SharePoint 2103 Check user permission on list

一、需求： check user 对SharePoint list 的permission

代码如下：

    private static string GetListPermission(SPList list, string loginName)
         {
             string perStr = string.Empty;
             SPSecurity.RunWithElevatedPrivileges(() =>
             {
                 try
                 {
                     SPUser user = list.ParentWeb.Users[loginName];
                     SPRoleAssignment roleAssignment = list.RoleAssignments.GetAssignmentByPrincipal(user);
                     SPRoleDefinitionBindingCollection defColl = roleAssignment.RoleDefinitionBindings;
                     foreach (SPRoleDefinition roleDef in defColl)
                     {
                         perStr += roleDef.Name + ";";
                     }
                 }
                 catch (Exception)
                 {
                     logger.Debug("Get user permission by list.GetUserEffectivePermissionInfo method, list title: {0}, loginName: {1}.", list.Title, loginName);
                     try
                     {
                         SPPermissionInfo permissionInfo = list.GetUserEffectivePermissionInfo(loginName);
                         var roleAssignments = permissionInfo.RoleAssignments;
                         foreach (SPRoleAssignment roleAssignment in roleAssignments)
                         {
                             SPRoleDefinitionBindingCollection roleDefColl = roleAssignment.RoleDefinitionBindings;
                             foreach (SPRoleDefinition roleDef in roleDefColl)
                             {
                                 perStr += roleDef.Name + ";";
                             }
                         }
                     }
                     catch (Exception ex)
                     {
                         logger.Error("An error occurred while getting permission by list.GetUserEffectivePermissionInfo method, list title: {0}, loginName: {1}, exception; {2}.",
                             list.Title, loginName, ex.ToString());
                     }
                 }
             });
             return perStr;
         }

注意： catch中的代码作用是check，当user是AD group中的member，但却不单独存在于web userInformation list中，此时如果直接获取user  SPRoleAssignment，则抛‘Index is out of range’, 所以这样的user可以通过

list.GetUserEffectivePermissionInfo(loginName); 来获取SPPermissionInfo，然后再获取user的SPRoleDefinition，有的读者会问，为什么不直接通过catch中的方法获取，这样无论这个user是否只存在于AD group中都不会抛异常

可以正确的获取到SPRoleDefinition，其实是可以的，之所以这样做，原因在于效率问题。

二、需求： set permission to list

代码如下：

 private static void SetLibPermission(SPList list,  bool isRead)
         {
             try
             {
                 SPSecurity.RunWithElevatedPrivileges(() =>
                 {
                     bool hasUnique = list.HasUniqueRoleAssignments;
                     list.ParentWeb.AllowUnsafeUpdates = true;
                     if (!hasUnique)
                     {
                         list.BreakRoleInheritance(false);
                         list.Update();
                     }
                        try
                         {
                             SPUser user = list.ParentWeb.EnsureUser(userInfo.Key);
                             SPRoleDefinitionCollection objDefiColl = list.ParentWeb.RoleDefinitions;
                             SPRoleAssignment objRoleAssign = new SPRoleAssignment(user);
                             SPRoleDefinition roleDefination = null;
                             if (isRead)
                             {
                                 roleDefination = objDefiColl.GetByType(SPRoleType.Reader);
                             }
                             else
                             {
                                 roleDefination = objDefiColl.GetByType(SPRoleType.Contributor);
                             }
                             objRoleAssign.RoleDefinitionBindings.Add(roleDefination);
                             list.RoleAssignments.Add(objRoleAssign);
                         }
                         catch (Exception ex)
                         {

                         }
                     list.Update();
                     list.ParentWeb.AllowUnsafeUpdates = false;
                 });

             }
             catch (Exception ex)
             {

             }
         }

注意：给list赋权限，需要打破继承，具体可以根据实际需求

代码中的userInfo.Key即为loginName

list.ParentWeb.EnsureUser(userInfo.Key);即把user保存到user information list中