Question

我已经做了一个月的C＃所以请原谅这个问题的“本地化”但是我已经研究了几个小时而且我已经碰壁了。

我已经看到了使用IIdentity和IPrincipal的WPF应用程序的基于角色的授权的左右示例。

我找不到很多信息，但是，更多基于权限的授权方法，在这个应用程序中，想象没有组，只有权限和用户列表，你可以任何人都可以给予任何许可。

我希望能够：

1）能够根据用户权限控制UI /元素，其状态包括：Enabled，ReadOnly，Invisible，Collapsed（如此处https://uiauth.codeplex.com/所示）
2）能够在类或方法级别指定需要哪些权限（类似于http://lostechies.com/derickbailey/2011/05/24/dont-do-role-based-authorization-checks-do-activity-based-checks/）

而不是：

[PrincipalPermission(SecurityAction.Demand, Role = "Administrators")]

我想要类似的东西：

[PrincipalPermission(SecurityAction.Demand, Permission = "Can add users")]

现在，我看到如何执行此操作的唯一方法是利用ICommand并使用大量字符串比较在CanExecute方法中放置授权逻辑，以查看用户是否具有执行所需的权限请求的行动如下：

// Employee class
public bool HasRight(SecurityRight right)
{
    return employee.Permissions.Contains(right);
}

// Implementation, check if employee has right to continue
if (employee.HasRight(db.SecurityRights.Single(sr => sr.Description == "Can edit users")))
{
    // Allowed to perform action
}
else
{
    // User does not have right to continue
    throw SecurityException;
}

我被告知Enum Flags可能正是我正在寻找的What does the [Flags] Enum Attribute mean in C#?

我认为我理解enum / flag / bits但不足以完成实现......

如果我有：

EmployeeModel
EmployeeViewModel
ThingTwoModel
ThingTwoViewModel
MainView

我不确定一切都在哪里以及如何将它们联系在一起....这就是我到目前为止所做的事情（我意识到这不是一个有效的例子......这就是我的问题！）：

    [Flags]
    public enum Permissions
    {
        None = 0,
        Create = 1 << 0,
        Read = 1 << 1,
        Update = 1 << 2,
        Delete = 1 << 3,

        User = 1 << 4,
        Group = 1 << 5
    }

    public static void testFlag()
    {
        Permissions p;
        var x = p.HasFlag(Permissions.Update) && p.HasFlag(Permissions.User);
        var desiredPermissions = Permissions.User | Permissions.Read | Permissions.Create;
        if (x & p == desiredPermissions)
        {
            //the user can be created and read by this operator
        }
    }

感谢您提供任何指导。

Answer 1

好testFlag无法正常工作。我想你想要的东西（LINQPad c＃程序片段）：

void Main()
{
    //can create user but not read the information back
    var userCanBeCreatedPermission = Permissions.Create | Permissions.User;

    //can create and readback
    var userCanBeCreatedAndReadBackPermission = userCanBeCreatedPermission | Permissions.Read;

    userCanBeCreatedPermission.HasFlag(Permissions.User).Dump(); //returns true

    (userCanBeCreatedPermission.HasFlag(Permissions.User) && userCanBeCreatedPermission.HasFlag(Permissions.Read)).Dump(); //returns false

    //alternative way of checking flags is to combine the flags and do an And mask check
    //the above can be written as
    ((userCanBeCreatedPermission & (Permissions.User | Permissions.Read)) == (Permissions.User | Permissions.Read)).Dump(); //returns false

    //using a variable to have combined permissions for readibility & using And mask:
    var desiredPermissions = Permissions.User | Permissions.Read;

    //checking with user that has both Create & Read permissions

    ((userCanBeCreatedAndReadBackPermission & desiredPermissions) == desiredPermissions).Dump(); // returns true because the user information can be read back by this user

    ((userCanBeCreatedAndReadBackPermission & Permissions.Delete) == Permissions.Delete).Dump(); // returns false because the user can't be deleted
}

[Flags]
public enum Permissions
{
   None = 0,
   Create = 1 << 0,
   Read = 1 << 1,
   Update = 1 << 2,
   Delete = 1 << 3,

   User = 1 << 4,
   Group = 1 << 5
}

这会回答你的问题吗？

Answer 2

最终解决方案（.linq）：

void Main()
{
    // Permissions definition
    var userCreate = new Authorization<User>(Permissions.Create);
    var userRead = new Authorization<User>(Permissions.Read);

    var carrotCreate = new Authorization<Carrot>(Permissions.Create);
    var carrotRead = new Authorization<Carrot>(Permissions.Read);

    // User
    var user = new User();

    // User has no permissions yet
    if(user.IsAuthorized<User>(Permissions.Create))
        "I can create User".Dump();
    else
        "No creating User for me".Dump();

    // Now user can Create users
    user.Authorizations.Add(userCreate);            
    if(user.IsAuthorized<User>(Permissions.Create))
        "I can create User".Dump();
    else
        "No creating User for me".Dump();

    // User can read carrots
    user.Authorizations.Add(carrotRead);

    if(user.IsAuthorized<Carrot>(Permissions.Create))
        "I can create carrots".Dump();
    else
        "No creating carrots for me".Dump();

    if(user.IsAuthorized<Carrot>(Permissions.Read))
        "I can read carrots".Dump();
    else
        "No reading carrots for me".Dump();

    // User can now create carrots
    user.Authorizations.Add(carrotCreate);
    if(user.IsAuthorized<Carrot>(Permissions.Create))
        "I can create carrots".Dump();
    else
        "No creating carrots for me".Dump();            

}

[Flags]
public enum Permissions : ulong
{
    Create = 1 << 0,
    Read = 1 << 1,
    Update = 1 << 2,
    Delete = 1 << 3
}

public abstract class Auth{

}
public class Authorization<T> : Auth {
    public Authorization(Permissions permissions){ this.Permissions = permissions; }
    public Permissions Permissions {get;set;}
}

public class Carrot{
    public int Id{get; set;}
}

public class User{
    public User(){ Authorizations = new List<Auth>(); }
    public List<Auth> Authorizations{get; set;}
    public bool IsAuthorized<T>(Permissions permission){
        foreach(var auth in Authorizations)
            if(auth is Authorization<T>){
                var a = auth as Authorization<T>;
                if(a.Permissions == permission)
                    return true;
            }

        return false;
    }
}

使用Enum Flag Bit的基于WPF权限的授权

2 个答案: