C# difference between casting and as?
C#CastingC# Problem Overview
> Possible Duplicate:
> What is the difference between the following casts in c#?
In C#, is a there difference between casting an object or using the as keyword? Hopefully this code will illustrate what I mean...
String text = "Hello hello";
Object obj = text;
String originalCast = ((String)obj).ToUpper();
String originalAs = (obj as String).ToUpper();
Thanks
:)
C# Solutions
Solution 1 - C#
as will never throw a InvalidCastException. Instead, it returns null if the cast fails (which would give you a NullReferenceException if obj in your example were not a string).
Solution 2 - C#
Other than InvalidCastException that's already mentioned...
as will not work if the target type is a value type (unless it's nullable):
obj as int // compile time error.
Solution 3 - C#
As far as I know!
Using 'as' will return null if the 'cast' fails where casting will throw an exception if the cast fails.
Solution 4 - C#
Using 'as' will not throw an exception if the obj is not a String. Instead it'll return null. Which in your case will still throw an exception since you're immediately referencing this null value.