Manually raising an event in c#

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I want to rais RichTextBlock_UpdatedLayout event manually in Windows 8 Metro App

Here is a sample code actual code is vary big

C#

public void rchblknew_LayoutUpdated(object sender, object e)
       {

           if (rchblknew.HasOverflowContent == true)
           {
               myspan.FontSize = 5;
               rchblknew.UpdateLayout();
           }

       }

at the same page i am raising that event

for(int i=1; i <= 3; i++)
{
 rchblknew.LayoutUpdated += new EventHandler<object>(mytest_LayoutUpdated);
}

Here i am expecting my event should rais three time but it is raising only one time when loop is completed

Please help me to rais my event three time

Posted 23-May-13 1:37am

Susheel Kumar Verma

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pramod.hegde 23-May-13 7:48am

First of all,
rchblknew.LayoutUpdated += new EventHandler<object>(mytest_LayoutUpdated);
this line of code, only subscribes to the event. It tells what is the handler (mytest_LayoutUpdated) when the event is raised.
Since you have subscribed the event thrice, mytest_LayoutUpdated method should get executed 3 times.

Just check whether you have unsubscribed the event anywhere in the handler code..
do you have something like this in the actual code.
rchblknew.LayoutUpdated -= new EventHandler<object>(mytest_LayoutUpdated);

[no name] 23-May-13 8:00am

No i have not unsubscribed the event anywhere in my code
Should i write that code to unsubscribe the event

pramod.hegde 23-May-13 11:45am

No. If you want the event handler to execute many times, then do not unsubscribe.

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E.F. Nijboer · Answer 1 · 2013-05-23T02:10:00

Solution 1

Did you put a breakpoint in the method rchblknew_LayoutUpdated to check if it is raised 3 times? UpdateLayout won't do anything if nothing changed. Check msdn for more info:
http://msdn.microsoft.com/en-us/library/system.windows.uielement.updatelayout.aspx[^]

Good luck!

Posted 23-May-13 2:10am

E.F. Nijboer

N_tro_P · Answer 2 · 2013-05-23T05:31:00

You are not actually raising the event but instead listening to the event 3 times.

To raise an event you just call on it and pass any appropriate arguments.
e.g.

C#

MySpeacialEventForThisObject(this, EventArgs.Empty);

Also, most people wrap it for safety and cleanliness
e.g.

C#

private void RaiseMySpeacialEventForThisObject(MySpeacialEventData data)
{
   var handler = MySpeacialEventForThisObject;
   if(handler != null)
   {
      handler(this, data);
   }
}
<pre>

Now we have that out of the way it seems you are trying to raise a protected/private event (most events are.. in fact it is bad design likely to have the event raisable publicly). You can not do that for the UI components. They are controlled by their base classes and should be. If you need speacial eventing you can often inherit from them and add your own events.