大佬教程收集整理的这篇文章主要介绍了当模型属性具有 [ConcurrencyCheck] 属性时，ASP.NET Core MVC ConcurrencyCheck 失败，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。
我是 ASP.NET Core MVC 中的并发检查的新手，一定是在这里实现了一些错误，但是 Microsoft 文档似乎很薄弱。有没有人能指出我正确的方向？
这是一个简单的用户类，可由管理员编辑。如果没有任何并发检查，表单更改将毫无问题地保存到数据库中，但是，当我将 [Concurrencycheck] 属性添加到模型属性之一时，即使字段值发生更改，保存到数据库也会失败（我是期望这只会在用户 A 在用户 B 之前更新字段时失败，等等）
任何帮助将不胜感激。
这里有一些片段。
型号
@H_502_11@public class MyUser : IDentityUser
{
[Concurrencycheck]
[PersonalData]
[displayname("First name")]
[column(Typename = "nvarchar(100)")]
public String Firstname { get; set; }
[PersonalData]
[displayname("last name")]
[column(Typename = "nvarchar(100)")]
public String Lastname { get; set; }
[displayname("created date")]
[column(Typename = "datetiR_508_11845@e")]
public datetiR_508_11845@e CreateddatetiR_508_11845@e { get; set; }
[displayname("Customer ID")]
[column(Typename = "int")]
public int CustomerID { get; set; }
public String GetFullname()
{
return $"{FirstnamE} {LastnamE}";
}
}
控制器
@H_502_11@
// GET: UserController/Edit/5
public ActionResult Edit(String ID)
{
// New user vIEw model.
Userviewmodel userviewmodel = new Userviewmodel();
// Get user details.
MyUser user = _context.Users.Where(u => u.id == ID).Single();
var roles = _context.UserRoles.Where(r => r.UserID == ID).ToList();
if (user != null)
{
// Set viewmodel user with user details.
userviewmodel.thisUser = user;
// userviewmodel.thisUserRoles = _context.UserRoles.Where()
// Get roles assigned to the user.
//userviewmodel.thisUserRoles = _context.userRoles.Where(r => r.UserID == ID).ToList();
// Set viewmodel variables based on which roles the user has.
if (roles.Count > 0)
{
foreach(var role in roles)
{
switch (_context.Roles.Where(r => r.ID == role.RolEID).SELEct(r => r.Name).Single().ToString())
{
case "User":
userviewmodel.UserRole = true;
break;
case "SALEs User":
userviewmodel.SALEsUserRole = true;
break;
case "SALEs Branch User":
userviewmodel.SALEsBranchUserRole = true;
break;
case "SALEs administrator":
userviewmodel.SALEsadministrator = true;
break;
case "administrator":
userviewmodel.administrator = true;
break;
}
}
}
return VIEw(userviewmodel);
}
else
{
VIEwBag.Errormessage = "The user Could not be found.";
return RedirectToAction("Index");
}
}
// POST: UserController/Edit/5
[httpPost]
[ValIDateAntiForgeryToken]
public ActionResult Edit(Userviewmodel userviewmodel)
{
if (ModelState.IsValID)
{
userviewmodel.thisUser.Username = userviewmodel.thisUser.Email;
userviewmodel.thisUser.normalizedUsername = userviewmodel.thisUser.Email.toupper();
userviewmodel.thisUser.normalizedEmail = userviewmodel.thisUser.Email.toupper();
try
{
_context.Entry(userviewmodel.thisUser).State = EntityState.ModifIEd;
_context.SaveChanges();
}
catch (Exception eX)
{
// Prompt the user to try again.
ModelState.AddModelError("","The information has been updated by someone else before you saved. Please try again.");
return VIEw(userviewmodel);
}
}
return RedirectToAction("Index");
}
查看
@H_502_11@@model MyApp.viewmodelS.Userviewmodel @{ VIEwData["title"] = "Edit"; Layout = "~/VIEws/Shared/_Layout.csHTML"; } @*<h1>Edit</h1>*@ @*<h5> Details </h5> <hr />*@ <div class="row"> <div class="col-md-4"> <form asp-action="Edit"> <div asp-valIDation-sumMary="All" class="text-danger"></div> @HTMl.HIDdenFor(m => m.thisUser.ID) @HTMl.HIDdenFor(m => m.thisUser.passwordHash) @HTMl.HIDdenFor(m => m.thisUser.LockoutEnd) @HTMl.HIDdenFor(m => m.thisUser.LockoutEnabled) @HTMl.HIDdenFor(m => m.thisUser.AccessFailedCount) @HTMl.HIDdenFor(m => m.thisUser.CreateddatetiR_508_11845@E) @HTMl.HIDdenFor(m => m.thisUser.SecurityStamp) @HTMl.HIDdenFor(m => m.thisUser.ConcurrencyStamp) @HTMl.HIDdenFor(m => m.thisUser.EmailConfirmed) <div class="form-group"> <label asp-for="thisUser.Firstname" class="control-label"></label> <input asp-for="thisUser.Firstname" class="form-control" /> <span asp-valIDation-for="thisUser.Firstname" class="text-danger"></span> </div> <div class="form-group"> <label asp-for="thisUser.Lastname" class="control-label"></label> <input asp-for="thisUser.Lastname" class="form-control" /> <span asp-valIDation-for="thisUser.Lastname" class="text-danger"></span> </div> <div class="form-group"> <label asp-for="thisUser.Email" class="control-label"></label> <input asp-for="thisUser.Email" class="form-control" /> <span asp-valIDation-for="thisUser.Email" class="text-danger"></span> </div> <div class="form-group"> <label asp-for="thisUser.Phonenumber" class="control-label"></label> <input asp-for="thisUser.Phonenumber" class="form-control" /> <span asp-valIDation-for="thisUser.Phonenumber" class="text-danger"></span> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="thisUser.PhonenumberConfirmed" /> @HTMl.displaynameFor(model => model.thisUser.PhonenumberConfirmed) </label> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="thisUser.TwoFactorEnabled" /> @HTMl.displaynameFor(model => model.thisUser.TwoFactorEnabled) </label> </div> <div class="form-group"> <label asp-for="thisUser.CustomerID" class="control-label"></label> <input asp-for="thisUser.CustomerID" class="form-control" /> <span asp-valIDation-for="thisUser.CustomerID" class="text-danger"></span> </div> <h5> Roles </h5> <hr /> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="UserRole" /> @HTMl.displaynameFor(model => model.UserRolE) </label> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="SALEsUserRole" /> @HTMl.displaynameFor(model => model.SALEsUserRolE) </label> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="SALEsBranchUserRole" /> @HTMl.displaynameFor(model => model.SALEsBranchUserRolE) </label> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="SALEsadministrator" /> @HTMl.displaynameFor(model => model.SALEsadministrator) </label> </div> <div class="form-group form-check"> <label class="form-check-label"> <input class="form-check-input" asp-for="administrator" /> @HTMl.displaynameFor(model => model.administrator) </label> </div> <div class="form-group"> <input type="submit" value="Save" class="btn btn-priMary" /> </div> </form> </div> </div> <div> <a asp-action="Index">BACk to List</a> </div> @section Scripts { @{await HTMl.RenderPartialAsync("_ValIDationScriptsPartial");} }
根据ms官方文档，推荐使用行版到handle concurrency conflicts。
从文档中总结一下，我们需要添加一个名为“RowVersion”的列，其数据类型为“rowversion”，并将其添加到您的实体中。
1654155318
public byte[] RowVersion { get; set; }
![当模型属性具有 [ConcurrencyCheck] 属性时，ASP.NET Core MVC ConcurrencyCheck 失败](https://i.stack.imgur.com/Eob7X.png "当模型属性具有 [ConcurrencyCheck] 属性时，ASP.NET Core MVC ConcurrencyCheck 失败")
接下来，在调用 await _context.SaveChangesAsync(); 之前，我们需要将原始 RowVersion 属性值放入实体的 OriginalValues 集合中
[httpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> EditAsync(UserviewModel userviewModel)
{
if (ModelState.IsValid)
{
try
{
_context.Entry(userviewModel.thisUser).Property("RowVersion").originalValue = userviewModel.thisUser.RowVersion;
_context.update(userviewModel.thisUser);
await _context.SaveChangesAsync();
}
catch (Exception eX)
{
// Prompt the user to try again.
ModelState.AddModelError("","The information has been updated by someone else before you saved. Please try again.");
return View(userviewModel);
}
}
return RedirectToAction("Index");
}
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