在库函数中正确使用泛型 - 如何知道要给出的类型

Question

I am trying to use a library function which requires specification of a generic type in the method call.
The method should open a file and extract a number of 1-D float arrays and return them to a type of dictionary defined in the library.

The documentation gives no examples, but does document the syntax as follows. Method I am trying to use:

public static NpzDictionary<T> Load<T>(byte[] bytes)
where T : class, ICloneable, IList, ICollection, IEnumerable, 
IStructuralComparable, IStructuralEquatable

http://accord-framework.net/docs/html/M_Accord_IO_NpzFormat_Load__1.htm

Where the NpzDictionary type is defined as:

public class NpzDictionary<T> : IDisposable, 
    IEnumerable
where T : class, ICloneable, IList, ICollection, IEnumerable, IStructuralComparable, IStructuralEquatab

http://accord-framework.net/docs/html/T_Accord_IO_NpzDictionary_1.htm

Here it says T is the type of arrays to be loaded.

I am expecting float arrays so I type:

var ret = NpzFormat.Load<float>(byte_array);

However I get the following error:

The type 'float' must be a reference type in order to use it as parameter 'T' in the generic type or method 'NpzFormat.Load<T>(byte[])'

What am I doing wrong?

Answer 1

From the generic constraints you can see that the type T must be a collection type ( ICollection, IList, IEnumerable ) but it must also implement the IStructuralComparable , IStructuralEquatable and ICloneable interfaces.

As far as I know there are no types in the .Net framework that implements all these so either your library has a collection type that matches these requirements of you have to implement it yourself.