Powershell Gui not returning SQL query results - powershell

Question

I'm building a simple GUI where support staff can look up basic user information. The GUI is supposed to pull this data from an SQL DB, but nothing happens when the button is pressed.
function SQLquery {
param (
[Parameter(Mandatory = $true)]
[ValidateSet('NemOrgDB')]
[string]
$System,
[string]
$Query
)
switch ($System) {
NemOrgDB { $ConnectionString = 'Place holder for Stack Overflow' }
}
#New SqlConnection object
$sqlConnection = New-Object System.Data.SqlClient.SqlConnection
$sqlConnection.ConnectionString = $ConnectionString
$sqlConnection.Open()
#New Sqlcommand object
$sqlCommand = New-Object System.Data.SqlClient.SqlCommand
$sqlCommand.Connection = $sqlConnection
$sqlCommand.CommandText = $Query
#Create new sqldataadapter object
$sqlDataAdapter = New-Object System.Data.SqlClient.SqlDataAdapter
$sqlDataAdapter.SelectCommand = $sqlCommand
#Create new dataset object
$DataSet = New-Object System.Data.DataSet
#Fill dataset with dataadapter input
try {
$sqlDataAdapter.Fill($DataSet) | Out-Null
$output = $DataSet.Tables
}
catch {
$output = $null
}
#Close sql connection
$sqlConnection.close()
$null = $sqlConnection
$output
}
Here is the Function in use:
#Søgnigns criteria
$EmployeeID = Read-Host -Prompt "What user to find?"
#SQL Query
SQLquery -System NemOrgDB -Query "Select [medarbejder_wnr]
,[navn]
,[stilling]
,[stilling_nr]
,[firmakode_txt]
FROM [PersonData_NemOrg].[dbo].[Personale]
WHERE medarbejder_wnr ='$EmployeeID';"
The 2 pieces of code work as they should in a console environment with no Gui attached, they return the following results:
EmployeeID: EmployeeID
Name: Name
Role: IT support
Role number : Number
fimakode_txt : Company
When the same code is run inside the GUI nothing happens, here is the GUI code:
#ButtonSearch
#
$ButtonSearch.BackColor = [System.Drawing.SystemColors]::ActiveBorder
$ButtonSearch.FlatStyle = [System.Windows.Forms.FlatStyle]::System
$ButtonSearch.Font = (New-Object -TypeName System.Drawing.Font -ArgumentList #([System.String]'Tahoma',[System.Single]9,[System.Drawing.FontStyle]::Bold,[System.Drawing.GraphicsUnit]::Point,([System.Byte][System.Byte]0)))
$ButtonSearch.Location = (New-Object -TypeName System.Drawing.Point -ArgumentList #([System.Int32]12,[System.Int32]118))
$ButtonSearch.Name = [System.String]'ButtonSearch'
$ButtonSearch.Size = (New-Object -TypeName System.Drawing.Size -ArgumentList #([System.Int32]150,[System.Int32]23))
$ButtonSearch.TabIndex = [System.Int32]24
$ButtonSearch.Text = [System.String]'Search'
$ButtonSearch.UseCompatibleTextRendering = $true
$ButtonSearch.UseVisualStyleBackColor = $false
$ButtonSearch.add_Click($ButtonSearch_Click)
#
AND
$ButtonSearch_Click = {
$Wnummer = $TextBoxWnummer1.Text
SQLquery -System NemOrgDB -Query "Select [medarbejder_wnr]
,[navn]
,[stilling]
,[stilling_nr]
,[firmakode_txt]
FROM [PersonData_NemOrg].[dbo].[Personale]
WHERE medarbejder_wnr ='$Wnummer';"
}
It simply returns nothing.