Write PowerShell Output (as it happens) to WPF UI Control

Question

I've been reading blogs about writing to the UI from different runspaces (http://learn-powershell.net/2012/10/14/powershell-and-wpf-writing-data-to-a-ui-from-a-different-runspace/).

I'm basically trying to make it so I can click a button in the UI and run a PowerShell script and capture the output of that script as it happens and update the WPF UI control without freezing up the UI.

I've tried a basic example of just writing some output directly, but it seems to hang the UI. I'm using runspaces and dispatcher, but I seem to be stuck on something.

Any ideas?

Thanks.

Add-Type –assemblyName PresentationFramework
Add-Type –assemblyName PresentationCore
Add-Type –assemblyName WindowsBase


$uiHash = [hashtable]::Synchronized(@{})
$newRunspace.ApartmentState = "STA"
$newRunspace.ThreadOptions = "ReuseThread"
$newRunspace.Open() 
$newRunspace.SessionStateProxy.SetVariable('uiHash',$uiHash)

$psCmd = [PowerShell]::Create().AddScript({
[xml]$xaml = @"
<Window 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Name="Window" Title="Patcher" Height="350" Width="525" Topmost="True">
    <Grid>
        <Label Content="A Builds" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="88" RenderTransformOrigin="0.191,0.566"/>
        <ListBox HorizontalAlignment="Left" Height="269" Margin="10,41,0,0" VerticalAlignment="Top" Width="88"/>
        <Label Content="New Build" HorizontalAlignment="Left" Margin="387,10,0,0" VerticalAlignment="Top"/>
        <TextBox HorizontalAlignment="Left" Height="23" Margin="387,41,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Label Content="B Builds" HorizontalAlignment="Left" Margin="117,10,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.528,-0.672"/>
        <ListBox HorizontalAlignment="Left" Height="269" Margin="103,41,0,0" VerticalAlignment="Top" Width="88"/>
        <Label Content="C Builds" HorizontalAlignment="Left" Margin="185,10,0,0" VerticalAlignment="Top"/>
        <ListBox HorizontalAlignment="Left" Height="269" Margin="196,41,0,0" VerticalAlignment="Top" Width="88"/>
        <Button x:Name="PatchButton" Content="Patch!" HorizontalAlignment="Left" Margin="426,268,0,0" VerticalAlignment="Top" Width="75"/>
        <RichTextBox x:Name="OutputTextBox" HorizontalAlignment="Left" Height="194" Margin="289,69,0,0" VerticalAlignment="Top" Width="218">
            <FlowDocument>
                <Paragraph>
                    <Run Text=""/>
                </Paragraph>
            </FlowDocument>
        </RichTextBox>

    </Grid>
</Window>
"@

$reader = (New-Object System.Xml.XmlNodeReader $xaml)
$uiHash.Window = [Windows.Markup.XamlReader]::Load($reader)

$uiHash.Button = $uiHash.Window.FindName("PatchButton")
$uiHash.OutputTextBox = $uiHash.Window.FindName("OutputTextBox")

$uiHash.OutputTextBox.Dispatcher.Invoke("Render", [Windows.Input.InputEventHandler]    {$uiHash.OutputTextBox.UpdateLayout()}, $null, $null)

$uiHash.Window.ShowDialog() | Out-Null
})
$psCmd.Runspace = $newRunspace
$data = $psCmd.BeginInvoke()

# The next line fails (null-valued expression)
<#
$uiHash.OutputTextBox.Dispatcher.Invoke("Normal", [action]{
    for ($i = 0; $i -lt 10000; $++) {
        $uiHash.OutputTextBox.AppendText("hi")
    }
})#>

Answer 1

Out of curiosity, have you considered that instead of PowerShell firing up WPF and displaying some output, it should be the other way around?

Perhaps you should be invoking PowerShell from within a WPF application, and capturing the output to be displayed?

http://www.codeproject.com/Articles/18229/How-to-run-PowerShell-scripts-from-C