unknown code 2

[bouwob]

I have a chunk of code that was written prior to me getting on the project.

PageSelection((int)((Page)((Control) sender).Parent).Tag)


Now I understand what page selection does and it accepts an int.

PageSelection((int) //set up method and cast to int

the next part is a call to a class

((Page)

but what exactly does this do?

((Control) sender). //Is this a page event? any ideas? When I go to the deffinition it takes me to the object browser and I am completly loss on what exactly this is trying to do and how to fix it.

tia

 

[JurkMonkey]

Control s = (Control)Sender; //Casting the object to a Control
Page p = (Page)s.Parent; //Casting the parent object to a Page
int pagenum = (int)p.Tag; //Casting the tag object of the page to an integer


That line basically finds the number stored in the Tag property of the current page. The code above just breaks down what that line of code is. When you see an object type in brackets (int)(Page)(Control) etc... you are saying that the basic object type that we know of is in fact the type shown in the brackets.

int num = (int)someobject; //convert someobject to int.

 

[chiph]

PageSelection((int)((Page)((Control) sender).Parent).Tag)

A good candidate for nomination at TheDailyWTF.com!

A better/safer way to do this would be to use the as keyword, as it won't throw an exception if the cast fails -- it just returns null, which you can test for.

Control c = sender as Control;
if (c != null)
{
   Page p = c.Parent as Page;
   if (p != null)
   {
      int t;
      if (int.TryParse(p.Tag, out t))
         PageSelection(t);
   }
}

Chip H.


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