set selected value in select list of cshtml using ViewBag

Question

User-1202579601 posted

@model StudentAttendance.Models.Semester
<h4>Edit Semester Details </h4>
<div class="row">
<form asp-action="Edit" class="form-horizontal">
<div class="col-md-6">
<div class="form-group">
<label asp-for="SemId" class="control-label col-md-2">Semester Id</label>
<div class="col-md-10">
<input asp-for="SemId" class="form-control" />
<span asp-validation-for="SemId" class="text-danger"></span>
</div>
</div>
<div class="form-group">
<label asp-for="Dos" class="control-label col-md-2">Start Date</label>
<div class="col-md-10">
<input asp-for="Dos" class="form-control" />
<span asp-validation-for="Dos" class="text-danger"></span>
</div>
</div>
<div class="form-group">
<label asp-for="Doe" class="control-label col-md-2">End Date</label>
<div class="col-md-10">
<input asp-for="Doe" class="form-control" />
<span asp-validation-for="Doe" class="text-danger"></span>
</div>
</div>
<div class="form-group">
<label asp-for="DepartmentId" class="control-label">Department</label>
<div class="col-md-6">
<select asp-for="DepartmentId" class="form-control" asp-items="@ViewBag.Dept" > //set option value selected to that of DepartmentId
<option value="">-- Select Department --</option>
</select>
<span asp-validation-for="DepartmentId" class="text-danger" />
</div>
</div>

<div class="form-group">
<input type="submit" value="Save" class="btn btn-default" />
&nbsp;&nbsp;&nbsp;&nbsp; <a asp-action="Index">Back to List</a>
</div>
</div>
</form>
</div>

Answer 1

User711641945 posted

Hi pmdrait,

Here is a working demo about how to set select list:

1.Model:

public class Semester
{
    public int SemId { get; set; }
    public string Dos { get; set; }
    public string Doe { get; set; }
    public int DepartmentId { get; set; }
    public Department Department { get; set; }
}
public class Department
{
    public int DepartmentId { get; set; }
    public string DepartmentName { get; set; }
}

2.View:

@model Semester
<h4>Edit Semester Details </h4>
<div class="row">
    <div class="col-md-6">
        <form asp-action="Edit" class="form-horizontal">
            <div class="form-group">
                <label asp-for="SemId" class="control-label col-md-2">Semester Id</label>
                <div class="col-md-10">
                    <input asp-for="SemId" class="form-control" />
                    <span asp-validation-for="SemId" class="text-danger"></span>
                </div>
            </div>
            <div class="form-group">
                <label asp-for="Dos" class="control-label col-md-2">Start Date</label>
                <div class="col-md-10">
                    <input asp-for="Dos" class="form-control" />
                    <span asp-validation-for="Dos" class="text-danger"></span>
                </div>
            </div>
            <div class="form-group">
                <label asp-for="Doe" class="control-label col-md-2">End Date</label>
                <div class="col-md-10">
                    <input asp-for="Doe" class="form-control" />
                    <span asp-validation-for="Doe" class="text-danger"></span>
                </div>
            </div>
            <div class="form-group">
                <label asp-for="DepartmentId" class="control-label">Department</label>
                <div class="col-md-6">
                    <select asp-for="DepartmentId" class="form-control" asp-items="@ViewBag.Dept">
                        <option value="">-- Select Department --</option>
                    </select>
                    <span asp-validation-for="DepartmentId" class="text-danger" />
                </div>
            </div>

            <div class="form-group">
                <input type="submit" value="Save" class="btn btn-default" />
                &nbsp;&nbsp;&nbsp;&nbsp; <a asp-action="Index">Back to List</a>
            </div>
        </form>
</div>  
</div>

3.Controller:

public class SemestersController : Controller
{
    private readonly YourDbContext _context;

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

    // GET: Semesters
    public async Task<IActionResult> Index()
    {
        var model = _context.Semester.Include(s => s.Department);
        return View(await model.ToListAsync());
    }
    // GET: Semesters/Edit/5
    public async Task<IActionResult> Edit(int? id)
    {
        if (id == null)
        {
            return NotFound();
        }

        var semester = await _context.Semester.FindAsync(id);
        if (semester == null)
        {
            return NotFound();
        }
        ViewBag.Dept = new SelectList(_context.Department, "DepartmentId", "DepartmentName", semester.DepartmentId);
        return View(semester);
    }

    // POST: Semesters/Edit/5
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Edit(int id, [Bind("SemId,Dos,Doe,DepartmentId")] Semester semester)
    {
        if (id != semester.SemId)
        {
            return NotFound();
        }

        if (ModelState.IsValid)
        {
            try
            {
                _context.Update(semester);
                await _context.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!SemesterExists(semester.SemId))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }
            return RedirectToAction(nameof(Index));
        }
        ViewBag.Dept = new SelectList(_context.Department, "DepartmentId", "DepartmentName", semester.DepartmentId);
        return View(semester);
    }
}

Result:

Best Regards,

Rena

Answer 2

User-1202579601 posted

Thanks for the complete solution .

Answer 3

User-1202579601 posted

if (!SemesterExists(semester.SemId))
The underlined part showing error. It refers to entity or table 

Answer 4

User711641945 posted

Hi pmdrait,

Here is the code:

private bool SemesterExists(int id)
{
    return _context.Semester.Any(e => e.SemId == id);
}

Best Regards,

Rena