C# 保存游戏文件的困难

我之所以尝试本教程，是因为我想在XML文件中保存一些数据：

但是我在

SaveGameData

类中得到了这个错误消息：

IAsyncResult result = device.BeginOpenContainer("StorageDemo", null, null);

命名空间不能直接包含字段或方法等成员

XmlSerializer serializer = new XmlSerializer(typeof(SaveGameData)); 

应为类、委托、枚举、接口或结构

怎么了

此外，我不知道如何在文件中写入内容。例如，如果玩家按Escape，我想将分数保存到保存游戏文件中。我该怎么做

public struct SaveGameData
    {
        public string PlayerName;
        public Vector2 AvatarPosition;
        public int Level;
        public int Score;
    }
    // Open a storage container.
IAsyncResult result = device.BeginOpenContainer("StorageDemo", null, null);

// Wait for the WaitHandle to become signaled.
result.AsyncWaitHandle.WaitOne();

StorageContainer container = device.EndOpenContainer(result);

// Close the wait handle.
result.AsyncWaitHandle.Close();

string filename = "savegame.sav";

// Check to see whether the save exists.
if (container.FileExists(filename))
   // Delete it so that we can create one fresh.
   container.DeleteFile(filename);

// Create the file.
Stream stream = container.CreateFile(filename);

// Convert the object to XML data and put it in the stream.
XmlSerializer serializer = new XmlSerializer(typeof(SaveGameData));
  serializer.Serialize(stream, data);

// Close the file.
stream.Close();

// Dispose the container, to commit changes.
container.Dispose();

// Open a storage container.
IAsyncResult result =
    device.BeginOpenContainer("StorageDemo", null, null);

// Wait for the WaitHandle to become signaled.
result.AsyncWaitHandle.WaitOne();

StorageContainer container = device.EndOpenContainer(result);

// Close the wait handle.
result.AsyncWaitHandle.Close();

string filename = "savegame.sav";

// Check to see whether the save exists.
if (!container.FileExists(filename))
{
   // If not, dispose of the container and return.
   container.Dispose();
   return;
}

// Open the file.
Stream stream = container.OpenFile(filename, FileMode.Open);

XmlSerializer serializer = new XmlSerializer(typeof(SaveGameData));

SaveGameData data = (SaveGameData)serializer.Deserialize(stream);

// Close the file.
stream.Close();

// Dispose the container.
container.Dispose();

---

你应该把你的代码放在一个方法中，我应该把整个代码放在一个方法中吗？或者只是其中的一部分？除了结构声明之外的所有内容。然后在需要时调用该方法