Run powershell from c# most efficient way to create multiple mailcontacts in Exchange Online

Question

I wish to create multiple mailcontacts (external Contacts) in the GAL in Microsoft Online by running Powershell command from C#. The code below works, but is very slow and takes about 15-20 min to run for 400 mailcontacts.

foreach(EmailAdressVM emailAddressVM in emailList.emailAddresses1)
{
    //Create New MailContact.
    Pipeline pplNewMailContact = runspace.CreatePipeline();

    Command cmdNewMailContact = new Command("New-MailContact");
    cmdNewMailContact.Parameters.Add("Name", emailAddressVM.sExternalEmailAddress);
    cmdNewMailContact.Parameters.Add("Displayname", emailAddressVM.sFullName.Trim());
    cmdNewMailContact.Parameters.Add("Lastname", emailAddressVM.sLastName.Trim());
    cmdNewMailContact.Parameters.Add("Firstname", emailAddressVM.sFirstName.Trim());
    cmdNewMailContact.Parameters.Add("ExternalEmailAddress", emailAddressVM.sExternalEmailAddress.Trim());

    pplNewMailContact.Commands.Add(cmdNewMailContact);
    pplNewMailContact.Invoke();
    pplNewMailContact.Stop();
    pplNewMailContact.Dispose();
}

I am guessing that this is slow since I create a new Pipeline for every new mailcontact that is added and there has to be a more eficient way of doing this since running...

import-csv <filename> | ForEach {
    new-mailcontact -name $_.emailaddress -displayname $_.FullName -lastname $_.lastname -firstname $_.firstname -externalemailaddress $_.emailaddress -alias $_.alias
}

...is much faster.

I have found some references after many hours of searching the web that you can do something similar to using a CSV when running Powershell commands from C#, ie send a list (or array) of values to a command (in this case the "new-mailcontact" command). But, I have not found any good example of how to send more than one value to a command and I need to supply many values (for example: -name $ .emailAddress -displayname $ .FullName, etc.) to the "new-mailcontact" command.

Is it possible to send a list (or array) in a similar way as the "import-csv" command (when using regular powershell) and will this be faster, or is there an evan better way? Would I get better performance if I use Powershell 3 instead of 1 (as I am using now).

Please provide working sample code i C#!

Please note that I cannot save a CSV file to disk and the execute powershell from CMD since I do not have write access to disk and that I do not think that I can run an entire script remotely (since remote scripting probably is disabled on Exchange Online).

Answer 1

The biggest reason I would think is because for each address you are creating a new Powershell instance and you are not multithreaded.

You code looks something like this from above:

Foreach email address{
    Declare a new Powershell process
    Add attributes to call later
    Start Powershell and pipe stuff in
    Close Powershell instance
}

I think you would be better off creating the Powershell instance / pipe once and then sending each object into it. More along the lines of:

Create PS Pipe
    Foreach email address{
     PS.SendArguments(Email, Name, DN, etc.);
     }

I am not in an environment to get something working or tested right now, so hopefully this gives you at least most of what you need...