Trying to get all roles in Identity

问题

I am trying to get a list of all the roles in my application. I have looked at the following post Getting All Users... and other sources. Here is my code which I think is what I am supposed to do.

var roleStore = new RoleStore<IdentityRole>(context)
var roleMngr  = new RoleManager<IdentityRole>(roleStore);
List<string> roles = roleMngr.Roles.ToList();

However, I’m getting the following error: Cannot implicitly convert type GenericList(IdentityRole) to List(string). Any suggestions? I am trying to get the list so I can populate a dropdown list on a registration page to assign a user to a particular role. Using ASPNet 4.5 and identity framework 2 (I think).

PS I’ve also tried the Roles.GetAllRoles method with no success.

回答1:

Looking at your reference link and question it self, it is clear that the role manager (roleMngr) is type of IdentityRole, so that roles has to be the same type if you trying to get the list of roles.

Use var insted of List<string> or use List<IdentityRole>.

var roleStore = new RoleStore<IdentityRole>(context);
var roleMngr = new RoleManager<IdentityRole>(roleStore); 

var roles = roleMngr.Roles.ToList();

Hope this helps.

回答2:

If it's a list of string role names you're after, you could do

List<string> roles = roleMngr.Roles.Select(x => x.Name).ToList();

I would personally use var, but included the type here to illustrate the return type.

回答3:

Adding this to help others who may have a custom type Identity (not the default string). If you have, let's say int, you can use this:

var roleStore = new RoleStore<AppRole, int, AppUserRole>(dbContext);
var roleMngr = new RoleManager<AppRole, int>(roleStore);

public class AppUserRole : IdentityUserRole<int> {}
public class AppRole : IdentityRole<int, AppUserRole> {}

来源：https://stackoverflow.com/questions/27090227/trying-to-get-all-roles-in-identity