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 Posted: Fri, 16th Jul 2010 13:00 Post subject: [C#] Boxing when using Properties? |
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Let's say I have this class:
| Code: | class WorldElement
{
private Byte tile;
public Byte Tile
{
get { return tile; }
set { tile = value; }
}
public WorldElement(Byte _tile)
{
tile = _tile;
}
}
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And I access it later on with:
| Code: | Int32 a = 5+5;
WorldElement worldElement = new WorldElement(5);
worldElement.Tile = a;
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Will boxing occur? Or will it be just a conversion from Int32 to Byte?
And can I use Byte where int (aka Int32) is expected? 
Or should I just go with Int32 all the time and shit on the less memory usage of a Byte?
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LeoNatan
☢ NFOHump Despot ☢
Posts: 73194
Location: Ramat Gan, Israel 🇮🇱
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| Posted: Fri, 16th Jul 2010 13:48 Post subject: |
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Basically, the rule is, if you are going from a small one to a larger one (there is no data loss), the conversion is implicit. That is, this will work:
| Code: | byte b = 12;
int a = b; |
On the other hand, when there is a possibility of data loss, you must explicitly convert the variable. For example:
| Code: | int a = 12;
//byte b = a; //Won't even compile.
byte b = (Byte) a; //Explicit conversion, will work. |
This is the same behavior as C++ and Java (and any type-safe language).
A table for your convenience:
http://msdn.microsoft.com/en-us/library/y5b434w4.aspx
But really, there are very few reasons to use bytes these days aside from compatibility reasons. 
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garus
VIP Member
Posts: 34200
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| Posted: Fri, 16th Jul 2010 13:49 Post subject: |
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snip
Last edited by garus on Tue, 27th Aug 2024 21:27; edited 1 time in total
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LeoNatan
☢ NFOHump Despot ☢
Posts: 73194
Location: Ramat Gan, Israel 🇮🇱
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| Posted: Fri, 16th Jul 2010 13:53 Post subject: |
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It should not compile at all, because data conversion is done in run time, while this will fail in compile time.
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| Posted: Fri, 16th Jul 2010 14:07 Post subject: |
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Int32 to Byte is not happening without conversion with (Byte)
But if you say that there is no usage to it, I'll drop the whole byte stuff I thought that C# might internally handle the Byte as something like... let's say Int8
The thing that I was worrying about is, that, as far as I know, with Properties you can say
Int32 blabla = 100;
worldElement.Tile = blabla;
And it shouldn't return an error, as Tile is the property and will do any conversion if needed to Byte. But 100 is a int32 and small enough to fit in Byte. So my question was, will C# do a conversion from 100 (Int32) to 100 (Byte) or does it handle it internally already as an int (like Int8)
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LeoNatan
☢ NFOHump Despot ☢
Posts: 73194
Location: Ramat Gan, Israel 🇮🇱
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| Posted: Fri, 16th Jul 2010 14:13 Post subject: |
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It doesn't matter if you are sending to a property, a variable or as a function parameter, it won't work. It won't even compile.
Properties are translated to getter and setter functions in CIL anyway.
BTW, why do you use Int32 and not int? int is Int32, short is Int16 and long is Int64.
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| Posted: Fri, 16th Jul 2010 14:38 Post subject: |
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As in C# internally int = Int32, why shouldn't I? It's like using bool instead of Boolean 
It's not like in Java where bool can just be true or false and Bool is an Object that can be true false or null 
Btw thanks! Will try to replace all Byte with Int32 and see how powerful the Visual Studio IDE is (should help me to replace all occurences, right? )
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LeoNatan
☢ NFOHump Despot ☢
Posts: 73194
Location: Ramat Gan, Israel 🇮🇱
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| Posted: Fri, 16th Jul 2010 14:46 Post subject: |
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I am just saying, conversion from int to Int32 is done at any rate by the compiler when creating the CIL assembly. So why write such bloat as Int32 when they are the same (especially when they are the same)? Do you also type Boolean instead of bool? 
I use var anyway nowadays It is just so much faster to use typing all these types
bool in C# can't be null because it is a structure and not a class. If you need it to be nullable, you can use the bool? type, or Nullable<bool>, which are the same. Then you can ask b.HasValue and act accordingly.
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