public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//"item" is viewmodel object => to Entity object before update!
Album updateitem = new Album
{
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
//staging in local mem
//at this point code will NOT have send to Database.
context.Entry(updateitem).State = System.Data.Entity.EntityState.Modified;
//commit to Database - on this command the item is shipped to entity deffinition validation then to context DB
context.SaveChanges();
//entity instance will have new Pkey attached to the object
}
}
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//due to the fact we have seperaated handling of our entities
//from the data traansfer beteen webapp and class library
//using viewmodel classes, we must create an instaance of the entity
//and move the data from the viewmodel class to the entity instance
Album updateItem = new Album
{
//Update needs a pkey value
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseLabel = item.ReleaseLabel,
ReleaseYear = item.ReleaseYear
};
//Staging
//Setup in local memory
context.Entry(updateItem).State = System.Data.Entity.EntityState.Modified;
//commit to database
//on this command you
// a)executee entity validtion annotation
// b)send local memory staging to the database for execution
//after successful execution your entity instance will have the new pkey(identity) value
context.SaveChanges();
}
}
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//Due to the fact that we have seperated the handling of our entities, from the data transfer between WebApp and Class library
// using the ViewModel classes, we MUST create an instance of the entity and move the data from the ViewModel class
// to the entity instance.
Album updateItem = new Album
{
//for an update, you need to supply your pkey value
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
//Staging
//Setup in Local Memory
context.Entry(updateItem).State = System.Data.Entity.EntityState.Modified;
//Commit to database
//On this command, you
// a) Execute entity validation annotation
// b) Send your local memory staging to the database for execution
context.SaveChanges();
}
}
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//due to the fact that we have separated the handling of our entities
// from the data transfer between web app and class library
//using the viewmodel classes, we MUST create an instance
//of the entity and move the data from the view model class to the entity instance.
Album updateitem = new Album
{
//for an update, you need to supply a pkey value
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
//staging
//setup in local memory
context.Entry(updateitem).State = System.Data.Entity.EntityState.Modified;
//commit to database
//on this command you
//A) execute entity validationm annotation
// B) send your local memory staging to the database for execution
// after a successful execution your entity instance will have the
// new pkey (identity) value
context.SaveChanges();
//at this point, your identity instance has the new pkey value
}
}
public int Album_Update(Album item)
{
using (var context = new ChinookSystemContext())
{
context.Entry(item).State = System.Data.Entity.EntityState.Modified;
return(context.SaveChanges()); //returned is number of rows affected
}
}
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
using (var context = new ChinookSystemContext())
{
//trx
//check to see if playlist exists
//no:error msg
//yes:
//create a list of tracks to kept
//remove the tracks in the incoming list
//re-sequence the kept tracks
//commit
List <string> errors = new List <string>();
Playlist exists = (from x in context.Playlists
where x.Name.Equals(playlistname) && x.UserName.Equals(username)
select x).FirstOrDefault();
if (exists == null)
{
errors.Add("Play list does not exist.");
}
else
{
//find the songs to keep
var trackskept = context.PlaylistTracks
.Where(tr => tr.Playlist.Name.Equals(playlistname) && tr.Playlist.UserName.Equals(username) && !trackstodelete.Any(tod => tod == tr.TrackId))
.OrderBy(tr => tr.TrackNumber)
.Select(tr => tr);
//remove the tracks to delete
PlaylistTrack item = null;
foreach (int deletetrackid in trackstodelete)
{
item = context.PlaylistTracks
.Where(tr => tr.Playlist.Name.Equals(playlistname) && tr.Playlist.UserName.Equals(username) && tr.TrackId == deletetrackid)
.Select(tr => tr).FirstOrDefault();
if (item != null)
{
exists.PlaylistTracks.Remove(item);
}
}
//re-sequence
int number = 1;
foreach (var track in trackskept)
{
track.TrackNumber = number;
context.Entry(track).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
number++;
}
//commit
context.SaveChanges();
}
}
}//eom
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
using (var context = new ChinookSystemContext())
{
//code to go here
// find playlist
var exists = (from x in context.Playlists
where x.UserName.Equals(username) &&
x.Name.Equals(playlistname)
select x).FirstOrDefault();
// check
if (exists == null)
{
//null - msg
throw new Exception("Playlist has been removed from the file.");
}
else
{
// exists
// find the tracks that will be kept
// these tracks will be in set A but not in set B
var tracksKept = exists.PlaylistTracks
.Where(tr => !trackstodelete.Any(td => td == tr.TrackId));
// remove the unwanted tracks from the database
PlaylistTrack item = null;
foreach (var dtrackid in trackstodelete)
{
// find track instance to delete
item = exists.PlaylistTracks.Where(tr => tr.TrackId == dtrackid).Select(tr => tr).FirstOrDefault();
// check
if (item != null)
{
// if its there then remove
exists.PlaylistTracks.Remove(item);
}
}
// renumber the tracks that were kept by updating their
// track numbers
int number = 1;
foreach (var tKept in tracksKept)
{
tKept.TrackNumber = number;
context.Entry(tKept).Property(y => y.TrackNumber).IsModified = true;
number++;
}
context.SaveChanges();
}
}
}//eom
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
Album updateItem = new Album()
{
AlbumId = item.AlbumId,
Title = item.Title,
ReleaseYear = item.ReleaseYear,
ArtistId = item.ArtistId,
ReleaseLabel = item.ReleaseLabel
};
context.Entry(updateItem).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
Album newItem = new Album
{
//pkey is identity, not needed
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseLabel = item.ReleaseLabel,
ReleaseYear = item.ReleaseYear
};
context.Entry(newItem).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Albums_Update(AlbumViewModel item)
{
DataValidation(item);
using (var context = new ChinookSystemContext())
{
Album info = new Album()
{
AlbumId = item.AlbumId,
Title = item.AlbumTitle,
ArtistId = item.ArtistId,
ReleaseYear = item.AlbumReleaseYear,
ReleaseLabel = item.AlbumReleaseLabel
};
context.Entry(info).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Tracks_Update(TrackViewModel item)
{
using (var context = new ChinookSystemContext())
{
Track info = new Track()
{
TrackId = item.TrackId,
MediaTypeId = item.TrackMediaTypeId,
Name = item.TrackName,
Composer = item.TrackComposer,
Milliseconds = item.TrackMilliseconds,
Bytes = item.TrackBytes,
UnitPrice = item.TrackUnitPrice
};
context.Entry(info).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Album_Update(AlbumList item)
{
using (var context = new ChinookSystemContext())
{
//moving the data from the external ViewModel instance
// into an internal instance of the entity
Album updateItem = new Album
{
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
context.Entry(updateItem).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Album_Update(AlbumList item)
{
using (var context = new ChinookSystemContext())
{
//moving the data from the external viewmodel instance into an internal instance of the entity
Album updateItem = new Album
{
//Remember for an update, I need to supply the primary key
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
context.Entry(updateItem).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Album_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//move the incoming viewmodel instance data into an instance
// of the internal entity
Album newItem = new Album
{
//pkey is needed for update to find the instance
// on the database
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
context.Entry(newItem).State = System.Data.Entity.EntityState.Modified;
context.SaveChanges();
}
}
public void Albums_Update(AlbumItem item)
{
using (var context = new ChinookSystemContext())
{
//need to move the data from the viewmodel class into
// an entity instance BEFORE staging
//on update you NEED to supply the table's pkey value
Album entityItem = new Album
{
AlbumId = item.AlbumId,
Title = item.Title,
ArtistId = item.ArtistId,
ReleaseYear = item.ReleaseYear,
ReleaseLabel = item.ReleaseLabel
};
//stagging is to local memory
context.Entry(entityItem).State = System.Data.Entity.EntityState.Modified;
//commit is the action of sending your request to
// the database for action.
context.SaveChanges();
}
}
}//eom
public void MoveTrack(string username, string playlistname, int trackid, int tracknumber, string direction)
{
using (var context = new ChinookSystemContext())
{
//code to go here
// since data can be accessed by multiple individuals at the same time
// your BLL method should do validation to ensure the data coming is appropriate
var exists = context.Playlists.Where(x => x.UserName.Equals(username) &&
x.Name.Equals(playlistname)).Select(x => x).FirstOrDefault();
// playlist no longer exists
if (exists == null)
{
throw new Exception("Playlist has been removed from files.");
}
else
{
var movetrack = exists.PlaylistTracks.Where(x => x.TrackId == trackid).Select(x => x).FirstOrDefault();
//playlist track no longer exists
if (movetrack == null)
{
throw new Exception("Playlist track has been removed from files - Movetrack.");
}
else
{
PlaylistTrack othertrack = null;
// determine direction
if (direction.Equals("up"))
{
if (movetrack.TrackNumber == 1)
{
throw new Exception("Playlist track already at top.");
}
else
{
//setup for track movement
othertrack = (from x in exists.PlaylistTracks
where x.TrackNumber == movetrack.TrackNumber - 1
select x).FirstOrDefault();
if (othertrack == null)
{
throw new Exception("Playlist tracks have been altered. Unable to Complete move");
}
else
{
movetrack.TrackNumber -= 1;
othertrack.TrackNumber += 1;
}
}
}
else
{
if (movetrack.TrackNumber == exists.PlaylistTracks.Count)
{
throw new Exception("Playlist track already at last.");
}
else
{
//setup for track movement
othertrack = (from x in exists.PlaylistTracks
where x.TrackNumber == movetrack.TrackNumber + 1
select x).FirstOrDefault();
if (othertrack == null)
{
throw new Exception("Playlist tracks have been altered. Unable to Complete move");
}
else
{
movetrack.TrackNumber += 1;
othertrack.TrackNumber -= 1;
}
}
}
//staging
//update
context.Entry(movetrack).Property(y => y.TrackNumber).IsModified = true;
context.Entry(othertrack).Property(y => y.TrackNumber).IsModified = true;
//commit
context.SaveChanges();
}
}
}
}//eom
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
//early var placeholders
Playlist playlistExist = null;
PlaylistTrack playlistTrackExist = null;
int tracknumber = 0;
using (var context = new ChinookSystemContext())
{
if (string.IsNullOrEmpty(playlistname))
{
//no playlist name supplied -error out
//BusinessRuleException -- part of freecode -import
brokenrules.Add(new BusinessRuleException <string>("playlist name is missing. unable to delete track",
nameof(playlistname), playlistname)); //nameof not requires if specific
}
if (string.IsNullOrEmpty(username))
{
//no playlist name supplied -error out
//BusinessRuleException -- part of freecode -import
brokenrules.Add(new BusinessRuleException <string>("username name is missing. unable to delete track",
"username", username));
}
if (trackstodelete.Count == 0)
{
//no playlist name supplied -error out
//BusinessRuleException -- part of freecode -import
brokenrules.Add(new BusinessRuleException <string>("tracks to delete. unable to delete track",
"track count", trackstodelete.Count.ToString()));
}
playlistExist = (from x in context.Playlists
where x.Name == playlistname && x.UserName == username
select x).FirstOrDefault();
if (playlistExist == null)
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("playlist no exist",
nameof(playlistname), playlistname));
}
else
{
//good data
//list all tracks that are to be kept
//compare lists of delete to list of kept
var trackskept = from x in context.PlaylistTracks
where x.Playlist.Name == playlistname && x.Playlist.UserName == username && !trackstodelete.Any(tod => tod == x.TrackId)
orderby x.TrackNumber
select x;
//remove the desired track refrences
PlaylistTrack item = null;
foreach (var deleterecord in trackstodelete)
{
item = (from x in context.PlaylistTracks
where x.Playlist.Name == playlistname && x.Playlist.UserName == username && x.TrackId == deleterecord
orderby x.TrackNumber
select x).FirstOrDefault();
if (item != null)
{
//delete
//stage via parent.nav.remove()
playlistExist.PlaylistTracks.Remove(item);
}
}
//resequence the kept tracks
// option - use a list and update the records of the list
//option - delete all children records and re-add only the new kept records list
tracknumber = 1;
foreach (var track in trackskept)
{
track.TrackNumber = tracknumber;
//stage
context.Entry(track).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
tracknumber++;
}
//commit
if (brokenrules.Count > 0)
{
throw new BusinessRuleCollectionException("Track removal concerns", brokenrules);
}
else
{
context.SaveChanges();
}
}
}
}//eom
}//eom
public void MoveTrack(MoveTrackItem movetrack)
{
using (var context = new ChinookSystemContext())
{
//inital value errorchecking
if (string.IsNullOrEmpty(movetrack.PlaylistName))
{
//no playlist name supplied -error out
//BusinessRuleException -- part of freecode -import
brokenrules.Add(new BusinessRuleException <string>("playlist name is missing. unable to delete track",
nameof(movetrack.PlaylistName), movetrack.PlaylistName)); //nameof not requires if specific
}
if (string.IsNullOrEmpty(movetrack.UserName))
{
//no playlist name supplied -error out
//BusinessRuleException -- part of freecode -import
brokenrules.Add(new BusinessRuleException <string>("username name is missing. unable to delete track",
"username", movetrack.UserName));
}
if (movetrack.TrackID <= 0)
{
brokenrules.Add(new BusinessRuleException <string>("trackID no bueno",
"trackID", movetrack.TrackID.ToString()));
}
if (movetrack.TrackNumber <= 0)
{
brokenrules.Add(new BusinessRuleException <string>("trackID no bueno",
"track Number", movetrack.TrackNumber.ToString()));
}
Playlist exist = (from x in context.Playlists
where x.Name == movetrack.PlaylistName && x.UserName == movetrack.UserName
select x).FirstOrDefault();
if (exist == null)
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("playlist no exist",
nameof(movetrack.PlaylistName), movetrack.PlaylistName));
}
else
{
//check if track exists on the database
PlaylistTrack trackexists = (from x in context.PlaylistTracks
where
x.Playlist.Name == movetrack.PlaylistName
&&
x.Playlist.UserName == movetrack.UserName
&&
x.TrackId == movetrack.TrackID
select x).FirstOrDefault();
if (trackexists == null)
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("playlist track no exist",
nameof(movetrack.TrackID), movetrack.TrackNumber.ToString())); //should lookup name.
}
else
{
//move it up or move it down
if (movetrack.Direction == "up")
{
//up
//check to see if at top - != 1
if (trackexists.TrackNumber != 1)
{
// do the move
//get adjacent track
PlaylistTrack othertrack = (from x in context.PlaylistTracks
where x.Playlist.Name == movetrack.PlaylistName
&&
x.Playlist.UserName == movetrack.UserName
&&
x.TrackNumber == trackexists.TrackNumber - 1
select x).FirstOrDefault();
//check other track exists
if (othertrack != null)
{
//good to swap
//swap is a matter of changing the track Number Values
trackexists.TrackNumber--;
othertrack.TrackNumber++;
//stage
context.Entry(trackexists).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(othertrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
else
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("track to swap is missing",
nameof(othertrack.Track.Name), othertrack.Track.Name));
}
}
else
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("playlist track already #1, refresh display",
nameof(movetrack.PlaylistName), trackexists.Track.Name));
}
}
else
{
int trackcountonexist = (from x in context.Playlists
where x.Name == movetrack.PlaylistName && x.UserName == movetrack.UserName
select x).FirstOrDefault().PlaylistTracks.ToList().Count();
trackcountonexist++; //lazy loader bullshi......
//down
//up
//check to see if at Bottom - != count of the existing playlist
if (trackexists.TrackNumber != trackcountonexist--)
{
// do the move
//get adjacent track
PlaylistTrack othertrack = (from x in context.PlaylistTracks
where x.Playlist.Name == movetrack.PlaylistName
&&
x.Playlist.UserName == movetrack.UserName
&&
x.TrackNumber == trackexists.TrackNumber + 1
select x).FirstOrDefault();
//check other track exists
if (othertrack != null)
{
//good to swap
//swap is a matter of changing the track Number Values
trackexists.TrackNumber++;
othertrack.TrackNumber--;
//stage
context.Entry(trackexists).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(othertrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
else
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("track to swap is missing",
nameof(othertrack.Track.Name), othertrack.Track.Name));
}
}
else
{
//broken rule
brokenrules.Add(new BusinessRuleException <string>("playlist track already #1, refresh display",
nameof(movetrack.PlaylistName), trackexists.Track.Name));
}
}
}
}
//resequence the kept tracks
// option - use a list and update the records of the list
//option - delete all children records and re-add only the new kept records list
//commit
if (brokenrules.Count > 0)
{
throw new BusinessRuleCollectionException("Track movement concerns", brokenrules);
}
else
{
context.SaveChanges();
}
}
}//eom
} //eom
public void MoveTrack(string username, string playlistname, int trackid, int tracknumber, string direction)
{
using (var context = new ChinookSystemContext())
{
//code to go here
//check to see if the playlist exists
//no:error exception
//yes:
////up:check if on the top
/////yes:error exception
/////no:find record above(tracknumber -1)
/////above record tracknumber modified to tracknumber +1
/////selected tracknumber modified to tracknumber-1
///////down:check if on the bottom
/////yes:error exception
/////no:find record below(tracknumber +1)
/////below record tracknumber modified to tracknumber -1
/////selected tracknumber modified to tracknumber+1
//stage record update
//commit
List <string> errors = new List <string>();//use for businessrule exception
PlaylistTrack moveTrack = null;
PlaylistTrack otherTrack = null;
Playlist exists = (from x in context.Playlists
where x.Name.Equals(playlistname) && x.UserName.Equals(username)
select x).FirstOrDefault();
if (exists == null)
{
errors.Add("Playlist does not exist.");
}
else
{
moveTrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) && x.Playlist.UserName.Equals(username) && x.TrackId == trackid
select x).FirstOrDefault();
if (moveTrack == null)
{
errors.Add("Playlist track does not exist");
}
else
{
if (direction.Equals("up"))
{
//this means the tracknumber of the selected track will decrease
//prep for move, check if the track is at the top of the list
if (moveTrack.TrackNumber == 1)
{
errors.Add("Song on play list already at the top.");
}
else
{
otherTrack = (from x in context.PlaylistTracks
where x.TrackNumber == (moveTrack.TrackNumber - 1) && x.Playlist.Name.Equals(playlistname) && x.Playlist.UserName.Equals(username)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missing required other song track record.");
}
else
{
moveTrack.TrackNumber -= 1;
otherTrack.TrackNumber += 1;
}
}
}
else
{
if (moveTrack.TrackNumber == exists.PlaylistTracks.Count)
{
errors.Add("Song on play list already at the bottom.");
}
else
{//4=>5
otherTrack = (from x in context.PlaylistTracks
where x.TrackNumber == (tracknumber + 1) && x.Playlist.Name.Equals(playlistname) && x.Playlist.UserName.Equals(username)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missing required other song track record.");
}
else
{
moveTrack.TrackNumber += 1;
otherTrack.TrackNumber -= 1;
}
}
}
}
}
if (errors.Count > 0)
{
throw new BusinessRuleException("Move Track", errors);
}
else
{
//stage
//1)you can stage an update to alter the entire entity(CRUD)
//2)You can stage an update to an entity referencing JUST the property to be modified
//in this example (b) will be used
context.Entry(moveTrack).Property("TrackNumber").IsModified = true;
context.Entry(otherTrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.SaveChanges();
}
}
}//eom
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
using (var context = new ChinookSystemContext())
{
Playlist playlistExists = null;
int tracknumber = 0;
if (string.IsNullOrEmpty(playlistname))
{
//there is a data error
//setting up an error message:
brokenRules.Add(new BusinessRuleException <string>("Playlist name is missing. Unable to add track.",
nameof(playlistname), playlistname));
}
if (string.IsNullOrEmpty(username))
{
//there is a data error
//setting up an error message:
brokenRules.Add(new BusinessRuleException <string>("User name is missing. Unable to remove track(s)",
"User Name", username));
}
if (trackstodelete.Count == 0)
{
//there is a data error
//setting up an error message:
brokenRules.Add(new BusinessRuleException <int>("Playlist name is missing. Unable to remove track(s)",
"Track list count", 0));
}
playlistExists = (from x in context.Playlists
where x.Name.Equals(playlistname) &&
x.UserName.Equals(username)
select x).FirstOrDefault();
if (playlistExists == null)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist does not exist.",
nameof(playlistname), playlistname));
}
else
{
//list of all tracks that are to be kept
var trackskept = context.PlaylistTracks
.Where(x => x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
!trackstodelete.Any(tod => tod == x.TrackId))
.OrderBy(x => x.TrackNumber)
.Select(x => x);
//remove the desired tracks
PlaylistTrack item = null;
foreach (var deleterecord in trackstodelete) //tracksids to delete
{
//getting a single record
item = context.PlaylistTracks
.Where(x => x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
x.TrackId == deleterecord)
.Select(x => x).FirstOrDefault();
//delete
//stage (parent.navproperty.Remove()
if (item != null)
{
playlistExists.PlaylistTracks.Remove(item);
}
}
//re-sequence the kept tracks
//Option A) use a list and update the records of the list.
//Option B) delete all children records and re-add only the necessary kept records.
//within this example, you will see how to update specific column(s) of a record. (OptionA)
tracknumber = 1;
foreach (var track in trackskept)
{
track.TrackNumber = tracknumber;
//Stage the update
context.Entry(track).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
tracknumber++;
}
}
//commit?
if (brokenRules.Count > 0)
{
throw new BusinessRuleCollectionException("Track Removal Concerns:", brokenRules);
}
else
{
context.SaveChanges();
}
}
}//eom
}//eom
public void MoveTrack(MoveTrackItem movetrack)
{
int numberoftracks = 0;
using (var context = new ChinookSystemContext())
{
if (string.IsNullOrEmpty(movetrack.PlaylistName))
{
//there is a data error
//setting up an error message
brokenRules.Add(new BusinessRuleException <string>("Playlist name is missing. Unable to remove track(s)",
"Playlist Name", movetrack.PlaylistName));
}
if (string.IsNullOrEmpty(movetrack.UserName))
{
//there is a data error
//setting up an error message
brokenRules.Add(new BusinessRuleException <string>("User name is missing. Unable to remove track(s)",
"User Name", movetrack.UserName));
}
if (movetrack.TrackID <= 0)
{
brokenRules.Add(new BusinessRuleException <int>("Invalid track identifier. Unable to remove track(s)",
"Track Identifier", movetrack.TrackID));
}
if (movetrack.TrackNumber <= 0)
{
brokenRules.Add(new BusinessRuleException <int>("Invalid track number. Unable to remove track(s)",
"Track Number", movetrack.TrackNumber));
}
Playlist exist = (from x in context.Playlists
where x.Name.Equals(movetrack.PlaylistName) &&
x.UserName.Equals(movetrack.UserName)
select x).FirstOrDefault();
if (exist == null)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist does not exist.",
nameof(MoveTrackItem.PlaylistName), movetrack.PlaylistName));
}
else
{
//due to the way that LInq executes in your program as a "lazy loader"
//we need to query directly the number of tracks in the playlist
numberoftracks = (context.PlaylistTracks
.Where(x => x.Playlist.Name.Equals(movetrack.PlaylistName) && x.Playlist.UserName.Equals(movetrack.UserName))
.Select(x => x)).Count();
//check to see if the desired track exists on the database
PlaylistTrack trackexist = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(movetrack.PlaylistName) &&
x.Playlist.UserName.Equals(movetrack.UserName) &&
x.TrackId == movetrack.TrackID
select x).FirstOrDefault();
if (trackexist == null)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist track does not exist.",
nameof(MoveTrackItem.PlaylistName), movetrack.PlaylistName));
}
else
{
//decide the logic depending on direction
if (movetrack.Direction.Equals("up"))
{
//up
//not at top
if (trackexist.TrackNumber == 1)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist track already at the top. Refresh your display.",
nameof(Track.Name), trackexist.Track.Name));
}
else
{
//do the move
//get the adjacent track
PlaylistTrack othertrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(movetrack.PlaylistName) &&
x.Playlist.UserName.Equals(movetrack.UserName) &&
x.TrackNumber == trackexist.TrackNumber - 1
select x).FirstOrDefault();
if (othertrack == null)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist track to swap seems to be missing. Refresh your display.",
nameof(MoveTrackItem.PlaylistName), movetrack.PlaylistName));
}
else
{
//good to swap
//the swap is a matter of changing the tracknumber values
trackexist.TrackNumber -= 1;
othertrack.TrackNumber += 1;
//staging
context.Entry(trackexist).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(othertrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
}
}
else
{
//down
//not at bottom
if (trackexist.TrackNumber == numberoftracks)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist track already at the bottom. Refresh your display.",
nameof(Track.Name), trackexist.Track.Name));
}
else
{
//do the move
//get the adjacent track
PlaylistTrack othertrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(movetrack.PlaylistName) &&
x.Playlist.UserName.Equals(movetrack.UserName) &&
x.TrackNumber == trackexist.TrackNumber + 1
select x).FirstOrDefault();
if (othertrack == null)
{
brokenRules.Add(new BusinessRuleException <string>("Playlist track to swap seems to be missing. Refresh your display.",
nameof(MoveTrackItem.PlaylistName), movetrack.PlaylistName));
}
else
{
//good to swap
//the swap is a matter of changing the tracknumber values
trackexist.TrackNumber += 1;
othertrack.TrackNumber -= 1;
//staging
context.Entry(trackexist).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(othertrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
}
}
}
}
//commit?
if (brokenRules.Count > 0)
{
throw new BusinessRuleCollectionException("Track Movement Concerns:", brokenRules);
}
else
{
context.SaveChanges();
}
}
}//eom
} //eom
public void MoveTrack(string username, string playlistname, int trackid, int tracknumber, string direction)
{
using (var context = new ChinookSystemContext())
{
//trx
//check to see if the playlist exsits
//no: error exception
//yes:
// check to see if song exists
// no: error exception
// yes:
// up
// check to see if the song is at the top
// yes: error exception
// no:
// move record 4; above record 3
// find record above (tracknumber -1)
// change above tracknumber (increment)
// move track tracknumber (decrement)
// down
// check to see if the song is at the bottom
// yes: error exception
// no:
// move record 4; below record 5
// find record below (tracknumber +1)
// change below tracknumber (decrement)
// move track tracknumber (increment)
//can I stage/commit
//no: throw the exception (BRE)
//yes:
// stage updates
// commit
PlaylistTrack moveTrack = null;
PlaylistTrack otherTrack = null;
List <string> errors = new List <string>(); // this is to be used by BusinessRuleException cast
//.FirstOrDefault() returns the first instance matching the criteria or null
Playlist exists = (from x in context.Playlists
where x.Name.Equals(playlistname) &&
x.UserName.Equals(username)
select x).FirstOrDefault();
if (exists == null)
{
errors.Add("Play list does not exist");
}
else
{
moveTrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
x.TrackId == trackid
select x).FirstOrDefault();
if (moveTrack == null)
{
errors.Add("Play list track does not exist");
}
else
{
if (direction.Equals("up"))
{
//up
//this means the tracknumber on the selected track
// will decrease (track 4 -> 3)
//prep for move, check if the track is at the top
if (moveTrack.TrackNumber == 1)
{
errors.Add("Play list track already at the top.");
}
else
{
//manipulate the actal records
otherTrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
x.TrackNumber == (moveTrack.TrackNumber - 1)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missng required othe song track record.");
}
else
{
moveTrack.TrackNumber -= 1;
otherTrack.TrackNumber += 1;
}
}
}
else
{
//down
//this means the tracknumber on the selected track
// will increase (track 4 -> 5)
//prep for move, check if the track is at the bottom
int songcount = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username)
select x).Count();
if (moveTrack.TrackNumber == songcount)
{
errors.Add("Play list track already at the bottom.");
}
else
{
//manipulate the actal records
otherTrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
x.TrackNumber == (moveTrack.TrackNumber + 1)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missng required othe song track record.");
}
else
{
moveTrack.TrackNumber += 1;
otherTrack.TrackNumber -= 1;
}
}
}
}
}
//check to see if an error has occured, if so throw
if (errors.Count > 0)
{
throw new BusinessRuleException("Move Track", errors);
}
else
{
//stage
//these are updates
//a) you can stage an update to alter the entire entity (CRUD)
//b) you can stage an update to an entity referencing JUST the property
// to be modified
//in this example do stage (b)
context.Entry(moveTrack).Property("TrackNumber").IsModified = true;
context.Entry(otherTrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
//commit
context.SaveChanges();
}
}
}//eom
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
using (var context = new ChinookSystemContext())
{
//trx
//check to see if the playlist exists
// no: msg
// yes:
// create a list of tracks to kept (need to know which records to renumber)
// remove the tracks in the incoming list (multiple deletes)
// re-sequence the kept tracks (update)
// commit
List <string> errors = new List <string>(); // this is to be used by BusinessRuleException cast
//.FirstOrDefault() returns the first instance matching the criteria or null
Playlist exists = (from x in context.Playlists
where x.Name.Equals(playlistname) &&
x.UserName.Equals(username)
select x).FirstOrDefault();
if (exists == null)
{
errors.Add("Play list does not exist");
}
else
{
//find tracks to keep
//used .Any technique of list a vs list b
//could this also be done with .Exclude()
var trackskept = context.PlaylistTracks
.Where(tr => tr.Playlist.Name.Equals(playlistname) &&
tr.Playlist.UserName.Equals(username) &&
!trackstodelete.Any(tod => tod == tr.TrackId))
.OrderBy(tr => tr.TrackNumber)
.Select(tr => tr);
//remove the tracks listed in trackstodelete
PlaylistTrack item = null;
foreach (int deletetrackid in trackstodelete)
{
item = context.PlaylistTracks
.Where(tr => tr.Playlist.Name.Equals(playlistname) &&
tr.Playlist.UserName.Equals(username) &&
tr.TrackId == deletetrackid)
.Select(tr => tr).FirstOrDefault();
if (item != null)
{
//stage the removal
exists.PlaylistTracks.Remove(item);
}
}
//re-sequence
//don't care if the remaining tracknumbers are 1,4,5,8,10
//renumber 1(1),2(4),3(5),4(8),5(10)
int number = 1;
foreach (var track in trackskept)
{
track.TrackNumber = number;
//stage update
context.Entry(track).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
number++;
}
}
if (errors.Count > 0)
{
throw new BusinessRuleException("Remove Tracks", errors);
}
else
{
context.SaveChanges();
}
}
}//eom
} //eom
public void MoveTrack(string username, string playlistname, int trackid, int tracknumber, string direction)
{
using (var context = new ChinookSystemContext())
{
//trx
//check to see if the playlist exists
//no: error exception
//yes:
// Check to see if song exists
// no: error exception
// yes:
//// //up:
//// //check to see if song is at the top
//// //yes: error exception
//// // no:
//// //find record above (tracknumber-1
//// //change above record tracknumber modified to tracknumber + 1
//// //selected record tracnumber modified to tracknumbere - 1
//// //down:
//// //check to see if song is at the botom
//// //yes: error exception
//// //no:
//// //find record above (tracknumber+1
//// //change above record tracknumber modified to tracknumber - 1
//// //selected record tracnumber modified to tracknumbere + 1
////stage records
//commit
PlaylistTrack moveTrack = null;
PlaylistTrack otherTrack = null;
List <string> errors = new List <string>(); //for use by BusinessRuleException
Playlist exists = (from x in context.Playlists
where x.Name.Equals(playlistname) &&
x.UserName.Equals(username)
select x).FirstOrDefault();
//if not
if (exists == null)
{
errors.Add("Playlist does not exist");
}
else
{
moveTrack = (from x in context.PlaylistTracks
where x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username) &&
x.TrackId == trackid
select x).FirstOrDefault();
if (moveTrack == null)
{
errors.Add("Playlist track does not exist");
}
else
{
if (direction.Equals("up")) //Move Uo
{
//this means the track number of the selectred track
// will decrease (track 4 => 3)
//preparation for move, check if the track is at the top of the list
if (moveTrack.TrackNumber == 1)
{
errors.Add("song on playlist already at the top");
}
else
{
//Manipulation of the actual records
//the following test conditions identify the playlistID value
// x.Playlist.Name.Equals(playlistname)
// x.Playlist.UserName.Equals(username)
otherTrack = (from x in exists.PlaylistTracks
where x.TrackNumber == tracknumber - 1 &&
x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missing required other song record.");
}
else
{
moveTrack.TrackNumber -= 1;
otherTrack.TrackNumber += 1;
}
}
}
else //Move Down
{
if (moveTrack.TrackNumber == exists.PlaylistTracks.Count)
{
errors.Add("song on playlist already at the bottom");
}
else
{
//Manipulation of the actual records
//(track 4->5)
otherTrack = (from x in exists.PlaylistTracks
where x.TrackNumber == tracknumber + 1 &&
x.Playlist.Name.Equals(playlistname) &&
x.Playlist.UserName.Equals(username)
select x).FirstOrDefault();
if (otherTrack == null)
{
errors.Add("Missing required other song record.");
}
else
{
moveTrack.TrackNumber += 1;
otherTrack.TrackNumber -= 1;
}
}
}
}
}
if (errors.Count > 0)
{
throw new BusinessRuleException("Move Track", errors);
}
else
{
//stage changes
//a)you can stage an update to alter the entire entity
//b) you can stage an update to an entity referencing JUST the property
// to be modified
//in this example B will be used
context.Entry(moveTrack).Property("TrackNumber").IsModified = true;
context.Entry(otherTrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
//commit
context.SaveChanges();
}
}
}//eom
}//eom
public void DeleteTracks(string username, string playlistname, List <int> trackstodelete)
{
Playlist playlistExist = null;
//PlaylistTrack playlisttrackExist = null;
int trackNumber = 0;
using (var context = new ChinookSystemContext())
{
//code to go here
if (string.IsNullOrEmpty(playlistname))
{
//there is a data error
//setting up an error message
//brokenRules.Add(new BusinessRuleException<datatype>("my message", //nameof("fieldnameinerror"), fieldnameinerror));
brokenRules.Add(new BusinessRuleException <string>("playlist name is missing, Unable to add track", "Playlist Name", playlistname));
}
if (string.IsNullOrEmpty(username))
{
brokenRules.Add(new BusinessRuleException <string>("username is missing, Unable to add a track", "User Name", username));
}
if (trackstodelete.Count == 0)
{
brokenRules.Add(new BusinessRuleException <int>("No tracks we selected. Unable to remove track(s)", "Track list count", 0));
}
playlistExist = context.Playlists.Where(x => x.Name.Equals(playlistname) && x.UserName.Equals(username)).FirstOrDefault();
if (playlistExist == null)
{
brokenRules.Add(new BusinessRuleException <string>("playlist does not exist", nameof(playlistname), playlistname));
}
else
{
//list of all tracks to be kept
var trackskept = context.PlaylistTracks.Where(x => x.Playlist.UserName.Equals(username) && x.Playlist.Name.Equals(trackNumber) && !trackstodelete.Any(tod => tod == x.TrackId)).OrderBy(x => x.TrackNumber).Select(x => x).ToList();
//remove the desired tracks
PlaylistTrack item = null;
foreach (var deleteRecord in trackstodelete)
{
item = context.PlaylistTracks.Where(x => x.Playlist.UserName.Equals(username) && x.Playlist.Name.Equals(trackNumber) && x.TrackId == deleteRecord).FirstOrDefault();
//delete
//stage (parent.navproperty.remove)
if (item != null)
{
playlistExist.PlaylistTracks.Remove(item);
}
}
//re-sequence the list
//option a) use a list and update the records of the list
//option b) to delete all children records and re add onl the necessary kept records
//Within this example, you'll see an update specific columns of a records(option a)
trackNumber = 1;
foreach (var track in trackskept)
{
track.TrackNumber = trackNumber;
//stage a single field to be updated
context.Entry(track).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
trackNumber++;
}
}
//commit?
if (brokenRules.Count > 0)
{
throw new BusinessRuleCollectionException("Track Removal concerns: ", brokenRules);
}
else
{
context.SaveChanges();
}
}
}//eom
}//eom
public void MoveTrack(MoveTrackItem moveTrack)
{
using (var context = new ChinookSystemContext())
{
//code to go here
if (string.IsNullOrEmpty(moveTrack.PlaylistName))
{
//there is a data error
//setting up an error message
//brokenRules.Add(new BusinessRuleException<datatype>("my message", //nameof("fieldnameinerror"), fieldnameinerror));
brokenRules.Add(new BusinessRuleException <string>("playlist name is missing, Unable to add track", "Playlist Name", moveTrack.PlaylistName));
}
if (string.IsNullOrEmpty(moveTrack.UserName))
{
brokenRules.Add(new BusinessRuleException <string>("username is missing, Unable to add a track", "User Name", moveTrack.UserName));
}
if (moveTrack.TrackId <= 0)
{
brokenRules.Add(new BusinessRuleException <int>("Invalid track identifier, Unable to move a track", "Track Identifier", moveTrack.TrackId));
}
if (moveTrack.TrackNumber <= 0)
{
brokenRules.Add(new BusinessRuleException <int>("Invalid track number, Unable to move a track(s)", "Track Number", moveTrack.TrackNumber));
}
Playlist exist = context.Playlists.Where(x => x.Name.Equals(moveTrack.PlaylistName) && x.UserName.Equals(moveTrack.UserName)).FirstOrDefault();
if (exist == null)
{
brokenRules.Add(new BusinessRuleException <string>("playlist does not exist", nameof(MoveTrackItem.PlaylistName), moveTrack.PlaylistName));
}
else
{
//list of all tracks to be kept
//Chec
PlaylistTrack trackExist = context.PlaylistTracks.Where(x => x.Playlist.Name.Equals(moveTrack.PlaylistName) && x.TrackId == moveTrack.TrackId && x.Playlist.UserName.Equals(moveTrack.UserName) && x.TrackNumber == moveTrack.TrackNumber).FirstOrDefault();
if (trackExist == null)
{
brokenRules.Add(new BusinessRuleException <string>("track name does not exist", "Track Name", moveTrack.PlaylistName));
}
else
{
if (moveTrack.Direction.Equals("up"))
{
if (trackExist.TrackNumber == 1)
{
brokenRules.Add(new BusinessRuleException <string>("playlist trac k already on the top.Refresh your display", nameof(Track.Name), trackExist.Track.Name));
}
else
{
//do tthe moeve
//get the adajacent track
PlaylistTrack otherTrack = context.PlaylistTracks.Where(x => x.Playlist.Name.Equals(moveTrack.PlaylistName) && x.Playlist.UserName.Equals(moveTrack.UserName) && x.TrackNumber == (trackExist.TrackNumber - 1)).Select(x => x).FirstOrDefault();
if (otherTrack == null)
{
brokenRules.Add(new BusinessRuleException <string>("playlist to swap seems to be missing.Refresh your display", nameof(MoveTrackItem.PlaylistName), moveTrack.PlaylistName));
}
else
{
//good to swap
//the swap is a mattter of changing track number value
trackExist.TrackNumber--;
otherTrack.TrackNumber++;
//staging
context.Entry(trackExist).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(otherTrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
}
}
else
{
//down
if (moveTrack.Direction.Equals("down"))
{
var play = context.PlaylistTracks.Where(x => x.Playlist.Name.Equals(moveTrack.PlaylistName) && x.Playlist.UserName.Equals(moveTrack.UserName)).Count();
if (trackExist.TrackNumber == play)
{
brokenRules.Add(new BusinessRuleException <string>("playlist track already on the bottom.Refresh your display", nameof(Track.Name), trackExist.Track.Name));
}
else
{
//do tthe moeve
//get the adajacent track
PlaylistTrack otherTrack = context.PlaylistTracks.Where(x => x.Playlist.Name.Equals(moveTrack.PlaylistName) && x.Playlist.UserName.Equals(moveTrack.UserName) && x.TrackNumber == (trackExist.TrackNumber + 1)).Select(x => x).FirstOrDefault();
if (otherTrack == null)
{
brokenRules.Add(new BusinessRuleException <string>("playlist to swap seems to be missing.Refresh your display", nameof(MoveTrackItem.PlaylistName), moveTrack.PlaylistName));
}
else
{
//good to swap
//the swap is a mattter of changing track number value
trackExist.TrackNumber++;
otherTrack.TrackNumber--;
//staging
context.Entry(trackExist).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
context.Entry(otherTrack).Property(nameof(PlaylistTrack.TrackNumber)).IsModified = true;
}
}
}
}
} //remove the desired tracks
if (brokenRules.Count > 0)
{
throw new BusinessRuleCollectionException("Track Move concerns: ", brokenRules);
}
else
{
context.SaveChanges();
}
}
}
}//eom
