Using delegates and Events in Silverlight

Using Delegates and Events in Silverlight follows the same procedure as in a windows or web program.

The scenario in which we use a delegate is also the same in silverlight. The Scenario is We have a UserControl A inside an other page or user control B, and we need an event to control the actions of A from B.

Our aim here is to add a mouse click event to the UserControl A
In this case, inside A we declare a delegate as shown below.

public delegate void UserControlClicked(object sender, MouseButtonEventArgs e);

We Now declare an event for this particular delegate. It is this event that we call to invoke the method.

public event UserControlClicked RectangleClicked;

Now we write in the LeftButtonDown event of the UserControl A,

private void UserControl_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (RectangleClicked!= null)
{
RectangleClicked(sender, e);
}
}

We check for the event condition to be null, just to verify that the event is called at B.

Now at B,

Rectangle b = new Rectangle();
b.RectangleClicked+= new Rectangle.userControlClicked(b_RectangleClicked );


and in the method RectangleClicked,


void b_RectangleClicked(object sender, MouseButtonEventArgs e)
{
FrameworkElement element = sender as FrameworkElement;
Rectangle box = (Rectangle)element;
string detail= "\Height: " + box.Height + " Width: " + box.Width + " Name: " + box.Name
HtmlPage.Window.Alert("Rectangle box "+detail);
}


For these to work, you must include the following namespaces.
using System.Windows.Browser; // to display the alert box.

Any mistakes in the post, please do add a comment.

Thank you.