Getting a StorageDevice Asynchronously
Complete Sample
The code in the topic shows you the technique for getting a StorageDevice asynchronously. You can download a complete code sample for this topic, including full source code and any additional supporting files required by the sample.
Getting a StorageDevice Asynchronously
To get a StorageDevice asynchronously using IsCompleted
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In your Game constructor, add a new GamerServicesComponent to your Components collection.
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Create a variable to track when a request for a StorageDevice is pending. In this case, declare GameSaveRequested.
When the player needs to access the StorageDevice for the first time (for example, to save a game), call StorageDevice.BeginShowSelector, specifying which player requested the save.
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Check Guide.IsVisible first to ensure the Guide is not already displayed.
Calling StorageDevice.BeginShowSelector when the Guide is visible results in a GuideAlreadyVisibleException. StorageDevice.BeginShowSelector returns an IAsyncResult interface that is used to determine when the asynchronous request is finished.
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Set your tracking variable to indicate a request is pending.
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When a request is pending, check IAsyncResult.IsCompleted periodically to determine when the player selected the storage device.
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When IsCompleted is true, call StorageDevice.EndShowSelector, passing the IAsyncResult provided by StorageDevice.BeginShowSelector.
The return value is the selected storage device.
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Use the return value of EndShowSelector to ensure that a valid device is chosen.
If the player declines to select a device, null is returned. If the device was removed, IsConnected is false.
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If the StorageDevice is connected, use it to load or save data.
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Reset your tracking variable.
public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; this.Components.Add(new GamerServicesComponent(this)); } IAsyncResult result; Object stateobj; bool GameSaveRequested = false; GamePadState currentState; protected override void Update(GameTime gameTime) { GamePadState previousState = currentState; currentState = GamePad.GetState(PlayerIndex.One); // Allows the default game to exit on Xbox 360 and Windows if (currentState.Buttons.Back == ButtonState.Pressed) this.Exit(); if ((currentState.Buttons.A == ButtonState.Pressed) && (previousState.Buttons.A == ButtonState.Released)) { // Set the request flag if ((!Guide.IsVisible) && (GameSaveRequested == false)) { GameSaveRequested = true; result = StorageDevice.BeginShowSelector( PlayerIndex.One, null, null); } } // If a save is pending, save as soon as the // storage device is chosen if ((GameSaveRequested) && (result.IsCompleted)) { StorageDevice device = StorageDevice.EndShowSelector(result); if (device != null && device.IsConnected) { DoSaveGame(device); } // Reset the request flag GameSaveRequested = false; } base.Update(gameTime); }
To get a StorageDevice asynchronously using AsyncCallback
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In your Game constructor, add a new GamerServicesComponent to your Components collection.
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Create an AsyncCallback object that represents the method to be called when the player chooses a device.
That function must take an IAsyncResult as a parameter, and return void.
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When the player needs to access the StorageDevice for the first time (for example, to save a game), call StorageDevice.BeginShowSelector, specifying which player requested the save, and your AsyncCallback object.
As an option, you may pass a tracking object to identify the request (or null).
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Check Guide.IsVisible first to ensure the guide is not already being displayed.
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Call StorageDevice.BeginShowSelector when the guide is visible results in a GuideAlreadyVisibleException.
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In your callback method, call StorageDevice.EndShowSelector, passing the same IAsyncResult passed into the callback method.
The return value is the selected storage device.
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Use the return value of EndShowSelector to ensure that a valid device is chosen.
If the player declines to select a device, null is returned. If the device was removed, IsConnected is false.
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If the StorageDevice is connected, use it to load or save data.
public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; this.Components.Add(new GamerServicesComponent(this)); } IAsyncResult result; Object stateobj; bool GameSaveRequested = false; GamePadState currentState; protected override void Update(GameTime gameTime) { GamePadState previousState = currentState; currentState = GamePad.GetState(PlayerIndex.One); // Allows the default game to exit on Xbox 360 and Windows if (currentState.Buttons.Back == ButtonState.Pressed) this.Exit(); if ((currentState.Buttons.B == ButtonState.Pressed) && (previousState.Buttons.B == ButtonState.Released)) { if (!Guide.IsVisible) { // Reset the device device = null; stateobj = (Object)"GetDevice for Player One"; StorageDevice.BeginShowSelector( PlayerIndex.One, this.GetDevice, stateobj); } } base.Update(gameTime); } StorageDevice device; void GetDevice(IAsyncResult result) { device = StorageDevice.EndShowSelector(result); if (device != null && device.IsConnected) { DoSaveGame(device); } }
