Question

您好我试图制作音乐应用程序以共享音乐，但我有以下问题。 Look red circle

我放置了红色圆圈，我想加载我在课堂上制作的艺术家。我尝试使用字典但不使用扩展名PagedList。

上面的网页视图如下所示：

<div class="panel panel-default">
<table class="table">

    @foreach (var item in (IEnumerable<Song>) ViewData["songs"])
    {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Name)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Genre)
            </td>
            <td>
                <a class="artist">Artiest</a>
            </td>
            <td>
                <a class="playbtn btn btn-sm btn-default btn-circle pull-right" data-item="@item.Mp3File"><span class="glyphicon glyphicon-play"></span></a>
            </td>
            <td>
                <button class="btn btn-default glyphicon glyphicon-plus favoritebutton pull-right">Add to favorites</button>
            </td>
        </tr>
    }
</table>

歌曲的控制器如下所示：

    public ActionResult Index(int page = 1, int pagesize = 8)
    {
            List<Artist> artists = artistRepository.GetArtistBySongID(int id);
            List<Song> songs = songRepository.ReadSongs();
            List<Song> recommended = songRepository.GetFavoritesById(Convert.ToInt32(Session["userid"]));
            ViewData["recommended"] = recommended;
            PagedList<Song> pagedList = new PagedList<Song>(songs, page, pagesize);
            ViewData["songs"] = pagedList;  
            return View();  
    }

我的歌曲课程如下：

public class Song
{
    private int id;
    private string name;
    private string genre;
    private DateTime release_date;
    private string mp3file;

    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    public string Name
    {
        get { return name; }
        set { name = value; }
    }

    public string Genre
    {
        get { return genre; }
        set { genre = value; }
    }

    public DateTime ReleaseDate
    {
        get { return release_date; }
        set { release_date = value; }
    }

    public string Mp3File
    {
        get { return mp3file; }
        set { mp3file = value; }
    }

    public Song(string name, string genre, DateTime release_date, string mp3file)
    {
        this.name = name;
        this.genre = genre;
        this.release_date = release_date;
        this.mp3file = mp3file;
    }

    public Song(int id, string name, string genre, DateTime release_date, string mp3file)
    {
        this.id = id;
        this.name = name;
        this.genre = genre;
        this.release_date = release_date;
        this.mp3file = mp3file;
    }

    public override string ToString()
    {
        return String.Format("{0}, {1}, {2}, {3}, {4}", Id, Name, Genre, ReleaseDate, mp3file);
    }

Answer 1

列出艺术家= artistRepository.GetArtistBySongID（int id）;

这是你的第一个问题。你想要一个艺术家列表 - 每个都对应一首歌，但你只给它一首歌的id。这将返回一个艺术家，而不是一个列表。所以，你需要通过你的歌曲列表，拉出id，获得该歌曲的艺术家，并建立一个列表。

import (
    "fmt"
    "net/smtp"
    "strings"
)

type Mail struct {
    from    string
    to      []string
    subject string
    body    string
}

type SMTPServer struct {
    host string
    port string
}

func (s *SMTPServer) serverName() string {
    return s.host + ":" + s.port
}

func (mail *Mail) buildMessage() string {
    message := ""
    message += fmt.Sprintf("From: %s\r\n", mail.from)
    if len(mail.to) > 0 {
        message += fmt.Sprintf("To: %s\r\n", strings.Join(mail.to, ";"))
    }

    message += fmt.Sprintf("Subject: %s\r\n", mail.subject)
    message += "\r\n" + mail.body

    return message
}

func Send(mail Mail, server SMTPServer) (err error) {


    // Connect to SMTP server
    c, err := smtp.Dial(server.serverName())
    if err != nil {
        return
    }

    // Set the sender and recipients
    if err = c.Mail(mail.from); err != nil {
        return
    }

    for _, t := range mail.to {
        if err = c.Rcpt(t); err != nil {
            return
        }
    }

    // Send the email body.
    wc, err := c.Data()
    if err != nil {
        return
    }

    if _, err = wc.Write([]byte(mail.buildMessage())); err != nil {
        return
    }

    if err = wc.Close(); err != nil {
        return
    }

    if err = c.Quit(); err != nil {
        fmt.Printf("%s", err)
        return
    }

    return nil

}


func main() {

    mail := Mail{"a@test.com", []string {"b@test.com", "c@test.com"}, "subject", "body"}
    server := SMTPServer{"host", "port"}

    err := Send(mail, server)
    fmt.Printf("%s", err)


}

但是，这只能解决部分问题，因为现在在视图中，我们必须在逐步浏览歌曲列表的同时逐步浏览艺术家列表。

我认为最简单的解决方案是向List<Artist> artists = new List<Artist>(); List<Song> songs = songRepository.ReadSongs(); PagedList<Song> pagedList = new PagedList<Song>(songs, page, pagesize); foreach(var song in pagedList) artists.Add(artistRepository.GetArtistBySongID(song.ID)); ViewData["songs"] = pagedList; ViewData["artists"] = artists;对象添加Artist属性，但这可能会导致问题。（但是，在继续之前先尝试一下）。

如果你不能将属性添加到SOng对象，那么接下来最好是制作一个元组。

Song

然后在你看来改变

List<Song> songs = songRepository.ReadSongs();

PagedList<Song> pagedList = new PagedList<Song>(songs, page, pagesize); 
var songartists = new List<Tuple<Song, Artist>> 

foreach(var song in pagedList)
      songartists .Add(Tuple.Creeate(song, artistRepository.GetArtistBySongID(song.ID)));

ViewData["songs"] = songartists ;

为：

@foreach (var item in (IEnumerable<Song>) ViewData["songs"])
{

无法在我的asp mvc网站上获得艺术家

1 个答案: