forms.Button
    $objACancelButton.Location  = New-Object System.Drawing.Size($objACancelButtonX, $objACancelButtonY)
    $objACancelButton.Size      = New-Object System.Drawing.Size($objAButtonDimX,$objAButtonDimY)
    $objACancelButton.FlatStyle = "Flat"
    $objACancelButton.Text      = "Cancel"
    $objACancelButton.Add_Click(
    {
     $objAForm.Close() | Out-Null
    })

     Log "Test 1"

    $objANextButton           = New-Object System.Windows.Forms.Button
    $objANextButton.Location  = New-Object System.Drawing.Size($objANextButtonX, $objANextButtonY)
    $objANextButton.Size      = New-Object System.Drawing.Size($objAButtonDimX,$objAButtonDimY)
    $objANextButton.FlatStyle = "Flat"
    $objANextButton.Text      = "Next"
    $objANextButton.Add_Click(
    {
       TestFunction
       Log "Test 2"

    })

     Log "Test 3"

    $objAForm.Controls.Add($objACancelButton)
    $objAForm.Controls.Add($objANextButton)

    # Display form

    [void]$objAForm.ShowDialog()
  }

  GenerateForm

Open in new window

On my environment the log outputs Test 1 and Test 2 which are both outside the 'scope' of the GUI button event handler, this is correct. But the other tests originating from within the event handler code and/or the function it calls are not output? I have added the 'Writing to Log' message to prove that the Log function is being called correctly - which it is... Just looks as though the Write-Output cmdlet does not work correctly (or how I would like) when called via the GUI's event handler. Hopefully that should be enough - let me know if not!

Blowfelt82

ASKER

Edit the above should read: Test 1 and Test 3

Jeremy Weisinger

Ah, I see. You'll need to set a variable since that is not in the stream.

Blowfelt82

ASKER

Could you provide an example with the code above, not sure exactly what is involved

Jeremy Weisinger

Here's a rudimentary example.

  Function Log
  {
    [CmdletBinding()]
  
    Param ([Parameter(Mandatory=$true)][AllowEmptyString()][string]$LogMessage)
  
    Process{
      Write-Host "Writing to Log:"
      $LogMessage
    }
  }

    $objAForm           = New-Object System.Windows.Forms.Form
    $objBForm         = New-Object System.Windows.Forms.Form

  Function TestFunction()
  {
    Log "Test: In Function"
  }

  Function GenerateForm
  {

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

    # define WinForm object size variables

    $frmASizeHeight      = 180 
    $frmASizeWidth       = 250 
    $objATreeViewHeight  = 250 
    $objATreeViewWidth   = 250
    $objANextButtonX     = 127
    $objANextButtonY     = 115
    $objACancelButtonX   = 37
    $objACancelButtonY   = 115
    $objAButtonDimX      = 80
    $objAButtonDimY      = 24
    $returnValue        = 0

    # create a Windows Form object
  
    $objAForm.Text            = "FORM 1"
    $objAForm.Size            = New-Object System.Drawing.Size($frmASizeWidth, $frmASizeHeight) 
    $objAForm.KeyPreview      = $True
    $objAForm.ControlBox      = $True

    # Buttons

    $objACancelButton           = New-Object System.Windows.Forms.Button
    $objACancelButton.Location  = New-Object System.Drawing.Size($objACancelButtonX, $objACancelButtonY)
    $objACancelButton.Size      = New-Object System.Drawing.Size($objAButtonDimX,$objAButtonDimY)
    $objACancelButton.FlatStyle = "Flat"
    $objACancelButton.Text      = "Cancel"
    $objACancelButton.Add_Click(
    {
     $objAForm.Close() | Out-Null
    })

     Log "Test 1"

    $objANextButton           = New-Object System.Windows.Forms.Button
    $objANextButton.Location  = New-Object System.Drawing.Size($objANextButtonX, $objANextButtonY)
    $objANextButton.Size      = New-Object System.Drawing.Size($objAButtonDimX,$objAButtonDimY)
    $objANextButton.FlatStyle = "Flat"
    $objANextButton.Text      = "Next"
    $objANextButton.Add_Click(
    {
       TestFunction
       $global:testResults = Log "Test 2"

    })
   
    
     Log "Test 3"

    $objAForm.Controls.Add($objACancelButton)
    $objAForm.Controls.Add($objANextButton)

    # Display form

    [void]$objAForm.ShowDialog()
  }

  GenerateForm
  #results of test 2
  Write-Output $testResults

Open in new window

Blowfelt82

ASKER

Unfortunately I am not sure this solution is what I need, the logging is only updated when the form is closed - and only handles a single line of output. I need a way to dynamically log from the event handler if possible?

ASKER CERTIFIED SOLUTION

Jeremy Weisinger

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Blowfelt82

ASKER

Thanks for your help, not the way I wanted it to work but managed to get logging working by using a global variable to capture the GUI input and then perform the processing outside of the form scripting as per your recommendation. Thanks for your help.