PowerShell GUI Output - powershell

Question

I'm writing a small PowerShell script, with GUI, that processes the Ping command. Currently I have the script reading input from the user to determine the IP Address / URL to ping, and then displaying the output to a rich-text-box.
However, currently, the command COMPLETES then writes the entire output at once. I want it to display each line of output in real time - so that it appears the same way that it would running the command in the shell.
When the Ping button is pushed, the following function is called (and I think this is where the issue is):
Function FNPing {
$OutputBox.Text = "Please Wait..."
$ping = ping ($InputBox.text)
$OutputBox.Text = ""
foreach ($line in $ping) {
$OutputBox.Appendtext($line+[char]13+[char]10)
}
}
I imagine that the issue can probably be solved in the ForEach statement, I'm just not aware of how to do it! All help is appreciated!

Answer 1

I would try using the test-connection cmdlet. The problem is that ping an external exe so all you are getting out of it is a blob of text when it completes. The only way to get the output of ping while it is running is going to be by using start-process and redirecting the output (this is quite messy).
With test-connection you won't get a pretty summary but the info is all there. For the summary info, measure-object can help. Here's an imitation of ping's output that should get you started:
function fnping {
$outputBox.Text = "Please Wait..."
$count = 4
$results = test-connection $inputbox.Text -count $count | foreach { $outputBox.AppendText("Reply from $($_.ProtocolAddress): bytes=$($_.ReplySize) time=$($_.ResponseTime)ms TTL=$($_.TimeToLive)`r`n"); $_ }
$summary = $results | measure-object -Property ResponseTime -Average -Minimum -Maximum
$lost = $count - $summary.Count
$percentLost = $lost * 100.0 / $count
$outputBox.AppendText("Packets: Sent = $count, Received = $($summary.Count), Lost = $lost ($($percentLost)% loss)`r`n")
$outputBox.AppendText("Minimum = $($summary.Minimum)ms, Maximum = $($summary.Maximum)ms, Average = $($summary.Average)ms`r`n")
}
Edit
Actually I stand corrected. Assigning the result to a variable ($ping) is causing powershell to wait for the output stream to be closed. You can easily do what you want, with foreach-object. Here I use a small helper function to clear the output box before writing the to the box:
function WriteEach-Object() {
param(
[Parameter(Mandatory=$true,ValueFromPipeline=$true)]
[object[]]$inputs
)
begin { $outputBox.Text = "" }
process { $inputs | foreach { $outputBox.AppendText($_) } }
end { $outputBox.AppendText("`r`n") }
}
function fnping() {
$outputBox.Text = "Please Wait..."
ping $inputBox.Text | writeeach-object
}

Answer 2

You need to add BEGIN {} PROCESS {} and END {} statements to control how your function works. If no such are given, Powershell assumes that everything is in the END {} statement, processing everything in one go.
Changing into this
Function FNPing {
BEGIN {
}
PROCESS {
$OutputBox.Text = "Please Wait..."
$ping = ping ($InputBox.text)
$OutputBox.Text = ""
foreach ($line in $ping) {
$OutputBox.Appendtext($line+[char]13+[char]10)
}
}
END {
}
}
should do the trick. Alternatively, you can replace Function with Filter, which assumes the code resides in the PROCESS {} block.
For more info: http://technet.microsoft.com/en-us/magazine/hh413265.aspx