We are trying to retrieve all registrants for an event but have hit the default limit of 50. The .NET SDK provides no means to override this. We will try to modify our copy of the SDK in the interest of time, but wanted to let you know the ConstantContact.GetAllRegistrants method is not implemented correctly.
Thank you for pointing this out. Normally, with other SDKs an array of parameters can be passed to the method, and one of these is “limit” which then gets appended to the URL. In the .NET SDK, this is replaced by single arguments, one of which being the limit. In this case, this was not written into the GetAllRegistrants method. I'll certainly create a feature request for this, as this would greatly extend the usefulness of that method.