Complete set: Intro to C - Bill Buchanan

uk.Gdp = 1000000000;
int c = uk.Region;
10.6 Creating an event
10.6.1 Why would we want to create an event
We use events in the user interface. The details are normally hidden – but the code
to our methods to the interface components is there:
private System.Windows.Forms.Button SortPop;
. . .
#region Windows Form Designer generated code
this.SortPop.Text = "Sort By Population";
this.SortPop.Click += new System.EventHandler(this.SortPop_Click);
. . .
private void SortPop_Click(object sender, System.EventArgs e)
Aside from the standard user interface components that do the hard work for us it is
a relatively unusual requirement to implement our own events. We might want to
create our own events if we want to be notified of some occurrence – but we do not
know what that might cause that.
We certainly want to create events if we want to implement our own components.
duction to .NET
Intro
10.6.2 What is involved in creating an event
We require the following
• An action to perform when the event is triggered (other people may create
other actions of the same type).
• A handler delegate – this restricts the signature of the actions that may subscribe.
• An event that holds a list of all subscribed actions.
The tasks that are required:
• In the publishing class we declare the delegate.
• In the publishing class we declare the event.
• In the publishing class we insert code to trigger the event under some circum‐
Agilent .NET Course: Module 10,page 8