generics - constraint

[Michael Moreno]

hello,

I am trying to write a generic class where the underlying type is
either an int, a float or a double:

public class CMatrix<T>: ICloneable where VarType: int, float, double

but that does not compile.

The error message is :

'int' is not a valid constraint. A type used as a constraint must be an
interface, a non-sealed class or a type parameter.

Is it possible to do what I want?

thanks.

 

[Jesse McGrew]

I am trying to write a generic class where the underlying type is
either an int, a float or a double:

public class CMatrix<T>: ICloneable where VarType: int, float, double

but that does not compile.

The error message is :

'int' is not a valid constraint. A type used as a constraint must be an
interface, a non-sealed class or a type parameter.

Is it possible to do what I want?

No, I think the best you can do is write a static constructor that
checks typeof(T) and throws an exception if it isn't int, float, or
double.

Jesse

 

[Michael Moreno]

No, I think the best you can do is write a static constructor that

checks typeof(T) and throws an exception if it isn't int, float, or
double.

Thanks. Generics are very limited then because you cannot perform any
operator >, <, +, -, *, / in the code.
I hope they will fix that!

 

[Jon Skeet [C# MVP]]

Thanks. Generics are very limited then because you cannot perform any
operator >, <, +, -, *, / in the code.
I hope they will fix that!

There are workarounds already. Have a look at
http://www.codeproject.com/csharp/genericnumerics.asp
for more information.