.net 运用二进制位运算进行数据库权限管理

/// <summary>
    /// 权限设置二进制
    /// </summary>
    [Flags]
    public enum Permissions
    {
        Add = 1,
        Del = 2,
        Mod = 4,
        Select = 8
    }

    /// <summary>
    /// 判断是否拥有此权限，false=不存在，true=存在
    /// </summary>
    /// <param name="value">权限类型值</param>
    /// <param name="per">操作类型：增删改查</param>
    /// <returns>判断是否拥有此权限，false=不存在，true=存在</returns>
    public static bool IsPermission(int value, Permissions per)
    {
        bool bo = false;//默认不存在
        switch (per)
        {
            case Permissions.Add:
                if ((value & Convert.ToInt32(Permissions.Add)) == Convert.ToInt32(Permissions.Add))//运算  (value & 1)==1
                    bo = true;
                break;
            case Permissions.Del:
                if ((value & Convert.ToInt32(Permissions.Del)) == Convert.ToInt32(Permissions.Del))//
                    bo = true;
                break;
            case Permissions.Mod:
                if ((value & Convert.ToInt32(Permissions.Mod)) == Convert.ToInt32(Permissions.Mod))//
                    bo = true;
                break;
            case Permissions.Select:
                if ((value & Convert.ToInt32(Permissions.Select)) == Convert.ToInt32(Permissions.Select))//
                    bo = true;
                break;
        }
        return bo;
    }