Pass extra parameters to an event handler?
private void setup(string someData)
{
Object.assignHandler((sender) => evHandler(sender,someData));
}
public void evHandler(Object sender, string someData)
{
// need someData here!!!
}
Captured variables:
private void setup(string someData)
{
Object.assignHandler((sender,args) => {
evHandler(sender, someData);
});
}
public void evHandler(Object sender, string someData)
{
// use someData here
}
Or (C# 2.0 alternative):
Object.assignHandler((EventHandler)delegate(object sender,EventArgs args) {
evHandler(sender, someData);
});
you can try doing this:
string yourObject;
theClassWithTheEvent.myEvent += (sender, model) =>
{
yourObject = "somthing";
}
I had a hard time figuring out @spender's example above especially with: Object.assignHandler((sender) => evHandler(sender,someData));
because there's no such thing as Object.assignHandler
in the literal sense. So I did a little more Googling and found this example. The answer by Peter Duniho was the one that clicked in my head (this is not my work):
snip
The usual approach is to use an anonymous method with an event handler that has your modified signature. For example:
void Onbutton_click(object sender, EventArgs e, int i) { ... } button.Click += delegate(object sender, EventArgs e) { Onbutton_click(sender, e, 172); };
Of course, you don't have to pass in 172, or even make the third parameter an int. :)
/snip
Using that example I was able to pass in two custom ComboBoxItem
objects to a Timer.Elapsed
event using lambda notation:
simulatorTimer.Elapsed +=
(sender, e) => onTimedEvent(sender, e,
(ComboBoxItem) cbPressureSetting.SelectedItem,
(ComboBoxItem) cbTemperatureSetting.SelectedItem);
and then into it's handler:
static void onTimedEvent(object sender, EventArgs e, ComboBoxItem pressure, ComboBoxItem temperature)
{
Console.WriteLine("Requested pressure: {0} PSIA\nRequested temperature: {1}° C", pressure, temperature);
}
This isn't any new code from the examples above, but it does demonstrate how to interpret them. Hopefully someone like me finds it instructive & useful so they don't spend hours trying to understand the concept like I did.
This code works in my project (except for a non-thread-safe exception with the ComboBoxItem
objects that I don't believe changes how the example works). I'm figuring that out now.