Update multiple rows in db table

I have an efcore application where I am creating new employees and assigning an employee multiple tasks. When they complete a task they are supposed to open this form where all the tasks are listed and check the corresponding box and send the form.

I know how to track a single entity and see if anything has changed but I'm loading my tasks in an IList and can't for the life of me figure out how to track any changes with Model Binding. In the Post method the IList is always empty and I can't find any working alternative ways to save the changes to my table.

I've been trying a couple of different approaches I found on the internet, so now my code is a bit of a mess.

The relevant parts of my model:

public class TasksOutstandingModel : DI_BasePageModel
{
[BindProperty]
public IList<TaskAssignment>? Tasks { get; set; }    
public async Task<IActionResult> OnGetAsync(int? id)
{
var tasks = _tasksContext.TaskAssignment.Where(t => t.EmpReferenceID == id);
Tasks = await tasks.ToListAsync();
if (tasks == null)
{
return NotFound(id);
}
return Page();
}
public async Task<IActionResult> OnPostAsync(uint? id, IList<TaskAssignment> tasksList)
{
if (!ModelState.IsValid)
{
return Page();
}
var originalEntity = await _tasksContext.TaskAssignment.AsNoTracking().FirstOrDefaultAsync(me => me.EmpReferenceID == id && me.HRID == 1);
var changed = Request.Form["hr+1"];
bool changedContrSent = originalEntity.Done != Convert.ToBoolean(changed);
if (changedContrSent)
{
//do stuff
}
foreach (var task in tasksList)
{
TaskAssignment taskAssignment = _tasksContext.TaskAssignment.Find(task.TaskAssignmentID);
taskAssignment.Done = task.Done;
_tasksContext.Entry(taskAssignment).State = EntityState.Modified;
Console.WriteLine(taskAssignment.TaskAssignmentID);
}
try
{
await _tasksContext.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!TasksExits((int)Tasks.FirstOrDefault().EmpReferenceID))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToPage("./TasksOutstanding", Tasks.FirstOrDefault().EmpReferenceID);
}

part of my view, there are a few variables that don't make sense, I've cut the parts where I get the values for those. With the variables at the top I was attempting to pass the IList to the Post Method. Which is only semi-helpful anyways, since those would be the old values, not the updated ones?

<form method="post">
@for (int i = 0; i < Model.Tasks.Count(); i++)
{
<input type="hidden" asp-for="Tasks[i].TaskAssignmentID"/>
<input type="hidden" asp-for="Tasks[i].EmpReferenceID"/>
<input type="hidden" asp-for="Tasks[i].AssistantID"/>
<input type="hidden" asp-for="Tasks[i].EduID"/>
<input type="hidden" asp-for="Tasks[i].FKID"/>
<input type="hidden" asp-for="Tasks[i].HRID"/>
<input type="hidden" asp-for="Tasks[i].PayrollID"/>
<input type="hidden" asp-for="Tasks[i].DueDateInD"/>
<input type="hidden" asp-for="Tasks[i].Dependency"/>
<input type="hidden" asp-for="Tasks[i].Done"/>
<input type="hidden" asp-for="Tasks[i].ITId"/>
}
<div class="correctWidth">
<button type="button" class="collapsibleHeading">Aufgaben für Bildungsmanagement</button>
<div class="collapsing-content">
@{
var allEdu = Model.Tasks.Where(t => t.EduID != null);
foreach (var item in allEdu)
{
<div class="form-group form-check">
@* if the item is already marked as done then we disable the checkbox so it can't be unchecked *@
@if (item.Done || disable)
{
<input class="form-check-input" asp-for="@item.Done" name="edu+@item.EduID" disabled/>
disable = false;
}
else
{
<input class="form-check-input" asp-for="@item.Done" name="edu+@item.EduID" />
}
@if (shortdesc != "")
{
<button type="button" class="collapsible">
<div class="summaryText">@summary</div>
@if (!duedate.Equals(01 / 01 / 0001))
{
<div class="dueDateDiv">@duedate</div>
}
else
{
<div class="dueDateDiv"></div>
}
<div class="SymbolDiv"></div>
</button>
<div class="collapsing-content">
@Html.Raw(shortdesc)
</div>
}
else
{
<div class="notCollapsible">
<div class="summaryText">@summary</div>
</div>
}
</div>
}
}
</div>
</div>
<div class="form-group">
<input type="hidden" asp-for="Tasks.First().EmpReferenceID"/>
<input type="submit" value="Speichern" class="btn btn-primary"/>
</div>
</form>

Edit:

Thanks to Jason Pan's comment I have my code working now.
In my view I removed the for loop, that's unnecessary or I didn't know how to work with it(probably the latter)

In my controller I added the suggested UpdateTasks() method:

private void UpdateTasks(uint? ident)
{
string ss = "";
byte key = 0;
bool donezoes = false;
var tasks = _tasksContext.TaskAssignment.Where(t => t.EmpReferenceID == ident);
Tasks = tasks.ToList();
var dict = Request.Form.ToDictionary(d => d.Key, d => d.Value);
foreach (var item in dict)
{
//The dictionary gets all changed variables
//Key is the name of the html element
//value is the value, in this case of my checkboxes. So either true or false
if (item.Key.Contains("EmpReferenceID")) break;
if (item.Key.Contains("edu"))
{
//my checkboxes are named "edu+x", x being the ID of the object I need to pull from the db.
ss = item.Key.Substring(4);
key = Convert.ToByte(ss);
//assigning the value(true/false) to my boolean
donezoes = Convert.ToBoolean(item.Value);
TaskAssignment ta = Tasks.FirstOrDefault(x => x.EduID == key);
//assigning the boolean to the db entity
ta.Done = donezoes;
//marking the entity as modified
_tasksContext.Entry(ta).State = EntityState.Modified;
}
//more if conditions, but you get the point.
}
}

Calling the method in my OnPostAsync method and, most importantly, saving the changes to the db.

public async Task<IActionResult> OnPostAsync(uint? id)
{
if (!ModelState.IsValid)
{
return Page();
}
UpdateTasks(id);
...
try
{
await _tasksContext.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!TasksExits((int)Tasks.FirstOrDefault().EmpReferenceID))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToPage("./TasksOutstanding", Tasks.FirstOrDefault().EmpReferenceID);
}

You code like below:

public IList<TaskAssignment>? Tasks { get; set; }   

The Tasks, I saw that they are not updated when you process the data, which seems to be the root cause of the problem.

public async Task<IActionResult> OnPostAsync(uint? id, IList<TaskAssignment> tasksList)
{
if (!ModelState.IsValid)
{
return Page();
}
...
if (changedContrSent)
{
//do stuff
}
...
--> Add Below code, you can create custom UpdateTask method to update Tasks
UpdateTask(Tasks);
try
{
await _tasksContext.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
...
}
return RedirectToPage("./TasksOutstanding", Tasks.FirstOrDefault().EmpReferenceID);
}