Asp.Net Core Razor Pages DropDownList 選定的項目值

Question

我是 Asp.Net Core Razor Pages 的新手。 這是我關於 Stack Overflow 的第一個問題。 當從創建工作頁面的下拉列表中選擇客戶時，我想從注冊客戶的客戶頁面接收客戶詳細信息，然后在創建工作頁面的相應表單字段中顯示手機號碼.

先感謝您。

客戶端型號：

public class Client
{
    public int ID { get; set; }

    [Required]
    [StringLength(50)]
    [Display(Name = "Last Name")]
    public string LastName { get; set; }

    [Required]
    [StringLength(50, ErrorMessage = "First name cannot be longer than 50 characters.")]
    [Column("FirstName")]
    [Display(Name = "First Name")]
    public string FirstName { get; set; }

    [DataType(DataType.PhoneNumber)]
    [Display(Name = "Cellphone Number")]
    public string CellNumber { get; set; }

    [EmailAddress]
    [Display(Name = "Email Address")]
    public string Email { get; set; }

    [Display(Name = "Residential Address")]
    public string ResidentialAddress { get; set; }

    [Display(Name = "Suburb")]
    public string Suburb { get; set; }

    [Display(Name = "City")]
    public string City { get; set; }

    [Display(Name = "Province")]
    public string Province { get; set; }

    [Display(Name = "Postal Code")]
    public string PostalCode { get; set; }


    [Display(Name = "Physical Address")]
    public string PhysicalAddress
    {
        get
        {
            return ResidentialAddress + ", " + Suburb + ", " + City + ", " + Province + ", " + PostalCode;
        }
    }

    [Display(Name = "Full Name")]
    public string FullName
    {
        get
        {
            return LastName + ", " + FirstName;
        }
    }

工作模式：

public class Job
{
    public int ID { get; set; }

    [StringLength(50, MinimumLength = 3)]
    public string Title { get; set; }

    [DataType(DataType.DateTime)]
    public string AppointmentDate { get; set; }

    [BindProperty, MaxLength(300)]
    public string Description { get; set; }

    public string PlumberID { get; set; }
    public string ClientID { get; set; }

    public Plumber Plumber { get; set; }

    public Client Client { get; set; }
}

在作業創建 page.cshtml 上，必須從下拉列表中選擇客戶，然后客戶的手機號碼必須顯示在手機號碼表單字段中。

<div class="form-group">
            <label asp-for="Job.Client" class="control-label"></label>
            <select asp-for="Job.ClientID" class="form-control"
                    asp-items="@Model.ClientNameSL">
                <option value="">-- Select Client --</option>
            </select>
            <span asp-validation-for="Job.ClientID" class="text-danger" />
        </div>
        <div class="form-group">
            <label asp-for="Job.Client.CellNumber" class="control-label"></label>
            <input asp-for="Job.Client.CellNumber" class="form-control" disabled />
            <span asp-validation-for="Job.Client.CellNumber" class="text-danger"></span>
        </div>

創建作業頁面.cshtml.cs：

public class CreateJobModel : DropDownPageModel
{
    private readonly RealAssisst.Data.ApplicationDbContext _context;

    public CreateJobModel(RealAssisst.Data.ApplicationDbContext context)
    {
        _context = context;
    }

    public IActionResult OnGet()
    {
        PopulatePlumbersDropDownList(_context);
        PopulateClientsDropDownList(_context);
        return Page();
    }

    [BindProperty]
    public Job Job { get; set; }
    public Client Client { get; set; }

    public async Task<IActionResult> OnPostAsync()
    {
        if (!ModelState.IsValid)
        {
            return Page();
        }

        var emptyJob = new Job();

        if (await TryUpdateModelAsync<Job>(
            emptyJob,
            "job",
            s => s.ID, s => s.PlumberID, s => s.ClientID, s => s.Title, s => s.AppointmentDate, s => s.Description))
        {
            _context.Jobs.Add(emptyJob);
            await _context.SaveChangesAsync();
            return RedirectToPage("./Index");
        }

        PopulatePlumbersDropDownList(_context, emptyJob.PlumberID);
        PopulateClientsDropDownList(_context, emptyJob.ClientID);
        return Page();
    }
}

填充下拉列表頁面：

public class DropDownPageModel : PageModel
{
    public SelectList PlumberNameSL { get; set; }
    public SelectList ClientNameSL { get; set; }
    public string ClientNumber { get; set; }

    public void PopulatePlumbersDropDownList(ApplicationDbContext _context,
        object selectedPlumber = null)
    {
        var plumbersQuery = from d in _context.Plumber
                            orderby d.FirstName
                            select d;

        PlumberNameSL = new SelectList(plumbersQuery.AsNoTracking(),
            "FullName", "FullName", selectedPlumber);
    }

    public void PopulateClientsDropDownList(ApplicationDbContext _context,
        object selectedClient = null)
    {
        var clientQuery = from d in _context.Client
                          orderby d.FirstName
                          select d;

        ClientNameSL = new SelectList(clientQuery.AsNoTracking(),
            "FullName", "FullName", selectedClient);
    }
}

Answer 1

Client.ID （也可能是Plumber.ID ）被輸入為int 。 但是，在您的Job ，您已將外鍵屬性輸入為string 。 此外，您的下拉列表使用FullName屬性作為選擇選項的文本和值。

將您的Job外鍵（ ClientID和PlumberID ）更改為int以匹配 PK 的實際類型，然后將您的選項的值設置為ID屬性：

ClientNameSL = new SelectList(clientQuery.AsNoTracking(),
        "ID", "FullName", selectedClient);