ASP.NET MVC - ViewModel 是否适合进行少量计算？

Question

我正在研究 UserViewModel，我想知道是否适合在虚拟机中进行少量计算，或者我是否需要将其进一步分离并在其他地方计算。

Public Class UserViewModel
    Public Property UserName As String
    Public Property Email As String
    Public Property Website As String
    Public Property ID As Integer
    Public Property OpenIds As List(Of OpenID)
    Public Property UserAge As String
    Public Property About As String
    Public Property Slug As String
    Public Property LastSeen As String
    Public Property Region As String
    Public Property MemberSince As String
    Public Property Reputation As String
    Public Property isUserMatch As Boolean = False
    Private MarkDownSharp As MarkdownSharp.Markdown

    Public Sub New(ByVal user As User)
        Dim currentuser As Authentication.AuthUserData = Authentication.CustomAuthentication.RetrieveAuthUser
        MarkDownSharp = New MarkdownSharp.Markdown
        With MarkDownSharp
            .AutoHyperlink = False
            .AutoNewLines = True
            .EncodeProblemUrlCharacters = True
            .LinkEmails = True
            .StrictBoldItalic = True
        End With

        _UserName = If(Not user.UserName Is Nothing, user.UserName, "User" & user.ID.ToString)
        _Email = user.Email
        _Website = user.WebSite
        _ID = user.ID
        _OpenIds = user.OpenIDs.ToList
        ''# Converts the users birthdate to an age representation
        ''#      IE: 29
        _UserAge = user.BirthDate.ToAge

        ''# 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.
        _About = Trim(Utilities.HtmlSanitizer.Sanitize(MarkDownSharp.Transform(user.About)))

        ''# Removes spaces from Usernames in order to properly display the
        ''# username in the address bar
        _Slug = Replace(user.UserName, " ", "-")

        ''# Returns a boolean result if the current logged in user matches the
        ''# details view of the user in question.  This is done so that we can
        ''# show the edit button to logged in users.
        _isUserMatch = If(currentuser.ID = user.ID, True, False)


        ''# Grabs the users registration data and formats it to a time span
        ''# The "timeago-nosuffix" CssClass is there to remove the "ago"
        ''# suffix from the "member for" string. Cuz when you think about
        ''# it... "Member for 5 days ago" just sounds stupid.
        _MemberSince = user.MemberSince.ToTimeSpan("timeago-nosuffix")

        ''# Grabs the users last activity and formats it to a time span
        _LastSeen = user.ActivityLogs.Reverse.FirstOrDefault.ActivityDate.ToTimeSpan("timeago", "ago")

        ''# Formats the users reputation to a comma Deliminated number 
        ''#    IE: 19,000 or 123k
        _Reputation = user.Reputation.ToShortHandNumber


        ''# Get the name of the users current Region.
        _Region = user.Region.Region.FirstOrDefault
    End Sub

End Class

Answer 1

如果这些计算涉及给定视图的格式，那么它就是确切的位置。看起来你正在做的就是这样：格式化视图，这是可以的（抱歉，如果我错过了一些东西，我的 VB.NET 代码阅读技能开始让我困惑:-)）。另一方面，如果它是一些领域逻辑，它可能更适合该模型，以便可以重用。

Answer 2

虽然我不同意达林的观点，但还有另一种方法。

您还可以将该逻辑放入用于将域模型对象转换为 dto 或 viewmodel 对象的任何层中，而不是将简单的逻辑放入 ViewModel 中。我们将其称为“映射层”。这使您的视图模型变得非常愚蠢和灵活，同时将所有自定义视图转换逻辑保留在单独的位置。

使用 AutoMapper 等工具可以轻松做到这一点。