CODEWITHSUNDEEP
powershell
BananaAcid
BananaAcid

Reputation: 3481

getting a powershell function reference by string as block

I am trying to get a handler added to a form/wpf button by Add_Click. I do not know the function name beforehand, so constructing the function name is important. Then passing it to Add_Click.

Trying the following, I get 

$num = 1
function somefn1 () {}

$fn = $Function:"somefn$num"

$somebutton.Add_Click($fn)

The error is

Cannot convert argument "value", with value: "somefn1", for "add_Click" to type "System.Windows.RoutedEventHandler": "Cannot convert the 
"somefn1" value of type "System.String" to type "System.Windows.RoutedEventHandler"."
At xyz
+ ... $somebutton.Add_Click("somefn$num") }
+                              ~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodArgumentConversionInvalidCastArgument

I am not sure, how to get around that. Any ideas or hints?

Upvotes: 0

Views: 153

Answers (1)

BananaAcid
BananaAcid

Reputation: 3481

Working: using a string to attach an existing function (mind the scope of the handler)

$elName = "theButton"  # => Name="theButton"
$fnName = "mynamespace." + "function_name"

$fns = Get-ChildItem function: | Where-Object { $_.Name -like $fnName }
$Form.FindName($elName).Add_Click( $fns[0].ScriptBlock )

function mynamespace.function_name($Sender, $EventArgs) {
  Write-Host "works !"
}

Upvotes: 1

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