Question

I have some checkboxes that are required to be checked before the user can go to the next page. What is the best way to display a validation message?

View:

@Html.CheckBox("terms_eligibility")
@Html.CheckBox("terms_accurate")
@Html.CheckBox("terms_identity_release")
@Html.CheckBox("terms_score_release")

Controller:

[HttpPost]
public ActionResult Review(ReviewModel model)
{
    // Make sure all Terms & Conditions checkboxes are checked
    var termsEligibility = Request.Form.GetValues("terms_eligibility")[0];
    var termsAccurate = Request.Form.GetValues("terms_accurate")[0];
    var termsIdentityRelease = Request.Form.GetValues("terms_identity_release")[0];
    var termsScoreRelease = Request.Form.GetValues("terms_score_release")[0];

    if (termsEligibility == "true" && termsAccurate == "true" &&
        termsIdentityRelease == "true" && termsScoreRelease == "true")
    {
        return RedirectToAction("CheckOut","Financial");
    }

    return null;
}

---

EDIT,

I made the suggested changes. Now how do i get the same page to display with error messages?

I changes the attributes in the model to this

 [RequiredToBeTrue(ErrorMessage = "*")]

here’s the conroller

[HttpPost]
public ActionResult Review(ReviewModel model)
{


    if(ModelState.IsValid)
    {
        return RedirectToAction("CheckOut", "Financial");
    }

    return RedirectToAction("Review");
}

Answer 1

I’d recommend you using a view model and a custom validation attribute:

public class RequiredToBeTrueAttribute : RequiredAttribute
{
    public override bool IsValid(object value)
    {
        return value != null && (bool)value;
    }
}

and the view model:

public class MyViewModel
{
    [RequiredToBeTrue]
    public bool TermsEligibility { get; set; }

    [RequiredToBeTrue]
    public bool TermsAccurate { get; set; }

    [RequiredToBeTrue]
    public bool TermsIdentityRelease { get; set; }

    [RequiredToBeTrue]
    public bool TermsScoreRelease { get; set; }

    ... some other properties that are used in your view
}

and the view will of course be strongly typed to the view model:

@model MyViewModel

@Html.ValidationSummary(false)
@using (Html.BeginForm())
{
    @Html.CheckBoxFor(x => x.TermsEligibility)   
    @Html.CheckBoxFor(x => x.TermsAccurate)   
    @Html.CheckBoxFor(x => x.TermsIdentityRelease)   
    @Html.CheckBoxFor(x => x.TermsScoreRelease)   
    ...
    <button type="submit">OK</button>
}

and finally your controller action will take the view model as parameter:

[HttpPost]
public ActionResult Review(MyViewModel model)
{
    if (!ModelState.IsValid)
    {
        // there were validation errors => redisplay the same view  
        // so that the user could fix them
        return View(model);
    }

    // at this stage we know that validation succeeded =>
    // we could proceed in processing the data and redirecting
    ...

    return RedirectToAction("CheckOut", "Financial");
}

Notice that things like Request.Form.GetValues("terms_eligibility")[0]; and termsEligibility == "true" are really not the kind of code you would like to see in a properly written application.