Events C#-调用异步方法的简单方法?
Events C#-调用异步方法的简单方法?,events,user-interface,asynchronous,Events,User Interface,Asynchronous,我正在开发一个c#user control@work。控件只是加载一些信息和数据并显示它。 现在我想为控件的用户提供一个选项来异步加载数据。。smth是这样的: Cntrl.LoadSmthAsync(..) Cntrl.LoadSmthComplete //EventHandler to give feedback if the Load was successfull. public async Task<byte[]> LoadByPos(int pos) {
我正在开发一个c#user control@work。控件只是加载一些信息和数据并显示它。
现在我想为控件的用户提供一个选项来异步加载数据。。smth是这样的:
Cntrl.LoadSmthAsync(..)
Cntrl.LoadSmthComplete //EventHandler to give feedback if the Load was successfull.
public async Task<byte[]> LoadByPos(int pos)
{
string url = await Pos2UrlAsync(pos);
// update gui
this.textBox1.Text = url;
byte[] res = await LoadByUrlAsync(url);
// update gui
this.textBox2.Text = BytesToString(res);
return res;
}
我决定使下载函数异步,并通过EventHandler提供返回值<但是代码变得相当复杂了。。毕竟
下面是一些代码,以了解控件应执行的操作:
public byte[] LoadByPos(int pos)
{
string url = Pos2Url(pos);
// update gui
this.textBox1.Text = url;
byte[] res = LoadByUrl(url);
// update gui
this.textBox2.Text = BytesToString(res);
return res;
}
public byte[] LoadByUrl(string url)
{
return Download(url);
}
//primary problem: download function
private byte[] Download(string url)
{
System.Threading.Thread.Sleep(1000 * 30);
return StringToBytes(url);
}
//secondary problem: an other function
private string Pos2Url(int pos)
{
System.Threading.Thread.Sleep(1000 * 5);
return pos.ToString();
}
// LoadByPosAsync
public delegate void LoadByPosDoneHandler(Object sender, byte[] e);
public event LoadByPosDoneHandler LoadByPosDone;
public void LoadByPosAsync(int pos)
{
string url = Pos2Url(pos);
// update gui
this.textBox1.Text = url;
LoadByUrlDone += new LoadByUrlDoneHandler(LoadByPosAsync_LoadByUrlDone);
LoadByUrlAsync(url);
}
public void LoadByPosAsync_LoadByUrlDone(object sender, byte[] e)
{
// update gui
this.textBox2.Text = BytesToString(e);
LoadByUrlDone = null;
LoadByPosDone(sender, e);
}
//LoadByUrlAsync
public delegate void LoadByUrlDoneHandler(Object sender, byte[] e);
public event LoadByUrlDoneHandler LoadByUrlDone;
public void LoadByUrlAsync(string url)
{
DownloadDone += new DownloadDoneHandler(LoadByUrlAsync_DownloadDone);
DownloadAsync(url);
}
private void LoadByUrlAsync_DownloadDone(object sender, byte[] e)
{
LoadByUrlDone(sender, e);
}
//DownloadAsync
private delegate void DownloadDoneHandler(Object sender, byte[] e);
private event DownloadDoneHandler DownloadDone;
private void DownloadAsync(string url)
{
BackgroundWorker bw_DownloadAsync = new BackgroundWorker();
bw_DownloadAsync.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_DownloadAsync_RunWorkerCompleted);
bw_DownloadAsync.DoWork += new DoWorkEventHandler(bw_DownloadAsync_DoWork);
bw_DownloadAsync.RunWorkerAsync(url);
}
void bw_DownloadAsync_DoWork(object sender, DoWorkEventArgs e)
{
byte[] res = Download((string)e.Argument);
e.Result = res;
}
void bw_DownloadAsync_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
DownloadDone(sender, (byte[])e.Result);
}
有没有更简单的方法来完成我打算做的事情
提前thx
有没有更简单的方法来完成我打算做的事情
实现端是分开的,但是如果您使用的是.NET4,我强烈建议您不要将此模型用于异步。我建议您使用Task
,而不是使用事件处理程序。如果没有任何固有的支持,您可以使用来创建任务,这意味着由于异步/等待支持,您的API在C#5中使用起来会更容易。此时,您的UI线程方法如下所示:
Cntrl.LoadSmthAsync(..)
Cntrl.LoadSmthComplete //EventHandler to give feedback if the Load was successfull.
public async Task<byte[]> LoadByPos(int pos)
{
string url = await Pos2UrlAsync(pos);
// update gui
this.textBox1.Text = url;
byte[] res = await LoadByUrlAsync(url);
// update gui
this.textBox2.Text = BytesToString(res);
return res;
}
public异步任务LoadByPos(int-pos)
{
字符串url=等待POS2URLSync(pos);
//更新图形用户界面
this.textBox1.Text=url;
字节[]res=wait loadbyurlsync(url);
//更新图形用户界面
this.textBox2.Text=BytesToString(res);
返回res;
}
异步将自然地在代码中流动 谢谢你的快速回复!我目前有点绑定到.Net 2.0,因为该控件可能也用于较旧的客户端应用程序中,我们目前无法移植。你发布的代码在我看来非常甜美。。但是我不知道我是否能在.NET2.0中使用它。。.NET2.0能够处理c#5吗?谢谢你的帮助。@nox:有可能通过大量的工作和黑客手段,你可以让它正常工作,但这并不是一个明智的选择。