Question

我想从我的ASP.net Identity Users表中查询所有用户，并将它们映射到这样的简单DTO：

public class UserDto
{
    public string Firstname { get; set; }
    public string Lastname { get; set; }
    public string Email { get; set; }
    public IEnumerable<string> Roles { get; set; }
}

角色列表应该只包含角色的名称，因此我从角色表中加入角色并获取名称。现在我想通过使用AutoMapper简化这一过程，并将结果直接映射到我的DTO。

var users = await _userManager.Users
            .AsNoTracking()
            .Include(u => u.Roles)
            .Select(u => new {
                User = u,
                Roles = u.Roles
                    .Join(_roleManager.Roles, 
                            a => a.RoleId, 
                            b => b.Id, 
                            (a, b) => b.Name)
                    .ToList()
            })
            .ToListAsync();

我很难找到一个很好的解决方案，可以使用AutoMapper将这些数据映射到UserDto对象列表。我尝试用户ProjectTo<UserDto>并在我的映射器配置中实现表连接，但是我收到很多efcore警告，我的查询在客户端上执行。

问题：使用AutoMapper和efcore有一种简单有效的方法吗？

更新即使没有AutoMapper，它也会产生警告：（

var users = await _userManager.Users
            .AsNoTracking()
            .Include(u => u.Roles)
            .Select(u => new UserDto {
                Firstname = u.Firstname,
                Lastname = u.Lastname,
                Email = u.Email,
                Roles = u.Roles
                    .Join(_roleManager.Roles, 
                            a => a.RoleId, 
                            b => b.Id, 
                            (a, b) => b.Name)
                    .ToList()
            })                
            .ToListAsync();

这是efcore日志记录输出：

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (2ms) [Parameters=[@__get_Item_0='?' (Size = 450)], CommandType='Text', CommandTimeout='30']
      SELECT TOP(1) [e].[Id], [e].[AccessFailedCount], [e].[Address], [e].[City], [e].[ConcurrencyStamp], [e].[Country], [e].[CustomerIdentifier], [e].[Email], [e].[EmailConfirmed], [e].[Firstname], [e].[Gender], [e].[Lastname], [e].[LockoutEnabled], [e].[LockoutEnd], [e].[NormalizedEmail], [e].[NormalizedUserName], [e].[PasswordHash], [e].[PhoneNumber], [e].[PhoneNumberConfirmed], [e].[Region], [e].[SecurityStamp], [e].[TwoFactorEnabled], [e].[UserName], [e].[ZipCode]
      FROM [AspNetUsers] AS [e]
      WHERE [e].[Id] = @__get_Item_0

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (2ms) [Parameters=[@__normalizedRoleName_0='?' (Size = 256)], CommandType='Text', CommandTimeout='30']
      SELECT TOP(2) [r].[Id], [r].[ConcurrencyStamp], [r].[Name], [r].[NormalizedName]
      FROM [AspNetRoles] AS [r]
      WHERE [r].[NormalizedName] = @__normalizedRoleName_0

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (6ms) [Parameters=[@__get_Item_0='?' (Size = 450), @__get_Item_1='?' (Size = 450)], CommandType='Text', CommandTimeout='30']
      SELECT TOP(1) [e].[UserId], [e].[RoleId]
      FROM [AspNetUserRoles] AS [e]
      WHERE ([e].[UserId] = @__get_Item_0) AND ([e].[RoleId] = @__get_Item_1)

warn: Microsoft.EntityFrameworkCore.Query.Internal.SqlServerQueryCompilationContextFactory[6]
      The Include operation for navigation: 'u.Roles' was ignored because the target navigation is not reachable in the final query results. To configure this warning use the DbContextOptionsBuilder.ConfigureWarnings API (event id 'CoreEventId.IncludeIgnoredWarning'). ConfigureWarnings can be used when overriding the DbContext.OnConfiguring method or using AddDbContext on the application service provider.

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (1ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
      SELECT [u].[Firstname], [u].[Lastname], [u].[Email], [u].[Id]
      FROM [AspNetUsers] AS [u]

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (2ms) [Parameters=[@_outer_Id='?' (Size = 450)], CommandType='Text', CommandTimeout='30']
      SELECT [b].[Name]
      FROM [AspNetUserRoles] AS [a]
      INNER JOIN [AspNetRoles] AS [b] ON [a].[RoleId] = [b].[Id]
      WHERE @_outer_Id = [a].[UserId]

info: Microsoft.EntityFrameworkCore.Storage.IRelationalCommandBuilderFactory[1]
      Executed DbCommand (1ms) [Parameters=[@_outer_Id='?' (Size = 450)], CommandType='Text', CommandTimeout='30']
      SELECT [b].[Name]
      FROM [AspNetUserRoles] AS [a]
      INNER JOIN [AspNetRoles] AS [b] ON [a].[RoleId] = [b].[Id]
      WHERE @_outer_Id = [a].[UserId]

更新2

发出警告后，我刚刚删除了Include语句，找到了一个可行的解决方案：

var users = await _userManager.Users
            .AsNoTracking()
            .Select(u => new UserDto {
                Firstname = u.Firstname,
                Lastname = u.Lastname,
                Email = u.Email,
                Roles = u.Roles
                    .Join(_roleManager.Roles, 
                            a => a.RoleId, 
                            b => b.Id, 
                            (a, b) => b.Name)
                    .ToList()
            })                
            .ToListAsync();

Answer 1

我从查询中删除了Include语句，将select语句移动到我的AutoMapper配置文件，并将roles表作为参数添加到我的ProjectTo语句中。现在它按预期工作，不会产生任何efcore警告。

ef query

        var users = await _userManager.Users
            .AsNoTracking()
            .ProjectTo<UserDto>(new { roles = _roleManager.Roles })              
            .ToListAsync();

automapper个人资料

        IQueryable<IdentityRole> roles = null;
        CreateMap<User, UserDto>()
            .ForMember(x => x.Roles, opt => 
                opt.MapFrom(src => 
                    src.Roles
                        .Join(roles, a => a.RoleId, b => b.Id, (a, b) => b.Name)
                        .ToList()
                )
            );

EFCore连接表和AutoMapper

1 个答案: