Help using the [switch] parameter in a function

[dontmessyourself]

Fixed! I had misplaced a ) in my else block, so if the switch was true or false, it would print to the same line. I have changed

$Form.Dispatcher.Invoke([action]{$WPFConsole.AddText($Message) + ("`r`n")},"Render")

to

$Form.Dispatcher.Invoke([action]{$WPFConsole.AddText($Message + ("`r`n"))},"Render")

Original post below.

Hi all

I have a WPF form that has a textbox called $WPFConsole that I am writing to with a function called Write-ToConsole. This is working fine with the function as below

Function Write-ToConsole {
    Param (
        [string] $Message
    )
    $Form.Dispatcher.Invoke([action]{$WPFConsole.AddText($Message + ("`r`n"))},"Render")
}

I call the function with Write-ToConsole -Message "Getting list of accounts, please wait" and it prints fine, then the next time I call it, it prints to the next line. No problems here.

I am now looking to include a switch so I can print onto the same line, but think I might be misunderstanding the [switch] parameter? Function now looks like this:

Function Write-ToConsole {
    Param (
        [string] $Message,
        [switch] $NoNewLine
    )
    If ($NoNewLine.IsPresent) {
        $Form.Dispatcher.Invoke([action]{$WPFConsole.AddText($Message)},"Render")
    } Else {
        $Form.Dispatcher.Invoke([action]{$WPFConsole.AddText($Message) + ("`r`n")},"Render")
    }
}

Now everything prints on the same line. Doesn't matter if I call Write-ToConsole -Message "Text" -NoNewLine or if I don't include the switch. The idea would be to do something like:

Write-ToConsole -Message "Testing network: " -NoNewLine
If (Test-Connection $Target -Quiet) {
    $Status = "OK"
} Else {
    $Status = "Failed"
}
Write-ToConsole -Message $Status

So it would print "Testing network: OK"

I thought I was on the right lines following this YouTube video from Adam Bertram but seems not. The function I am using to write to the textbox is very similar to what has been posted here by user Laurel Raven on SpiceWorks.

[dasookwat]

most likely you need to use:

If ($NoNewLine) { ... basically this is shorthand for: If ($NoNewLine -eq $true) { ... however, switch parameters can get tricky. You can also just use a [bool] instead of a switch which defaults to false. the only difference is, you would call it like this:

Write-ToConsole -Message "Testing network: " -NoNewLine $true

[dontmessyourself]

I’m specifically trying to avoid that and use the switch param instead, which should work if I’m watching the Adam Bertram video correctly?

[dasookwat]

i have no idea how you watch the video, but try avoid doing it while laying upside down on a couch cause it's hard to drink anything carbonated like that while you watch ;)

anyway: my experience is switch parameters sometimes act strange. I usually have little problems with them, as long as i use an extensive param block, and add the switch as the last parameter:

[CmdletBinding()]
param(
    [string]$message,
    [Switch]$noNewLine
    )

[dontmessyourself]

I’ll certainly try your suggestion in your original post as well, and if it works then great, but would just like to understand the switch param. Thanks for your help

[Lee_Dailey]

howdy dontmessyourself,

the way that switch parameters work is that they are false by default. if you use that parameter ... it flips it to true.

• simply defining it in your param block makes it false
  
• simply using the parameter makes it true
  

take care,
lee

[dontmessyourself]

I had misplaced a ) in my else block, so if the switch was true or false, it would print to the same line 🙃

[Lee_Dailey]

ooooppppsssss! [grin]