When I try to save to my database I get the error
SqlException: Cannot insert explicit value for identity column in table 'Photo' when IDENTITY_INSERT is set to OFF.
I am using asp.net 5 MVC 6 with EF 7 on Visual Studio 2015 There are a lot of similar questions. Most have solutions that are not supported by asp.net 5 MVC 6 or EF 7(One said to use a Data Annotation that would fix the problem in EF 6). The others have not worked. I try not to ask except as a last resort.
My design is that every user will have many folders, and a folder will have many photos.
I added public ICollection<UserFolder> UserFolders { get; set; }
to ApplicationUser
The Model:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations.Schema;
namespace FamPhotos.Models
{
public class UserFolder
{
public int ID { get; set; }
public string Name { get; set; }
public ICollection<Photo> Photo { get; set; }
public string ApplicationUserId { get; set; }
public virtual ApplicationUser ApplicationUser { get; set; }
}
public class Photo
{
public int ID { get; set; }
public string Description { get; set; }
public DateTime UploadDate { get; set; }
public string Url { get; set; }
public int UserFolderId { get; set; }
public UserFolder UserFolder { get; set; }
}
}
The Controller method
// POST: Photos/Create
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create(Photo photo, IFormFile files, int id)
{
if (files == null)
{
ModelState.AddModelError(string.Empty, "Please select a file to upload.");
}
else if (ModelState.IsValid)
{
photo.UploadDate = DateTime.Now;
photo.UserFolderId = id;
var folderName = _context.UserFolder.Where(q => q.ID == id).Single().Name;
//TODO: Check for image types
var fileName = photo.ID.ToString() + ContentDispositionHeaderValue.Parse(files.ContentDisposition).FileName.Trim('"');
var filePath = Path.Combine(_applicationEnvironment.ApplicationBasePath, "Photos", User.GetUserName(), folderName, fileName);
await files.SaveAsAsync(filePath);
photo.UserFolder = _context.UserFolder.Where(q => q.ID == id).Single();
photo.Url = "~/Photos/" + fileName;
_context.Add(photo);
_context.SaveChanges();
return RedirectToAction("Index");
}
return View(photo);
}
The View:
@model FamPhotos.Models.Photo
@{
ViewData["Title"] = "Create";
}
<h2>Create</h2>
<form asp-action="Create" asp-controller="Photos" method="post" enctype="multipart/form-data">
<div class="form-horizontal">
<h4>Photo</h4>
<hr />
<div asp-validation-summary="ValidationSummary.ModelOnly" class="text-danger"></div>
<input type="file" name="files" />
<label asp-for="Description" class="col-md-2 control-label"></label>
<div class="col-md-10">
<input asp-for="Description" class="form-control" />
<span asp-validation-for="Description" class="text-danger" />
</div>
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</form>
<div>
<a asp-action="Index">Back to List</a>
</div>
@section Scripts {
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script src="~/lib/jquery-validation/dist/jquery.validate.min.js"></script>
<script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.min.js"></script>
}
My DbContext:
namespace FamPhotos.Models
{
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
protected override void OnModelCreating(ModelBuilder builder)
{
builder.Entity<UserFolder>()
.HasMany(q => q.Photo)
.WithOne(c => c.UserFolder)
.HasForeignKey(c => c.UserFolderId);
base.OnModelCreating(builder);
// Customize the ASP.NET Identity model and override the defaults if needed.
// For example, you can rename the ASP.NET Identity table names and more.
// Add your customizations after calling base.OnModelCreating(builder);
}
public DbSet<Photo> Photo { get; set; }
public DbSet<ApplicationUser> ApplicationUser { get; set; }
public DbSet<UserFolder> UserFolder { get; set; }
}
}
Thanks.
If you do not want an ID to be database generated, then you should use the DatabaseGenerated attribute on your model, as in
public class MyModel
{
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int ID {get;set;}
...
}
This attribute is in fact supported in EF7.
See https://learn.microsoft.com/en-us/ef/core/modeling/generated-properties
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