foreach(UserControl uc in plhMediaBuys.Controls)
{
if (uc is MySpecificType)
{
return (uc as MySpecificType).PulblicPropertyIWantAccessTo;
}
}
Kon
2008-10-22 19:00:35
+3
A:
Actually, if you use the "as" keyword or just cast the variable, you are doing the same thing. The only difference between the two is "as" returns null if it can't cast, instead of throwing an exception.
Chris Pietschmann
2008-10-22 19:10:49
True, but it'll never hit that line if it's not able to cast.
Kon
2008-10-22 19:16:15
+7
A:
foreach(UserControl uc in plhMediaBuys.Controls) {
MyControl c = uc as MyControl;
if (c != null) {
c.PublicPropertyIWantAccessTo;
}
}
Chris Pietschmann
2008-10-22 19:01:39
In fact, this example seems less efficient to me, because you're creating another instance of MyControl.
Kon
2008-10-22 19:05:01
This code doesn't actually create a new instance of MyControl, it just creates a new reference to one. References are essentially pointers, so there should be no performance penalty here.
Charlie
2008-10-22 19:10:07
Actually, if you use the "as" keyword or just cast the variable, you are doing the same thing. The only difference between the two is "as" returns null if it can't cast, instead of throwing an exception.
Chris Pietschmann
2008-10-22 19:10:14
I stand corrected, however it still seems unnecessary - adds onto the complexity of the code.
Kon
2008-10-22 19:14:56
do I need some sort of using directive or an assembly reference in my code behind that refrences MyControl?
rockstardev
2008-10-22 19:22:15
Perhaps it is more complex to someone unfamiliar with C#, but it also saves a cast (quasi-expensive).
SoloBold
2008-10-22 19:24:47
+1
A:
Casting
I prefer to use:
foreach(UserControl uc in plhMediaBuys.Controls)
{
ParticularUCType myControl = uc as ParticularUCType;
if (myControl != null)
{
// do stuff with myControl.PulblicPropertyIWantAccessTo;
}
}
Mainly because using the is keyword causes two (quasi-expensive) casts:
if( uc is ParticularUCType ) // one cast to test if it is the type
{
ParticularUCType myControl = (ParticularUCType)uc; // second cast
ParticularUCType myControl = uc as ParticularUCType; // same deal this way
// do stuff with myControl.PulblicPropertyIWantAccessTo;
}
References
SoloBold
2008-10-22 19:04:08