我有两个相关的表与一对多的关系,我试图得到一个JSON
响应,填充ICollection<PatPar> PatPar
控制器的代码读取罚款只要我有只有一个相关记录,一旦我有多个相关记录,我会得到一个选择异常。如何阅读相关数据使用LINQ/C#[一对多]
这些都与Models
public class PatReg
{
[NotMapped]
private Int64 _FileId;
[Key, Display(Name = "File Id"), ScaffoldColumn(false), DatabaseGenerated(DatabaseGeneratedOption.None)]
public Int64 FileId
{
get
{
return this._FileId;
}
set
{
this._FileId = value;
}
}
[Required, Display(Name = "First Name")]
public string FName { get; set; }
public ICollection<PatPar> PatPar { get; set; }
}
public class PatPar
{
[Key]
public Int64 RecId { get; set; }
[Display(Name = "Patient File Id"), Required]
public Int64 FileId { set; get; }
[Display(Name = "Partner File Id"), Required]
public Int64 ParFileId { set; get; }
[Display(Name = "Start Date"), DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true), Required]
public DateTime SDate { set; get; }
[Display(Name = "End Date"), DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
public DateTime? EDate { set; get; }
}
这是我API Controller
[HttpGet]
public IEnumerable<PatReg> GetPatReg()
{
return _context.PatReg;
}
[HttpGet("{id}")]
public async Task<IActionResult> GetPatReg([FromRoute] long id)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
var patReg = await _context.PatReg.SingleOrDefaultAsync(m => m.FileId == id);
var parinfo = await _context.PatPar.SingleOrDefaultAsync(m => m.FileId == id); // I should select many records here
if (patReg == null)
{
return NotFound();
}
var DataRes = new {
sData = patReg
};
return Ok(DataRes);
}
我知道,我应该使用selectMany
,而不是使用SingleOrDefaultAsync
所以我试图
IEnumerable<PatPar> parinfo = await _context.PatPar.SelectMany(m => m.FileId == id);
但是编译器给我e反应如何?
如果你得到一个编译错误是什么错误? –
'方法enumerable selectmany的类型参数不能从用法中推断' – JSON