[C#] Thread Safe in - How to?

[litewarez]

heya guys

Im working on a C# Application and im having some issues with the ThreadSafe thingimabob.

When i try execute the a command i get the Thread not safe.

heres my Code!

using System;
using System.Threading;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using ComponentFactory.Krypton.Toolkit;
using System.Windows.Forms;

namespace XXXXX
{
    public partial class Login : KryptonForm
    {

        public Login()
        {
            InitializeComponent();
        }

        private void Login_Load(object sender, EventArgs e)
        {
            //Hide Elements
            this.login_progress_bar.Visible = false;
        }

        private void ExitApp_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void doLogin(object sender, EventArgs e)
        {
            string u = login_username.Text;
            string p = login_password.Text;

            //Check for default values

            if (u.Length == 0 || p.Length == 0)
            {
                this.SetLoginStatus("Please fill out all login feilds");
                return;
            }
            this.LoginEnabled(false);
           /*
                      Removed all execution code here because its private application :) 
           */
        }

        //Handlers



        /*I Run the this.SetLoginStatus witch is located below, but it strikes an unsafe thread error*/
        private void j_XError(object sender, Exception ex) { this.SetLoginStatus("Incorrect Username or Password");}




        private void j_XAuth(object sender){/*ShowDialog("Authenticated: " + sender.ToString());*/}
        private void j_XWrite(object sender, string txt){if (txt == " ") return;/*ShowDialog("SEND: " + txt);*/}
        private void j_XRead(object sender, string txt){if (txt == " ") return;/*ShowDialog("RECV: " + txt);*/}
      
        //Dialog Box
        private void ShowDialog(string Message){MessageBox.Show(Message);}

        private void SetLoginStatusTest(string message)
        {
            label1.Text = message;
        }

        private void SetLoginStatus(string message)
        {
            label1.Text = message;
        }

        private void LoginEnabled(bool status) 
        {
            login_username.Enabled = login_password.Enabled = login_button.Enabled = status;
        }

        //Menu Actions
        private void OptionsMenuOpen(object sender, EventArgs e)
        {
            Settings Settings = new Settings();
            Settings.Show();
        }
    }
} 

Ok so i have j_XError above witch calls the SetLoginStatus But i get an error about not being Thread Safe.

Can someone explain to me whats going in

litewarez Reviewed by litewarez on 5th Jul 2010. [C#] Thread Safe in - How to? heya guys Im working on a C# Application and im having some issues with the ThreadSafe thingimabob. When i try execute the a command i get the Thread not safe. heres my Code! using System; Rating: 5

[Hyperz]

Your form runs on a different thread so you can't call members just like that. If it's a normal winforms application you can use the Invoke method.

For example:

// some code running in a new thread
// change the text of a label on a form:
this.Invoke(() => this.lblTest.Text = "my string");

http://msdn.microsoft.com/en-us/library/zyzhdc6b.aspx

[litewarez]

Ok so because its an event the event is being executed by another object from another name-space and therefore it cant cross thread ?

[Hyperz]

No. Whatever is calling your method is doing so from a thread that is not the GUI thread. It has little to do with objects or namespaces. It can't help you any further since you use non standard controls.

[litewarez]

Okay.

For your information heres wahts going on

I have a library that's i use to contact a Jabber Server, and i Assign callbacks / events for Successful Connection, Login Failed etc etc... Its the methods that i tell it to call that has has problem.

What ive done is create a separate class to hold the Methods that will be called on the event attached to it... I have to learn about the threading to get the Callbacks class to be able to modify the the Form class.. I think

So now i have defined my callbacks Class in my Form Class like so:

private XXXX.JabberCallbacks.JabberCallbacks _JabberCallbacks = new XXXX.JabberCallbacks.JabberCallbacks(); 

And then when the login button is click it will run a method within the login Class, After basic input validation i assign the callbacks like So

Jabber.OnError += new bedrock.ExceptionHandler(_JabberCallbacks.OnError); 

So that _JabberCallbacks.OnError will be called if an error accrues.

On the _JabberCllbacks class heres the OnError Method:

public void OnError(object sender, Exception ex)
        {
              //Here i need to be able to set a Label in the Login Form :/
        } 

[Hyperz]

lambda + yourForm.Invoke() = solution
As I said in the first post .

So, this

        private void SetLoginStatus(string message)
        {
            label1.Text = message;
        } 

becomes

        private void SetLoginStatus(string message)
        {
            this.Invoke(() => this.label1.Text = message);
        } 

Also, give your controls meaningfull names lol. lblTitle > label1. txtPassword > textbox1.

[litewarez]

With your code i still get a few errors witch im unsure of:

Error	1
Cannot convert lambda expression to type 'System.Delegate' because it is not a delegate type
C:\Users\XXXX\documents\visual studio 2010\Projects\XXXX\XXXX\Login.cs

Edit, I Also changed the Private to Public so i can call it from another Class

[Hyperz]

Whoops

var a = new Action(() => this.label1.Text = message);
this.Invoke(a); 

[litewarez]

OK that seemed to have fixed the errors but im confused about whats going on!


Ok so i have this line:

//From the main form:DoLogin()
Jabber.OnError += new bedrock.ExceptionHandler(_JabberCallbacks.OnError); 

Witch then will run the following method:

public void OnError(object sender, Exception ex)
{
    //Here i want to run the follwing
    Login.SetLoginStatus("Error: " + ex.ToString());

   /*
        The line above strings the following error!
        An object reference is required for the non-static field, method, or property 'XXXX.Login.SetLoginStatus(string)'

   */
} 

Witch is located in the main form

public void SetLoginStatus(string message)
{
    var a = new Action(() => this.label1.Text = message);
    this.Invoke(a);
} 

[Hyperz]

What's confusing about that?