c# - Linq C# 基于最大值

Question

我从数据库中获取数据，结果如下结构。按InputFileId和Filename分组，只选择Failed的最大值。

InputFileId = 12, FileName = "Filename_12", Failed = false
InputFileId = 13, FileName = "Filename_13", Failed = false  
InputFileId = 13, FileName = "Filename_13", Failed = true   

现在我只想看到这个结果:

InputFileId = 12, FileName = "Filename_12", Failed = false
InputFileId = 13, FileName = "Filename_13", Failed = true   

到目前为止，我的 Linq 查询是:

Files = (this.InputFileStatusService.GetFilesUploadedByDay(StartOfDay(SelectedDate), EndOfDay(SelectedDate), this.Deal.Id))
            .Where(a => a.InputFileId > 0)
            .GroupBy(m => new { m.InputFileId, m.FileName, Failed = m.Failed ? 1 : 0 })
            .Select(m => new 
            { 
                InputFileId = m.Key.InputFileId, 
                FileName = m.Key.FileName,
                Failed = m.Max(x=>x.Failed) 
            }).ToList();

但这不起作用，有人对此有解决方案吗？

Answer 1

应该足以将 Max 替换为 Any

Failed = m.Any(x => x.Failed) 

并删除 Failed = m.Failed ？ 1 : 0 在

.GroupBy(m => new { m.InputFileId, Failed = m.Failed ? 1 : 0 })

由于这些列似乎彼此对应，您可能会考虑为 m.FileName 添加一个分组。