Where C# fails, VB delivers.
Recently I've came across a strange behavior that took me some thinking to work around.
As you may know, my language of choice has been VB for as long as I can remember. However, I, like any good developer, can work just as good in C#. Really, it's no biggie.
Anyway, what I'm talking about here is dynamic type resolution.
For instance let's say we have the following VB program:
When ran, the above program will generate the following output:
Easy enough, huh?
Now, if we port this program to C# like this:
Which is the literal translation of the VB program above, we can't even compile to program, because the C# compiler gives the following errors:
It's the same damn code, how come C# can't convert from object to IFormattable?
Well, the answer is that the C# compiler requires that all types to be known at compile time, rater than establish at runtime.
As you may know, my language of choice has been VB for as long as I can remember. However, I, like any good developer, can work just as good in C#. Really, it's no biggie.
Anyway, what I'm talking about here is dynamic type resolution.
For instance let's say we have the following VB program:
Module Program
Sub Main()
Dim value As Object = 123
Format(123)
Format(value)
End Sub
Sub Format(ByVal value As IFormattable)
Console.WriteLine(value.ToString(Nothing, Nothing))
End Sub
End ModuleWhen ran, the above program will generate the following output:
123 123
Easy enough, huh?
Now, if we port this program to C# like this:
class Program
{
static void Main(string[] args)
{
object value = 123;
Format(123);
Format(value);
}
static void Format(IFormattable value)
{
Console.WriteLine(value.ToString(null, null));
}
}
Which is the literal translation of the VB program above, we can't even compile to program, because the C# compiler gives the following errors:
error CS1502: The best overloaded method match for 'DynamicCS.Formatter.Format(System.IFormattable)' has some invalid arguments
error CS1503: Argument '1': cannot convert from 'object' to 'System.IFormattable'
It's the same damn code, how come C# can't convert from object to IFormattable?
Well, the answer is that the C# compiler requires that all types to be known at compile time, rater than establish at runtime.
posted by Paulo Santos
|
3/31/2010 12:24:00 PM
|
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