Entity Framework Validation confusion - maximum string length of '128'
Solution 1
Default length of string field in code first is 128. If you are using EF validation it will throw exception. You can extend the size by using:
[StringLength(Int32.MaxValue)]
public string Body { get; set; }
This post became somehow popular so I'm adding second approach which also works:
[MaxLength]
public string Body { get; set; }
StringLengthAttribute
is from System.ComponentModel.DataAnnotations assembly and MaxLengthAttribute
is from EntityFramework assembly (EF 4.1).
Solution 2
If you get this error using a Model First approach, check the EF Model: it may be simply that a property on the Entity you're updating has the Max Length
attribute set.
Solution 3
May be you have used
Property(m => m.Body ).IsRequired().HasMaxLength(128);
On your dbcontext class in OnModelCreating. So change as per your length
Phil.Wheeler
I am a development manager for a Dunedin, New Zealand based technology company working in the education and life science sector. I've been a developer for over 10 years specialising in web applications on the Microsoft ecosystem and have since moved through project leadership, team leadership and management. In my spare time I blog a bit and do a little moonlighting as a professional consultant / developer. In whatever time I have left, I play the drums and get a bit of exercise in playing squash and cricket. Follow @Phil_Wheeler.
Updated on April 14, 2021Comments
-
Phil.Wheeler about 3 years
I'm faced with a confusing problem where in my Edit or Create action result methods, EF4 will throw a DbEntityValidationException with the inner message stating:
The field Body must be a string or array type with a maximum length of '128'.
The model in question looks like this:
[Table("tblArticles")] public class Article { [Key] public int ID { get; set; } [Required(ErrorMessage="Title must be included")] public string Title { get; set; } [AllowHtml] public string Body { get; set; } [Required(ErrorMessage="Start Date must be specified")] [Display(Name="Start Date")] [DisplayFormat(DataFormatString="dd-mm-yyyy")] public DateTime? StartDate { get; set; } [Required(ErrorMessage = "End Date must be specified")] [Display(Name = "End Date")] public DateTime? EndDate { get; set; } public int Priority { get; set; } public bool Archived { get; set; } public virtual ICollection<ArticleImage> Images { get; set; } }
The "Body" field in the actual database is of type Text, so there's no obvious limit there. The data that I'm trying to post is this:
<p> This is an example to confirm that new articles are looking right.</p> <p> <img alt="" src="http://www.google.co.nz/logos/2011/houdini11-sr.jpg" style="width: 160px; height: 56px; float: left;" /></p>
An example of the Edit method looks like this:
[HttpPost] public ActionResult Edit(Article article) { if (ModelState.IsValid) { try { articleRepository.Update(article); } catch (DbEntityValidationException dbevEx) { ErrorSignal.FromCurrentContext().Raise(dbevEx); ModelState.AddModelError("FORM", dbevEx); return View("Edit", article); } // Other exception handling happens... } return RedirectToAction("Index"); }
And finally, the method that actually does the grunt work is:
public void Update(T Entity) { dbset.Attach(Entity); db.Entry(Entity).State = System.Data.EntityState.Modified; db.Commit(); }
I can't see anything in code or in the database that might be causing the problem, so where else should I look?