Bind properties from a ViewModel to another model

Question

I'm curious about binding properties from a ViewModel to another Model.

ViewModel:

 

public class StoreIndexData

{

public Store Stores { get; set; }

public District Districts { get; set; }

public Department Departments { get; set; }

}

 

Important note: I use a ViewModel because I need these models together in order to make a cascading dropdownlist to work, however this model is not added in the DB context.

In the view, the user can pickup a Department, then the dropdownlist for District populates, and finally the user adds the information of the Store.

Problem: The problem comes when I want to save the properties the user wrote inside the Store model, since the view is constructed using:

 

@model Application.Models.ApplicationviewModels.StoreIndexData

 

and the inputs point to this model.

Relevant info:

This is my view. I access each model from the ViewModel (Department, District, Stores) in order to get each property:

<form asp-action="Create" role="form">@*
        @await Html.PartialAsync("_ModalHeader", new ModalHeader
    { Heading = String.Format("{0} Store", @Model.Stores.StoreID == 0 ? "Add" : "Edit") })*@

    <div asp-validation-summary="ModelOnly" class="text-danger"></div>
    <div class="modal-body form-horizontal">
        <div class="form-group">
            <label asp-for="Departments.DepartmentID" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <select asp-for="Departments.DepartmentID" class="form-control"
                        asp-items="@(new SelectList(@ViewBag.ListofDepartment,"DepartmentID","DepartmentName"))"></select>
            </div>
        </div>
        <div class="form-group">
            <label class="col-md-2 control-label">District</label>
            <div class="col-md-10">
                <select class="form-control" id="DistrictID" name="DistrictID" asp-for="Departments.DistrictID"
                        asp-items="@(new SelectList(string.Empty,"DistrictID","DistrictName"))"></select>
            </div>
        </div>
        <div class="form-group">
            <label asp-for="Stores.StoreChainID" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <select asp-for="Stores.StoreChainID" class="form-control" asp-items="ViewBag.ChainList"></select>
                <span asp-validation-for="Stores.StoreChainID" class="text-danger"></span>
            </div>
        </div>
        <div class="form-group">
            <label asp-for="Stores.StoreName" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <input asp-for="Stores.StoreName" class="form-control" />
                <span asp-validation-for="Stores.StoreName" class="text-danger"></span>
            </div>
        </div>
        <div class="form-group">
            <label asp-for="Stores.StoreAddress" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <input asp-for="Stores.StoreAddress" class="form-control" />
                <span asp-validation-for="Stores.StoreAddress" class="text-danger"></span>
            </div>
        </div>
        <div class="form-group">
            <label asp-for="Stores.StoreArea" class="col-md-2 control-label"></label>
            <div class="col-md-10">
                <input asp-for="Stores.StoreArea" class="form-control" />
                <span asp-validation-for="Stores.StoreArea" class="text-danger"></span>
            </div>
        </div>
        @await Html.PartialAsync("_ModalFooter", new ModalFooter { })
    </div>
</form>

 

 

The trick must come here I suposse, in the Post method:

 

[HttpPost, ActionName("Create")]

[ValidateAntiForgeryToken]

public async Task Create(int? id, [Bind("StoreID,DistrictID,StoreChainID,StoreName,StoreAddress,StoreArea")]Store store)

{

if (ModelState.IsValid)

{

bool isNew = !id.HasValue;

if (isNew)

{

_context.Add(store);

await _context.SaveChangesAsync();

return RedirectToAction("Index");

}

var storetoupdate = await _context.Stores.SingleOrDefaultAsync(s => s.StoreID == id);

}

ViewData["DistrictID"] = new SelectList(_context.Districts, "DistrictID", "DistrictID", store.DistrictID);

ViewData["StoreChainID"] = new SelectList(_context.StoreChains, "StoreChainID", "StoreChainID", store.StoreChainID);

return RedirectToAction("Index");

}

 

First, I would need to change:

 

[Bind("StoreID,DistrictID,StoreChainID,StoreName,StoreAddress,StoreArea")]Store store)

 

For the ViewModel StoreIndexData.

But then, I'm lost. Maybe if I put a conditional when

 

if (!ModelState.IsValid)

 

And since this will be true, initialize a new Store model with the values that are coming from the Post method, but I don't know how to do this.

Thanks in advance for any help, I hope the problem is clear.

Regards,