更新:
再次感谢你的例子，它们对我很有帮助，我并不是说
夺走他们的一切。
Aren't the currently given examples, as far as I understand them & state-machines, only half of what we usually understand by a state-machine?
In the sense that the examples do change state but that's only represented by changing the value of a variable (and allowing different value- changes in different states), while usually, a state machine should also change its behavior, and behavior not (only) in the sense of allowing different value changes for a variable depending on the state, but in the sense of allowing different methods to be executed for different states.
还是我对状态机及其常用用法有误解?
最初的问题:
我发现了关于c#中的状态机和迭代器块的讨论，以及用于创建状态机和c#的工具，所以我发现了很多抽象的东西，但作为一个新手，所有这些都有点令人困惑。
因此，如果有人能提供一个c#源代码-示例，实现一个简单的状态机，可能只有3,4个状态，那就太好了，只是为了了解它的要点。
让我们从这个简单的状态图开始:
我们有:
4种状态(非活动、活动、暂停和退出)
5种状态转换(开始命令，结束命令，暂停命令，恢复命令，退出命令)。
您可以通过几种方式将其转换为c#，例如在当前状态和命令上执行switch语句，或者在转换表中查找转换。对于这个简单的状态机，我更喜欢一个转换表，它很容易使用Dictionary表示:
using System;
using System.Collections.Generic;
namespace Juliet
{
public enum ProcessState
{
Inactive,
Active,
Paused,
Terminated
}
public enum Command
{
Begin,
End,
Pause,
Resume,
Exit
}
public class Process
{
class StateTransition
{
readonly ProcessState CurrentState;
readonly Command Command;
public StateTransition(ProcessState currentState, Command command)
{
CurrentState = currentState;
Command = command;
}
public override int GetHashCode()
{
return 17 + 31 * CurrentState.GetHashCode() + 31 * Command.GetHashCode();
}
public override bool Equals(object obj)
{
StateTransition other = obj as StateTransition;
return other != null && this.CurrentState == other.CurrentState && this.Command == other.Command;
}
}
Dictionary<StateTransition, ProcessState> transitions;
public ProcessState CurrentState { get; private set; }
public Process()
{
CurrentState = ProcessState.Inactive;
transitions = new Dictionary<StateTransition, ProcessState>
{
{ new StateTransition(ProcessState.Inactive, Command.Exit), ProcessState.Terminated },
{ new StateTransition(ProcessState.Inactive, Command.Begin), ProcessState.Active },
{ new StateTransition(ProcessState.Active, Command.End), ProcessState.Inactive },
{ new StateTransition(ProcessState.Active, Command.Pause), ProcessState.Paused },
{ new StateTransition(ProcessState.Paused, Command.End), ProcessState.Inactive },
{ new StateTransition(ProcessState.Paused, Command.Resume), ProcessState.Active }
};
}
public ProcessState GetNext(Command command)
{
StateTransition transition = new StateTransition(CurrentState, command);
ProcessState nextState;
if (!transitions.TryGetValue(transition, out nextState))
throw new Exception("Invalid transition: " + CurrentState + " -> " + command);
return nextState;
}
public ProcessState MoveNext(Command command)
{
CurrentState = GetNext(command);
return CurrentState;
}
}
public class Program
{
static void Main(string[] args)
{
Process p = new Process();
Console.WriteLine("Current State = " + p.CurrentState);
Console.WriteLine("Command.Begin: Current State = " + p.MoveNext(Command.Begin));
Console.WriteLine("Command.Pause: Current State = " + p.MoveNext(Command.Pause));
Console.WriteLine("Command.End: Current State = " + p.MoveNext(Command.End));
Console.WriteLine("Command.Exit: Current State = " + p.MoveNext(Command.Exit));
Console.ReadLine();
}
}
}
根据个人喜好，我喜欢用GetNext函数来确定地返回下一个状态，用MoveNext函数来改变状态机。
让我们从这个简单的状态图开始:
我们有:
4种状态(非活动、活动、暂停和退出)
5种状态转换(开始命令，结束命令，暂停命令，恢复命令，退出命令)。
您可以通过几种方式将其转换为c#，例如在当前状态和命令上执行switch语句，或者在转换表中查找转换。对于这个简单的状态机，我更喜欢一个转换表，它很容易使用Dictionary表示:
using System;
using System.Collections.Generic;
namespace Juliet
{
public enum ProcessState
{
Inactive,
Active,
Paused,
Terminated
}
public enum Command
{
Begin,
End,
Pause,
Resume,
Exit
}
public class Process
{
class StateTransition
{
readonly ProcessState CurrentState;
readonly Command Command;
public StateTransition(ProcessState currentState, Command command)
{
CurrentState = currentState;
Command = command;
}
public override int GetHashCode()
{
return 17 + 31 * CurrentState.GetHashCode() + 31 * Command.GetHashCode();
}
public override bool Equals(object obj)
{
StateTransition other = obj as StateTransition;
return other != null && this.CurrentState == other.CurrentState && this.Command == other.Command;
}
}
Dictionary<StateTransition, ProcessState> transitions;
public ProcessState CurrentState { get; private set; }
public Process()
{
CurrentState = ProcessState.Inactive;
transitions = new Dictionary<StateTransition, ProcessState>
{
{ new StateTransition(ProcessState.Inactive, Command.Exit), ProcessState.Terminated },
{ new StateTransition(ProcessState.Inactive, Command.Begin), ProcessState.Active },
{ new StateTransition(ProcessState.Active, Command.End), ProcessState.Inactive },
{ new StateTransition(ProcessState.Active, Command.Pause), ProcessState.Paused },
{ new StateTransition(ProcessState.Paused, Command.End), ProcessState.Inactive },
{ new StateTransition(ProcessState.Paused, Command.Resume), ProcessState.Active }
};
}
public ProcessState GetNext(Command command)
{
StateTransition transition = new StateTransition(CurrentState, command);
ProcessState nextState;
if (!transitions.TryGetValue(transition, out nextState))
throw new Exception("Invalid transition: " + CurrentState + " -> " + command);
return nextState;
}
public ProcessState MoveNext(Command command)
{
CurrentState = GetNext(command);
return CurrentState;
}
}
public class Program
{
static void Main(string[] args)
{
Process p = new Process();
Console.WriteLine("Current State = " + p.CurrentState);
Console.WriteLine("Command.Begin: Current State = " + p.MoveNext(Command.Begin));
Console.WriteLine("Command.Pause: Current State = " + p.MoveNext(Command.Pause));
Console.WriteLine("Command.End: Current State = " + p.MoveNext(Command.End));
Console.WriteLine("Command.Exit: Current State = " + p.MoveNext(Command.Exit));
Console.ReadLine();
}
}
}
根据个人喜好，我喜欢用GetNext函数来确定地返回下一个状态，用MoveNext函数来改变状态机。
finitestatemmachine是一个简单的状态机，用c# Link编写
使用我的库finitestatemmachine的优点:
定义一个“context”类，向外界呈现一个单独的接口。
定义一个State抽象基类。
将状态机的不同“状态”表示为state基类的派生类。
在适当的State派生类中定义特定于状态的行为。
在“context”类中维护一个指向当前“state”的指针。
要更改状态机的状态，请更改当前的“state”指针。
下载DLL下载
LINQPad上的示例:
void Main()
{
var machine = new SFM.Machine(new StatePaused());
var output = machine.Command("Input_Start", Command.Start);
Console.WriteLine(Command.Start.ToString() + "-> State: " + machine.Current);
Console.WriteLine(output);
output = machine.Command("Input_Pause", Command.Pause);
Console.WriteLine(Command.Pause.ToString() + "-> State: " + machine.Current);
Console.WriteLine(output);
Console.WriteLine("-------------------------------------------------");
}
public enum Command
{
Start,
Pause,
}
public class StateActive : SFM.State
{
public override void Handle(SFM.IContext context)
{
//Gestione parametri
var input = (String)context.Input;
context.Output = input;
//Gestione Navigazione
if ((Command)context.Command == Command.Pause) context.Next = new StatePaused();
if ((Command)context.Command == Command.Start) context.Next = this;
}
}
public class StatePaused : SFM.State
{
public override void Handle(SFM.IContext context)
{
//Gestione parametri
var input = (String)context.Input;
context.Output = input;
//Gestione Navigazione
if ((Command)context.Command == Command.Start) context.Next = new StateActive();
if ((Command)context.Command == Command.Pause) context.Next = this;
}
}
