Question

I’m creating an Xbox application and I have this problem with the content pipeline.
Loading .xnb files is not a problem but I can’t seem to find any helpful tutorials on writing via the content pipeline. I want to write an XML whenever the user presses a custom made "save" button.
I’ve searched the web for "saving game sate" etc. but so far I haven’t found a solution for my case.

So, summarized: is there a way to write data (in XML format) via the content pipeline, if my Save() method is called?

Answer 1

Saving and loading during an XNA game involves a series of asynchronous method calls. You’ll find the objects you need in the Microsoft.Xna.Framework.Storage namespace.

Specifically, you need a StorageDevice and a StorageContainer;

private static StorageDevice mStorageDevice;
private static StorageContainer mStorageContainer;

To Save:

public static void SaveGame()
{
   // Call this static method to begin the process; SaveGameDevice is another method in your class
   StorageDevice.BeginShowSelector(SaveGameDevice, null);
}

// this will be called by XNA sometime after your call to BeginShowSelector
// SaveGameContainer is another method in your class
private static void SaveGameDevice(IAsyncResult pAsyncResult)
{       
   mStorageDevice = StorageDevice.EndShowSelector(pAsyncResult);
   mStorageDevice.BeginOpenContainer("Save1", SaveGameContainer, null);
}

// this method does the actual saving
private static void SaveGameContainer(IAsyncResult pAsyncResult)
{
   mStorageContainer = mStorageDevice.EndOpenContainer(pAsyncResult);

   if (mStorageContainer.FileExists("save.dat"))
      mStorageContainer.DeleteFile("save.dat");

   // in my case, I have a BinaryWriter wrapper that I use to perform the save
   BinaryWriter writer = new BinaryWriter(new System.IO.BinaryWriter(mStorageContainer.CreateFile("save.dat")));

   // I save the gamestate by passing the BinaryWriter
   GameProgram.GameState.SaveBinary(writer);

   // then I close the writer
   writer.Close();     

   // clean up
   mStorageContainer.Dispose();
   mStorageContainer = null;
}

Loading is very similar:

public static void LoadGame()
{
    StorageDevice.BeginShowSelector(LoadGameDevice, null);
}

private static void LoadGameDevice(IAsyncResult pAsyncResult)
{
   mStorageDevice = StorageDevice.EndShowSelector(pAsyncResult);
   mStorageDevice.BeginOpenContainer("Save1", LoadGameContainer, null);
}

private static void LoadGameContainer(IAsyncResult pAsyncResult)
{
   mStorageContainer = mStorageDevice.EndOpenContainer(pAsyncResult))

   // this is my wrapper of BinaryReader which I use to perform the load
   BinaryReader reader = null;

   // the file may not exist
   if (mStorageContainer.FileExists("save.dat"))
   {
      reader = new BinaryReader(new System.IO.BinaryReader(mStorageContainer.OpenFile("save.dat", FileMode.Open)));

      // pass the BinaryReader to read the data
      GameProgram.LoadGameState(reader);
      reader.Close();
   }

   // clean up
   mStorageContainer.Dispose();
   mStorageContainer = null;
}