How to get the reference value at the same time?-CodePudding

How does the corresponding value display?

I select the stage I have created.

enter image description here

And I want the corresponding price of the stage to be displayed after I select the stage, what should I do?

enter image description here

This is my code:

<div >
            <label asp-for="PricelistId" ></label>
            <select asp-for="PricelistId" class ="form-control" asp-items="ViewBag.PricelistId"></select>
        </div>
        <div >
            <label asp-for="Price" ></label>
            <input asp-for="Price"  />
            <span asp-validation-for="Price" ></span>
        </div>

PricelistId is the foreign key I reference from the Price list in first pic

CodePudding user response：

You only shared a very small piece of your code so I created new project to demonstrate how you can do what you want.

Fruit.cs

public class Fruit
{
    public string Id { get; set; }
    public string Name { get; set; }
    public int Price { get; set; }
}

Index.cshtml.cs

public class IndexModel : PageModel
{
    private readonly List<Fruit> _fruitList = new()
    {
        new Fruit { Id = "1", Name = "Banana", Price = 200 },
        new Fruit { Id = "2", Name = "Apple", Price = 47 },
        new Fruit { Id = "3", Name = "Orange", Price = 75 },
        new Fruit { Id = "4", Name = "Lemon", Price = 123 },
    };

    [BindProperty]
    public string SelectedFruit { get; set; } = "1";

    public int? SelectedFruitPrice =>
        _fruitList.FirstOrDefault(x => x.Id == SelectedFruit)?.Price;

    public SelectList Options { get; set; }

    public void OnGet()
    {
        Options = new SelectList(_fruitList, "Id", "Name");
    }

    public void OnPost()
    {
        Options = new SelectList(_fruitList, "Id", "Name");
    }
}

Index.cshtml

@page
@model IndexModel
@{
    ViewData["Title"] = "Home page";
}

<div >
    <div >

        <form method="post">
            <div >
                <select onchange="this.form.submit()" asp-for="SelectedFruit"  asp-items="@Model.Options"></select>
            </div>
        </form>

        <input  value="@Model.SelectedFruitPrice" />

    </div>
</div>

Basically I added onchange="this.form.submit()" to the <select> element so every time it changes it submits a form that sets the SelectedFruit property. Then based on SelectedFruit property I calculate the SelectedFruitPrice and show this value inside an <input> element.

You can find the project here: https://github.com/Jimmys20/SO73601166