Cannot convert argument second time in Powershell - powershell

Question

I am trying to call a web service. If I just start up Powershell fresh, the following code runs perfectly. Any subsequent run will give the following error.
Cannot convert argument "fieldsWithValues", with value:
"FileHold.LibraryManager.FieldWithValue[]", for "SetMetadata" to type
"FileHold.LibraryManager.FieldWithValue[]": "Cannot convert the
"FileHold.LibraryManager.FieldWithValue" value of type
"FileHold.LibraryManager.FieldWithValue" to type
"FileHold.LibraryManager.FieldWithValue"."
At Z:\VM_Transfer\Customers\Oregon\UpdateMetadata\CannotConvertTest.ps1:19 char:1
Here is the code with the problem.
$fh = "http://fileholdtest8/fh/filehold"
$uri = $fh + "/UserRoleManager/SessionManager.asmx?WSDL"
$SessionManager = New-WebServiceProxy -Uri $uri -Namespace FileHold.SessionManager
$sessionId = $SessionManager.StartSession( 'sysadm', '12345', 4 )
$uri = $fh + "/LibraryManager/DocumentManager.asmx?WSDL"
$dm = New-WebServiceProxy -Uri $uri -Namespace FileHold.LibraryManager
$dm.CookieContainer = New-Object System.Net.CookieContainer
$cookie = New-Object System.Net.Cookie( 'FHLSID', $sessionId, "/", ([System.Uri]$dm.Url).Host )
$dm.CookieContainer.Add( $cookie )
$newFieldValue = [FileHold.LibraryManager.FieldWithValue]::new()
$newFieldValue.FieldId = 1007
$newFieldValue.FieldValue = $true
[FileHold.LibraryManager.FieldWithValue[]]$fieldsWithValues = #( $newFieldValue )
$dm.SetMetadata( 4033, 1002, "EmployeeInfo_filled1-test", $fieldsWithValues, $false, $null )
What do I need to do to be able to run this every time without restarting the ISE.
Btw. I can use this technique to call other methods without any problem as long as their parameters are simple types. It seems the issue only occurs when I have a complex object like FileHold.LibraryManager.FieldWithValue.
PSVersion = 5.1.14393.1532

Answer 1

I found a solution by ensuring I do not reuse the variable. Of course, I will need to deal with a potential expired cookie, but that is another problem.
$fh = "http://fileholdtest8/fh/filehold"
$uri = $fh + "/UserRoleManager/SessionManager.asmx?WSDL"
$SessionManager = New-WebServiceProxy -Uri $uri -Namespace FileHold.SessionManager
$sessionId = $SessionManager.StartSession( 'sysadm', '12345', 4 )
if ( !(Test-Path variable:dm) )
{
$uri = $fh + "/LibraryManager/DocumentManager.asmx?WSDL"
$dm = New-WebServiceProxy -Uri $uri -Namespace FileHold.Library
$FieldWithValueType = "{0}.FieldWithValue" -f $dm.GetType().Namespace
$dm.CookieContainer = New-Object System.Net.CookieContainer
$cookie = New-Object System.Net.Cookie( 'FHLSID', $sessionId, "/", ([System.Uri]$dm.Url).Host )
$dm.CookieContainer.Add( $cookie )
}
$newFieldValue = [FileHold.Library.FieldWithValue]::new()
$newFieldValue.FieldId = 1007
$newFieldValue.FieldValue = $true
$fieldsWithValues = #( ,$newFieldValue )
$dm.SetMetadata( 4041, 1002, "EmployeeInfo_filled1-test", $fieldsWithValues, $false, $null )