Powershell Get-ADUser Informationen und Richtextbox

Add-Type -AssemblyName System.Windows.Forms

function Get-ADUserInfo{
	[CmdletBinding()]
	[OutputType([System.Int32])]
	param(
		[Parameter(Position=0, Mandatory=$true)]
		[ValidateNotNullOrEmpty()]
		[System.String]
		$Name,

		[Parameter(Position=1)]
		[ValidateNotNull()]
		[System.Int32]
		$Index
	)
    try {
        $user = $(try {get-aduser -identity $Name} catch {$null})
        if ($user -ne $null) {
          return $user
        } else {
          return "User doesn't exist"  
        }		
	}
	catch {
		throw 
	}
}

$Resolve_UserADInfo = New-Object system.Windows.Forms.Form 
$Resolve_UserADInfo.Text = "Get User AD Information"  
$Resolve_UserADInfo.TopMost = $true
$Resolve_UserADInfo.Width = 800
$Resolve_UserADInfo.Height = 600
$Resolve_UserADInfo.FormBorderStyle = 'FixedDialog'  
$Resolve_UserADInfo.MaximizeBox = $False
$Resolve_UserADInfo.MinimizeBox = $False
$Resolve_UserADInfo.StartPosition = 'CenterScreen'  

$lb_UserName = New-Object system.windows.Forms.Label 
$lb_UserName.Text = "UserName"  
$lb_UserName.AutoSize = $true
$lb_UserName.Width = 25
$lb_UserName.Height = 10
$lb_UserName.location = new-object system.drawing.point(15,15)
$lb_UserName.Font = "Microsoft Sans Serif,10"  
$Resolve_UserADInfo.controls.Add($lb_UserName) 

$tb_UserName = New-Object system.windows.Forms.TextBox 
$tb_UserName.Width = 264
$tb_UserName.Height = 20
$tb_UserName.location = new-object system.drawing.point(117,15)
$tb_UserName.Font = "Microsoft Sans Serif,10"  
$Resolve_UserADInfo.controls.Add($tb_UserName) 

$btn_Resolve = New-Object system.windows.Forms.Button 
$btn_Resolve.Text = "Resolve"  
$btn_Resolve.Width = 366
$btn_Resolve.Height = 30
$btn_Resolve.location = new-object system.drawing.point(15,45)
$btn_Resolve.Font = "Microsoft Sans Serif,10"  
$Resolve_UserADInfo.controls.Add($btn_Resolve) 


$rtb_User = New-Object System.Windows.Forms.RichTextBox
$rtb_User.Enabled = $False
$rtb_User.Location = '15, 80'  
$rtb_User.Name = 'richtextbox2'  
$rtb_User.Size = '760, 470'  
$Resolve_UserADInfo.controls.Add($rtb_User) 


$btn_Resolve.Add_Click({ 

    if($tb_UserName.Text -eq ""){  
        $rtb_User.Text = "Bitte geben Sie einen Usernamen ein!"  
    }else{
        $rtb_User.text = Get-ADUserInfo -Name $tb_UserName.Text
    }

})

[void]$Resolve_UserADInfo.ShowDialog() 

$Resolve_UserADInfo.Dispose() 

DistinguishedName :
Enabled           : True
GivenName         : 
Name              : 
ObjectClass       : user
ObjectGUID        : 
SamAccountName    : 
SID               : 
Surname           : 
UserPrincipalName :