ABP.IO：如何无需分页获取ReadOnlyAppService的全部数据？

我通过ReadOnlyAppService将NetworkDevice对象暴露给Angular前端，编写的AppService如下：

public class NetworkDeviceAppService: ReadOnlyAppService<NetworkDevice, NetworkDeviceDto, Guid>, INetworkDeviceAppService
{
    public NetworkDeviceAppService(IReadOnlyRepository<NetworkDevice, Guid> repository) : base(repository)
    {
    }
}

但Angular客户端调用时必须传入PagedAndSortedResultRequestDto才能获取数据：

private getNetworkDevices() {
  let request = new PagedAndSortedResultRequestDto();
  this.networkDeviceService
    .getList(request)
    .subscribe(res => {
      this.networkDevices = res.items;
    })
}

我不想指定maxResultCount，希望直接获取全部数据，目前想到的方案都不够优雅：

• 传入2000000作为maxResultCount
• 在NetworkDeviceAppService中添加public async Task<IListResult<NetworkDeviceDto>> GetAllAsync()方法
• 在客户端循环请求数据

想知道是否存在无需PagedAndSortedResultRequestDto的等效ReadOnlyAppService，或者更优雅的实现方式？

方案1：重写GetListAsync，兼容无分页逻辑 #

利用ABP框架的扩展能力，重写基类的GetListAsync方法，通过约定值（比如-1）触发全量数据返回，既保留原有分页逻辑的兼容性，又能实现无分页获取：

public class NetworkDeviceAppService: ReadOnlyAppService<NetworkDevice, NetworkDeviceDto, Guid>, INetworkDeviceAppService
{
    public NetworkDeviceAppService(IReadOnlyRepository<NetworkDevice, Guid> repository) : base(repository)
    {
    }

    public override async Task<PagedResultDto<NetworkDeviceDto>> GetListAsync(PagedAndSortedResultRequestDto input)
    {
        // 当maxResultCount为-1时，返回全部数据
        if (input.MaxResultCount == -1)
        {
            var entities = await Repository.GetListAsync();
            var dtos = ObjectMapper.Map<List<NetworkDevice>, List<NetworkDeviceDto>>(entities);
            return new PagedResultDto<NetworkDeviceDto>(dtos.Count, dtos);
        }
        // 否则沿用原有分页逻辑
        return await base.GetListAsync(input);
    }
}

前端调用时只需传入约定值：

private getNetworkDevices() {
  let request = new PagedAndSortedResultRequestDto();
  request.maxResultCount = -1; // 标记获取全量数据
  this.networkDeviceService
    .getList(request)
    .subscribe(res => {
      this.networkDevices = res.items;
    })
}

方案2：添加标准全量获取接口 #

如果希望明确区分分页和全量接口，可以添加符合ABP规范的GetAllAsync方法，借助框架的自动映射能力保证代码简洁：

public class NetworkDeviceAppService: ReadOnlyAppService<NetworkDevice, NetworkDeviceDto, Guid>, INetworkDeviceAppService
{
    public NetworkDeviceAppService(IReadOnlyRepository<NetworkDevice, Guid> repository) : base(repository)
    {
    }

    public async Task<IListResult<NetworkDeviceDto>> GetAllAsync()
    {
        var entities = await Repository.GetListAsync();
        var dtos = ObjectMapper.Map<List<NetworkDevice>, List<NetworkDeviceDto>>(entities);
        return new ListResultDto<NetworkDeviceDto>(dtos);
    }
}

同时在接口中声明该方法：

public interface INetworkDeviceAppService : IReadOnlyAppService<NetworkDeviceDto, Guid>
{
    Task<IListResult<NetworkDeviceDto>> GetAllAsync();
}

前端直接调用新接口即可：

private getNetworkDevices() {
  this.networkDeviceService
    .getAll()
    .subscribe(res => {
      this.networkDevices = res.items;
    })
}

方案3：封装通用全量只读基类 #

如果多个业务服务都需要全量获取能力，可以封装通用基类避免重复代码：

public class FullReadOnlyAppService<TEntity, TEntityDto, TKey> : ReadOnlyAppService<TEntity, TEntityDto, TKey>
    where TEntity : class, IEntity<TKey>
    where TEntityDto : IEntityDto<TKey>
{
    public FullReadOnlyAppService(IReadOnlyRepository<TEntity, TKey> repository) : base(repository)
    {
    }

    public virtual async Task<IListResult<TEntityDto>> GetAllAsync()
    {
        var entities = await Repository.GetListAsync();
        var dtos = ObjectMapper.Map<List<TEntity>, List<TEntityDto>>(entities);
        return new ListResultDto<TEntityDto>(dtos);
    }
}

后续业务服务直接继承该基类即可：

public class NetworkDeviceAppService: FullReadOnlyAppService<NetworkDevice, NetworkDeviceDto, Guid>, INetworkDeviceAppService
{
    public NetworkDeviceAppService(IReadOnlyRepository<NetworkDevice, Guid> repository) : base(repository)
    {
    }
}

内容的提问来源于stack exchange，提问作者Damien R