简单C#递归（向前查找上工序）

/// <summary>
/// 递归查找前工序，直到找到没有跳序的前工序
/// </summary>
/// <param name="process"></param>
/// <returns></returns>
private async Task<List<string>> HasReportedWorkAsync(List<WorkOrderProcedureEntity> proceduList)
{
    if (proceduList.Count <= 0) return new List<string>();

    //前工序ID
    var pId = proceduList.Select(x => x.PreNid).ToList();

    //查询前工序任务
    var preWOProList = await BaseDal.Db.Queryable<WorkOrderProcedureEntity>().Where(p => p.WorkorderId == proceduList[0].WorkorderId && p.IsDelete == 0 && pId.Contains(p.OperationNo)).ToListAsync();

    if (preWOProList.Count <= 0) return new List<string>();

    //查询未跳序的工序
    var isFlagSkip = preWOProList.Where(x => x.SkipOperation == 0).ToList();

    //没有未跳序并且有前序时
    if (isFlagSkip.Count <= 0 && preWOProList.Count > 0)
    {
        //没有未跳序的工序，则继续往上工序找
        return await HasReportedWorkAsync(preWOProList);
    }
    else
    {
        //存在没有跳序的工序，则直接返回
        return preWOProList.Select(x => x.Nid).ToList();
    }
}