EchoBotAccessors.cs

首先，第一個部分是EchoBotAccessors.cs，這邊定義了會用到的Accessor以及他的Property（字串）對應名稱：

public class EchoBotAccessors
{
	...
	/// <summary>
	/// Gets the <see cref="IStatePropertyAccessor{T}"/> name used for the <see cref="CounterState"/> accessor.
	/// </summary>
	/// <remarks>Accessors require a unique name.</remarks>
	/// <value>The accessor name for the counter accessor.</value>
	public static string CounterStateName { get; } = $"{nameof(EchoBotAccessors)}.CounterState";

	/// <summary>
	/// Gets or sets the <see cref="IStatePropertyAccessor{T}"/> for CounterState.
	/// </summary>
	/// <value>
	/// The accessor stores the turn count for the conversation.
	/// </value>
	public IStatePropertyAccessor<CounterState> CounterState { get; set; }

	...
}

這個部分對應到了這篇一開始提到的Accessor的概念，接下來這個怎麽被整合到Framework裡面呢？

Startup.cs

切換到Startup.cs，這邊在ConfigureServices方法裡面做了兩件事情：

設定ConversationState的Storage為Memory

services.AddBot<EchoWithCounterBot>(options =>
{
	....
	IStorage dataStore = new MemoryStorage();

	var conversationState = new ConversationState(dataStore);

	options.State.Add(conversationState);
	....
});

設定Accessor為Singleton

services.AddSingleton<EchoBotAccessors>(sp =>
{
	var options = sp.GetRequiredService
		<IOptions<BotFrameworkOptions>>().Value;

	var conversationState = options.State.
		OfType<ConversationState>().FirstOrDefault();

	var accessors = new EchoBotAccessors(conversationState)
	{
		CounterState = conversationState.
			CreateProperty<CounterState>(
				EchoBotAccessors.CounterStateName),
	};

	return accessors;
});

設定好了之後，在Bot裡面怎麽實際使用呢？

EchoWithCounterBot.cs

這個時候切換到實際的Bot程式碼：EchoWithCounterBot.cs

在OnTurnAsync裡面：

.....
if (turnContext.Activity.Type == ActivityTypes.Message)
{
	// 取得bot state
	var state = await _accessors.CounterState.
		GetAsync(turnContext, () => new CounterState());

	// 把第幾輪的數字加一
	state.TurnCount++;

	// 把值存回去
	await _accessors.CounterState.SetAsync(turnContext, state);

	// 實際寫到Storage裡面
	await _accessors.ConversationState.SaveChangesAsync(turnContext);

	.....
}
....