docs/geode-native-docs-cpp/serialization/dotnet-serialization/custom-class-igfserializable.html.md.erb

---
title:  Using a Custom Class With IDataSerializable
---

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An example shows how to use the `BankAccount` custom key type and the `AccountHistory` value type that were previously defined.

## Using a BankAccount Object

``` pre
class AccountHistory : IDataSerializable   
   {
      #region Private members
      private List<string> m_history;
      #endregion
      public AccountHistory()
      {
         m_history = new List<string>();
      }
      public void ShowAccountHistory()
      {
         Console.WriteLine("AccountHistory:");
         foreach (string hist in m_history) {
           Console.WriteLine("\t{0}", hist);
         }
      }
      public void AddLog(string entry)
      {
         m_history.Add(entry);
      }
         public static IDataSerializable CreateInstance()
      {
         return new AccountHistory();
      }
      #region IDataSerializable Members
      public void FromData(DataInput input)
      {
         int len = input.ReadInt32();
         m_history.Clear();
         for (int i = 0; i < len; i++) {
            m_history.Add(input.ReadUTF());
         }
         return this;
      }
      public void ToData(DataOutput output)
      {
         output.WriteInt32(m_history.Count);
         foreach (string hist in m_history) {
            output.WriteUTF(hist);
         }
      }
         public UInt32 ClassId
      {
         get
         {
            return 0x05;
         }
      }
      public UInt32 ObjectSize
      {
         get
         {
            UInt32 objectSize = 0;
            foreach (string hist in m_history) {
              objectSize += (UInt32)(hist == null ? 0 : sizeof(char) * hist.Length);
            }
            return objectSize;
         }
      }
      #endregion
   }
      public class TestBankAccount
      {
         public static void Main()
         {
            // Register the user-defined serializable type.
            Serializable.RegisterType(AccountHistory.CreateInstance);
            Serializable.RegisterType(BankAccountKey.CreateInstance);
            // Create a cache.
            CacheFactory cacheFactory = CacheFactory.CreateCacheFactory(null);
            Cache cache = cacheFactory.Create();
            // Create a region.
            RegionFactory regionFactory =
            cache.CreateRegionFactory(RegionShortcut.CACHING_PROXY);
            Region region = regionFactory.Create("BankAccounts");
            // Place some instances of BankAccount cache region.
            BankAccountKey baKey = new BankAccountKey(2309, 123091);
            AccountHistory ahVal = new AccountHistory();
            ahVal.AddLog("Created account");
            region.Put(baKey, ahVal);
            Console.WriteLine("Put an AccountHistory in cache keyed with
            BankAccount.");
            // Display the BankAccount information.
            Console.WriteLine(baKey.ToString());
            // Call custom behavior on instance of AccountHistory.
            ahVal.ShowAccountHistory();
            // Get a value out of the region.
            AccountHistory history = region.Get(baKey) as AccountHistory;
            if (history != null)
            {
               Console.WriteLine("Found AccountHistory in the cache.");
               history.ShowAccountHistory();
               history.AddLog("debit $1,000,000.");
               region.Put(baKey, history);
               Console.WriteLine("Updated AccountHistory in the cache.");
            }
            // Look up the history again.
            history = region.Get(baKey) as AccountHistory;
            if (history != null)
            {
               Console.WriteLine("Found AccountHistory in the cache.");
               history.ShowAccountHistory();
            }
            // Close the cache.
            cache.Close();
         }
      }

      //Example 5.12 Using ICacheLoader to Load New Integers in the Region
      class ExampleLoaderCallback : ICacheLoader
      {
         #region Private members
         private int m_loads = 0;
         #endregion
         #region Public accessors
         public int Loads
         {
            get
            {
               return m_loads;
            }
         }
         #endregion
      }
```