应用程序试图执行安全策略不允许的操作。要授予此应用程序所需的权限，请与系统管理员联系，或在配置文件中更改该应用程序的信任级别

今天运行一个站点遇到这个问题

说明: 应用程序试图执行安全策略不允许的操作。要授予此应用程序所需的权限，请与系统管理员联系，或在配置文件中更改该应用程序的信任级别。

异常详细信息: System.Security.SecurityException: 请求“System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089”类型的权限已失败。

源错误:

执行当前 Web 请求期间生成了未处理的异常。可以使用下面的异常堆栈跟踪信息确定有关异常原因和发生位置的信息。

堆栈跟踪:

[SecurityException: 请求“System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089”类型的权限已失败。]
   System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Assembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed) +150
   System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed) +100
   System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandle rmh, Object assemblyOrString, SecurityAction action, Boolean throwException) +284
   System.Security.PermissionSetTriple.CheckSetDemand(PermissionSet demandSet, PermissionSet& alteredDemandset, RuntimeMethodHandle rmh) +69
   System.Security.PermissionListSet.CheckSetDemand(PermissionSet pset, RuntimeMethodHandle rmh) +150
   System.Security.PermissionListSet.DemandFlagsOrGrantSet(Int32 flags, PermissionSet grantSet) +30
   System.Threading.CompressedStack.DemandFlagsOrGrantSet(Int32 flags, PermissionSet grantSet) +40
   System.Security.CodeAccessSecurityEngine.ReflectionTargetDemandHelper(Int32 permission, PermissionSet targetGrant, CompressedStack securityContext) +123
   System.Security.CodeAccessSecurityEngine.ReflectionTargetDemandHelper(Int32 permission, PermissionSet targetGrant) +54

在web.config里

  <trust level="Full" />

将信任等级改成Full就好了