C＃從對象

Question

調用一個方法，所以我大概得到這個：

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

    public void repaint() 
    { 

    } 
} 

class GameEngine 
{ 
    public void update() 
    { 

    } 
} 

現在，我想補充一點的update（）方法，這使得它調用重繪（）方法，該實例的內Form1類，其中GameEngine類的相應對象已創建。

在java中我可能已經做了這樣的

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

，並調用repaintCaller（）在update（）方法，但是，這並不在C＃中的工作，就是現在的equilvalent的方式做這在C＃中？有它

Answer 1

一種方法是：

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

你可以一個行動委託傳遞給GameEngine.update方法將repaint方法的形式實例

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是一種將參數傳遞給被調用方法（更新）的方法（repaint）。當然，您可以將整個Form1實例傳遞給更新，但是此方法將GameEngine類綁定到Form1類。使用Action方法，您可以不受此耦合的影響，並且可以傳遞任何其他返回void的方法，並且不會在程序的任何類中定義任何參數。這將釋放您的GameEngine.update方法，從任何特定的綁定到調用者。

Answer 3

我會嘗試這樣的事情

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) 
} 

我不知道的東西，我不習慣C＃。 我只是希望這將有助於一點:)

Answer 4

您還可以設置活動從形式，像這樣：

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()); 
    } 
}