我有一个 ViewModel，它获取一些模型数据并稍微改变它。
我这样做的方式“有效”，因为我只是将
DomainModelViewModel这是一个 ViewModel 的示例，它做了一些额外的事情。
public class UsersDetailsViewModel
{
public string UserName { get; set; }
public string Email { get; set; }
public string Website { get; set; }
public int ID { get; set; }
public List<OpenID> OpenIds { get; set; }
public string UserAge { get; set; }
public string About { get; set; }
public string Slug { get; set; }
public System.DateTime LastSeen { get; set; }
public string Region { get; set; }
public string MemberSince { get; set; }
public string Reputation { get; set; }
public bool IsUserMatch { get; set; }
private readonly MarkdownDeep.Markdown _markdown;
public UsersDetailsViewModel(Domain.User user)
{
AuthUserData currentuser = AuthenticationHelper.RetrieveAuthUser;
_markdown.NoFollowLinks = true;
_markdown.SafeMode = true;
_markdown.ExtraMode = false;
_markdown.MarkdownInHtml = true;
// We want to ensure that the user has a username, even if they
// haven't set one yet. What this does is check to see if the
// user.UserName field is blank, and if it is, it will set the
// username to "UserNNNN" where NNNN is the user ID number.
_UserName = (user.UserName != null) ? user.UserName : "User" + user.ID.ToString;
// Nothing fancy going on here, we're just re-passing the object from
// the database to the View. No data manipulation!
_Email = user.Email;
_Website = user.WebSite;
_ID = user.ID;
// Get's a list of all of the user's OpenID's
_OpenIds = user.OpenIDs.ToList;
// Converts the users birthdate to an age representation
_UserAge = user.BirthDate.ToAge;
//IE: 29
// Because some people can be real ass holes and try to submit bad
// data (scripts and shitè) we have to modify the "About" content in
// order to sanitize it. At the same time, we transform the Markdown
// into valid HTML. The raw input is stored without sanitization in
// the database. this could mean Javascript injection, etc, so the
// output ALWAYS needs to be sanitized.
// This method below was used in conjunction with MarkDownSharp
// _About = Trim(Utilities.HtmlSanitizer.Sanitize(Markdown.Transform(user.About)))
_About = _markdown.Transform(user.About);
// Removes spaces from Usernames in order to properly display the
// username in the address bar
_Slug = Strings.Replace(user.UserName, " ", "-");
// Returns a boolean result if the current logged in user matches the
// details view of tBhe user in question. This is done so that we can
// show the edit button to logged in users.
_IsUserMatch = (currentuser.ID == user.ID);
// Grabs the users registration data and formats it to a <time> tag
// for use with the timeago jQuery plugin
_MemberSince = user.MemberSince;
// Grabs the users last activity and formats it to a <time> tag
// for use with the timeago jQuery plugin
_LastSeen = user.ActivityLogs.Reverse.FirstOrDefault.ActivityDate;
// Formats the users reputation to a comma Deliminated number
// IE: 19,000 or 123k
_Reputation = user.Reputation.ToShortHandNumber;
// Get the name of the users Default Region.
_Region = user.Region.Name.FirstOrDefault;
}
}
这是我目前使用上述 ViewModel 的方式
public ActionResult Details(int id)
{
User user = _userService.GetUserByID(id);
if (user != null) {
Domain.ViewModels.UsersDetailsViewModel userviewmodel = new Domain.ViewModels.UsersDetailsViewModel(user);
return View(userviewmodel);
} else {
// Because of RESTful URL's, some people will want to "hunt around"
// for other users by entering numbers into the address. We need to
// gracefully redirect them to a not found page if the user doesn't
// exist.
throw new ResourceNotFoundException();
}
}
在进行上面看到的自定义处理时，如何使用（或者应该使用）AutoMapper 将 DomainModel 映射到 ViewModel？
在创建映射的自动映射器上，您可以为目标类型的特定成员指定其他进程。
那么你的默认地图在哪里
Mapper.Map<Domain.User, UsersDetailsViewModel>();
有一个流畅的语法来定义更复杂的映射：
Mapper.Map<Domain.User, UsersDetailsViewModel>()
.ForMember(vm=>vm.UserName, m=>m.MapFrom(u=>(u.UserName != null)
? u.UserName
: "User" + u.ID.ToString()));
这里 ForMember 有两个参数，第一个参数定义您要映射到的属性。第二个提供了定义映射的方法。作为一个例子，我已经放弃并展示了一个简单的映射。
如果您需要更困难的映射（例如 CurrentUser 映射），您可以创建一个实现 IResolver 接口的类，将映射逻辑合并到该新类中，然后将其添加到映射中。
Mapper.Map<Domain.User, UsersDetailsViewModel>()
.ForMember(vm=>vm.IsUserMatch, m=>m.ResolveUsing<MatchingUserResolver>()));
当 Mapper 进行映射时，它将调用您的自定义解析器。
一旦您发现了 .ForMember 方法的语法，其他所有内容就都到位了。
可以通过以下代码在 global.ascx（启动时）中定义自定义映射：
AutoMapper.Mapper.CreateMap<Domain.User, UsersDetailsViewModel>()
.ForMember(o => o.Email, b => b.MapFrom(z => z.Email))
.ForMember(o => o.UserName , b => b.MapFrom(user => (user.UserName != null) ? user.UserName : "User" + user.ID.ToString));
您可以通过BeforeMap()方法进行一些初始化。但您可能需要在视图模型中进行一些更改。
我认为语法在 2019 年（ASP.NET Core 2.2）略有变化，现在使用 MapperConfiguration 处理此方法，并且静态方法不再可用。
但是我同意@KJSR，这篇文章仍然非常有用:-)
private Mapper UserMapper= new Mapper(new MapperConfiguration(cfg => (cfg.CreateMap<Domain.User, UsersDetailsViewModel>())
.ForMember(x=>x.Email, y=>y.MapFrom(z=>z.Email))
.ForMember(x => x.UserName , y => y.MapFrom(user => (user.UserName != null) ? user.UserName : "User" + user.ID.ToString))));
创建地图