I have a sample form with 3 windows. Each window has a label and the main form has a button.
I have a class with the following code:
public class CustomEventArgs : EventArgs
{
public string Message { get; set; }
public CustomEventArgs(string message)
{
Message = message;
}
}
public delegate void CustomEventHandler(object sender, CustomEventArgs args);
public class EventCode
{
public void Process()
{
var cea = new CustomEventArgs("I was processed");
if (MyEvent != null)
{
MyEvent.Invoke(this, cea);
}
}
public event CustomEventHandler MyEvent;
}
On my main form, I am going to push the button and have it process code in my EventCode class, and then invoke the event. I want the event to send a message to both forms that are open, which will then display a message on the screen.
Here is my button click code in Form1:
private void Form1_Load(object sender, EventArgs e)
{
Window1 w1 = new Window1();
w1.Show();
Window2 w2 = new Window2();
w2.Show();
}
private void button1_Click(object sender, EventArgs e)
{
EventCode ec = new EventCode();
ec.Process();
}
In Window 1:
EventCode ec = new EventCode();
public Window1()
{
InitializeComponent();
ec.MyEvent += new CustomEventHandler(ec_MyEvent);
}
void ec_MyEvent(object sender, CustomEventArgs args)
{
label1.Text = args.Message;
}
Repeated for Window 2
When I click on the button, the event subscription does not display the text on each of the forms. If i create an event subscription on the main form, it will display.
I am not sure which route to take to make this functionality to work.
Thoughts?
Subscriptions to events only work for the instances you subscribe on. If you create a new instance of EventCode and subscribe to the events, the event will only be raised if you call Process on that specific instance.
Quick solution: pass the EventCode instance you create in the main window to the two child windows.
public Window1(EventCode eventCode)
{
InitializeComponent();
eventCode.MyEvent += new CustomEventHandler(ec_MyEvent);
}
void ec_MyEvent(object sender, CustomEventArgs args)
{
label1.Text = args.Message;
}
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