How to automatically update symbology with unique colors

[AaronThompson]

Hi there,

So I have a unique symbology for project area polygons in a web map, where each polygon is a unique color. This is based off of a field with the project's name in it. As users add new project polygons into the map, I need them to be their own unique color? Is there a way to do this without having to open Arcmap periodically, re-update the symbology, and republish the service?

Thanks

[JayantaPoddar]

Do you have the list of all the project names? Then you could Create Subtypes and define appropriate symbology to the feature class (even if the features are not yet created in it). 

You could also standardize the process in which the user will get the list of project names in a drop-down by creating Attribute Domain. Exercise 3: Create subtypes and attribute domains—ArcGIS Help | ArcGIS Desktop 

[AaronThompson]

I am unable to create subtypes and domains for this project because the list of projects is constantly changing, as new projects are being added all the time. So that idea likely wont work. Thanks for the response though!

[Anonymous User]

Maybe you could use the ObjectID? If colors are already assigned to a certain amount of numbers (1 to ...), the colors will show up as soon as a user creates a new feature which will be attributed the ObjectID.

To apply the symbology, you may need to create some features to assign colors to numbers and then delete these features...