Type conversion

**Jon Skeet [C# MVP]** · Nov 13 '07, 08:55 PM

Re: Type conversion

chris fellows <chrisfellows@n ospam.co.ukwrot e:

I'm using a third party .NET 2 DLL from VB.NET and I'm am setting a property
of type 'int'. However, if I set a value larger than a 'short' (32k) then
reading the property back returns a negative number. Can someone tell me
what is likely to be happening within the property procedure that would
cause this? (The property should just be storing the value but appears to be
doing something unintentionally .)

I suspect it's being converted to a short behind the scenes, whether
intentionally or not.

I have a SQL stored proc that receives the negative value and, as a
temporary bug fix, I want to be able to reverse the procedure to get back to
the original number. I appreciate that a narrowing conversion has probably
occured so its possible that I can't get back to the original number.

Well exactly. In C# you could cast from int to ushort, then back to int
again... for instance:

using System;

public class Test
{
static short dodgy;

public static int Dodgy
{
get { return dodgy; }
set { dodgy = (short) value; }
}

public static int SlightlyDodgy
{
get { return (ushort) Dodgy; }
set { Dodgy = value; }
}

public static void Main()
{
Dodgy = 60000;
Console.WriteLi ne (Dodgy);
Console.WriteLi ne (SlightlyDodgy) ;
}
}

However, that won't work for numbers over 65535. What happens when you
set the property to, say, 100000?

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
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Type conversion

Type conversion

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