Returning a match from the list <KeyValuePair <string, string >>

Question

I currently have a class that uses KeyValuePairc Listto store a collection of tracks in the format Key = track, Value = artist.

I am trying to provide a way to search for a specific track, and if there are any matches, return the entire matching CD.

This is my attempt:

public CompilationCD FindTrackInComCD(string track)
{
    CompilationCD temp = new CompilationCD();

    List<CD> tempComCols = _cdCollection.FindAll(delegate(CD cd)
    { return cd.GetType() == temp.GetType(); });

    foreach (KeyValuePair<string, string> comCD in tempComCols)
    {
        if (comCD.Key.Contains(track))
        {
            return comCD;
        }
    }

    throw new ArgumentException("No matches found");
}

I have a Cd set of type CD ( List<CD>), so I am creating a new List<>suitable type by comparing it with a temporary list.

When compiling, I get the following errors:

Cannot convert type 'CDCollection.CD' to System.Collections.Generic.KeyValuePair<string,string>'

Cannot implicitly convert type 'System.Collections.Generic.KeyValuePair<string,string>'

(CDCollection is my project namespace, and CD / CompilationCD are classes)

, . , , ; List<> KeyValuePair.

CD:

using System;

System.Collections; System.Collections.Generic; System.Linq; System.Text;

CDCollection {    CD   {       #region Fields        readonly _artist;       private readonly string _album;       private List _track = new List();       #endregion

    #region Constructors
    public CD()
    {
        _artist = "";
        _album = "";
        _track = null;
    }

    public CD(string albumName)
    {
        _album = albumName;
    }

    public CD(string artistName, string albumName)
    {
        _artist = artistName;
        _album = albumName;
    }

    #endregion

    #region Properties
    /// <summary>
    /// Get/Set Artist Name
    /// </summary>
    public virtual string Artist
    {
        get
        {
            return _artist;
        }
        set
        {
            value = _artist;
        }
    }

    /// <summary>
    /// Get/Set Album
    /// </summary>
    public string Album
    {
        get
        {
            return _album;
        }
        set
        {
            value = _album;
        }
    }

    /// <summary>
    /// Get/Set Track Name
    /// </summary>
    public virtual List<string> Track
    {
        get
        {
            return _track;
        }
        set
        {
            value = _track;
        }
    }

    #endregion

    #region ToString()
    /// <summary>
    /// Custom ToString() Method
    /// </summary>
    /// <returns></returns>
    public override string ToString()
    {
        //Create new StringBuilder object
        StringBuilder sb = new StringBuilder();

        sb.Append("Artist Name");

        //Display error if Artist is not available
        if (_artist == null || _artist == "")
        {
            sb.Append("\nNo Artist Entered");
        }
        else
        {
            sb.Append("\n" + this._artist);
        }

        sb.Append("\n");
        sb.Append("\nAlbum Name");

        //Display error if Album is not available
        if (_album == null || _album == "")
        {
            sb.Append("\nNo Album Entered");
        }
        else
        {
            sb.Append("\n" + this._album);
        }

        sb.Append("\n");
        sb.Append("\nTrack Name");
        sb.Append("\n");

        //Iterate through all tracks stored in list
        foreach (string trackName in _track)
        {
            //Print each artist
            sb.Append("\n" + trackName);
        }

        sb.Append("\nEnd of CD Record.........");

        return sb.ToString();
    }

    #endregion
}

}

CompilationCD:

using System;

System.Collections.Generic; System.Linq; System.Text;

CDCollection {    CompilationCD: CD   {       #region Fields

    private readonly string _artist;
    private readonly string _album;
    private List<KeyValuePair<string,string>> _tracks = new List<KeyValuePair<string,string>>();

    //List<KeyValuePair> Reference.
    //http://msdn.microsoft.com/en-us/library/6sh2ey19(VS.85).aspx

    #endregion

    #region Constructors

    public CompilationCD()
    {
        _album = "";
        _artist = "Various Artists";
    }

    public CompilationCD(string albumName):base(albumName)
    {
        _album = albumName;
        _artist = "Various Artists";
    }

    #endregion

    public void AddTracks(string track, string artist)
    {
        _tracks.Add(new KeyValuePair<string, string>(track, artist));
    }

    #region Properties

    public override string Artist
    {
        get
        {
            return this._artist;
        }
    }

    public new List<KeyValuePair<string,string>> Track
    {
        get
        {
            return _tracks;
        }
        set
        {
            _tracks = value;
        }
    }


    #endregion

    #region ToString()

    //TEST
    public override string ToString()
    {
        //Create new StringBuilder object
        StringBuilder sb = new StringBuilder();

        sb.Append("Artist Name");

        //Display error if Artist is not available
        if (_artist == null || _artist == "")
        {
            sb.Append("\nNo Artist Entered");
        }
        else
        {
            sb.Append("\n" + this._artist);
        }

        sb.Append("\n");
        sb.Append("\nAlbum Name");

        //Display error if Album is not available
        if (base.Album == null || base.Album == "")
        {
            sb.Append("\nNo Album Entered");
        }
        else
        {
            sb.Append("\n" + base.Album);
        }

        sb.Append("\n");
        sb.Append("\nTrack Name");
        sb.Append("\n");

        ////Iterate through all tracks stored in list
        //foreach (string trackName in base.Track)
        //{
        //    //Print each artist
        //    sb.Append("\n" + trackName);
        //}

        for(int i = 0; i <= _tracks.Count; i++)
        {
            string track = _tracks[i].Key;
            string artist = _tracks[i].Value;

            sb.Append("\nTrack");
            sb.Append(track);
            sb.Append("\nArtist");
            sb.Append(artist);
        }

        sb.Append("\nEnd of Compilation CD Record.........");

        return sb.ToString();
    }

    #endregion
}

}

, , CD, CompilationCD, List > , , . Crazy =/

, cd CD (List).

Answer 1

foreach. tempComCols List<CD>, comCD KeyValuePair<string, string>. , .

, , CD (?), .

: , ( ):

public CompilationCD FindTrackInComCD(string track)
{
    CompilationCD temp = new CompilationCD();

    temp = _cdCollection.Where(cd => cd is CompilationCD)
                        .Cast<CompilationCD>()
                        .Where(com_cd => com_cd.Tracks.ContainsKey(track))
                        .FirstOrDefault();

    if (temp != null)
        return temp;
    else throw new ArgumentException("No matches found");
}

CompilationCD KeyValuePair<string, string>, CompilationCD. extenion IEnumerable<T>, System.Linq, .

Answer 2

? , .

Answer 3

tempComCols CD, KeyValuePair<string, string>

Answer 4

List KeyValuePairs, , . - :

foreach (CD comCD in tempComCols)
{
    if (comCD.MyKeyValueProp.Key.Contains(track))
    {
        return comCD;
    }
}

, , CD , KeyValuePair, a Dictionary .

Answer 5

tempComCols - CD : List<CD> tempComCols ..., - IEnumerable: foreach (KeyValuePair<string, string> comCD in tempComCols)

Answer 6

List<CD> KeyValuePair<string, string>.

LINQ # 3 :

public CompilationCD FindTrackInComCD(string track) {
    return _cdCollection.OfType<CompilationCD>().FirstOrDefault(cd => cd.Name.Contains(track, StringComparison.CurrentCultureIgnoreCase));
}

, System.Type CompilationCD, typeof(CompilationCD); GetType().

Answer 7

• :

  {cd is CompilationCD};
  

  { return cd.GetType() == temp.GetType(); });
  

• CD - , :

  public CompilationCD FindTrackInComCD(string track)
  {
      return (CompilationCD)_cdCollection.Find(delegate(CD cd)
      { return (cd is CompilationCD) && (cd.Contains(track))});
  }
  

Answer 8

KeyedCollection http://msdn.microsoft.com/en-us/library/ms132438.aspx