Databases
StackOverflow2013
Postsdbo
POHow to update textbox on GUI from another thread
Body
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to update textbox on GUI from another thread
    text
    copied!<p>I'm new with C# and I'm trying to make a simple client server chat application.</p> <p>I have RichTextBox on my client windows form and I am trying to update that control from server which is in another class. When I try to do it I get the error: <em>"Cross-thread operation not valid: Control textBox1 accessed from a thread other than the thread it was created on".</em></p> <p>Here the code of my Windows form:</p> <pre><code>private Topic topic; public RichTextBox textbox1; bool check = topic.addUser(textBoxNickname.Text, ref textbox1, ref listitems); </code></pre> <p>Topic class:</p> <pre><code>public class Topic : MarshalByRefObject { //Some code public bool addUser(string user, ref RichTextBox textBox1, ref List&lt;string&gt; listBox1) { //here i am trying to update that control and where i get that exception textBox1.Text += "Connected to server... \n"; } </code></pre> <p>So how to do that? How can I update the textbox control from another thread? </p> <hr> <p>I'm trying to make some basic chat client/server application using .net remoting. I want to make windows form client application and console server application as separate .exe files. Here im trying to call server function AddUser from client and i want to AddUser function update my GUI. Ive modified code as you suggested Jon but now instead of cross-thread exception i've got this exception ... <em>"SerializationException: Type Topic in Assembly is not marked as serializable"</em>. </p> <p>Ill post my whole code bellow, will try to keep it simple as possible.<br> Any suggestion is welcome. Many thanks.</p> <p><strong>Server:</strong> </p> <pre><code> namespace Test { [Serializable] public class Topic : MarshalByRefObject { public bool AddUser(string user, RichTextBox textBox1, List&lt;string&gt; listBox1) { //Send to message only to the client connected MethodInvoker action = delegate { textBox1.Text += "Connected to server... \n"; }; textBox1.BeginInvoke(action); //... return true; } public class TheServer { public static void Main() { int listeningChannel = 1099; BinaryServerFormatterSinkProvider srvFormatter = new BinaryServerFormatterSinkProvider(); srvFormatter.TypeFilterLevel = TypeFilterLevel.Full; BinaryClientFormatterSinkProvider clntFormatter = new BinaryClientFormatterSinkProvider(); IDictionary props = new Hashtable(); props["port"] = listeningChannel; HttpChannel channel = new HttpChannel(props, clntFormatter, srvFormatter); // Register the channel with the runtime ChannelServices.RegisterChannel(channel, false); // Expose the Calculator Object from this Server RemotingConfiguration.RegisterWellKnownServiceType(typeof(Topic), "Topic.soap", WellKnownObjectMode.Singleton); // Keep the Server running until the user presses enter Console.WriteLine("The Topic Server is up and running on port {0}", listeningChannel); Console.WriteLine("Press enter to stop the server..."); Console.ReadLine(); } } } } </code></pre> <p><strong>Windows form client:</strong> </p> <pre><code>// Create and register a channel to communicate to the server // The Client will use the port passed in as args to listen for callbacks BinaryServerFormatterSinkProvider srvFormatter = new BinaryServerFormatterSinkProvider(); srvFormatter.TypeFilterLevel = TypeFilterLevel.Full; BinaryClientFormatterSinkProvider clntFormatter = new BinaryClientFormatterSinkProvider(); IDictionary props = new Hashtable(); props["port"] = 0; channel = new HttpChannel(props, clntFormatter, srvFormatter); //channel = new HttpChannel(listeningChannel); ChannelServices.RegisterChannel(channel, false); // Create an instance on the remote server and call a method remotely topic = (Topic)Activator.GetObject(typeof(Topic), // type to create "http://localhost:1099/Topic.soap" // URI ); private Topic topic; public RichTextBox textbox1; bool check = topic.addUser(textBoxNickname.Text,textBox1, listitems); </code></pre>
 

Querying!

 
Guidance
An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload