Record Update In c#

I have faced a problem. I want to save and update record .Record Save successfully but update case i have face problem. It's my model classes.

public class Root
{
public UserInjuries UserInjuries { get; set; }
}
public class UserInjuries
{
public int? UserId { get; set; }
public List UserInjuriesList { get; set; }
}
[Table("TblInjurie")]
public class InjerisDetail
{
public string UserInjuriesTypeId { get; set; }
public string Description { get; set; }
public bool? IsActive { get; set; }
[Column(TypeName = "date")]
public string Date { get; set; }
}
It's me save and update code .
Root Json)
{
InjuerisResult obj_result = new InjuerisResult();
try
{
var injurie = _context.TblInjurie.Where(x => x.UserId == Json.UserInjuries.UserId && x.UserInjuriesTypeId==Json.UserInjuries.UserInjuriesList.).FirstOrDefault();Here Not I have showing UserInjuriesTypeId .Please provide solution please it's imp for me
if (injurie != null)
{
List list_Injurie = new List();
foreach (var res in Json.UserInjuries.UserInjuriesList)
{
//var obj_tblInjurie = new TblInjurie();
injurie.Date = DateTime.ParseExact(res.Date, "d/M/yyyy", CultureInfo.InvariantCulture);
injurie.Description = res.Description;
injurie.UserInjuriesTypeId = Convert.ToInt32(res.UserInjuriesTypeId);
injurie.UserId = Json.UserInjuries.UserId;
injurie.IsActive = true;
injurie.UserInjurieStatus = true;
injurie.UpdatedDate = DateTime.UtcNow;
list_Injurie.Add(injurie);
_context.SaveChanges();
}
//_context.TblInjurie.AddRange(list_Injurie);
//_context.SaveChanges();
}
else
{
List list_Injurie = new List();
foreach (var res in Json.UserInjuries.UserInjuriesList)
{
var obj_tblInjurie = new TblInjurie();
obj_tblInjurie.Date = DateTime.ParseExact(res.Date, "d/M/yyyy", CultureInfo.InvariantCulture);
obj_tblInjurie.Description = res.Description;
obj_tblInjurie.UserInjuriesTypeId =Convert.ToInt32 (res.UserInjuriesTypeId);
obj_tblInjurie.UserId = Json.UserInjuries.UserId;
obj_tblInjurie.IsActive = true;
obj_tblInjurie.UserInjurieStatus = true;
obj_tblInjurie.UpdatedDate = DateTime.UtcNow;
list_Injurie.Add(obj_tblInjurie);
}
_context.TblInjurie.AddRange(list_Injurie);
_context.SaveChanges();
}
obj_result.Response = 1;
obj_result.ErrorMessage = "No Error Found";
}
catch (Exception ex)
{
obj_result.Response = 0;
obj_result.ErrorMessage = "Internal Server Error";
}
return obj_result;
}