如何在 LINQ 中实现角色提供程序？

Question

我想将以下示例角色提供程序实现转换为 LINQ。

How to: Sample Role-Provider Implementation

我想使用 ADO.NET 实体数据模型（Entity Framework 6）。

Answer 1

找到解决办法：

using System.Web.Security;
using System.Configuration.Provider;
using System;
using System.Linq;

/*

 This provider works with the following schema for the tables of role data.

CREATE TABLE [tblRoles] (
 [Rolename]        NVARCHAR (255) NOT NULL,
 [ApplicationName] NVARCHAR (255) NOT NULL,
 CONSTRAINT [PKRoles] PRIMARY KEY
 CLUSTERED ([Rolename] ASC, [ApplicationName] ASC)
);

CREATE TABLE [tblUsersInRoles] (
[Username]        NVARCHAR (255) NOT NULL,
[Rolename]        NVARCHAR (255) NOT NULL,
[ApplicationName] NVARCHAR (255) NOT NULL,
CONSTRAINT [PKUsersInRoles] PRIMARY KEY 
CLUSTERED ([Username] ASC, [Rolename] ASC, [ApplicationName] ASC)
); 

*/

namespace mvc2.Models
{
  public class CustomRoleProvider : RoleProvider
  {
    private string pApplicationName = "MyApplicationName";
    Database1Entities db; //ADO.NET Entity Data Mode(Entity Framework 6.0)
    public override string ApplicationName
    {
        get { return pApplicationName; }
        set { pApplicationName = value; }
    }
    public override bool DeleteRole(string rolename, bool throwOnPopulatedRole)
    {
        db = new Database1Entities();
        if (!RoleExists(rolename))
        {
            throw new ProviderException("Role does not exist.");
        }
        if (throwOnPopulatedRole && GetUsersInRole(rolename).Length > 0)
        {
            throw new ProviderException("Cannot delete a populated role.");
        }

        var resultRoles = db.tblRoles.Where(x => x.Rolename == rolename &&
            x.ApplicationName == ApplicationName);
        db.tblRoles.RemoveRange(resultRoles);

        var resultUserInRoles = db.tblUsersInRoles.Where(x => x.Rolename == rolename &&
           x.ApplicationName == ApplicationName);
        db.tblUsersInRoles.RemoveRange(resultUserInRoles);
        db.SaveChanges();
        return true;
    }
    public override string[] GetAllRoles()
    {
        db = new Database1Entities();
        return db.tblRoles.Where(x => x.ApplicationName == ApplicationName)
            .Select(x => x.Rolename).ToArray();
    }
    public override string[] GetUsersInRole(string rolename)
    {
        db = new Database1Entities();
        return db.tblUsersInRoles.Where(x => x.Rolename == rolename &&
            x.ApplicationName == ApplicationName).Select(x => x.Username).ToArray();
    }
    public override void RemoveUsersFromRoles(string[] usernames, string[] rolenames)
    {
        foreach (string rolename in rolenames)
        {
            if (!RoleExists(rolename))
            {
                throw new ProviderException("Role name not found.");
            }
        }
        foreach (string username in usernames)
        {
            foreach (string rolename in rolenames)
            {
                if (!IsUserInRole(username, rolename))
                {
                    throw new ProviderException("User is not in role.");
                }
            }
        }
        db = new Database1Entities();
        foreach (string username in usernames)
        {
            foreach (string rolename in rolenames)
            {
                tblUsersInRole result = db.tblUsersInRoles.Where(x =>
                    x.Username == username &&
                    x.Rolename == rolename &&
                    x.ApplicationName == ApplicationName).FirstOrDefault();
                if (result != null)
                {
                    db.tblUsersInRoles.Remove(result);
                }
            }
        }
        db.SaveChanges();
    }
    public override string[] FindUsersInRole(string rolename, string usernameToMatch)
    {
        db = new Database1Entities();
        return db.tblUsersInRoles.Where(x =>
            x.Username == usernameToMatch &&
            x.Rolename == rolename &&
            x.ApplicationName == ApplicationName
            ).Select(x => x.Username).ToArray();
    }
    public override bool RoleExists(string rolename)
    {
        Database1Entities db = new Database1Entities();
        bool exists = db.tblRoles.Where(x => x.Rolename == rolename &&
            x.ApplicationName == ApplicationName).Count() > 0 ? true : false;
        return exists;
    }
    public override void AddUsersToRoles(string[] usernames, string[] rolenames)
    {
        db = new Database1Entities();
        int RoleCheck = rolenames.Where(x => RoleExists(x)).Count();
        if (RoleCheck == 0)
        {
            throw new ProviderException("Role name not found.");
        }
        int CheckCommasInUsername = usernames.Where(x => x.ToString().Contains(",")).Count();
        if (CheckCommasInUsername > 0)
        {
            throw new ArgumentException("User names cannot contain commas.");
        }
        foreach (string username in usernames)
        {
            foreach (string rolename in rolenames)
            {
                if (IsUserInRole(username, rolename))
                {
                    throw new ProviderException("User is already in role.");
                }
            }
        }
        foreach (string username in usernames)
        {
            foreach (string rolename in rolenames)
            {
                tblUsersInRole newRecord = new tblUsersInRole();
                newRecord.Username = username;
                newRecord.Rolename = rolename;
                newRecord.ApplicationName = ApplicationName;
                db.tblUsersInRoles.Add(newRecord);                    
            }
        }
        db.SaveChanges();

    }
    public override void CreateRole(string rolename)
    {
        if (rolename.Contains(","))
        {
            throw new ArgumentException("Role names cannot contain commas.");
        }
        if (RoleExists(rolename))
        {
            throw new ProviderException("Role name already exists.");
        }
        db = new Database1Entities();
        tblRole newRole = new tblRole();
        newRole.Rolename = rolename;
        newRole.ApplicationName = ApplicationName;
        db.tblRoles.Add(newRole);
        db.SaveChanges();
    }
    public override string[] GetRolesForUser(string username)
    {
        db = new Database1Entities();
        return db.tblUsersInRoles.Where(x => x.Username == username &&
            x.ApplicationName == ApplicationName).Select(x => x.Rolename).ToArray();
    }
    public override bool IsUserInRole(string username, string rolename)
    {
        db = new Database1Entities();
        return db.tblUsersInRoles.Where(x =>
            x.Username == username &&
            x.Rolename == rolename &&
            x.ApplicationName == ApplicationName).Count() > 0 ? true : false;
    }
  }
}