调用带参数的事件处理程序 [英] call an eventhandler with arguments

问题描述

Visual Studio 2008中，C＃3.0。

下面我有它调用的事件处理程序的方法。我想通过该方法的事件处理程序收到两个参数

我愿做这样的事情：

  wc.DownloadDataCompleted + = wc.DownloadedDataCompleted（strtitle，placeid）; 
  

这甚至可能，如果是，我怎么会去这样做？

代码段：

 公共无效downloadphoto（字符串struri，串strtitle，串placeid） 
 {使用
（Web客户端WC =新的WebClient（））
 {
 wc.DownloadDataCompleted + = wc_DownloadDataCompleted; 
 wc.DownloadDataAsync（新的URI（struri））; 
} 
} 
  

解决方案

的要做到这一点最简单的方法是使用的匿名函数的（匿名方法或lambda表达式）认购事件，然后做出你的方法有你想要的参数：

 公共无效downloadphoto（字符串struri，串strtitle，串placeid）使用
 {
（Web客户端WC =新的WebClient（）） 
 {
 wc.DownloadDataCompleted + =（发件人，参数）=> 
 DownloadDataCompleted（strtitle，placeid，参数）; 
 wc.DownloadDataAsync（新的URI（struri））; 
} 
} 
 
 //请重新命名要说它做什么，而不是它的使用在这里:) 
私人无效DownloadDataCompleted（字符串名称，字符串ID的方法， 
 DownloadDataCompletedEventArgs参数）
 {
 //做的东西在这里
} 
  

Visual Studio 2008, C# 3.0.

I have a method below which calls an event handler. I would like to pass the two arguments received by the method to the event handler.

I would like to do something like this:

wc.DownloadDataCompleted += wc.DownloadedDataCompleted(strtitle, placeid);

Is this even possible, if yes, how would I go about doing it ?

Code Snippet:

public void downloadphoto(string struri,string strtitle,string placeid)
{
    using (WebClient wc = new WebClient())
    {
        wc.DownloadDataCompleted += wc_DownloadDataCompleted;
        wc.DownloadDataAsync(new Uri(struri));
    }
}

解决方案

The easiest way to do this is to use an anonymous function (an anonymous method or a lambda expression) to subscribe to the event, then make your method have just the parameters you want:

public void downloadphoto(string struri, string strtitle, string placeid)
{
    using (WebClient wc = new WebClient())
    {
        wc.DownloadDataCompleted += (sender, args) => 
            DownloadDataCompleted(strtitle, placeid, args);
        wc.DownloadDataAsync(new Uri(struri));
    }
}

// Please rename the method to say what it does rather than where it's used :)
private void DownloadDataCompleted(string title, string id, 
                                   DownloadDataCompletedEventArgs args)
{
    // Do stuff here
}

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