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group:Socket is freezing my datagrid
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we here have an app where the server push some data assynch to the clients connected via tcp socket. This data is then captured in the client and inserted in a datagrid. So far no problem. But sometimes, when the incoming data is in a too short period, my client freezes. any hints on this? should I implement any 'wait' mechanism in my client or server? TIA
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On Tue, 26 Jul 2005 15:54:22 +0800, Edge wrote: > we here have an app where the server push some data assynch to the > clients connected via tcp socket. This data is then captured in the > client and inserted in a datagrid. So far no problem. > But sometimes, when the incoming data is in a too short period, my > client freezes. > > any hints on this? should I implement any 'wait' mechanism in my client > or server? Are you sure that you are always accessing your datagrid (which is a UI Control) only from the UI thread in which it has been created and not from a worker thread. If you try to access your Datagrid from a worker thread, it's gonna freeze randomly (UI controls are not thread safe and should only be accessed from the UI thread). On the other side, if you are not using worker thread to read data on your socket but doing everything in the UI thread, then you'll have freezes too since the whole UI is gonna freeze whenever you'll wait for data to arrive
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Edge wrote: > hi, > > we here have an app where the server push some data assynch to the > clients connected via tcp socket. This data is then captured in the > client and inserted in a datagrid. So far no problem. > But sometimes, when the incoming data is in a too short period, my > client freezes. > > any hints on this? should I implement any 'wait' mechanism in my client > or server? > > TIA > Edge Hi, I found the problem for this case. I just had to call the update method within a BeginInvoke method.
hi
thanks for your reply. Actually I was thinking I found a solution, but yes, it is freezing randomically. I do not know about this worker thread. Do I have to follow any guideline to update my UI control? any sample code that I can see? and as far as I know I am not implementing any thread in my app. Please advice. TIA -Edge [quoted text, click to view] "Mehdi" <vioccc@REMOVEME.gmail.com> wrote in message news:149tr6yz8mctx.1ixoodrxynhl2.dlg@40tude.net... > On Tue, 26 Jul 2005 15:54:22 +0800, Edge wrote: > > Are you sure that you are always accessing your datagrid (which is a UI > Control) only from the UI thread in which it has been created and not from > a worker thread. If you try to access your Datagrid from a worker thread, > it's gonna freeze randomly (UI controls are not thread safe and should > only > be accessed from the UI thread). > > On the other side, if you are not using worker thread to read data on your > socket but doing everything in the UI thread, then you'll have freezes too > since the whole UI is gonna freeze whenever you'll wait for data to arrive > on your socket.
[quoted text, click to view] "Mehdi" <vioccc@REMOVEME.gmail.com> wrote in message news:nzy6h1zgit7i$.1vrf7cnfybbyr.dlg@40tude.net... > On Fri, 12 Aug 2005 11:18:28 +0800, edge wrote: > >> I do not know about this worker thread. >> Do I have to follow any guideline to update my UI control? >> any sample code that I can see? >> >> and as far as I know I am not implementing any thread in my app. Please >> advice. > > There are 3 situation where your code can be executed within a worker > thread: > 1) you manually create a new Thread and start it. This is apparently not > what you are doing > 2) you are queuing your methods in the threadpool queue so that they get > executed in one of the ThreadPool thread. This is probably not what you > are > doing either since you would know that you are using threads if you had > done that > 3) you are starting an asynchronous operation and supplying a callback > method that gets executed once the asynchronous operation has completed. > This callback is always executed within a worker thread. The Socket class > provides such methods (BeginConnect, BeginSend, BeginReceive...). If you > are using them, then you are in a multi-threaded situation. > > In order to safely update your datagrid from a worker thread, you should > marshall the call to the method that accesses your datagrid to the UI > thread (the thread where all the UI controls of your application have been > created). You can do that by using either the Invoke or BeginInvoke method > of the Control class. > > Say that you have a control called uiControl (this can be anything, your > form, your datagrid, anything as long as it derives from the Control > class). Here is the code to do what you want safely: > > void UpdateDatagrid() > { > // Here do whatever you want > // with your Datagrid > } > > void WorkerThreadMethod() > { > // This is the method executing > // in a worker thread where > // you want to update the datagrid > > // Marshall the call to UpdateDatagrid() to the > // UI thread > uiControl.Invoke(new MethodInvoker(UpdateDatagrid)); > } > > One important thing here is that the Invoke method relies on uiControl to > have a valid Handle in order to properly marshall the call to the UI > thread. So you should make sure that uiControl has a valid handle. You can > be sure that uiControl has a valid Handle if it has been displayed on the > screen. Great hints! Well, seems that it is working, but instead of calling the new MethodInvoker I am using a delegate. Please look at how i am doing: in my ClientForm.cs I have this class: public class MyCallbackClass : RemotelyDelegatableObject { private ClientForm mainChild = null; public MyCallbackClass (ClientForm pMain) { mainChild = pMain ; } protected override void InternalSubmissionCallback (object sender, RemoteEventArgs e) { try { //mainChild is my client form, UpdateClient is the workerThread //I think here is the secret. I must call a threadsafe method to update my grid. //FYI, I was doing mainChild.AddRowToDataGrid( e.MyStringData ) and it was freezing mainChild.UpdateMyClient( e.MyStringData ); } catch( Exception ex ) { //mainChild.listbox2.Items.Add( ex.Message+"-"+ex.Source+"-"+ex.InnerException.Message ); } } and my ClientForm has this: public void UpdateMyClient( string data ) { // I created a delegate called SetIncomingDataTextDelegate this.Invoke( new SetIncomingDataTextDelegate( AddRowToDataGrid ), new object[] { data } ); // AddRowToDataGrid inserts the data string feed into the datagrid } a few more questions: Is this the way it should be? is it a valid alternative? Also I noticed that the client form is acting a little slow when I drag-and-move it in my screen. maybe because the listening? at first I was trying to use BeginInvoke() with no success, looks like the correct way it is Inkove(); TIA -Edge
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On Fri, 12 Aug 2005 11:18:28 +0800, edge wrote: > I do not know about this worker thread. > Do I have to follow any guideline to update my UI control? > any sample code that I can see? > > and as far as I know I am not implementing any thread in my app. Please > advice. There are 3 situation where your code can be executed within a worker thread: 1) you manually create a new Thread and start it. This is apparently not what you are doing 2) you are queuing your methods in the threadpool queue so that they get executed in one of the ThreadPool thread. This is probably not what you are doing either since you would know that you are using threads if you had done that 3) you are starting an asynchronous operation and supplying a callback method that gets executed once the asynchronous operation has completed. This callback is always executed within a worker thread. The Socket class provides such methods (BeginConnect, BeginSend, BeginReceive...). If you are using them, then you are in a multi-threaded situation. In order to safely update your datagrid from a worker thread, you should marshall the call to the method that accesses your datagrid to the UI thread (the thread where all the UI controls of your application have been created). You can do that by using either the Invoke or BeginInvoke method of the Control class. Say that you have a control called uiControl (this can be anything, your form, your datagrid, anything as long as it derives from the Control class). Here is the code to do what you want safely: void UpdateDatagrid() { // Here do whatever you want // with your Datagrid } void WorkerThreadMethod() { // This is the method executing // in a worker thread where // you want to update the datagrid // Marshall the call to UpdateDatagrid() to the // UI thread uiControl.Invoke(new MethodInvoker(UpdateDatagrid)); } One important thing here is that the Invoke method relies on uiControl to have a valid Handle in order to properly marshall the call to the UI thread. So you should make sure that uiControl has a valid handle. You can be sure that uiControl has a valid Handle if it has been displayed on the
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On Sat, 13 Aug 2005 06:55:09 +0800, edge wrote: > Great hints! > Well, seems that it is working, but instead of calling the new MethodInvoker > I am using a delegate. Please look at how i am doing: MethodInvoker is actually just a normal delegate provided for your convenience in the .NET framework. [quoted text, click to view] > a few more questions: > Is this the way it should be? is it a valid alternative? Yes, it looks alright to me. Something that i like to do, but this is purely for aestetical reasons, is to put the marshalling code and the actual UI code in a single method. In your code, you've got the AddRowToDataGrid method that modifies your datagrid and the UpdateMyClient method that just marshall the call to AddRowToDataGrid to the UI thread. You could rewrite it with a single method like that: public void UpdateMyClient( string data ) { if (this.InvokeRequired) { // We are in a workder thread, // let's marshall ourself to the UI thread this.Invoke( new SetIncomingDataTextDelegate( UpdateMyClient ), new object[] { data } ); } else { // We are now in the UI thread, let's update // this datagrid // Put the code that was in AddRowToDataGrid here } } [quoted text, click to view] > Also I noticed that the client form is acting a little slow when I > drag-and-move it in my screen. maybe because the listening? There are many reasons that could cause the form to be slow to repaint itself. It could be because the CPU is too busy or because you are doing some long running operations in the UI thread, hence preventing the thread from being able to repaint your controls when the form is moved. [quoted text, click to view] > at first I was trying to use BeginInvoke() with no success, looks like the > correct way it is Inkove(); BeginInvoke should work. The only difference between Control.Invoke and Control.BeginInvoke is that Invoke blocks until the invoked method has completed while BeginInvoke returns immediately. But the invoked method
Great. Indeed, it passed through the test this weekend. Next step is to put
a similar behavior in the SQL. My server (winform) calls a method called SendMsgToClient( string message, int channelID ) to deliver the data string to the connected clients. Can I do the same call via stored procedure using the OA objects? I used regasm to generate the typelib and placed my RemoteServer.dll in the GAC but the message was not sent to the client. have you done something similar to it? any ideas how to accomplish this? namespace WRemoteServer { public delegate void RegisterEventHandler (object sender, RemoteEventArgs e); public class RemoteServer : MarshalByRefObject { public static event RegisterEventHandler InvokeHostForm; public event RegisterEventHandler InvokeCallbackMethod, InvokeCallbackMethod2; public void RemoteServerMethod(string str, out string strOut) { RemoteEventArgs e = new RemoteEventArgs(str); if(InvokeHostForm != null) InvokeHostForm(this, e); strOut = str + " Returned from Server!"; } public void SendMsgToClient(string str, int msg) { RemoteEventArgs e = new RemoteEventArgs(str); // Fire Client Event if (InvokeCallbackMethod != null && (msg == 1 || msg==0)) InvokeCallbackMethod(this, e); else if (InvokeCallbackMethod2 != null && (msg == 2 || msg==0)) InvokeCallbackMethod2(this, e); } // This is to insure that when created as a Singleton, the first instance never dies, // regardless of the time between users messages. public override object InitializeLifetimeService() { return null; } } public abstract class RemotelyDelegatableObject : MarshalByRefObject { public void SubmissionCallback (object sender, RemoteEventArgs submitArgs) { try { InternalSubmissionCallback (sender, submitArgs) ; } catch{} } protected abstract void InternalSubmissionCallback (object sender, RemoteEventArgs submitArgs) ; } [Serializable] public class RemoteEventArgs : EventArgs { public string SendMessage; public string usrName, srvType; public RemoteEventArgs(string msg) { this.SendMessage = msg; } public RemoteEventArgs(string msg, string name, string type) { this.SendMessage = msg; this.usrName = name; this.srvType = type; } } } [quoted text, click to view] "Mehdi" <vioccc@REMOVEME.gmail.com> wrote in message
news:wnjeiauybgdw$.yjpg8eacbljr$.dlg@40tude.net... > On Sat, 13 Aug 2005 06:55:09 +0800, edge wrote: > >> Great hints! >> Well, seems that it is working, but instead of calling the new >> MethodInvoker >> I am using a delegate. Please look at how i am doing: > > MethodInvoker is actually just a normal delegate provided for your > convenience in the .NET framework. > >> a few more questions: >> Is this the way it should be? is it a valid alternative? > > Yes, it looks alright to me. Something that i like to do, but this is > purely for aestetical reasons, is to put the marshalling code and the > actual UI code in a single method. In your code, you've got the > AddRowToDataGrid method that modifies your datagrid and the UpdateMyClient > method that just marshall the call to AddRowToDataGrid to the UI thread. > You could rewrite it with a single method like that: > > public void UpdateMyClient( string data ) > { > if (this.InvokeRequired) > { > // We are in a workder thread, > // let's marshall ourself to the UI thread > this.Invoke( new SetIncomingDataTextDelegate( UpdateMyClient ), new > object[] { data } ); > } > else > { > // We are now in the UI thread, let's update > // this datagrid > // Put the code that was in AddRowToDataGrid here > } > } > >
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