IISExpress - Get the site to identify its own SSL port binding - asp.net

Question

OK, so a little background on the environment configuration at present:
Using VS2017
IISExpress folder present in my documents folder with applicationhost.config file
When I run my web project in VS2017, it runs successfully through IISExpress. If I view the IISExpress config window then it shows me that my app is running successfully and that it's using the config from my source\repos folder and not the main IISExpress folder in my documents. If I look at the config file in the IISExpress folder there is no mention of the bindings for my currently running application (makes sense, as it apparently uses a different config file).
However, within my app I need to be able to use the Microsoft.Web.Administration toolset to try and identify the port bound to https for the current site to handle a redirect to a page that must be secure. In the production environment this is just handled by pushing to https:// because we know an SSL certificate will be present. But, when debugging locally I need to switch to SSL and take the port number otherwise my redirect is broken, for obvious reasons.
Using _Manager_ServerManager As New ServerManager
For Each _Loop_Binding As Binding In _Manager_ServerManager.Sites(System.Web.Hosting.HostingEnvironment.ApplicationHost.GetSiteName()).Bindings
If (_Loop_Binding.IsIPPortHostBinding) AndAlso (_Loop_Binding.Protocol.ToLower() = "https") Then Return _Loop_Binding.EndPoint.Port
Next
End Using
The code above causes an error when running, as the current site does not exist within _Manager_ServerManager.Sites. If I inspect this property then I can only see the applications that are configured in the configuration file taken from the IISExpress folder in my documents, not the current site!
I'm really scratching my head on this one, is there any way programmatically that I can get this information for the currently running website?!
EDIT
Based on some of the comments below, more clarity has been requested as to what I'm actually trying to achieve. The website typically operates on standard HTTP, however, when progressing to one particular page for security reasons we need to shift to HTTPS:
Response.Redirect("https://" & Request.Url.DnsSafeHost & "/my-page.aspx")
When debugging this website locally, using IISExpress, this results in you being redirected to https://localhost/my-page.aspx, which is incorrect because the site runs on a port of localhost (i.e. http://localhost:64905 and https://localhost:64906). This means that I cannot just append Request.Url.Port onto the end of DnsSafeHost, because it will not be the HTTPS port required. Thus, so that we can run this project locally on our dev machines we need to automatically switch the port to the HTTPS version so that we can continue seamlessly without any disruption and having to manually rebuild the URL each time we get redirected.