Launching a Remote Console, the Smart Way

Today, I kind of stumbled across a way of connecting to a remote host quite a bit more sophisticated. Basically, the difference is that it will check to see if the connection was successful or not.

This still works off the basic premise of opening a new PowerShell process and using the -ArgumentList parameter to instantly connect to a remote system. This is the command I use (THIS IS JUST FOR CLEARER EXPLANATION, USE THE ONE-LINER BELOW):

Start-Process PowerShell -ArgumentList "-noexit -command Clear-Host; 
    try{ 
        Enter-PSSession -ComputerName $COMPUTERNAMEHERE -ErrorAction Stop; 
        Write-Host 'You should now be connected to the remote host, check below...' -ForeGroundColor Green 
    
    }catch{
        Write-Host 'Could not perform action - most likely that access is denied for the invoke' -ForeGroundColor Red 
    
    } 
"

Or as a one-liner:

Start-Process PowerShell -ArgumentList "-noexit -command Clear-Host; try{ Enter-PSSession -ComputerName $COMPUTERNAMEHERE -ErrorAction Stop; Write-Host 'You should now be connected to the remote host, check below...' -ForeGroundColor Green }catch{Write-Host 'Could not perform action - most likely that access is denied for the invoke' -ForeGroundColor Red } "

This is what the command does

  • Starts a new powershell console
  • clears the host
  • tries to the connection
  • writes output to console

Enjoy!

Handling Textbox Keydown Events

Welcome to another instalment of “how much can I confused myself today…”

Here, I will you how to recognise a keydown event on a textbox and also how to “identify” which key was pressed. This was useful to me because I wanted a button to be pressed when the user pressed the enter key whilst typing in a textbox. Similar to when you type a question into Google and press enter instead of pressing the search button.

First, I found what control I want the event to handle and added a raiseevent onto the button I wanted pressing. You can see this below:

$syncHash.Textbox.Add_KeyDown({
    if ($args[1].key -eq 'Enter'){
        $syncHash.Button.RaiseEvent((New-Object -TypeName System.Windows.RoutedEventArgs -ArgumentList $([System.Windows.Controls.Button]::ClickEvent)))
    }
})

So in this scenario, when the user wants to search they can just press enter in the textbox and the button will be pressed. You can also do this for the entire form. Meaning that if you have multiple textboxes and want an enter in any of them to press a button, you can just put the handler onto the entire form. You can see this below:

$syncHash.Window.Add_KeyDown({
    if ($args[1].key -eq 'Enter'){
        $syncHash.Button.RaiseEvent((New-Object -TypeName System.Windows.RoutedEventArgs -ArgumentList $([System.Windows.Controls.Button]::ClickEvent)))

    }
})

Enjoy!

Adding an BASE64 Icon to a WPF GUI

Nice and simple one today. I’m going to show you how to add an icon to a WPF GUI in PowerShell using BASE64 data.

I won’t be putting my BASE64 data into this post since its a MASSIVELY long string of characters but it should look something like this ” iVBORw0KG…”

First, we need to create a new variable to hold the data and then use the bitmapimage object to convert the data into a usable icon. You can see this below:

[string]$script:base64=@"
iVBORw0KGgo...
"@

$script:bitmap = New-Object System.Windows.Media.Imaging.BitMapImage
$bitmap.BeginInit()
$bitmap.StreamSource = [System.IO.MemoryStream][System.Convert]::FromBase64String($base64)
$bitmap.EndInit()
$bitmap.Freeze()

After this we can simply assign the new icon to the form using the code below:

$window.Icon = $bitmap

Enjoy!

Responsive PowerShell WPF Form Introduction #2

Following on from my last post, I’m going to show you how to update a textbox using a button on the same form. I will be adding the following code starting on line 38:

#BUTTON LOGIC
$syncHash.Button.Add_Click({

    $syncHash.Window.Dispatcher.Invoke(
        [action]{
            $syncHash.TextBox.AppendText("This is a test")
        }
    )
})

This is fairly basic in what it does. It just adds “This is a test” to the textbox. Say if I want the button to run a task and then update the textbox with the results, but the results took a long time to come, the form would freeze. This is because whatever command you run in the same runspace as the GUI, takes controls and stops the GUI being responsive.

So, what I’m going to do is ping google 5 times, get the average from all of those and then update the textbox without the GUI becoming unresponsive. To do this, I’m going to create a new runspace and add the code I want to run. You can see this below:

#BUTTON LOGIC
$syncHash.Button.Add_Click({
    #ASSIGNING HOST VARIABLE
    $syncHash.host = $Host
    #CREATING NEW RUNSPACE
    $pingrunspace = [runspacefactory]::CreateRunspace()
    $pingrunspace.ApartmentState = "STA"
    $pingrunspace.ThreadOptions = "ReuseThread"
    $pingrunspace.Open()
    #PUTTING THE SYNCHASH VARIABLE INSIDE THE NEW RUNSPACE
    $pingrunspace.SessionStateProxy.SetVariable("syncHash",$syncHash)

    #THIS IS THE CODE THAT WILL BE EXECUTED IN THE NEW RUNSPACE
    $code = {

        #CONNECTION TO GOOGLE AND CALCULATING AVERAGE IN NEW RUNSPACE
        $connection = Test-Connection -ComputerName google.co.uk -Count 5
        $average = [math]::Round(($connection.responsetime | Measure-Object -Average).Average)
        #UPDATING THE TEXTBOX WITH CONNECTION AVERAGE IN NEW RUNSPACE
        $syncHash.Window.Dispatcher.Invoke(
            [action]{
                $syncHash.TextBox.AppendText($average)
            }
        )

    }
        
    #ADDING AND RUNNING THE CODE IN THE NEW RUNSPACE
    $PSInstance = [powershell]::Create().AddScript($code)
    $PSinstance.Runspace = $pingrunspace
    $job = $PSinstance.BeginInvoke()
    
})

This will run the code in a separate runspace to the GUI and allow you to interact with it whilst the commands complete in the background.

Just in case you want the entire this, this is what the whole file looks like 🙂

#CREATE HASHTABLE AND RUNSPACE FOR GUI
$syncHash = [hashtable]::Synchronized(@{})
$newRunspace =[runspacefactory]::CreateRunspace()
$newRunspace.ApartmentState = "STA"
$newRunspace.ThreadOptions = "ReuseThread"         
$newRunspace.Open()
$newRunspace.SessionStateProxy.SetVariable("syncHash",$syncHash)      
#BUILD GUI AND ADD TO RUNSPACE CODE
$psCmd = [PowerShell]::Create().AddScript({   
    [xml]$xaml = @"
    <Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    Name="Window" Height="400" Width="600">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>

        <Button Name="Button" Content="Press" Height="200" Width="580" Grid.Row="0" Grid.Column="0" />
        <TextBox Name="Textbox" Height="200" Width="580" Grid.Row="1" Grid.Column="0" />
    </Grid>
</Window>
"@
  
    #INTERPRET AND LOAD THE GUI
    $reader=(New-Object System.Xml.XmlNodeReader $xaml)
    $syncHash.Window=[Windows.Markup.XamlReader]::Load( $reader )

    #EXTRACT THE CONTROLS FROM THE GUI
    $syncHash.TextBox = $syncHash.window.FindName("Textbox")
    $syncHash.Button = $syncHash.Window.FindName("Button")

    #BUTTON LOGIC
    $syncHash.Button.Add_Click({

        $syncHash.host = $Host
        $pingrunspace = [runspacefactory]::CreateRunspace()
        $pingrunspace.ApartmentState = "STA"
        $pingrunspace.ThreadOptions = "ReuseThread"
        $pingrunspace.Open()
        $pingrunspace.SessionStateProxy.SetVariable("syncHash",$syncHash)

        $code = {

            $connection = Test-Connection -ComputerName google.co.uk -Count 5
            $average = [math]::Round(($connection.responsetime | Measure-Object -Average).Average)
            $syncHash.Window.Dispatcher.Invoke(
                [action]{
                    $syncHash.TextBox.AppendText($average)
                }
            )

        }

        $PSInstance = [powershell]::Create().AddScript($code)
        $PSinstance.Runspace = $pingrunspace
        $job = $PSinstance.BeginInvoke()
    })


    #FINALISE AND CLOSE GUI RUNSPACE UPON EXITING
    $syncHash.Window.ShowDialog() | Out-Null
    $syncHash.Error = $Error
    $Runspace.Close()
    $Runspace.Dispose()
    
})
#LOAD RUNSPACE WITH GUI IN
$psCmd.Runspace = $newRunspace
$data = $psCmd.BeginInvoke()

Enjoy!

Responsive PowerShell WPF Form Introduction #1

Hooooly jebus chwist! This took a LONG time for me to get my head around and an even longer time to implement and get working (still breaking it every minute!). I used this website and this website to help me learn the basics.

Today, I’m going to show you how to create a responsive WPF from using PowerShell. This utilises runspaces and a synchronised hashta… never mind the technical stuff!

This is the code that I used:

#CREATE HASHTABLE AND RUNSPACE FOR GUI
$syncHash = [hashtable]::Synchronized(@{})
$newRunspace =[runspacefactory]::CreateRunspace()
$newRunspace.ApartmentState = "STA"
$newRunspace.ThreadOptions = "ReuseThread"         
$newRunspace.Open()
$newRunspace.SessionStateProxy.SetVariable("syncHash",$syncHash)      
#BUILD GUI AND ADD TO RUNSPACE CODE
$psCmd = [PowerShell]::Create().AddScript({   
    [xml]$xaml = @"
    <Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    Name="Window" Height="400" Width="600">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>

        <Button Name="Button" Content="Press" Height="200" Width="580" Grid.Row="0" Grid.Column="0" />
        <TextBox Name="Textbox" Height="200" Width="580" Grid.Row="1" Grid.Column="0" />
    </Grid>
</Window>
"@
  
    #INTERPRET AND LOAD THE GUI
    $reader=(New-Object System.Xml.XmlNodeReader $xaml)
    $syncHash.Window=[Windows.Markup.XamlReader]::Load( $reader )

    #EXTRACT THE CONTROLS FROM THE GUI
    $syncHash.TextBox = $syncHash.window.FindName("Textbox")
    $syncHash.Button = $syncHash.Window.FindName("Button")

    #FINALISE AND CLOSE GUI RUNSPACE UPON EXITING
    $syncHash.Window.ShowDialog() | Out-Null
    $syncHash.Error = $Error
    $Runspace.Close()
    $Runspace.Dispose()
    
})
#LOAD RUNSPACE WITH GUI IN
$psCmd.Runspace = $newRunspace
$data = $psCmd.BeginInvoke()

Using this, you can then use the same command prompt used to launch the script to change the form. E.g. to change the text in the textbox we would use:

$syncHash.Window.Dispatcher.Invoke(
    [action]{$syncHash.TextBox.Text = "Updated text here"}
)

In another post, I’ll show you how to update the textbox using a button on the same form. Exciting stuff, right?

Leave a comment if you have any questions or issues. Enjoy!