返回对象类型，而不是字符串类型

Question

public interface IApiUserProvider
{
    Dictionary<Guid, string> UserNamesByToken { get; }
    string this[Guid token] { get; }


}

public class ApiUserProvider : IApiUserProvider
{
    private readonly ICacheProvider _cacheProvider;
    private readonly IEntitySet<ApiUser> _apiUsers;

    private string CacheKey
    {
        get
        {
            return string.Format("{0}-{1}", GetType().Name, "ApiUsersByToken");
        }
    }

    public ApiUserProvider(ICacheProvider cacheProvider, IEntitySet<ApiUser> apiUsers)
    {
        _cacheProvider = cacheProvider;
        _apiUsers = apiUsers;
    }

    public Dictionary<Guid, string> UserNamesByToken
    {
        get
        {
            return _cacheProvider.Get(CacheKey, () => _apiUsers.Where(u => u.IsActive).ToDictionary(u => u.Token, u => u.Name));
        }
    }

    public string this[Guid token]
    {
        get { return UserNamesByToken.GetValueOrDefault(token); }
    }
}

当我用ApiUser this[Guid token] { get; }替换string this[Guid token] { get; }时，我在这段代码中得到错误，如下所示

return string : cannot convert to object


return _cacheProvider.Get(CacheKey, () => _apiUsers.Where(u => u.IsActive).ToDictionary(u => u.Token, u => u.Name));

请告诉我如何将其转换为object类型

Answer 1

首先，您必须更新字段UserNamesByToken

public Dictionary<Guid, ApiUser> UserNamesByToken
    {
        get
        {
            return _cacheProvider.Get(CacheKey, () => _apiUsers.Where(u => u.IsActive).ToDictionary(u => u.Token, u => u));
        }
    }

别忘了更新ToDictionary(u => u.Token, u => u)

然后更新您的IApiUserProvider接口

public interface IApiUserProvider
{
    Dictionary<Guid, string> UserNamesByToken { get; }
    ApiUser this[Guid token] { get; }
}

在更新索引器之后

public string this[Guid token]
{
    get { return UserNamesByToken.GetValueOrDefault(token); }
}

如果这不起作用，请让我知道:)