<#
=============================================================================================
Name:           Export Distrbution Groups a user is member of
Description:    This script exports all users and their distribution group membership
Website:        o365reports.com
Script by:      o365reports Team
For detailed script execution: https://o365reports.com/2022/04/19/list-all-the-distribution-groups-a-user-is-member-of-using-powershell/
============================================================================================
#>
Param
(
    [string]$UserName=$Null,
    [string]$Password=$Null,
	[string]$UserPrincipalName=$Null,
	[string]$InputCsvFilePath=$Null
)
Function Connect_Exo
{		
    #Check for EXO v2 module inatallation
    $Module = Get-Module ExchangeOnlineManagement -ListAvailable
    If($Module.count -eq 0) 
    {			
        Write-Host "Exchange Online PowerShell V2 module is not available"  -ForegroundColor yellow  
        $Confirm= Read-Host "Are you sure you want to install module? [Y] Yes [N] No" 
        If($Confirm -match "[yY]")			   
        {						
            Write-host "Installing Exchange Online PowerShell module"
            Install-Module ExchangeOnlineManagement -Repository PSGallery -AllowClobber -Force
        } 
        Else 
        { 
            Write-Host EXO V2 module is required to connect Exchange Online.Please install module using Install-Module ExchangeOnlineManagement cmdlet. 
            Exit
        }
    }   
    #Importing Module by default will avoid the cmdlet unrecognized error
    Import-Module ExchangeOnlineManagement
    Write-Host Connecting to Exchange Online...
    #Storing credential in script for scheduling purpose/ Passing credential as parameter - Authentication using non-MFA account
    If(($UserName -ne "") -and ($Password -ne ""))
    {			
        $SecuredPassword = ConvertTo-SecureString -AsPlainText $Password -Force
        $Credential  = New-Object System.Management.Automation.PSCredential $UserName,$SecuredPassword
        Connect-ExchangeOnline  -Credential $Credential
    }
    Else
    {
        Connect-ExchangeOnline
    }
} 

Function Import_Csv
{
    #Importing UserPrincipalName From The Csv
    Try
    {
        $UserDetails=@()
        Write-Host "Importing UserPrincipalNames from Csv..."
        $UPNs=Import-Csv $InputCsvFilePath 
        foreach ($UPN in $UPNs)
        {
        $UserPrincipalName=$UPN.User_Principal_Name
            Try
	        {   
		         Get-Mailbox -Identity $UserPrincipalName -ErrorAction Stop |foreach{
                     List_DLs_That_User_Is_A_Member
                   
	        }
}
	        Catch
            {
		        Write-Host "$UserPrincipalName is not a valid user"
	        }
        }

    }
    catch
    {
        Write-Host "$InputCsvFilePath is not a valid file path"
    }     
}
Function List_DLs_That_User_Is_A_Member
{
    #Finding Distribution List that  User is a Member
	$Result= @()
    $DistinguishedName=$_.DistinguishedName
    $Filter = "Members -Like ""$DistinguishedName"""
    $UserPrincipalName=$_.UserPrincipalName
    $UserDisplayName=$_.DisplayName
    Write-Progress -Activity "Find Distribution Lists that user is a member" -Status "Processed User Count: $Global:ProcessedUserCount" -CurrentOperation "Currently Processing in  $UserPrincipalName"
    $DLs=Get-DistributionGroup -ResultSize Unlimited -Filter $Filter
    $GroupCount=$DLs | Measure-Object | select count
    If($GroupCount.count -ne 0)
    {    
	    $DLsCount=$GroupCount.count
		$DLsName=$DLs.Name
	    $DLsEmailAddress=$DLs.PrimarySmtpAddress
    }
    Else
    {
	    $DLsName="-"
	    $DlsEmailAddress="-"
		$DLsCount='0'
    }
    $Result=New-Object PsObject -Property @{'User Principal Name'=$UserPrincipalName;'User Display Name'=$UserDisplayName;'No of DLs that user is a member'=$DLsCount;'DLs Name'=$DLsName -join ',';'DLs Email Adddress'=$DLsEmailAddress -join ',';} 
    $Result|Select-Object 'User Principal Name','User Display Name','No Of DLs That User Is A Member','DLs Name','DLs Email Adddress'| Export-Csv  $OutputCsv -NoTypeInformatio -Append 
    $Global:ProcessedUserCount++		
  
}
Function OpenOutputCsv
{  		
    #Open Output File After Execution 
    If((Test-Path $OutputCsv) -eq "True") 
    {			
        Write-Host "The Output file available in $OutputCsv" 
        Write-Host `nThe output file contains $ProcessedUserCount users. -ForegroundColor Green
        $Prompt = New-Object -ComObject wscript.shell    
        $UserInput = $Prompt.popup("Do you want to open output file?",` 0,"open output file",4)    
        If($UserInput -eq 6)    
        {    
            Invoke-Item "$OutputCsv"    
        }  
    } 	
}
Connect_Exo
$Global:ProcessedUserCount=1
$OutputCsv=".\ListDLs_UsersIsMemberOf_$((Get-Date -format MMM-dd` hh-mm` tt).ToString()).csv"
If($UserPrincipalName -ne "")
{  
	Try
	{
        write-Host "Checking $UserPrincipalName is a valid user or not"
		Get-Mailbox -Identity $UserPrincipalName -ErrorAction Stop|ForEach{
            List_DLs_That_User_Is_A_Member
        }
	}
	Catch
    {
		Write-Host "$UserPrincipalName is not a valid user"
	}
}		
Elseif($InputCsvFilePath -ne "")
{	
    Import_Csv
}
Else
{ 
    Get-Mailbox -ResultSize unlimited -RecipientTypeDetails UserMailbox | ForEach{
	    List_DLs_That_User_Is_A_Member
    }
}
OpenOutputCsv
#Removing connected session
Get-PSSession |Remove-PSSession