21

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);
}

我想要做的是括号（[和]）之间。但是，就那样做显然是行不通的……

4

1 回答 1

50

您不能在方法本身内执行此操作 - 您必须让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);
}

在这里，匿名方法（带有delegate关键字的位）创建了一个知道Indexto 参数的委托InitTimer。它只是调用KeepAliveElapsed方法。我使用了匿名方法语法，因为您不需要发送者或事件参数；如果您确实需要它们，我可能会改用 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);
}

（请注意，通常Index应该调用参数index，顺便说一句。）

于 2010-06-22T15:06:23.107 回答