C# で Exchange Management Tools のスナップインを使用して Exchange Server 2019 へ接続する

using System;
using System.Collections.ObjectModel;
using System.Management.Automation.Runspaces;
using System.Management.Automation;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            // Connect Exchange Server using the Microsoft.Exchange.Management.PowerShell.RecipientManagement snap-in in the Exchange Management Tools.
            // The Exchange Management Tools need to be installed.
            // Application need to be built as x64 app.

            // If you don't know which PowerShell Nuget Packages you should use, read this blog.
            // https://devblogs.microsoft.com/powershell/depending-on-the-right-powershell-nuget-package-in-your-net-project/
            // You need to install Microsoft.PowerShell.5.1.ReferenceAssemblies when you use Windows PowerShell 5.1.

            RecipientManagementSnapInPowerShell();

            Console.ReadLine();
        }

        public static void WriteStreams(PSDataStreams Streams)
        {
            // Write Error, Warning and Information stream

            PSDataCollection<ErrorRecord> errorStream = Streams.Error;
            foreach (ErrorRecord errorRecord in errorStream)
            {
                Console.WriteLine(errorRecord.ToString());
            }

            PSDataCollection<WarningRecord> warningRecords = Streams.Warning;
            foreach (WarningRecord warningRecord in warningRecords)
            {
                Console.WriteLine(warningRecord.ToString());
            }

            PSDataCollection<InformationRecord> informationRecords = Streams.Information;
            foreach (InformationRecord informationRecord in informationRecords)
            {
                Console.WriteLine(informationRecord.ToString());
            }

            Console.WriteLine("");
        }

        public static void RecipientManagementSnapInPowerShell()
        {
            Collection<PSObject> results;

            using (Runspace runspace = RunspaceFactory.CreateRunspace(RunspaceConfiguration.Create()))
            {
                // Open local runspace
                runspace.Open();

                // Add Microsoft.Exchange.Management.PowerShell.RecipientManagement snap-in
                using (PowerShell shell = PowerShell.Create())
                {
                    Console.WriteLine("Running : Add-PSSnapin *RecipientManagement");

                    shell.Runspace = runspace;
                    shell.Commands.AddScript("Add-PSSnapin *RecipientManagement");
                    shell.Invoke();

                    WriteStreams(shell.Streams);
                }

                // Run Get-RemoteMailbox
                using (PowerShell shell = PowerShell.Create())
                {
                    Console.WriteLine("Running : Get-RemoteMailbox -ResultSize Unlimited");

                    shell.Runspace = runspace;
                    shell.AddScript("Get-RemoteMailbox -ResultSize Unlimited");

                    results = shell.Invoke();

                    foreach (PSObject result in results)
                    {
                        Console.WriteLine(result.Properties["UserPrincipalName"].Value.ToString());
                    }

                    WriteStreams(shell.Streams);
                }
            }
        }
    }
}