編輯和刪除數據庫中的特定用戶

Question

正如標題所示。我試圖爲管理員啓用刪除和編輯系統。

管理員指定與數據庫中的數據相匹配的日期時間和用戶ID，並顯示給出的選擇。

現在我需要知道如何編輯或刪除特定的數據。

型號：

public partial class Stamping 
{ 
    [Key] 
    [Column(Order = 0)] 
    [DatabaseGenerated(DatabaseGeneratedOption.None)] 
    public int UserId { get; set; } 

    [Key] 
    [Column(Order = 1)] 
    [DataType(DataType.DateTime)] 
    public DateTime Timestamp { get; set; } 

    [Required] 
    [StringLength(3)] 
    public string StampingType { get; set; } 

    public virtual User User { get; set; } 
} 

查看：

@model IEnumerable<Aviato.Models.Stamping> 
     @Html.DisplayNameFor(model => model.UserId) 
     @Html.DisplayNameFor(model => model.Timestamp) 
     @Html.DisplayNameFor(model => model.StampingType) @foreach (var item in Model) { 
     @Html.DisplayFor(modelItem => item.UserId) 
     @Html.DisplayFor(modelItem => item.Timestamp) 
     @Html.DisplayFor(modelItem => item.StampingType) 

     @Html.ActionLink("Edit", "Edit", new { id=item.UserId }) | 
     @Html.ActionLink("Delete", "Delete", new { id=item.UserId })} 

控制器：

[AuthenticateRoles(Roles = "admin")] 
public class StampingsController : Controller 
{ 
    private AviatoModel db = new AviatoModel(); //Database Connection. 

    public ActionResult Index(Stamping model) 
    { 
     var startTime = model.Timestamp; 
     var endTime = model.Timestamp.AddDays(1); 

     var stampings = db.Stampings.Where(s => s.Timestamp >= startTime && s.Timestamp <= endTime) 
      .Where(s => s.UserId == model.UserId).ToList(); 

     return View(stampings); 
    } 

     public ActionResult Edit(int? id) 
    { 
     var stamping = db.Stampings.Find(id); /*An exception of type 'System.ArgumentException' occurred in EntityFramework.dll but was not handled in user code. Additional information: The number of primary key values passed must match number of primary key values defined on the entity.*/ 

     ViewBag.UserId = new SelectList(db.Users, "UserId", "SocialSecurityNumber", stamping.UserId); 
     return View(stamping); 
    } 

    [HttpPost] 
    [ValidateAntiForgeryToken] 
    public ActionResult Edit([Bind(Include = "UserId,Timestamp,StampingType")] Stamping stamping) 
    { 
     if (ModelState.IsValid) 
     { 
      db.Entry(stamping).State = EntityState.Modified; 
      db.SaveChanges(); 
      return RedirectToAction("Index"); 
     } 
     ViewBag.UserId = new SelectList(db.Users, "UserId", "SocialSecurityNumber", stamping.UserId); 
     return View(stamping); 
    } 

     public ActionResult Delete(int? id) 
    { 
     if (id == null) 
     { 
      return new HttpStatusCodeResult(HttpStatusCode.BadRequest); 
     } 
     Stamping stamping = db.Stampings.Find(id); //Same error as in Edit ActionResult. 
     if (stamping == null) 
     { 
      return HttpNotFound(); 
     } 
     return View(stamping); 
    } 

    [HttpPost, ActionName("Delete")] 
    [ValidateAntiForgeryToken] 
    public ActionResult DeleteConfirmed(int id) 
    { 
     Stamping stamping = db.Stampings.Find(id); 
     db.Stampings.Remove(stamping); 
     db.SaveChanges(); 
     return RedirectToAction("Index"); 
    } 

如何將我解決這個問題？ Iv'e試着圍繞錯誤搜索，但沒有成功。

所有幫助將不勝感激！

Answer 1

您的實體具有由UserId和Timestamp組成的複合主鍵，但您只將單個值傳遞給Find()方法。該方法需要主鍵中指定的每個列的值。

您應該解決的關鍵，只能是單個列（刪除Timestamp的Key屬性）或通過在這兩個值：

public ActionResult Edit(int? id, DateTime timestamp) 
{ 
    var stamping = db.Stampings.Find(id, timestamp); 
    //snip 
} 

而且不要忘了更改視圖：

@Html.ActionLink("Edit", "Edit", new { id=item.UserId, timestamp = item.Timestamp })