Question

I have recently created a new application that is using MVC4 and EF5. The tables already existed, so we are using Database first. This is all new to me, it is my first time in MVC or EF.

I have some models in my EMDX file, and in one of them I inherited IValidatableObject and put some code in the Validate function. This was working fine, then I changed my view to use a ViewModel, now I get an error from validate, and I am stumped. It is still calling my validate function, but no longer posting it back to the screen, i just get a yellow screen.

Error:

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.

Model:

public partial class Names : IValidatableObject {
  public int Id { get; set; }
  public string Name { get; set; }
  public bool Active { get; set; }

  public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {
    // some logic, this works
  }
}

ViewModel:

public class NamesVM {
  public Names Name { get; set; }
  // some other stuff in this model, but not part of this problem
}

Controller: Edit Function:

[HttpPost]
public ActionResult Edit(NamesVM nvm) {

  if (ModelState.IsValid) {
    dbCommon.Entry(nvm.Name).State = EntityState.Modified;
    dbCommon.SaveChanges();
    return RedirectToAction("Index");
  }

  return View(nvm);
}

View:

@model NamesVM
<div class="editor-label">
  @Html.LabelFor(model => model.Name.Id)
</div>
<div class="editor-field">
  @Html.EditorFor(model => model.Name.Id)
  @Html.ValidationMessageFor(model => model.Name.Id)
</div>

<div class="editor-label">
  @Html.LabelFor(model => model.Name.Name)
</div>
<div class="editor-field">
  @Html.EditorFor(model => model.Name.Name)
  @Html.ValidationMessageFor(model => model.Name.Name)
</div>

<div class="editor-label">
  @Html.LabelFor(model => model.Name.Active)
</div>
<div class="editor-field">
  @Html.EditorFor(model => model.Name.Active)
  @Html.ValidationMessageFor(model => model.Name.Active)
</div>
<input type="submit" value="Save" />

The codes works fine if everything is correct on the screen, but when validation fails, i don’t get a nice error, I get a yellow screen. I am sure I am missing something, I just don’t know what.

Answer 1

finally solved it. The IValidatableObject needs to be moved to the ViewModel, as well as the logic for it.

Model

public partial class Names { //: IValidatableObject { //Remove the IValidateableObject from here
    public int Id { get; set; }
    public string Name { get; set; }
    public bool Active { get; set; }

    // this whole method can be commented out
    //public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {
        // some logic, this works
    //}
}

View Model

public class NamesVM : IValidatableObject { // add the IValidatableObject to your view model
    public Names Name { get; set; }
        // some other stuff in this model, but not part of this problem

    // and move your validation logic to here
    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) {
        // some logic, this works
    }
}