Dropdown asp.net core Set selected item

Question

i need to set selected item in dropdown

<div class="form-group">
    <label asp-for="Transaction.CCurrency" class="control-label"> Currency </label>

    @(Html.DropDownList("CurrencyDropDownList", Model.Currency, "--Choose currency--", new { @class = "form-control" }))

    <span asp-validation-for="CurrencyDropDownList" class="text-danger"></span>
</div>

I am filling it in controller

model.Currency = database.ZCurrency.Where(x => x.LActive == true).Select(c => new SelectListItem
                 {
                     Value = c.CCode.ToString(),
                     Text = c.CName,
                 });

This is in my view model

public IEnumerable<SelectListItem> Currency { get; set; }

However, i have no idea how to set it from my database, i can get to CCode and to Cname through it, but not how to set it. This is in my EDIT form, where i need to see which value i had before and re-set it on another if needed.

Thank you very much, would appreciate any help.

Answer 1

You can just set the selected property as true in the SelectListItem, which will make this option selected by default in the page. I made a simple demo based on your codes like below:

View:

<div class="form-group">

    @(Html.DropDownList("CurrencyDropDownList", Model.Currency, "--Choose currency--", new { @class = "form-control" }))

</div>

Model:

public class ZCurrency
{
    public int CCode { get; set; }
    public string CName { get; set; }
}

public class ViewModel
{
    public IEnumerable<SelectListItem> Currency { get; set; }
}

Controller:

public IActionResult Index()
    {
        List<ZCurrency> currencies = new List<ZCurrency>
        {
            new ZCurrency{ CCode = 1, CName = "AAA" },
            new ZCurrency{ CCode = 2, CName = "BBB" },
            new ZCurrency{ CCode = 3, CName = "CCC" },
        };
        ViewModel viewModel = new ViewModel();
        viewModel.Currency = currencies.Select(c => new SelectListItem
        {
            Value = c.CCode.ToString(),
            Text = c.CName,
            Selected = c.CCode == 2 ? true: false
        });

        return View(viewModel);
    }

Here, I set the record which CCode is 2 (new ZCurrency{ CCode = 2, CName = "BBB" }) as the selected item by setting Selected as true.