关于Principal类型转换出错一问

[yantaian]

程序出错的位置实现的是利用数据库的Roles表、Permission表实现角色权限机制的功能。不知道这条错误是什么意思，百思不得其解：（

请前辈们帮忙，谢谢～～

“/Per”应用程序中的服务器错误。
--------------------------------------------------------------------------

指定的转换无效。

说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.InvalidCastException: 指定的转换无效。

源错误:


行 27：private void Page_Load(object sender, System.EventArgs e)
行 28：{
行 29： FreakPrincipal currentPrincipal = (FreakPrincipal)Context.User;
行 30： if (!currentPrincipal.HasPermission((int)AccountsPermissions.CreateRoles))
行 31： {


源文件: c:\inetpub\wwwroot\per\modules\secure\admin\roles.aspx.cs 行: 29

堆栈跟踪:

[InvalidCastException: 指定的转换无效。]
Freak.WebModules.Accounts.Web.Roles.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\per\modules\secure\admin\roles.aspx.cs:29
System.EventHandler.Invoke(Object sender, EventArgs e) +0
System.Web.UI.Control.OnLoad(EventArgs e)
System.Web.UI.Control.LoadRecursive()
System.Web.UI.Page.ProcessRequestMain()




--------------------------------------------------------------------------------
版本信息: Microsoft .NET Framework 版本:1.1.4322.573; ASP.NET 版本:1.1.4322.573

[luckyfool]

行 29： FreakPrincipal currentPrincipal = (FreakPrincipal)Context.User;
这行有错误，给出FreakPrincipal的定义先

[yantaian]

FreakPrincipal是继承自IPrincipal的自定义类，实现一些安全校验授权之类的功能：

using System;
using System.Collections;
using System.Security;
using System.Security.Cryptography;
using System.Text;

using Freak.WebModules.Accounts;

namespace Freak.WebModules.Accounts.Business
{
public class FreakPrincipal: Freak.WebModules.Business.BizObject, System.Security.Principal.IPrincipal
{
protected System.Security.Principal.IIdentity identity;
protected ArrayList permissionList;
protected ArrayList roleList;

public System.Security.Principal.IIdentity Identity
{
get
{
return identity;
}
set
{
identity = value;
}
}

public bool IsInRole(string role)
{
return roleList.Contains( role );
}

public bool HasPermission( int permissionId )
{
return permissionList.Contains( permissionId );
}

public ArrayList Roles
{
get
{
return roleList;
}
}

public ArrayList Permissions
{
get
{
return permissionList;
}
}

public FreakPrincipal( int userId )
{
Configuration.ModuleSettings moduleSettings = Configuration.ModuleConfig.GetSettings();
Data.User dataUser = new Data.User( moduleSettings.ConnectionString );

Identity = new SiteIdentity( userId );
permissionList = dataUser.GetEffectivePermissionList( userId );
roleList = dataUser.GetUserRoles( userId );

}

public FreakPrincipal( string email )
{
Configuration.ModuleSettings moduleSettings = Configuration.ModuleConfig.GetSettings();
Data.User dataUser = new Data.User( moduleSettings.ConnectionString );

Identity = new SiteIdentity( email );
permissionList = dataUser.GetEffectivePermissionList( ((Business.SiteIdentity)Identity).UserId );
roleList = dataUser.GetUserRoles( ((Business.SiteIdentity)Identity).UserId );

}

public static FreakPrincipal ValidateLogin(string email, string password)
{
Configuration.ModuleSettings moduleSettings = Configuration.ModuleConfig.GetSettings();
int newId;

byte[] cryptPassword = EncryptPassword( password );

Data.User dataUser = new Data.User( moduleSettings.ConnectionString );
if ( (newId = dataUser.ValidateLogin(email, cryptPassword)) > -1 )
return new FreakPrincipal( newId );
else
return null;
}

public static byte[] EncryptPassword(string password)
{
UnicodeEncoding encoding = new UnicodeEncoding();
byte[] hashBytes = encoding.GetBytes( password );

// compute SHA-1 hash.
SHA1 sha1 = new SHA1CryptoServiceProvider();
byte[] cryptPassword = sha1.ComputeHash ( hashBytes );

return cryptPassword;
}

}
}

[cuike519]

FreakPrincipal newUser = new FreakPrincipal( Context.User.Identity.Name );
Context.User = newUser;

要在基类里面先执行上面的代码才能做正确的转换！

[yantaian]

谢谢，可是我的基类里是有这种代码的啊！

private void FreakPage_Load(object sender, System.EventArgs e)
{
// TODO: Place any code that will take place BEFORE the Page_Load event
// in the regular page, e.g. cache management, authentication verification,
// etc.
if (Context.User.Identity.IsAuthenticated)
{
if (!(Context.User is FreakPrincipal))
{
// ASP.NET's regular forms authentication picked up our cookie, but we // haven't replaced the default context user with our own. Let's do that
// now. We know that the previous context.user.identity.name is the email
// address (because we forced it to be as such in the login.aspx page)
FreakPrincipal newUser = new FreakPrincipal( Context.User.Identity.Name );
Context.User = newUser;
}
}
}

为什么不能转换？前辈们请指点我一下～ 谢谢～

[cuike519]

你的这种方法是使用基类实例自己的FreakPrincipal用来基于角色的身份验证。
你的页面一定继承一个BasePage在BasePage的On_load里面将当前的User实例成自定义个FreakPrincipal对象，然后在子类中使用。

[cuike519]

如果你继承了这个页面可能是你的Page_Load没有执行！你看看基类里面的Page_Load执行了没有。如果没有执行将这些代码放到OnInit里面应该可以解决你的问题！

[yantaian]

啊！我把那两行代码放在OnInit里，程序真的就通过了～～～

太感谢您了！！！！