I have a C# application that acts as a web server to the local machine only. I have used the example from this site as the base for my web server.
So, here is my problem, the main application spawns a listener thread to listen for and handle the response.
In Program.cs
static class Program
{
[STAThread]
static void Main()
{
Application.Run(new SysTrayApp());
}
}
In SysTrayApp.cs:
public partial class SysTrayApp : Form
{
...
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
WebServer myWebServer = new WebServer(WebServer.Response, "http://localhost:8080/");
myWebServer.Run();
}
}
In WebServer.cs
...
public void Run()
{
ThreadPool.QueueUserWorkItem((o) =>
{
Console.WriteLine("Webserver running...");
try
{
while (_listener.IsListening)
{
var ctx = _listener.GetContext();
try
{
string rstr = _responderMethod(ctx.Request);
byte[] buf = Encoding.UTF8.GetBytes(rstr);
ctx.Response.ContentLength64 = buf.Length;
ctx.Response.OutputStream.Write(buf, 0, buf.Length);
}
catch { } // suppress any exceptions
finally
{
// always close the stream
ctx.Response.OutputStream.Close();
}
}
}
catch { } // suppress any exceptions
});
}
When a request is received, I want to display a Windows Form to the local environment (not the HTTP response). The problem is that I am no longer in the main STAThread when I receive the request, so I can't open a form properly.
If I try open it in the listener thread, the form just freezes because the listener starts listening and blocks the thread. A similar thing happens if I open a threadpool thread.
public static string Response(HttpListenerRequest request)
{
Form form = new Form();
form.Show();
return "TEST!";
}
If I open it in a new normal Thread, the form pops up and then the thread closes and then the form closes again.
public static string Response(HttpListenerRequest request)
{
Thread thread = new Thread(startForm);
thread.Start();
return "TEST!";
}
public static void startForm()
{
Form form = new Form();
form.Show();
}
So, from what I can figure out, only forms in the main application/UI thread seem to work properly and also, you can't block the main thread, or else the forms freeze. So, from within the WebServer listener, how do I trigger the opening of a form on the main thread? Should I create an event on the main form that launches the second form and try to trigger it from the listener thread?
Or is there a better way to do it?
PS I am a PHP/Python programmer that has had to venture into C# just for a single project, so I am not really sure what I am doing.
You can invoke a method of SysTrayApp
in the worker thread as below
public class SysTrayApp : Form
{
public SysTrayApp()
{
Task.Factory.StartNew(Process, TaskCreationOptions.LongRunning);
}
void ActualWork(DateTime dt)
{
this.Text = dt.ToString();
}
void Process()
{
while(true)
{
this.Invoke((Action)(() => ActualWork(DateTime.Now)));
Thread.Sleep(1000);
}
}
}
BTW: Don't use threads from threadpool for long running tasks. Why .net Threadpool is used only for short time span tasks?
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