How to costraint a generics to be a number

[Matteo Migliore]

Hi.

I want to costraint a generics T to be a number (Int32, Double, Byte etc...)
but
how I can do?

I need beacuse I want to use arithmetic operators (+, -...).

Thx! ;-)

 

[Nicholas Paldino [.NET/C# MVP]]

Matteo,

You can't, at least not at compile time using constraints. You could
perform a check against the type parameter at run time in the static
constructor for the type and see if it is Int32, Double, etc, etc.

 

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

I want to costraint a generics T to be a number (Int32, Double, Byte
etc...) but
how I can do?

I need beacuse I want to use arithmetic operators (+, -...).

You can't.

Many people have wished so, but it is not possible.

Try read:
http://www.codeproject.com/csharp/genericnumerics.asp
for an example.

Arne

 

[Matteo Migliore]

Try read:

http://www.codeproject.com/csharp/genericnumerics.asp
for an example.

Thanks all!

I just reader the article on CodeProject. The possibile
solution is that .

Thx again! ;-)

 

[not_a_commie]

I use "where T: IComparable<T>" for this. It seems to work okay. Odds
are you needed it constrained to be a number because you need to use
less than, greater than, or equals on it. All of those are easily
possible with the compare interface.

 

[Peter Laan]

Hi.

I want to costraint a generics T to be a number (Int32, Double, Byte
etc...) but
how I can do?

I need beacuse I want to use arithmetic operators (+, -...).

You might be able to use extension methods in .Net 3.5. Somthing like this:

public static int Sum(this MyClass<int> list)
{
int sum = 0;
foreach (int i in list)
sum += i;
return sum;
}

And then use it like this:

MyClass<int> a;
int total = a.Sum();


Peter

 

[Matteo Migliore]

You might be able to use extension methods in .Net 3.5. Somthing like

this:

Thank you for support . I know that is possible in .NET 3.x but
I needed to solve problem writing a class.

I solved thanks again! ;-)