By Erlend Larsen
I'm pretty new to C#, but have already found out how easy multithreading is in this tailored language. I've used Visual C# .NET to come out with the recipe below. It's kind of a reference to remember the important points of creating a thread which can update the GUI on its own.
You need:
- One Form file for user interface
- One Component class file added from menu: Project-Add Component.
1. Declare an instance of the Component class (Teller) in the Form class and create the object in the constructor of the Form class.
private Teller Teller1; // Outside the constructor
Teller1 = new Teller(); // Inside the constructor
// Enables a function in Teller class to use UpdateLabel(...) through a delegate
// declared in Teller class.
Teller1.Delegerer += new Teller.DelegatEn(this.UpdateLabel); //Inside the constructor
2. Create a function in the Form class to update/edit controls from threads.
private void UpdateLabel(int Label, int integer)
{
lblTeller.Text = integer.ToString();
lblTeller2.Text = Label.ToString();
}
3. Add function to deal with starting the thread, for instance by the click of a button.
private void btnStart_Click(object sender, System.EventArgs e)
{
btnStart.Enabled = false;
// Teller1.Counter is the function the thread will work through.
Thread thread = new Thread(new ThreadStart(Teller1.Counter));
thread.Start();
}
4. That was all changes to the Form file. Now we'll change the Component file. In the Component class we declare a delegate and an event. The event is an instance of the delegate. The delegate must have the exact same parameters as the function in the Form class to update/edit controls from threads.
public delegate void DelegatEn(int Label, int integer);
public event DelegatEn Delegerer;
5. Finally, all we need is the code for the thread.
public void Counter()
{
// Write something else to do here.
for (int i=0; i < 100000) Delegerer(1, i); // Uses UpdateLabel in Form class
}
6. Build it and run it. Voila
