How can I let create and view list of details in the same view

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C#7.0

ASP.NET-Core

I study asp.net core , and i wnat to view create form and list of details in the same view page
For Example:
if i have two tables (Department - Employee) , in the department Index view when i click details button the controller will redirect to details view , i want the update details view to be (Create Department) and view all employee who work in this department
i hope the idea clear

What I have tried:

i try to implement ViewModel , but it's not work successfully