以下代码演示了一个简单的基于计时器的状态机。在这种情况下，机器的状态是当前玩家的回合。此示例通过将状态设置为下一个玩家，让每个 Play 决定何时让下一个玩家轮到她。为程序应检查的其他内容添加其他状态。这种程序架构运行相对平稳，因为程序线程没有被阻塞在紧密的循环中。每个玩家完成并退出回合的“速度”越快越好 - 即使玩家的回合重复 10000 次，在让下一个玩家玩之前没有做任何事情。
在下面的示例中，Click 事件处理程序将机器状态从轮到人类推进到轮到 AI。这有效地暂停了游戏，直到人类点击。由于转弯没有在紧密循环中被阻塞，因此您可以设置其他按钮供人类点击，例如“通过”、“重新开始”和“退出”。
using System;
using System.Windows.Forms;
using System.Timers;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
private System.Timers.Timer machineTimer = new System.Timers.Timer();
// These are our Machine States
private const int BEGIN_PLAY = 0;
private const int HUMAN_PLAYER_TURN = 1;
private const int AI_PLAYER_TURN = 2;
// This is the Current Machine State
private int currentPlayer = BEGIN_PLAY;
// Flag that lets us know that the Click Event Handler is Enabled
private bool waitForClick = false;
// The AI members, for example 100 of them
private const int AIcount = 100;
private object[] AIplayer = new object[AIcount];
private int AIcurrentIndex = 0; // values will be 0 to 99
public Form1()
{
InitializeComponent();
this.Show();
// The Timer Interval sets the pace of the state machine.
// For example if you have a lot of AIs, then make it shorter
// 100 milliseconds * 100 AIs will take a minimum of 10 seconds of stepping time to process the AIs
machineTimer.Interval = 100;
machineTimer.Elapsed += MachineTimer_Elapsed;
MessageBox.Show("Start the Game!");
machineTimer.Start();
}
private void MachineTimer_Elapsed(object sender, ElapsedEventArgs e)
{
// Stop the Timer
machineTimer.Stop();
try
{
// Execute the State Machine
State_Machine();
// If no problems, then Restart the Timer
machineTimer.Start();
}
catch (Exception stateMachineException)
{
// There was an Error in the State Machine, display the message
// The Timer is Stopped, so the game will not continue
if (currentPlayer == HUMAN_PLAYER_TURN)
{
MessageBox.Show("Player Error: " + stateMachineException.Message, "HUMAN ERROR!",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else if (currentPlayer == AI_PLAYER_TURN)
{
MessageBox.Show("Player Error: " + stateMachineException.Message, "AI ERROR!",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
MessageBox.Show("Machine Error: " + stateMachineException.Message, "Machine ERROR!",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
}
private void State_Machine()
{
// This routine is executing in the Timer.Elapsed Event's Thread, not the Main Form's Thread
switch (currentPlayer)
{
case HUMAN_PLAYER_TURN:
Play_Human();
break;
case AI_PLAYER_TURN:
Play_AI();
break;
default:
Play_Begin();
break;
}
}
private void Play_Human()
{
// This routine is executing in the Timer.Elapsed Event's Thread, not the Main Form's Thread
// My Turn!
if (!waitForClick)
{
// Please Wait until I take a card...
// I am using this.Invoke here because I am not in the same thread as the main form GUI
// If we do not wrap the code that accesses the GUI, we may get threading errors.
this.Invoke((MethodInvoker)delegate
{
pictureBox1.Click += PictureBox1_Click;
});
// set this flag so we do not re-enable the click event until we are ready next time
waitForClick = true;
}
}
private void PictureBox1_Click(object sender, EventArgs e)
{
// This routine is executing in the Main Form's Thread, not the Timer's Thread
// Stop the game for a little bit so we can process the Human's turn
machineTimer.Stop();
// Disable the Click Event, we don't need it until next time
pictureBox1.Click -= PictureBox1_Click;
waitForClick = false;
// To Do: Human's Turn code...
// Let the AI Play now
currentPlayer = AI_PLAYER_TURN;
machineTimer.Start();
}
private void Play_AI()
{
// This routine is executing in the Timer.Elapsed Event's Thread, not the Main Form's Thread
if (AIcurrentIndex < AIcount)
{
// If we do not wrap the code that accesses the GUI, we may get threading errors.
this.Invoke((MethodInvoker)delegate
{
// To Do: AI Player's Turn code...
});
// Advance to the next AI
AIcurrentIndex++;
}
else
{
// Reset to the beginning
AIcurrentIndex = 0;
currentPlayer = BEGIN_PLAY;
}
}
private void Play_Begin()
{
// This routine is executing in the Timer.Elapsed Event's Thread, not the Main Form's Thread
// If we do not wrap the code that accesses the GUI, we may get threading errors.
this.Invoke((MethodInvoker)delegate
{
// ... do stuff to setup the game ...
});
// Now let the Human Play on the next Timer.Elapsed event
currentPlayer = HUMAN_PLAYER_TURN;
// After the Human is done, start with the first AI index
AIcurrentIndex = 0;
}
}
}