Usage of User.IsInRole() in a View

问题

In my mvc5 project to disable an action link for unauthorized users i did like this

@if (User.IsInRole("Admin") | User.IsInRole("Manager"))
{ 
        @Html.ActionLink("Add New Record", "ProductTypeIndex", "ProductType")
} 

But if there are many roles to check then this @if() gets long. How to avoid this? Do i need custom helpers for this(if so how can i approach it)? Help appreciated..

回答1:

You could write your own extension method and use it in your code.

public static class PrincipalExtensions
{
    public static bool IsInAllRoles(this IPrincipal principal, params string[] roles)
    {
        return roles.All(r => principal.IsInRole(r));
    }

    public static bool IsInAnyRoles(this IPrincipal principal, params string[] roles)
    {
        return roles.Any(r => principal.IsInRole(r));
    }
}

Now simply you could call this extension method like this:

// user must be assign to all of the roles  
if(User.IsInAllRoles("Admin","Manager","YetOtherRole"))
{
    // do something
} 

// one of the roles sufficient
if(User.IsInAnyRoles("Admin","Manager","YetOtherRole"))
{
    // do something
} 

While you could use these extension methods in views as well but try to avoid writing your apps logic in views as much as possible since views not unit testable easily.

回答2:

<% if (Page.User.IsInRole("Admin")){ %>

来源：https://stackoverflow.com/questions/32369229/usage-of-user-isinrole-in-a-view