CODEWITHSUNDEEP
c#generics
XN16
XN16

Reputation: 5889

List of generic objects with unknown type

I have the following two classes. The ConvertToType<T> class is an existing class and works fine, however when it is used an instance is created each time (via reflection), therefore I am creating a wrapper class to hold all the instances as they are created for efficiency.

public class TypeConverterHelper
{
    private IList<ConvertToType<>> types;
}

internal class ConvertToType<T>
{
    //snip
}

However, as you can see I need a list of my ConvertToType<T> class, but I can't specify the type as the whole point of these classes is that the type is unknown until runtime. I have researched this issue a fair amount, but without finding a successful solution. I know I could set the generic type to be an object, but there you could get un/boxing issues at some point. Adding an interface/abstract base class which is restricted to a struct looked like a good option, but unfortunately T could be a string, and possibly other custom classes at a later date so that solution doesn't work.

So does anyone have any other solutions/suggestions?

Upvotes: 0

Views: 2386

Answers (1)

Jon
Jon

Reputation: 437854

The list type has to be non-generic (since the generic type arguments cannot be predicted), so object would do, but it might be better to use a common non-generic base. Boxing/unboxing does not come into the discussion because ConvertToType is a reference type.

You would of course have to cast the values in the list back to ConvertToType<T> before being able to use them; the implementation could look like this:

public class TypeConverterHelper
{
    private IList<object> types;

    public ConvertToType<T> GetConverter<T>()
    {
        return types.OfType<ConvertToType<T>>.FirstOrDefault();
    }
}

Upvotes: 3

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