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如何将参数传递给ElapsedEventHandler调用的函数?

elapsed timer events c#

lesderid · 技术社区 · 16 年前

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。但是像这样做显然不起作用…

1 回复 | 直到 16 年前

Jon Skeet 16 年前

您不能在方法本身内这样做-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 delegate 关键字)创建了一个委托,该委托知道 Index 参数到 InitTimer . 它只是呼叫 KeepAliveElapsed 方法。我使用了匿名方法语法,因为您不需要sender或event参数;如果您做如果需要,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 索引 应调用参数 index ,BTW)