Function not found on first attempt - function

Question

I have a script, which creates a GUI to put in parameters to create an AD user. The script contains a large function (one that creates a AD browser that I found on the net). The function is called right at the start of the script (one textbox requires input from the function to prefill a value) or by clicking a button in the GUI. Problem is, that when I run the script, I get error message saying, that "The term 'Browse-AD' (=name of the function) is not recognised as the name of a cmdlet, function..." When I run it from PowerShell ISE, I get this error for the first time I try, the script launches (but the browser doesn't work) and after cancelling the script and running it again the browser works fine, no error message is displayed. I didn't touch the script in the mean time, I just run it for the second time, no changes made. But the bigger problem is, that when the script is launched from a file directly (which is naturally its intended way of usage), it's always the first attempt and therefore the error is always displayed and browser doesn't work. Any idea what's happening?
This is the function:
function Browse-AD()
{
# original inspiration: https://itmicah.wordpress.com/2013/10/29/active-directory-ou-picker-in-powershell/
# author: Rene Horn the.rhorn#gmail.com
<#
Copyright (c) 2015, Rene Horn
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#>
$dc_hash = #{}
$selected_ou = $null
Import-Module ActiveDirectory
$forest = Get-ADForest
[System.Reflection.Assembly]::LoadWithPartialName("System.Drawing") | Out-Null
[System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") | Out-Null
function Get-NodeInfo($sender, $dn_textbox)
{
$selected_node = $sender.Node
$dn_textbox.Text = $selected_node.Name
}
function Add-ChildNodes($sender)
{
$expanded_node = $sender.Node
if ($expanded_node.Name -eq "root") {
return
}
$expanded_node.Nodes.Clear() | Out-Null
$dc_hostname = $dc_hash[$($expanded_node.Name -replace '(OU=[^,]+,)*((DC=\w+,?)+)','$2')]
$child_OUs = Get-ADObject -Server $dc_hostname -Filter 'ObjectClass -eq "organizationalUnit" -or ObjectClass -eq "container"' -SearchScope OneLevel -SearchBase $expanded_node.Name
if($child_OUs -eq $null) {
$sender.Cancel = $true
} else {
foreach($ou in $child_OUs) {
$ou_node = New-Object Windows.Forms.TreeNode
$ou_node.Text = $ou.Name
$ou_node.Name = $ou.DistinguishedName
$ou_node.Nodes.Add('') | Out-Null
$expanded_node.Nodes.Add($ou_node) | Out-Null
}
}
}
function Add-ForestNodes($forest, [ref]$dc_hash)
{
$ad_root_node = New-Object Windows.Forms.TreeNode
$ad_root_node.Text = $forest.RootDomain
$ad_root_node.Name = "root"
$ad_root_node.Expand()
$i = 1
foreach ($ad_domain in $forest.Domains) {
Write-Progress -Activity "Querying AD forest for domains and hostnames..." -Status $ad_domain -PercentComplete ($i++ / $forest.Domains.Count * 100)
$dc = Get-ADDomainController -Server $ad_domain
$dn = $dc.DefaultPartition
$dc_hash.Value.Add($dn, $dc.Hostname)
$dc_node = New-Object Windows.Forms.TreeNode
$dc_node.Name = $dn
$dc_node.Text = $dc.Domain
$dc_node.Nodes.Add("") | Out-Null
$ad_root_node.Nodes.Add($dc_node) | Out-Null
}
return $ad_root_node
}
$main_dlg_box = New-Object System.Windows.Forms.Form
$main_dlg_box.ClientSize = New-Object System.Drawing.Size(400,600)
$main_dlg_box.MaximizeBox = $false
$main_dlg_box.MinimizeBox = $false
$main_dlg_box.FormBorderStyle = 'FixedSingle'
# widget size and location variables
$ctrl_width_col = $main_dlg_box.ClientSize.Width/20
$ctrl_height_row = $main_dlg_box.ClientSize.Height/15
$max_ctrl_width = $main_dlg_box.ClientSize.Width - $ctrl_width_col*2
$max_ctrl_height = $main_dlg_box.ClientSize.Height - $ctrl_height_row
$right_edge_x = $max_ctrl_width
$left_edge_x = $ctrl_width_col
$bottom_edge_y = $max_ctrl_height
$top_edge_y = $ctrl_height_row
# setup text box showing the distinguished name of the currently selected node
$dn_text_box = New-Object System.Windows.Forms.TextBox
# can not set the height for a single line text box, that's controlled by the font being used
$dn_text_box.Width = (14 * $ctrl_width_col)
$dn_text_box.Location = New-Object System.Drawing.Point($left_edge_x, ($bottom_edge_y - $dn_text_box.Height))
$main_dlg_box.Controls.Add($dn_text_box)
# /text box for dN
# setup Ok button
$ok_button = New-Object System.Windows.Forms.Button
$ok_button.Size = New-Object System.Drawing.Size(($ctrl_width_col * 2), $dn_text_box.Height)
$ok_button.Location = New-Object System.Drawing.Point(($right_edge_x - $ok_button.Width), ($bottom_edge_y - $ok_button.Height))
$ok_button.Text = "Ok"
$ok_button.DialogResult = 'OK'
$main_dlg_box.Controls.Add($ok_button)
# /Ok button
# setup tree selector showing the domains
$ad_tree_view = New-Object System.Windows.Forms.TreeView
$ad_tree_view.Size = New-Object System.Drawing.Size($max_ctrl_width, ($max_ctrl_height - $dn_text_box.Height - $ctrl_height_row*1.5))
$ad_tree_view.Location = New-Object System.Drawing.Point($left_edge_x, $top_edge_y)
$ad_tree_view.Nodes.Add($(Add-ForestNodes $forest ([ref]$dc_hash))) | Out-Null
$ad_tree_view.Add_BeforeExpand({Add-ChildNodes $_})
$ad_tree_view.Add_AfterSelect({Get-NodeInfo $_ $dn_text_box})
$main_dlg_box.Controls.Add($ad_tree_view)
# /tree selector
if ($main_dlg_box.ShowDialog() -eq [System.Windows.Forms.DialogResult]::OK)
{
return $dn_text_box.Text
}
return $null
}
This is definition of the button that shall launch the browser:
$Select_AD_path = New-Object System.Windows.Forms.Button
$Select_AD_path.Text = "Browse..."
$Select_AD_path.Width = 100
$Select_AD_path.Height = 30
$Select_AD_path.Location = New-Object System.Drawing.Point(90,155)
$Select_AD_path.Font = 'Microsoft Sans Serif,10'
$Select_AD_path.add_Click({
$dn = Browse-AD
if ($dn)
{
$Location_val.Text = $dn
}
})
Also, I put the function to the value of a textbox, so that the browser launches before the script itself runs and prefills the AD path directly to the value I need it:
$Location_val = New-Object system.Windows.Forms.TextBox
$Location_val.multiline = $false
$Location_val.text = Browse-AD
$Location_val.width = 250
$Location_val.height = 20
$Location_val.location = New-Object System.Drawing.Point(200,160)
The precise error message is this:
Browse-AD : The term 'Browse-AD' is not recognized as the name of a cmdlet, function, script file, or operable
program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At C:\Users\a.Petr.Synek\Documents\New_ADuser_woodgroup_complete.ps1:204 char:42
+ $Location_standard_val.Text = Browse-AD
+ ~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (Browse-AD:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
At the 204th row there is this text: $Location_val.text = Browse-AD

Answer 1

As requested, my comment as answer:
In your script, you need to put the Browse-AD function on top and all the rest of your code beneath that.
If this order is incorrect, the first time running, the function is called before it has been parsed, giving you the error message.
The second time, PowerShell already parsed the entire code, so then the function is known. PowerShell (unlike VBScript) parses code from top to bottom.