What is the difference between bool and Boolean types in C#

Question

What is the difference between bool and Boolean types in C#?

Solution 1

bool is an alias for System.Boolean just as int is an alias for System.Int32. See a full list of aliases here: Built-In Types Table (C# Reference).

Solution 2

I don't believe there is one.

bool is just an alias for System.Boolean

Solution 3

They are one in the same. bool is just an alias for Boolean.

Solution 4

There is no difference - bool is simply an alias of System.Boolean.

http://msdn.microsoft.com/en-us/library/c8f5xwh7(VS.71).aspx

Solution 5

I realise this is many years later but I stumbled across this page from google with the same question.

There is one minor difference on the MSDN page as of now.

VS2005

Note:

If you require a Boolean variable that can also have a value of null, use bool. For more information, see Nullable Types (C# Programming Guide).

VS2010

Note:

If you require a Boolean variable that can also have a value of null, use bool?. For more information, see Nullable Types (C# Programming Guide).

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Comments

[aroon65]

Out of interest - why would you use both? I advocate using one or the other. Either use the aliases or don't, otherwise the code looks messy and inconsistent.

[Scott Dorman]

I think it looks messy when you don't use both. Use the alias for declaring the datatype and use the actuall class name when accessing static methods: string x = String.Format("Today is: {0}", DateTime.Now);

[aroon65]

So you'd do: int i = Int32.Parse(...); ? I have a couple of problems with that. Firstly, VS will highlight differently by default (I know you can change this but most devs just use the default syntax highlighting). Secondly, searching is harder especially with longs (long / Int64).

[AviD]

Yes, that is the exact way it should be done. int is not the class name, you should not be calling methods on it. On the other hand, it is the builtin type, and defining Int32 i; is too verbose and not natural.

[Beep beep]

So wouldn't bool be better for cross-platform compatibility?

[Arne Claassen]

mixing aliases and class names just adds nothing to code clarity. Pick one and stick with it, imho

[Asim Sajjad]

From the above link microsoft says The C# type keywords and their aliases are interchangeable But why we need Aliases, From my point of view Boolean is more meaningful then bool and Int32 is more meaningful then int then why aliases ???

[aroon65]

@asim: laziness? It's less typing and avoids the need to import System. Personally, I prefer the aliases. Typing "int" is far quicker than typing "Int32".

[Mike Chamberlain]

@asmin: It's a C thing. int, float etc are familiar keywords to C and C++ programmers, so Microsoft decided to use these aliases for consistency.

[max]

@Mikey I'm pretty sure that Java decided to use these aliases for consistency, and Microsoft decided to use Java for consistency... :-)

[Rosdi Kasim]

@MaxWell In Java, boolean and Boolean is not the same thing. One is a primitive data type and the other is an object.

[max]

yeah I know, I was just making a funny.

[Michael12345]

This alias just caused me a problem. I use bool because I thought it was the "correct" type, then I got confused why my "bool" MVC DisplayTemplate wasn't firing. Turns out I need to name it Boolean. If I realized Boolean was the official type and bool was just an alias for convenience, I'd have used Boolean from the outset.

[Logan Pickup]

I was tripped up by this - it seems to be a bug in the documentation. I saw the VS2005 page first (it appears higher in Google rankings for me!), and thought it implied that bool could contain null, but Boolean couldn't. Even though there is a link from the older to the newer documentation, I didn't read the newer documentation thoroughly enough to notice the single ? difference.

[Servy]

bool and Boolean are not two different types, that one type is not a reference type, you can call a static method on that one type using either identifier, and you don't in fact need to call a ConvertTo method to convert it to another type.

[Servy]

Boolean is a value type, not a reference type.

[Tanner - reinstate LGBT people]

It's not correct that "bool and Boolean are both reference types". The words bool and Boolean both refer to the same type, and that type is a value type, not a reference type.

[bvdb]

Thanks, I was trying to check if C# acted the same as java in this field. You answer is the only one that compares it to java (even though maybe not intentionally). :)

[Choi]

I agreed with Kent Boogaart's comment. Yes, int i = Int32.Parse is weird. But for java user, Using bool and boolean the alias when declaring Boolean class is not bad idea.

[Nat]

It's System.Boolean rather than just Boolean. The using System; was showing up because it allowed Boolean to be properly interpreted as System.Boolean. Not really lighter so much as just less verbose.

[Legends]

What is the difference between Bool and bool?

[The incredible Jan]

@Timothy Macharia Who/what is wrong? What does "convert to null" mean?

[bakalolo]

Thumbs down because this didn't answer the question on what is the difference.