我有这个错误在线
db.Comments.Add(comment);
db.SaveChanges();
我无法修复它... 有什么问题?我已经阅读了很多关于该问题的问题,但在我的代码中找不到问题所在。
我正在使用 asp.net mvc4、c# 和实体框架。
我的评论模型有一个PostId
属性。
INSERT 语句与 FOREIGN KEY 约束“FK_dbo.Comments_dbo.Posts_PostId”冲突。冲突发生在数据库 Myproject、表“dbo.Posts”、列“PostId”中。
该语句已终止。
编辑 :
我注意到,调用 SaveChanges() 时,我的 comment.PostId 等于 0
我注意到,如果我@Html.HiddenFor(model => model.PostId)
在 CreateComment 视图中有,那么我就没有错误了,但是当我单击添加评论时没有任何反应
PostController
:
public ActionResult ListPost()
{
var post = db.Posts.ToList();
return PartialView("ListPost", post);
}
public ActionResult Create()
{
return View();
}
[HttpPost]
public ActionResult Create(FormCollection values)
{
var post = new Post();
TryUpdateModel(post);
if (ModelState.IsValid)
{
var context = new UsersContext();
var username = User.Identity.Name;
var user = context.UserProfiles.SingleOrDefault(u => u.UserName == username);
var userid = user.UserId;
post.UserId = userid;
post.Date = DateTime.Now;
db.Posts.Add(post);
db.SaveChanges();
return RedirectToAction("Create", "Post");
}
return View(post);
}
public ActionResult CreateComment()
{
ViewBag.PostId = new SelectList(db.Posts, "PostId", "Content");
return View("CreateComment");
}
[HttpPost]
public ActionResult CreateComment(FormCollection values)
{
var comment = new Comment();
TryUpdateModel(comment);
if (ModelState.IsValid)
{
var context = new UsersContext();
var username = User.Identity.Name;
var user = context.UserProfiles.SingleOrDefault(u => u.UserName == username);
var userid = user.UserId;
comment.UserId = userid;
comment.Date = DateTime.Now;
db.Comments.Add(comment);
db.SaveChanges();
return RedirectToAction("Create", "Post");
}
ViewBag.PostId = new SelectList(db.Posts, "PostId", "Content", comment.PostId);
return View(comment);
}
创建视图(调用 ListPost 部分视图):
@model Myproject.Models.Post
@using (Html.BeginForm("Create", "Post", FormMethod.Post))
{
<legend>Add Post</legend>
<div class="editor-field">
@Html.EditorFor(model => model.Content)
@Html.ValidationMessageFor(model => model.Content)
<input type="file" name="Photo" id="Photo"/>
</div>
<p>
<input type="submit" value="Post" />
</p>
}
@{Html.RenderAction("ListPost", "Post");}
ListPost 部分视图(调用 CreateComment 视图):
@model IEnumerable<MyProject.Models.Post>
@foreach (var item in Model.OrderByDescending(x => x.Date))
{
<tr>
<td>
@Html.DisplayFor(modelItem => item.Content)
</td>
</tr>
<tr>
<td>
@Html.DisplayFor(modelItem => item.Date)
<span>@Html.DisplayFor(modelItem => item.Users.UserName)</span>
</td>
</tr>
<tr>
<td> @Html.ActionLink("Add Comment", "CreateComment", new {id=item.PostId})</td>
</tr>
}
编辑 2
帖子表:
CREATE TABLE [dbo].[Posts] (
[PostId] INT IDENTITY (1, 1) NOT NULL,
[UserId] INT NOT NULL,
[Content] NVARCHAR (MAX) NULL,
[Date] DATETIME NOT NULL,
[Picture] VARBINARY (MAX) NULL,
CONSTRAINT [PK_dbo.Posts] PRIMARY KEY CLUSTERED ([PostId] ASC),
CONSTRAINT [FK_dbo.Posts_dbo.UserProfile_UserId] FOREIGN KEY ([UserId]) REFERENCES [dbo].[UserProfile] ([UserId]) ON DELETE CASCADE
);
GO
CREATE NONCLUSTERED INDEX [IX_UserId]
ON [dbo].[Posts]([UserId] ASC);
评论表
CREATE TABLE [dbo].[Comments] (
[CommentId] INT IDENTITY (1, 1) NOT NULL,
[UserId] INT NOT NULL,
[PostId] INT NOT NULL,
[Content] NVARCHAR (MAX) NULL,
[Date] DATETIME NOT NULL,
CONSTRAINT [PK_dbo.Comments] PRIMARY KEY CLUSTERED ([CommentId] ASC),
CONSTRAINT [FK_dbo.Comments_dbo.Posts_PostId] FOREIGN KEY ([PostId]) REFERENCES [dbo].[Posts] ([PostId]) ON DELETE CASCADE
);
GO
CREATE NONCLUSTERED INDEX [IX_PostId]
ON [dbo].[Comments]([PostId] ASC);
谢谢