User.Identity.GetUserId是否已缓存或每次从数据库中获取？

我正在使用ASP.Net MVC 5，我在我的代码中调用了这一行

string userId = User.Identity.GetUserId(); 

ASP.NET MVC是否会从表中为每次调用获取此内容，还是会缓存？

Answer 1

登录时似乎缓存了id和username 。

我已经使用过SQL Server Profiler并在登录后运行User.Identity.GetUserId(); 身份系统不对数据库进行查询 。

这是在loggin上进行的查询：

 exec sp_executesql N'SELECT [UnionAll2].[C2] AS [C1], [UnionAll2].[C3] AS [C2], [UnionAll2].[C4] AS [C3], [UnionAll2].[C5] AS [C4], [UnionAll2].[C6] AS [C5], [UnionAll2].[C7] AS [C6], [UnionAll2].[C8] AS [C7], [UnionAll2].[C9] AS [C8], [UnionAll2].[C10] AS [C9], [UnionAll2].[C11] AS [C10], [UnionAll2].[C12] AS [C11], [UnionAll2].[C13] AS [C12], [UnionAll2].[C14] AS [C13], [UnionAll2].[C1] AS [C14], [UnionAll2].[C15] AS [C15], [UnionAll2].[C16] AS [C16], [UnionAll2].[C17] AS [C17], [UnionAll2].[C18] AS [C18], [UnionAll2].[C19] AS [C19], [UnionAll2].[C20] AS [C20], [UnionAll2].[C21] AS [C21], [UnionAll2].[C22] AS [C22], [UnionAll2].[C23] AS [C23], [UnionAll2].[C24] AS [C24], [UnionAll2].[C25] AS [C25] FROM (SELECT [UnionAll1].[C1] AS [C1], [UnionAll1].[AccessFailedCount] AS [C2], [UnionAll1].[Id] AS [C3], [UnionAll1].[Email] AS [C4], [UnionAll1].[EmailConfirmed] AS [C5], [UnionAll1].[PasswordHash] AS [C6], [UnionAll1].[SecurityStamp] AS [C7], [UnionAll1].[PhoneNumber] AS [C8], [UnionAll1].[PhoneNumberConfirmed] AS [C9], [UnionAll1].[TwoFactorEnabled] AS [C10], [UnionAll1].[LockoutEndDateUtc] AS [C11], [UnionAll1].[LockoutEnabled] AS [C12], [UnionAll1].[AccessFailedCount1] AS [C13], [UnionAll1].[UserName] AS [C14], [UnionAll1].[UserId] AS [C15], [UnionAll1].[RoleId] AS [C16], [UnionAll1].[UserId1] AS [C17], [UnionAll1].[C2] AS [C18], [UnionAll1].[C3] AS [C19], [UnionAll1].[C4] AS [C20], [UnionAll1].[C5] AS [C21], [UnionAll1].[C6] AS [C22], [UnionAll1].[C7] AS [C23], [UnionAll1].[C8] AS [C24], [UnionAll1].[C9] AS [C25] FROM (SELECT CASE WHEN ([Extent2].[UserId] IS NULL) THEN CAST(NULL AS int) ELSE 1 END AS [C1], [Limit1].[AccessFailedCount] AS [AccessFailedCount], [Limit1].[Id] AS [Id], [Limit1].[Email] AS [Email], [Limit1].[EmailConfirmed] AS [EmailConfirmed], [Limit1].[PasswordHash] AS [PasswordHash], [Limit1].[SecurityStamp] AS [SecurityStamp], [Limit1].[PhoneNumber] AS [PhoneNumber], [Limit1].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Limit1].[TwoFactorEnabled] AS [TwoFactorEnabled], [Limit1].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Limit1].[LockoutEnabled] AS [LockoutEnabled], [Limit1].[AccessFailedCount] AS [AccessFailedCount1], [Limit1].[UserName] AS [UserName], [Extent2].[UserId] AS [UserId], [Extent2].[RoleId] AS [RoleId], [Extent2].[UserId] AS [UserId1], CAST(NULL AS int) AS [C2], CAST(NULL AS varchar(1)) AS [C3], CAST(NULL AS varchar(1)) AS [C4], CAST(NULL AS varchar(1)) AS [C5], CAST(NULL AS varchar(1)) AS [C6], CAST(NULL AS varchar(1)) AS [C7], CAST(NULL AS varchar(1)) AS [C8], CAST(NULL AS varchar(1)) AS [C9] FROM (SELECT TOP (1) [Extent1].[Id] AS [Id], [Extent1].[Email] AS [Email], [Extent1].[EmailConfirmed] AS [EmailConfirmed], [Extent1].[PasswordHash] AS [PasswordHash], [Extent1].[SecurityStamp] AS [SecurityStamp], [Extent1].[PhoneNumber] AS [PhoneNumber], [Extent1].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Extent1].[TwoFactorEnabled] AS [TwoFactorEnabled], [Extent1].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Extent1].[LockoutEnabled] AS [LockoutEnabled], [Extent1].[AccessFailedCount] AS [AccessFailedCount], [Extent1].[UserName] AS [UserName] FROM [dbo].[AspNetUsers] AS [Extent1] WHERE [Extent1].[Id] = @p__linq__0 ) AS [Limit1] LEFT OUTER JOIN [dbo].[AspNetUserRoles] AS [Extent2] ON [Limit1].[Id] = [Extent2].[UserId] UNION ALL SELECT 2 AS [C1], [Limit2].[AccessFailedCount] AS [AccessFailedCount], [Limit2].[Id] AS [Id], [Limit2].[Email] AS [Email], [Limit2].[EmailConfirmed] AS [EmailConfirmed], [Limit2].[PasswordHash] AS [PasswordHash], [Limit2].[SecurityStamp] AS [SecurityStamp], [Limit2].[PhoneNumber] AS [PhoneNumber], [Limit2].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Limit2].[TwoFactorEnabled] AS [TwoFactorEnabled], [Limit2].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Limit2].[LockoutEnabled] AS [LockoutEnabled], [Limit2].[AccessFailedCount] AS [AccessFailedCount1], [Limit2].[UserName] AS [UserName], CAST(NULL AS varchar(1)) AS [C2], CAST(NULL AS varchar(1)) AS [C3], CAST(NULL AS varchar(1)) AS [C4], [Extent4].[Id] AS [Id1], [Extent4].[UserId] AS [UserId], [Extent4].[ClaimType] AS [ClaimType], [Extent4].[ClaimValue] AS [ClaimValue], CAST(NULL AS varchar(1)) AS [C5], CAST(NULL AS varchar(1)) AS [C6], CAST(NULL AS varchar(1)) AS [C7], CAST(NULL AS varchar(1)) AS [C8] FROM (SELECT TOP (1) [Extent3].[Id] AS [Id], [Extent3].[Email] AS [Email], [Extent3].[EmailConfirmed] AS [EmailConfirmed], [Extent3].[PasswordHash] AS [PasswordHash], [Extent3].[SecurityStamp] AS [SecurityStamp], [Extent3].[PhoneNumber] AS [PhoneNumber], [Extent3].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Extent3].[TwoFactorEnabled] AS [TwoFactorEnabled], [Extent3].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Extent3].[LockoutEnabled] AS [LockoutEnabled], [Extent3].[AccessFailedCount] AS [AccessFailedCount], [Extent3].[UserName] AS [UserName] FROM [dbo].[AspNetUsers] AS [Extent3] WHERE [Extent3].[Id] = @p__linq__0 ) AS [Limit2] INNER JOIN [dbo].[AspNetUserClaims] AS [Extent4] ON [Limit2].[Id] = [Extent4].[UserId]) AS [UnionAll1] UNION ALL SELECT 3 AS [C1], [Limit3].[AccessFailedCount] AS [AccessFailedCount], [Limit3].[Id] AS [Id], [Limit3].[Email] AS [Email], [Limit3].[EmailConfirmed] AS [EmailConfirmed], [Limit3].[PasswordHash] AS [PasswordHash], [Limit3].[SecurityStamp] AS [SecurityStamp], [Limit3].[PhoneNumber] AS [PhoneNumber], [Limit3].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Limit3].[TwoFactorEnabled] AS [TwoFactorEnabled], [Limit3].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Limit3].[LockoutEnabled] AS [LockoutEnabled], [Limit3].[AccessFailedCount] AS [AccessFailedCount1], [Limit3].[UserName] AS [UserName], CAST(NULL AS varchar(1)) AS [C2], CAST(NULL AS varchar(1)) AS [C3], CAST(NULL AS varchar(1)) AS [C4], CAST(NULL AS int) AS [C5], CAST(NULL AS varchar(1)) AS [C6], CAST(NULL AS varchar(1)) AS [C7], CAST(NULL AS varchar(1)) AS [C8], [Extent6].[LoginProvider] AS [LoginProvider], [Extent6].[ProviderKey] AS [ProviderKey], [Extent6].[UserId] AS [UserId], [Extent6].[UserId] AS [UserId1] FROM (SELECT TOP (1) [Extent5].[Id] AS [Id], [Extent5].[Email] AS [Email], [Extent5].[EmailConfirmed] AS [EmailConfirmed], [Extent5].[PasswordHash] AS [PasswordHash], [Extent5].[SecurityStamp] AS [SecurityStamp], [Extent5].[PhoneNumber] AS [PhoneNumber], [Extent5].[PhoneNumberConfirmed] AS [PhoneNumberConfirmed], [Extent5].[TwoFactorEnabled] AS [TwoFactorEnabled], [Extent5].[LockoutEndDateUtc] AS [LockoutEndDateUtc], [Extent5].[LockoutEnabled] AS [LockoutEnabled], [Extent5].[AccessFailedCount] AS [AccessFailedCount], [Extent5].[UserName] AS [UserName] FROM [dbo].[AspNetUsers] AS [Extent5] WHERE [Extent5].[Id] = @p__linq__0 ) AS [Limit3] INNER JOIN [dbo].[AspNetUserLogins] AS [Extent6] ON [Limit3].[Id] = [Extent6].[UserId]) AS [UnionAll2] ORDER BY [UnionAll2].[C3] ASC, [UnionAll2].[C1] ASC',N'@p__linq__0 nvarchar(4000)',@p__linq__0=N'b73f9738-76ed-48d5-a8fd-cbf23a233fe9' 

Answer 2

查看Microsoft.AspNet.Identity.Core.dll的反编译源，您可以看到它从当前标识的声明中检索用户标识。 所以它不从数据库中获取此信息。

 public static string GetUserId(this IIdentity identity) { if (identity == null) throw new ArgumentNullException("identity"); ClaimsIdentity identity1 = identity as ClaimsIdentity; if (identity1 != null) return IdentityExtensions.FindFirstValue(identity1, "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier"); return (string) null; }