如何将参数传递给ElapsedEventHandler调用的函数？

Question

如何将参数传递给ElapsedEventHandler调用的函数？

我的代码:

private static void InitTimer(int Index)
{
    keepAlive[Index] = new Timer();
    keepAlive[Index].Interval = 3000;
    keepAlive[Index].Elapsed += new ElapsedEventHandler(keepAlive_Elapsed[, Index]);
    keepAlive[Index].Start();
}

public static void keepAlive_Elapsed(object sender, EventArgs e[, int Index])
{

    PacketWriter writer = new PacketWriter();
    writer.AppendString("KEEPALIVE|.\\");
    ServerSocket.Send(writer.getWorkspace(), Index);
    ServerSocket.DisconnectSocket(Index);
}

我想做的是在括号([和])之间.但只是这样做显然不起作用......

Answer 1

您无法在方法本身内执行此操作 - 您必须使事件处理程序有效地了解其上下文.最简单的方法是使用lambda表达式或匿名方法:

private static void InitTimer(int Index)
{
    keepAlive[Index] = new Timer();
    keepAlive[Index].Interval = 3000;
    keepAlive[Index].Elapsed += delegate { KeepAliveElapsed(Index); };
    keepAlive[Index].Start();
}

public static void KeepAliveElapsed(int Index)
{    
    PacketWriter writer = new PacketWriter();
    writer.AppendString("KEEPALIVE|.\\");
    ServerSocket.Send(writer.getWorkspace(), Index);
    ServerSocket.DisconnectSocket(Index);
}

这里,匿名方法(带有delegate关键字的位)创建了一个知道Index参数的委托InitTimer.它只是调用KeepAliveElapsed方法.我使用了匿名方法语法,因为你不需要发送者或事件args; 如果你确实需要它们,我可能会使用lambda表达式,例如

private static void InitTimer(int Index)
{
    keepAlive[Index] = new Timer();
    keepAlive[Index].Interval = 3000;
    keepAlive[Index].Elapsed += (sender, args) => KeepAliveElapsed(sender, Index);
    keepAlive[Index].Start();
}

public static void KeepAliveElapsed(object sender, int Index)
{    
    PacketWriter writer = new PacketWriter();
    writer.AppendString("KEEPALIVE|.\\" + sender);
    ServerSocket.Send(writer.getWorkspace(), Index);
    ServerSocket.DisconnectSocket(Index);
}

(注意,传统上Index应该调用参数index,顺便说一句.)