c#通用接口，其中参数是通用的

Question

I have an interface

public interface IOfflineBackedRepo<TSummary,TDetail>
{
    Task SyncAsync();
}

this has different concrete implementations. I am trying to develop a service lets developers register different implementations of IOfflineBackedRepo interface and separately call SyncAsync at a later point in time. The new interface should be similar to the below, except this is not a valid syntax.

public interface ISyncManager<T> where T : IOfflineBackedRepo<TSummary, TDetail>
{
    void Register(T repo);

    Task SyncNowAsync(); // this loops through and calls SyncAsync on the repo
}

How to fix the syntax issue?

Answer 1

ISyncManager does not have anywhere mentioning TSummary,TDetail in it's scope

TSummary and TDetail is defined and exist only around IOfflineBackedRepo . When you try to use it anywhere else you must define a type you will use in substitute for them. It could be actual type or a type that you would get from generic argument but you must define it somewhere around ISyncManager

At the most basic ways,

public interface ISyncManager<T,U,V> where T : IOfflineBackedRepo<U,V>
{
    void Register(T repo);

    Task SyncNowAsync(); // this loops through and calls SyncAsync on the repo
}

For the ease of use I think you should just separate interface

public interface IOfflineBackedRepo
{
    Task SyncAsync(); // this function is not typed specific right?
}

public interface IOfflineBackedRepo<TSummary,TDetail> : IOfflineBackedRepo
{
    // other definition about type specific
}

public interface ISyncManager<T> where T : IOfflineBackedRepo
{
    void Register(T repo);

    Task SyncNowAsync(); // this loops through and calls SyncAsync on the repo
}

And I guess ISyncManager is actually just a collection. I think it would be better if you could just make extension method for collection

public static class SyncManagerExt
{
    // Register is just Add to collection
    public static Task SyncNowAsync(this ICollection<T> items) where T : IOfflineBackedRepo
    {
        // loops through items and calls SyncAsync on the repo
    }
}