C＃从对象

Question

调用一个方法，所以我大概得到这个：

public partial class Form1 : Form 
{ 
    GameEngine engine; 
    public Form1() 
    { 
     engine = new GameEngine(); 
    } 

    public void repaint() 
    { 

    } 
} 

class GameEngine 
{ 
    public void update() 
    { 

    } 
} 

现在，我想补充一点的update（）方法，这使得它调用重绘（）方法，该实例的内Form1类，其中GameEngine类的相应对象已创建。

在java中我可能已经做了这样的

 engine = new GameEngine() 
     { 
      public void repaintCaller() 
      { 
       repaint(); 
      } 
     }; 

，并调用repaintCaller（）在update（）方法，但是，这并不在C＃中的工作，就是现在的equilvalent的方式做这在C＃中？有它

Answer 1

一种方法是：

public partial class Form1 : Form 
{ 
    GameEngine engine; 
    public Form1() 
    { 
     engine = new GameEngine(); 
     engine.update(this); 
    } 

    public void repaint() 
    { 

    } 
} 

class GameEngine 
{ 
    public void update(Form1 form) 
    { 
     form.repaint(); 
    } 
} 

Answer 2

你可以一个行动委托传递给GameEngine.update方法将repaint方法的形式实例

public partial class Form1 : Form 
{ 
    GameEngine engine; 
    public Form1() 
    { 
     engine = new GameEngine(); 
     // I put the call here for demo purpose, 
     // of course you call the engine.update 
     // method when you need and where you want 
     engine.update(repaint) 
    } 

    public void repaint() 
    { 
     Console.WriteLine("repaint called in the Form1 instance"); 
    } 
} 

class GameEngine 
{ 
    public void update(Action clientUpdate) 
    { 
     if(clientUpdate != null) 
      clientUpdate.Invoke(); 
      // or just... clientUpdate(); 
    } 
} 

C＃中的parameterless Action delegate是一种将参数传递给被调用方法（更新）的方法（repaint）。当然，您可以将整个Form1实例传递给更新，但是此方法将GameEngine类绑定到Form1类。使用Action方法，您可以不受此耦合的影响，并且可以传递任何其他返回void的方法，并且不会在程序的任何类中定义任何参数。这将释放您的GameEngine.update方法，从任何特定的绑定到调用者。

Answer 3

我会尝试这样的事情

class GameEngine 
{ 
    public void update(ref Form1 caller) 
    { 
     caller.Refresh() //msdn says "Forces the control to invalidate its client area and immediately redraw itself and any child controls." 
    } 
} 

public partial class Form1 : Form 
{ 
    [...] 
    engine = new GameEngine() 
    engine.update(ref This) 
} 

我不知道的东西，我不习惯C＃。 我只是希望这将有助于一点:)

Answer 4

您还可以设置活动从形式，像这样：

public partial class Form1 : Form 
{ 
    GameEngine engine; 

    public Form1() 
    { 
     InitializeComponent(); 
     engine = new GameEngine(); 
     engine.repaintRequired += engine_repaintRequired; 
     engine.update(); 
    } 

    private void engine_repaintRequired(object sender, EventArgs e) 
    { 
     repaint(); 
    } 

    public void repaint() 
    { 
     Console.Write("repaint"); 
    } 
} 

class GameEngine 
{ 
    public event EventHandler repaintRequired; 

    public void update() 
    { 
     onRepaintRequired(); 
    } 

    private void onRepaintRequired() 
    { 
     if (repaintRequired != null) 
      repaintRequired(this, new EventArgs()); 
    } 
}