C# Sort array of Objects by object type (Icomparable?) - sorting

Question

I want to sort anarray by the object type. So all songs are together, all book are together, and all movies are together.
I am reading a file and determine what each object should be. then creating the object and adding it to the array.
EDIT: Here is the actual code.
static Media[] ReadData()
{
List<Media> things = new List<Media>();
try
{
String filePath = "resources/Data.txt";
string Line;
int counter = 0; // used to check if you have reached the max
number of allowed objects (100)
using (StreamReader File = new System.IO.StreamReader(filePath))
{
while ((Line = File.ReadLine()) != null)
{
This is where each object is created. The file
search for a key word in the beginning of the line, then
creates the corresponding object. It will split the
information on the first line of the object and will
read each line until a "-" character is found and
pass each line into the summary. The summary is then
decrypted and the created object is passed into an
array List. Finally if the array list reaches 100, it
will print "You have reach max number of objects" and
stop reading the file.
if (Line.StartsWith("BOOK"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray){Console.WriteLine(x);} //This is used
for testing
Book tempBook = new Book(tempArray[1],
int.Parse(tempArray[2]), tempArray[3]);
while ((Line = File.ReadLine()) != null)
{
if (Line.StartsWith("-")){break;}
tempBook.Summary = tempBook.Summary + Line;
}
tempBook.Summary = tempBook.Decrypt();
things.Add(tempBook);
counter++;
}
else if (Line.StartsWith("SONG"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray)
{Console.WriteLine(x);} //This is used for testing
Song tempSong = new Song(tempArray[1],
int.Parse(tempArray[2]), tempArray[3], tempArray[4]);
things.Add(tempSong);
counter++;
}
else if (Line.StartsWith("MOVIE"))
{
String[] tempArray = Line.Split('|');
//foreach (string x in tempArray)
{Console.WriteLine(x);} //This is used for testing
Movie tempMovie = new Movie(tempArray[1],
int.Parse(tempArray[2]), tempArray[3]);
while ((Line = File.ReadLine()) != null)
{
if (Line.StartsWith("-")) { break; }
tempMovie.Summary = tempMovie.Summary + Line;
}
tempMovie.Summary = tempMovie.Decrypt();
things.Add(tempMovie);
counter++;
}
if (counter == 100)
{
Console.WriteLine("You have reached the maximum number of media
objects.");
break;
}
}
File.Close();
}
}
return things.ToArray(); // Convert array list to an Array and return the
array.
}
In the main code, I have this:
Media[] mediaObjects = new Media[100];
Media[] temp = ReadData();
int input; // holds the input from a user to determin which action to take
for (int i = 0; i<temp.Length;i++){ mediaObjects[i] = temp[i]; }
I want the array of mediaObjects to be sorted by the what type of objects.
I have also used Icomparable to do an arrayList.sort() but still no luck.
public int CompareTo(object obj)
{
if (obj == null)
{
return 1;
}
Song temp = obj as Song;
if (temp != null)
{
//Type is a string
return this.Type.CompareTo(temp.Type);
}
else
{
return 1;
}
}

Answer 1

So I see you have BOOK, SONG and MOVIE types.
This is a classic case of implementing the IComparable interface - although you are correct with the interface name to implement, you are not using this correctly.
Create a base class by the name MediaObject - this will be the main one for your other types of objects you create.
Add the correct properties you need. In this case, the media type is the one in need.
Let this class implement IComparable to help you with the comparison.
override the CompareTo() method in the PROPER way
public class MediaObject : IComparable
{
private string mediaType;
public string MediaType
{
get {return mediaType;}
set {mediaType=value;}
}
public MediaObject(string mType)
{
MediaType = mType;
}
int IComparable.CompareTo(object obj)
{
MediaObject mo = (MediaObject)obj;
return String.Compare(this.MediaType,mo.MediaType); //implement a case insensitive comparison if needed (for your research)
}
}
You can now compare the MediaObject objects In your main method directly.

Answer 2

Thank for the advice. I ended up just reformating how I was creating the list while reading it. I made multiple lists for each object then just happened each one on to the master list so It showed up sorted. I wish I figured that out before I made this long post.
As far as I could find, you can't sort by the type of object in a generic array. If anyone has a better solution feel free to post it.