new Constraint (C# Reference)
The new constraint specifies that any type argument in a generic class declaration must have a public parameterless constructor. To use the new constraint, the type cannot be abstract.
Example
Apply the new constraint to a type parameter when your generic class creates new instances of the type, as shown in the following example:
class ItemFactory<T> where T : new()
{
public T GetNewItem()
{
return new T();
}
}
When you use the new() constraint with other constraints, it must be specified last:
public class ItemFactory2<T>
where T : IComparable, new()
{
}
For more information, see Constraints on Type Parameters (C# Programming Guide).
C# Language Specification
For more information, see the C# Language Specification. The language specification is the definitive source for C# syntax and usage.
See Also
Reference
Operator Keywords (C# Reference)
Generics (C# Programming Guide)