轮询 Web 服务 [英] Polling a web service
问题描述
我有一个 C# 桌面 Windows 窗体应用程序.
I have a C# desktop Windows form application.
每 3 秒我就会调用一次网络服务,以检查服务器目录中的消息.
Every 3 seconds I am invoking a call to a web service to check for messages in a directory on my server.
我有一个由线程启动的 while (true)
循环.在这个循环中调用 Web 服务.我知道我应该避免无限循环,但我不知道及时通知我的客户有新消息的简单方法.
I have a while (true)
loop, which was started by a thread. Inside this loop the call to the web service is made. I know I should avoid infinite loops, but I do not know an easy way of notifying my client of a new message in a timely fashion.
请问有其他替代方案吗?
Are there alternatives I could look at please?
谢谢!
推荐答案
您可能可以为此使用 BackgroundWorker
- 教程
You can probably use a BackgroundWorker
for this - tutorial
您仍然需要使用 while(true) 循环,但您可以使用 BackgroundWorker 的 ReportProgress 方法与客户端进行通信:
You'd still need to use while(true) loop but you can communicate to the client by use the BackgroundWorker's ReportProgress Method:
// start the BackgroundWorker somewhere in your code:
DownloadDataWorker.RunWorkerAsync(); //DownloadDataWorker is the BackgroundWorker
然后为 DoWork
和 ProgressChanged
private void DownloadRpdBgWorker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
while (true)
{
worker.ReportProgress(1);
if (!controller.DownloadServerData())
{
worker.ReportProgress(2);
}
else
{
//data download succesful
worker.ReportProgress(3);
}
System.Threading.Thread.Sleep(3000); //poll every 3 secs
}
}
private void DownloadRpdBgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
switch(e.ProgressPercentage){
case 1: SetStatus("Trying to fetch new data.."); break;
case 2: SetStatus("Error communicating with the server"); break;
case 3: SetStatus("Data downloaded!"); break;
}
}
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