Call Exchange Powershell Commands from C# using minimal module definitions only

ExchangePowershellQuery.cs

static readonly SerializationTypeConverter Converter = new SerializationTypeConverter();
static readonly Command SelectSerializationDataCommand = new Command("Select-Object") { Parameters = { { "Property", "SerializationData" } } };
static IEnumerable<T> ExchangeSerializerCastTo<T>(IEnumerable<object> results) => results.Where(x => Converter.CanConvertFrom(x, typeof(T)))
                    .Select(x => Converter.ConvertFrom(x, typeof(T), CultureInfo.CurrentCulture, false))
                    .OfType<T>();
void Main()
{
    var state = InitialSessionState.CreateDefault2();

    //Exchange2010SP3.psm1 was created using `Export-PSSession -OutputModule Exchange2010SP3 -CommandName *` command
    //Of course you can use it with any exchange version (provided you have compatible module definition or export another one)
    //We only need this bit to able to call commands like Get-Mailbox from the session
    state.ImportPSModule(new[] { Path.Combine(Path.GetDirectoryName(typeof(Mailbox).Assembly.Location), "Exchange2010SP3.psm1") });

    using (var runspace = RunspaceFactory.CreateRunspace(state))
    {
        try
        {
            runspace.Open();

            //Voodoo to pull error from powershell instance - otherwise things will die quietly without a trace
            var errors = (runspace.SessionStateProxy.PSVariable.Get("Error").Value as ArrayList)
                            .OfType<ErrorRecord>()
                            .Select(x => x.Exception)
                            .ToArray();

            if (errors.Length > 0)
                errors.Dump("Errors while loading module", 1);

            using (var pipeline = runspace.CreatePipeline())
            {
                //If we wanted to pull entire exchange mailbox db, you'd leave parameters empty like in powershell - not recommended of course!
                pipeline.Commands.Add(new Command("Get-MailBox") { Parameters = { { "Identity", "user@domain.local" } } });
                pipeline.Commands.Add(SelectSerializationDataCommand);

                var results = pipeline.Invoke();

                if (pipeline.HadErrors)
                {
                    pipeline.Error.ReadToEnd()
                        .OfType<PSObject>()
                        .Select(x => x.BaseObject)
                        .OfType<ErrorRecord>()
                        .Select(x => x.Exception)
                        .Dump("Errors during last invoke", 1);
                    return;
                }

                ExchangeSerializerCastTo<Mailbox>(results).Dump(2);
            }
        }
        //We *must* close the runspace no matter what else happens otherwise we're going to run out
        //of runspace handles on remote server and get stuck
        finally { runspace.Close(); }
    }
}

Linqpad References & Nugets.xml

<!--  This is the header of LINQPad save file actually while the .cs file is the rest of .linq file
      Only broken up in here to enable syntax highlights since gist can't handle .linq files
      The only key thing to remember: this is an AnyCPU query. This will not run in 32bit Linqpad.
-->
<Query Kind="Program">
  <Reference Relative="ExchangeModuleLibs\Exchange2010SP3.psm1">D:\ExchangeModuleLibs\Exchange2010SP3.psm1</Reference>
  <Reference Relative="ExchangeModuleLibs\Microsoft.Exchange.Data.Directory.dll">D:\ExchangeModuleLibs\Microsoft.Exchange.Data.Directory.dll</Reference>
  <Reference Relative="ExchangeModuleLibs\Microsoft.Exchange.Data.dll">D:\ExchangeModuleLibs\Microsoft.Exchange.Data.dll</Reference>
  <GACReference>System.Management.Automation, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35</GACReference>
  <Namespace>Microsoft.Exchange.Data</Namespace>
  <Namespace>Microsoft.Exchange.Data.Directory.Management</Namespace>
  <Namespace>System.Globalization</Namespace>
  <Namespace>System.Management.Automation</Namespace>
  <Namespace>System.Management.Automation.Runspaces</Namespace>
</Query>

thank you!