[Serializable]

I am trying to create my project to [Serializable] but I dont know if I am doing the right thing.

on all my classes I have added above my class.....  [Serializable]

then in my form I am trying to save it. See code below.

If I choose from my menu Save it jumps to.....saveToolStripMenuItem
here I send  my animalManager object into binaryFileSerialize
but here it throws a catch:

System.Runtime.Serialization.SerializationException was unhandled
  Message="Type 'Animals.AnimalManager' in Assembly 'Animals, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable."
  Source="mscorlib"
  StackTrace:
       at System.Runtime.Serialization.FormatterServices.InternalGetSerializableMembers(RuntimeType type)
       at System.Runtime.Serialization.FormatterServices.GetSerializableMembers(Type type, StreamingContext context)
       at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitMemberInfo()
       at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter)
       at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.Serialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter)
       at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)
       at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck)
       at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph).............
     

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using Animals;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
 
 
namespace Modul1_Malmoe
{
    [Serializable]
    public partial class Animal : Form
    {       
       AnimalManager animalManager = new AnimalManager();
 
 
        /// <summary>
        /// 
        /// </summary>
        public Animal()
        {
            InitializeComponent();
            
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Form1_Load(object sender, EventArgs e)
        {
            housingCombobox.DataSource = Enum.GetValues(typeof(HousingType));
            sortComboBox.DataSource = Enum.GetValues(typeof(MeatDjur));
            nrOfLegsTextBox.Text = "4";
            nrOfItems.Text = Convert.ToString(animalManager.Counter);
            changeButton.Enabled = false;
            deleteButton.Enabled = false;
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Add_Click(object sender, EventArgs e)
        {
            if (nickNameTextBox.Text.Trim() == String.Empty)
            {
                MessageBox.Show("Please write something in Nick Name before adding", "Information");
            }
 
            else
            {
                string text = sortComboBox.SelectedItem.ToString();
                animalManager.AddNewAnimal(text, nickNameTextBox.Text, (HousingType)housingCombobox.SelectedIndex);
                nrOfItems.Text = Convert.ToString(animalManager.Counter);
                Updater();
            }
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void sortComboBox_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (sortComboBox.SelectedItem.ToString() == "Dog" ||
                sortComboBox.SelectedItem.ToString() == "Giraffe" ||
                sortComboBox.SelectedItem.ToString() == "Wolf" ||
                sortComboBox.SelectedItem.ToString() == "Horse")
                nrOfLegsTextBox.Text = "4";
 
            else if (sortComboBox.SelectedItem.ToString() == "Duck")
                nrOfLegsTextBox.Text = "2";
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        private void Updater()
        {
            AnimalDataGridView.DataSource = null;
            AnimalDataGridView.AutoGenerateColumns = true;
            AnimalDataGridView.DataSource = animalManager.AnimalList;
            nickNameTextBox.Text = "";
            nrOfItems.Text = Convert.ToString(animalManager.Counter);            
            if (animalManager.AnimalList.Count > 0)
            {
                deleteButton.Enabled = true;
                addButton.Enabled = true;
            }
 
            else
            {
                deleteButton.Enabled = false;
                changeButton.Enabled = false;
                addButton.Enabled = true;
            }
         }
 
 
 
        
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void selectedRowsButton_Click(object sender, DataGridViewCellEventArgs e)
        {
            if (MessageBox.Show("Fill in the correct values and press change to save it", "Change", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                addButton.Enabled = false;
                Int32 selected = AnimalDataGridView.CurrentRow.Index;
                nickNameTextBox.Text = animalManager.AnimalList[selected].Name;
                nrOfLegsTextBox.Text = Convert.ToString(animalManager.AnimalList[selected].NumberOfLegs);
                
                int nFoundEl = -1;
                for (int i = 0; i < housingCombobox.Items.Count; i++) 
                {
                    if (housingCombobox.Items[i].ToString().Equals(animalManager.AnimalList[selected].Housing.ToString())) 
                        nFoundEl = i; 
 
                    if (nFoundEl >= 0) 
                    { 
                        housingCombobox.SelectedIndex = nFoundEl; 
                    } //end if
                } //end for
 
                Type t = animalManager.AnimalList[selected].GetType();
                nFoundEl = -1;
                for (int i = 0; i < sortComboBox.Items.Count; i++)
                {
                    if (sortComboBox.Items[i].ToString().Equals(t.Name))
                        nFoundEl = i;
 
                    if (nFoundEl >= 0)
                    {
                        sortComboBox.SelectedIndex = nFoundEl;
                    } //end if
                } //end for
 
                changeButton.Enabled = true;
            } //end if 
 
                      
        } //end selectedRowsButton_Click
 
 
 
 
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void exitButton_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void deleteButton_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Really delete?", "Confirm delete", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                Int32 selected = AnimalDataGridView.CurrentRow.Index;
                animalManager.AnimalList.RemoveAt(selected);                
                animalManager.Counter--;
                Updater();
                changeButton.Enabled = false;
            } 
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void resetButton_Click(object sender, EventArgs e)
        {
            housingCombobox.DataSource = Enum.GetValues(typeof(HousingType));
 
            if(meatRadioButton.Checked)                
                sortComboBox.DataSource = Enum.GetValues(typeof(MeatDjur));
 
            else
                sortComboBox.DataSource = Enum.GetValues(typeof(PlantDjur));
 
            nrOfLegsTextBox.Text = "4";
            nrOfItems.Text = Convert.ToString(animalManager.Counter);
            
            nickNameTextBox.Text = "";
 
            if (animalManager.AnimalList.Count > 0)
            {
                deleteButton.Enabled = true;
                addButton.Enabled = true;
            }
 
            else
            {
                deleteButton.Enabled = false;
                changeButton.Enabled = false;
                addButton.Enabled = true;
            }
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void changeButton_Click(object sender, EventArgs e)
        {
 
            Int32 selected = AnimalDataGridView.CurrentRow.Index;
            animalManager.AnimalList.RemoveAt(selected);
            animalManager.Counter--;
            Add_Click(this, EventArgs.Empty);
            resetButton_Click(this, EventArgs.Empty);
            MessageBox.Show("Saved", "Saved");
            changeButton.Enabled = false;
            
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void meatRadioButton_CheckedChanged(object sender, EventArgs e)
        {
            sortComboBox.DataSource = Enum.GetValues(typeof(MeatDjur));
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PlantRdioButton_CheckedChanged(object sender, EventArgs e)
        {
            sortComboBox.DataSource = Enum.GetValues(typeof(PlantDjur));
        }
 
        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
 
        }
 
        private void menuStrip1_ItemClicked(object sender, ToolStripItemClickedEventArgs e)
        {
 
        }
 
        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
 
        private void saveToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Object obj = animalManager;
            binaryFileSerialize(obj, Convert.ToString(Environment.SpecialFolder.MyDocuments));
            
 
 
        }
 
 
        public static void binaryFileSerialize(Object obj, string filePath)
        {
            FileStream fileStream = null;
            
             
            try
            {
                fileStream = new FileStream(filePath,  FileMode.Create);
                BinaryFormatter b =  new BinaryFormatter();
                b.Serialize(fileStream, obj);
            }
 
            catch
            {
                throw;
            }
            finally
            {
                if (fileStream != null)
                fileStream.Close();
            }
        }
 
        private void newToolStripMenuItem_Click(object sender, EventArgs e)
        {
 
        }
 
        private void openToolStripMenuItem_Click(object sender, EventArgs e)
        {
            string nameOfFile = "";
            OpenFileDialog openExtensFile = new OpenFileDialog();
            openExtensFile.Title = "C#";
            openExtensFile.InitialDirectory = @"c:\";
            openExtensFile.Filter = "All files (*.*)|*.*|All files (*.*)|*.*";
            openExtensFile.FilterIndex = 2;
            openExtensFile.RestoreDirectory = true;
            if (openExtensFile.ShowDialog() == DialogResult.OK)
            {
                //nameOfFile = fdlg.FileName ; 
            } 
        }
 
        private void saveAsToolStripMenuItem_Click(object sender, EventArgs e)
        {
            SaveFileDialog saveFileDialog1 = new SaveFileDialog(); 
            saveFileDialog1.InitialDirectory = Convert.ToString(Environment.SpecialFolder.MyDocuments); 
            saveFileDialog1.Filter = "Your extension here (*.EXT)|*.ext|All Files (*.*)|*.*" ; 
            saveFileDialog1.FilterIndex = 1; if(saveFileDialog1.ShowDialog() == DialogResult.OK) 
            {         
                Console.WriteLine(saveFileDialog1.FileName);//Do what you want here
                //this.textBox1.Text = saveFileDialog.FileName;
            }
        }
 
 
 
    }
}
 
 
............................................................................................................
 
 
 
using System;
using System.Collections.Generic;
using System.Text;
 
namespace Animals
{
    [Serializable]
    public class AnimalManager
    {
        private int count = 0;
        private List<Animal> animalList = new List<Animal>();     
 
 
        /// <summary>
        /// 
        /// </summary>
        public AnimalManager()
        {
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        public int Counter
        {
            get { return count; }
            set { count = value; }
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        public List<Animal> AnimalList
        {
            get { return animalList; }
            set { animalList = value; }
        }
 
 
 
        /// <summary>
        /// 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="animal"></param>
        /// <param name="searchedType"></param>
        /// <returns></returns>
        public int Search<T>(List<Animal> animal, Type searchedType)
          where T : class
        {
            int count = 0;
 
            List<String> ids = new List<String>();
            Type typ = typeof(Animal);
 
            for (int i = 0; i < animal.Count; i++)
            {
 
                if (searchedType.IsAssignableFrom(animal[i].GetType()))
                {
                    typ = animal[i].GetType();
                    ids.Add(animal[i].ID);
                    count++;
                }
            }
             
            ids.Sort();
 
            int counter = 1;
            for (int i = 0; i < animal.Count; i++)
            {
                int m = 0;
                foreach (string j in ids)
                {
                    
                    int temp = Convert.ToInt32(ids[m].Substring(4));
                    m++;
                    if (counter != temp)
                     break;
                 counter++;
                 
                }
               
            }
 
           return counter;
 
}  
 
 
         
 
        /// <summary>
        /// 
        /// </summary>
        /// <param name="ids"></param>
        /// <param name="j"></param>
        /// <param name="typ"></param>
        /// <returns></returns>
        public bool Exists(String ids, int j, Type typ)
        {
            String nr = "";
            j++;
            if (typ.Name.Equals("Dog"))
            {
                if (j < 10)
                    nr = "ID:D00" + Convert.ToString((j));
 
                else if (j < 100)
                    nr = "ID:D0" + Convert.ToString((j));
 
                else
                    nr = "ID:D" + Convert.ToString((j));
 
 
                if (nr.Equals(ids))
                {
                    return true;
                }
            }
            return false;
        }
 
       
        /// <summary>
        /// 
        /// </summary>
        /// <param name="text"></param>
        /// <param name="nickName"></param>
        /// <param name="housing"></param>
        public void AddNewAnimal(String text, String nickName, HousingType housing)
        {
            if (text == "Dog")
            {
                //int test = Exists<Animal>(animalList, 
                int dogCount = Search<Animal>(animalList, typeof(Dog)); 
 
                string id;
 
                if (dogCount < 10)
                    id = "ID:D00" + Convert.ToString(dogCount);
 
                else if (dogCount < 100)
                    id = "ID:D0" + Convert.ToString(dogCount);
 
                else
                    id = "ID:D" + Convert.ToString(dogCount);
 
                Dog dog = new Dog(nickName, id, housing);
                animalList.Add(dog);
                Counter++;
 
            }
 
            else if (text == "Giraffe")
            {                
                int giraffeCount = Search<Animal>(animalList, typeof(Giraffe));
                string id;
                if (giraffeCount < 10)
                    id = "ID:G00" + Convert.ToString(giraffeCount);
 
                else if (giraffeCount < 100)
                    id = "ID:G0" + Convert.ToString(giraffeCount);
 
                else
                    id = "ID:G" + Convert.ToString(giraffeCount);
 
                Giraffe giraffe = new Giraffe(nickName, id, housing);
                animalList.Add(giraffe);
                Counter++;
            }
 
            else if (text == "Wolf")
            {
                int wolfCount = Search<Animal>(animalList, typeof(Wolf));
                string id;
                if (wolfCount < 10)
                    id = "ID:W00" + Convert.ToString(wolfCount);
 
                else if (wolfCount < 100)
                    id = "ID:W0" + Convert.ToString(wolfCount);
 
                else
                    id = "ID:W" + Convert.ToString(wolfCount);
 
                Wolf wolf = new Wolf(nickName, id, housing);
                animalList.Add(wolf);
                Counter++;
            }
 
            else if (text == "Horse")
            {
                int horseCount = Search<Animal>(animalList, typeof(Horse));
                string id;
                if (horseCount < 10)
                    id = "ID:H00" + Convert.ToString(horseCount);
 
                else if (horseCount < 100)
                    id = "ID:H0" + Convert.ToString(horseCount);
 
                else
                    id = "ID:H" + Convert.ToString(horseCount);
 
                Horse horse = new Horse(nickName, id, housing);
                animalList.Add(horse);
                Counter++;
            }
 
            else if (text == "Duck")
            {
                int duckCount = Search<Animal>(animalList, typeof(Duck));
                string id;
                if (duckCount < 10)
                    id = "ID:U00" + Convert.ToString(duckCount);
 
                else if (duckCount < 100)
                    id = "ID:U0" + Convert.ToString(duckCount);
 
                else
                    id = "ID:U" + Convert.ToString(duckCount);
 
                Duck duck = new Duck(nickName, id, housing);
                animalList.Add(duck);
                Counter++;
            }
 
            //else
              //  MessageBox.Show("Något gick fel (Form1, button1_Click()", "Information");             
        }
 
 
        /// <summary>
        /// 
        /// </summary>
        public void TestFood()
        {
            //MessageBox.Show(AnimalList[0].eat("Grass"), "Information");  //ÖRK
            //MessageBox.Show(AnimalList[0].eat("Cats"), "Information");  //GOTT
        }
    }
}

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