public async Task <IActionResult> Edit(int?id, byte[] RowVersion)
{
if (id == null)
{
return(NotFound());
}
var department = await _context.Department.Include(a => a.Administrator).SingleOrDefaultAsync(a => a.Id == id);
if (department == null)
{
var Delete = new Department();
await TryUpdateModelAsync(Delete);
ModelState.AddModelError(string.Empty, "信息可能已被其他人删除，请重试！");
ViewData["instructorId"] = new SelectList(_context.Instructor, "Id", "RealName", Delete.InstructorId);
return(View(Delete));
;
}
_context.Entry(department).Property("RowVersion").OriginalValue = RowVersion;
if (await TryUpdateModelAsync(department, "", b => b.name, b => b.StarDate, b => b.InstructorId, b => b.Budget))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToAction(nameof(Index)));
}
catch (DbUpdateException ex)
{
var excepyionEntity = ex.Entries.Single();
//返回ef中追踪的对象，ef在内存中
var clientValue = (Department)excepyionEntity.Entity;
//返回数据库中的内容/对象
var databaseEntity = excepyionEntity.GetDatabaseValues();
if (databaseEntity == null)
{
ModelState.AddModelError(string.Empty, "信息可能已被其他人删除，请重试！");
}
else
{
var databaseValue = (Department)databaseEntity.ToObject();
if (databaseValue.name != clientValue.name)
{
ModelState.AddModelError("name", $"数值错误：{databaseValue.name}");
}
if (databaseValue.StarDate != clientValue.StarDate)
{
ModelState.AddModelError("StarDate", $"数值错误：{databaseValue.StarDate}");
}
if (databaseValue.Budget != clientValue.Budget)
{
ModelState.AddModelError("Budget", $"数值错误：{databaseValue.Budget}");
}
//可能存在有人把老师给删了级联操作改动部门（可能老师时部门主任或者更换主任）所以判断老师是否存在
if (databaseValue.InstructorId != clientValue.InstructorId)
{
//查询老师信息
var InstuctorEntity = await _context.Instructor.SingleOrDefaultAsync(a => a.Id == databaseValue.Id);
//用id进行数据库操作，用姓名显示
ModelState.AddModelError("InstructorId", $"数值错误：{InstuctorEntity?.RealName}");
}
ModelState.AddModelError("", $"您的操作已经被其他用户提前修改，请刷新页面使用修改后的值进行操作！");
department.RowVersion = (byte[])databaseValue.RowVersion;
ModelState.Remove("RowVersion");
}
}
}
ViewBag.InstructorId = new SelectList(_context.Instructor, "Id", "RealName", department.InstructorId);
return(View(department));
}
