Store Sessions using C# and EF

Dave Bell

Hello, My Session Object looks like below -

public class Session
{
    public int Id { get; set; }
    public int StudentId { get; set; }
    public string? SessionDetails { get; set; }
    public DateTime StartTime  { get; set; }
    public DateTime EndTime { get; set; }
    public int Valid { get; set; }
}

I wish to create a POST that will create an instance of session with StartTime as systemdate (EF: Add). After session is over I would call the EF : Update call to store the EndTime.

Question: Is there any way to get the system generated Id in response when I Add the instance? That way I can keep the Id and then use it to Update.

3 Replies

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Anandu G Nath2y ago

Check Below Code for yor refrences

public class SessionController : ControllerBase
{
    private readonly YourDbContext _context;

    public SessionController(YourDbContext context)
    {
        _context = context;
    }

    // POST: api/sessions/start
    [HttpPost("start")]
    public async Task> StartSession(Session session)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        // Set the start time to the current system date
        session.StartTime = DateTime.Now;

        _context.Sessions.Add(session);
        await _context.SaveChangesAsync();

        return CreatedAtAction(nameof(GetSession), new { id = session.Id }, session);
    }

    // PUT: api/sessions/end/5
    [HttpPut("end/{id}")]
    public async Task EndSession(int id)
    {
        var session = await _context.Sessions.FindAsync(id);

        if (session == null)
        {
            return NotFound();
        }

        // Set the end time to the current system date when the session is over
        session.EndTime = DateTime.Now;

        _context.Entry(session).State = EntityState.Modified;

        try
        {
            await _context.SaveChangesAsync();
        }
        catch (DbUpdateConcurrencyException)
        {
            if (!SessionExists(id))
            {
                return NotFound();
            }
            else
            {
                throw;
            }
        }

        return NoContent();
    }

    private bool SessionExists(int id)
    {
        return _context.Sessions.Any(e => e.Id == id);
    }
}

Sachin Singh3y ago

follow this

At session start

[HttpPost]
public async Task CreateSession(Session session)
{
    session.StartTime = DateTime.Now;
    _context.Sessions.Add(session);
    await _context.SaveChangesAsync();

    return View(session); // or return json
                  //and use the Id of session object to post when session ends
}

on session end

[HttpPost]
public async Task UpdateSession(Session session)
{
    
  var currentSession= _context.Sessions.where(x=>x.Id==session.Id);
session.EndTime= DateTime.Now;

//for new EF version

  _context.Sessions.Update(currentSession);
    await _context.SaveChangesAsync();

//end
//for old EF version
_context.entry(currentSession).State= EntityState.Modified;
//end
    return View(Session); // or return json 
                          
}

Naimish Makwana3y ago
Hello Dave,

Try below code :
```
[HttpPost]
public async Task CreateSession(Session session)
{
    session.StartTime = DateTime.Now;
    _context.Sessions.Add(session);
    await _context.SaveChangesAsync();

    return Ok(session.Id);
}
```
the SaveChangesAsync method is called after adding the new session instance to the database. This method will update the Id property of the session instance with the system-generated Id.

Thanks

Naimish Makwana
+5