How to set a default value rather than choose from drop-down list in Create-View

Question

I'm quite new to ASP.Net and I'm trying to make a reservation to a specified branch. When I click the reservation link of a branch, it comes to a drop-down list for me to choose a branch from those already existed in the database. What I want is the branch has already been set based on the reservation link of that branch I clicked. In the database, the reservation entity has an attribute referencing to the branchId in the branch entity. I have viewed some related questions such as MVC5 - How to set “selectedValue” in DropDownListFor Html helper, but neither solved my question properly. I still have no idea of this for now.

The following images are what it looks like now.

This is the create action in my reservation controller:

// GET: Reservations/Create
public ActionResult Create()
{
    ViewBag.branchId = new SelectList(db.Branches, "branchId", "name");
    return View();
}


[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "reservationId,branchId,customerId,date")] Reservation reservation)
    {
        reservation.customerId = User.Identity.GetUserId();
        ModelState.Clear();
        TryValidateModel(reservation);
        if (ModelState.IsValid)
        {
            db.Reservations.Add(reservation);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        ViewBag.branchId = new SelectList(db.Branches, "branchId", "name", reservation.branchId);
        return View(reservation);
    }

This is my reservation create view:

@model Mel_Medicare_Location_Reservation_System.Models.Reservation

@{
    ViewBag.Title = "Create";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h2>Create</h2>


@using (Html.BeginForm()) 
{
@Html.AntiForgeryToken()

<div class="form-horizontal">
    <h4>Reservation</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    <div class="form-group ">
        @Html.LabelFor(model => model.branchId, "branchId", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">

            @Html.DropDownList("branchId", null, htmlAttributes: new { @class = "form-control" })
            @Html.ValidationMessageFor(model => model.branchId, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.customerId, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.customerId, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.customerId, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.date, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.date, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model.date, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Create" class="btn btn-default" />
        </div>
    </div>
</div>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

score 0 · Answer 1 · answered Sep 19 '18 at 15:41

You should have the dropdown options as a get-only property of your model, then use the @Html.DropDownListFor() HTML helper to bind model.branchId to that list, which will set the value appropriately.

I would re-write your Create() controller method to return the view with an instance of the Reservation view model bound to it. This will involve adding a constructor to the view model class which accepts a branch id as a parameter. Something like:

// GET: Reservations/Create
public ActionResult Create(int branchId)
{
    return View(new Reservation(branchId));
}

And in your Reservation model:

public class Reservation
{
    public int BranchId { get; set; }
    // Other properties...

    public SelectList BranchOptions
    {
        get
        {
            return new SelectList(db.Branches);
        }
    }

    public Reservation(int branchId)
    {
        this.BranchId = branchId;
    }
}

Then in your view:

@Html.DropDownListFor(m => m.BranchId, Model.BranchOptions, htmlAttributes: new { @class = "form-control" })

How to set a default value rather than choose from drop-down list in Create-View

1 Answers1