使用委托调用异步方法

Question

我正在调用async api 来获取详细信息。 目标api 端点可以更改并希望将其作为动态函数传递。

既然所有api的细节分页都是一样的，我们如何才能使它成为delegate函数和async return value?

private async Task<List<Items>> GetItemsAsync(HttpClient client, string arg1)
{
    var totalResults = new List<Items>();
    int skip = 0, resultsCount = 1;

    while (resultsCount != 0)
    {
        var results = await GetItems(client, arg1, skip);
        if (results != null)
        {
            totalResults.AddRange(results);
            resultsCount = results.Count;
            skip += resultsCount;
        }
        else
        {
            resultsCount = 0;
        }
    }

    return totalResults;
}

private async Task<List<Users>> GetUsersAsync(HttpClient client, string arg1)
{
    var totalResults = new List<Users>();
    int skip = 0, resultsCount = 1;

    while (resultsCount != 0)
    {
        var results = await GetUsers(client, arg1, skip);
        if (results != null)
        {
            totalResults.AddRange(results);
            resultsCount = results.Count;
            skip += resultsCount;
        }
        else
        {
            resultsCount = 0;
        }
    }

    return totalResults;
}

Answer 1

类似于以下内容：

private async Task<List<T>> Get<T>(Func<Task<int, int, List<T>>> factory, int skip, int take)
{
    var totalResults = new List<T>();
    var resultsCount = 1;

    while (resultsCount != 0)
    {
        var results = await factory(skip, take);
        if (results != null)
        {
            totalResults.AddRange(results);
            resultsCount = results.Count;
            skip += resultsCount;
        }
        else
        {
            resultsCount = 0;
        }
    }

    return totalResults;
}

public Task<List<User>> GetUsersAsync(HttpClient httpClient, string arg1)
{
    return Get<User>((skip, take) => GetUsers(httpClient, arg1, skip, take), 0, 10);
}

public Task<List<Item>> GetItemsAsync(HttpClient httpClient, string arg1)
{
    return Get<Item>((skip, take) => GetItems(httpClient, arg1, skip, take), 10, 10);
}

在某些情况下，以下可能也足够了，但显然不是您的情况，因为您似乎需要对 skip 参数做更多的事情：

private async Task<List<T>> Get<T>(Func<Task<List<T>>> factory)
{
    ...
}

public Task<List<User>> GetUsersAsync(HttpClient httpClient, string arg1)
{
    return Get<User>(() => GetUsers(httpClient, arg1, 0, 10));
}

public Task<List<Item>> GetItemsAsync(HttpClient httpClient, string arg1)
{
    return Get<Item>(() => GetItems(httpClient, arg1, 10, 10));
}