I have written an attribute before, but I I have not written a validation attribute before. I am seriously confused about how it all works together. I have read most of the tutorials online about how to go about accomplishing this. But I am left with a couple of questions to ponder.
Keep in mind that I am trying to write a requiredIf attribute that will only call a remote function if a certain Jquery variable is set... which incidentally is a variable that is pulled from view state... I guess I could make that part of my view model. But I digress
1) The C# code is slightly confusing. I know my attribute should extend the ValidationAttribute, IClientValidatable class and interface respectively. But I am a little confused about what each of the overidden methods should be doing? I am trying to write a requiredIf, how does overwriting these methods help me accomplish this goal?
2) If the variable is not there, I simply don't want the remote function to attempt to validate the field. I don't want any message to pop up on my form. Alot of the tutorials seem to revolve around that.
3) I am confused about what I need to do with the jquery to add this function to the view... What do I need to add to the JQuery to get this thing to work... It seems like a lot of extra coding when I could simply just type up a jquery function that did the same thing with just the same ore less coding... I know it also adds server side validation which is good. But still...
Here is what I have for my jquery side of this equation...
(function ($) {
$validator.unobtrusive.adapters.addSingleVal("requiredifattribute", "Dependent");
$validator.addMethod("requiredifattribute", function (value, element, params) {
if (!this.optional(element)) {
var otherProp = $('#' + params)
return (otherProp.val() != value);
}
return true;
})
}(jQuery));
Here is my Attribute (which is basically carbon copied out of one the required if tutorials... I know I need to customize it more, but once I get a better idea of what every piece is doing I will do that...
[AttributeUsage(AttributeTargets.Property)]
public class RequiredIfAttribute : ValidationAttribute, IClientValidatable {
private const string errorMessage = "The {0} is required.";
//public string
private RequiredAttribute innerAttribute = new RequiredAttribute();
public string DependentProperty { get; set; }
public object TargetValue { get; set; }
public RequiredIfAttribute(string dependentProperty, object targetValue){
this.DependentProperty = dependentProperty;
this.TargetValue = targetValue;
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext) {
var field = validationContext.ObjectInstance.GetType().GetProperty(DependentProperty);
if (field != null) {
var dependentValue = field.GetValue(validationContext.ObjectInstance, null);
if ((dependentValue == null && TargetValue == null) || (dependentValue.Equals(TargetValue))) {
if (!innerAttribute.IsValid(value))
return new ValidationResult(ErrorMessage);
}
}
return ValidationResult.Success;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) {
ModelClientValidationRule modelClientValidationRule = new ModelClientValidationRule {
ErrorMessage = FormatErrorMessage(metadata.DisplayName),
ValidationType = "requiredifattribute"
};
modelClientValidationRule.ValidationParameters.Add("dependent", DependentProperty);
yield return modelClientValidationRule;
}
}
UPDATE: What I have simply isn't working
Here is how a property in my model is anotated with the above attribute
[RequiredIf("isFlagSet", true)]
[Remote("ValidateHosFin", "EditEncounter", AdditionalFields = "hospitalFin, encflag", ErrorMessage = "Got Damn this is complex!")]
[MinLength(6)]
public string HostpitalFinNumber { get; set; }
The value in my view that I was trying to key this validation on is set up like so...
ViewData["ADDENCOREDITTEMP"] = encflag;
if (encflag == "AddEnc"){
isFlagSet = true;
}
I embed it into my page like so...
#Html.Hidden("isFlagSet", isFlagSet, new { id = "isFlagSet"})
I can't get my form to submit... The person who said he just tried this and got it to work, could you post the code?
Model:
public class X
{
[RequiredIf("y", "y", ErrorMessage = "y is not y")]
public string x { get; set; }
public string y { get; set; }
}
View:
#using(Html.BeginForm())
{
#Html.ValidationSummary()
#Html.TextBoxFor(m => m.x)
#Html.TextBoxFor(m => m.y)
<input type="submit"/>
}
I assume your validation fails on the server side? do you have isFlagSet property in your view model?
Related
Can I do something like this in ASP.NET Core 2.0?
For example, I have this ViewModel:
public class TodoViewModel
{
[Required(ErrorMessage = "Required !")] // <--- Required
public int? Key { get; set; } // Is Nullable
[Required(ErrorMessage = "Required !")] // <--- Required
public int? Value { get; set; } Nullable
[Required(ErrorMessage = "Required !")] // <--- Required
public byte Type { get; set; }
}
In View for Example, I have this:
#Html.BeginForm(FormMethod.Post)
{
#if (Model.Type == 1)
{
#Html.TextBoxFor(x => x.Key)
#Html.ValidationMessageFor(x => x.Key)
}
#if (Model.Type == 2)
{
#Html.TextBoxFor(x => x.Value)
#Html.ValidationMessageFor(x => x.Key)
}
}
and in Action I have this:
[HttpPost]
public IActionResult Todo(TodoViewModel model)
{
// My problem
// if model.type = 1 return ModelState has error validate for Property (Value) is Required
// and if model.type = 2 return ModelState has error validate for Property (Key) is Required
if (!ModelState.IsValid) // <-- Here is my problem
return View(model);
}
I do not want to use #Html.HiddenFor()
To override validation for other property
I tried to use ActionFilterAttribute:
public class TodoActionFilter : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext context)
{
TodoViewModel model = (TodoViewModel) context.ActionArguments["model"];
if (model.Type == 1)
model.Value = 0;
if (model.Type == 2)
model.Key = 0;
}
}
But unfortunately, Execute for (OnActionExecuting) is after ModelState is Validation.
Is there a specific way to do this?
I want to exclude ModelState validate for "Key" property if "Type" property equal 1,
and exclude ModelState validate for "Value" property if "Type" property equal 2
Implement the IValidatableObject Interface.
using System.ComponentModel.DataAnnotations;
public class TodoViewModel : IValidatableObject
{
public int? Key { get; set; }
public int? Value { get; set; }
[Required(ErrorMessage = "Required !")]
public byte Type { get; set; }
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
if (Type == 1)
{
yield return
new ValidationResult(errorMessage: "Property (Value) is Required",
memberNames: new[] { "Value" });
}
if (Type == 2)
{
yield return
new ValidationResult(errorMessage: "Property (Key) is Required",
memberNames: new[] { "Key" });
}
}
}
This is a clear indication that you actually need two ViewModels. Either that or you do just a rough validation on the ViewModel and do a more detailed one in your business logic.
Of course you could write your own validation attribute (but not via ActionFilterAttribute but by inheriting from ValidationAttribute (Custom Validation Attribute) and putting it on the View Model instead of [Required])), which will check if one is required, but this essentially just covers/hides your intent that you have two different type of models.
Validation attributes aren't there to enforce business rules, they should be kinda simple and validate if the data looks good at the first look before the business validations are applied (which may required additional checks, services or database round-trips).
But remember if you go with the custom validation attribute, there won't be any client sided validation (via JavaScript in the browser). You'd also need to implement an AttributeAdapterBase<T> RequiredAttribute Example.
I'm working on the first MVC3 project at our company, and I've hit a block. No one can seem to figure out what's going on.
I have a complex Model that I'm using on the page:
public class SpaceModels : List<SpaceModel> {
public bool HideValidation { get; set; }
[Required(ErrorMessage=Utilities.EffectiveDate + Utilities.NotBlank)]
public DateTime EffectiveDate { get; set; }
public bool DisplayEffectiveDate { get; set; }
}
In the Controller, I create a SpaceModels object with blank SpaceModels for when Spaces get combined (this would be the destination Space).
// Need a list of the models for the View.
SpaceModels models = new SpaceModels();
models.EffectiveDate = DateTime.Now.Date;
models.DisplayEffectiveDate = true;
models.Add(new SpaceModel { StoreID = storeID, SiteID = siteID, IsActive = true });
return View("CombineSpaces", models);
Then in the View, I am using that SpaceModels object as the Model, and in the form making a TextBox for the Effective Date:
#model Data.SpaceModels
#using (Html.BeginForm("CombineSpaces", "Space")) {
<div class="EditLine">
<span class="EditLabel LongText">
New Space Open Date
</span>
#Html.TextBoxFor(m => m.EffectiveDate, new {
size = "20",
#class = "datecontrol",
// Make this as a nullable DateTime for Display purposes so we don't start the Calendar at 1/1/0000.
#Value = Utilities.ToStringOrDefault(Model.EffectiveDate == DateTime.MinValue ? null : (DateTime?)Model.EffectiveDate, "MM/dd/yyyy", string.Empty)
})
#Html.ValidationMessageFor(m => m.EffectiveDate)
</div>
<hr />
Html.RenderPartial("_SpaceEntry", Model);
}
The Partial View that gets rendered iterates through all SpaceModels, and creates a containing the Edit fields for the individual SpaceModel objects. (I'm using the List to use the same Views for when the Spaces get Subdivided as well.)
Then on the HttpPost, the EffectiveDate is still back at it's DateTime.MinValue default:
[HttpPost]
public ActionResult CombineSpaces(SpaceModels model, long siteID, long storeID, DateTime? effectiveDate) {
// processing code
}
I added that DateTime? effectiveDate parameter to prove that the value when it gets changed does in fact come back. I even tried moving the rendering of the TextBox into the _SpaceEntry Partial View, but nothing worked there either.
I did also try using the #Html.EditorFor(m => m.EffectiveDate) in place of the #Html.TextBoxFor(), but that still returned DateTime.MinValue. (My boss doesn't like giving up the control of rendering using the #Html.EditorForModel by the way.)
There has to be something simple that I'm missing. Please let me know if you need anything else.
Looking at the source code for DefaultModelBinder, specifically BindComplexModel(), if it detects a collection type it will bind the individual elements but will not attempt to bind properties of the list object itself.
What model binding does is attempt to match the names of things or elements in the view to properties in your model or parameters in your action method. You do not have to pass all of those parameters, all you have to do is add them to your view model, then call TryUpdateModel in your action method. I am not sure what you are trying to do with SpaceModel or List but I do not see the need to inherit from the List. Im sure you have a good reason for doing it. Here is how I would do it.
The view model
public class SpacesViewModel
{
public DateTime? EffectiveDate { get; set; }
public bool DisplayEffectiveDate { get; set; }
public List<SpaceModel> SpaceModels { get; set; }
}
The GET action method
[ActionName("_SpaceEntry")]
public PartialViewResult SpaceEntry()
{
var spaceModels = new List<SpaceModel>();
spaceModels.Add(
new SpaceModel { StoreID = storeID, SiteID = siteID, IsActive = true });
var spacesVm = new SpacesViewModel
{
EffectiveDate = DateTime.Now,
DisplayEffectiveDate = true,
SpaceModels = spaceModels
};
return PartialView("_SpaceEntry", spacesVm);
}
The POST action method
[HttpPost]
public ActionResult CombineSpaces()
{
var spacesVm = new SpacesViewModel();
// this forces model binding and calls ModelState.IsValid
// and returns true if the model is Valid
if (TryUpdateModel(spacesVm))
{
// process your data here
}
return RedirectToAction("Index", "Home");
}
And the view
<label>Effective date: </label>
#Html.TextBox("EffectiveDate", Model.EffectiveDate.HasValue ?
Model.EffectiveDate.Value.ToString("MM/dd/yyyy") : string.empty,
new { #class = "datecontrol" })
Sometimes you need to explicitly bind form data using hidden fields such as
#Html.HiddenField("EffectiveDate", Model.EfectiveDate.)
In order to bind the properties of the SpaceModel object you can add individual properties such as SiteID to the view model or add a SpaceModel property for a single SpaceModel. If you want to successfully bind a complex model, add it as a Dictionary populated with key-value pairs rather than a List. You should then add the dictionary to the view model. You can even add a dictionary of dictionaries for hierarchical data.
I hope this helps :)
I have an input form containing several input fields. Each input field has a ElementModel which has properties basically for the label and the value. The input fields to display are specified in a XML document, so I have kind of a dynamic view with only a list of elements.
The problem is, that each element should be either displayed as a decimal or as percentage value. And of course, if it's a percentage value, the user shoud be able to input something like "45%" and the value in the model should then be 0.45.
My first thought when I found this article was to use an abstract view model class with an abstract property for the value and to define a PercentageElementModel deriving from my base ElementModelclass that makes use of a custom model binder. Unfortunately, if I use that abstract base class in my view, the data annotations made in the PercentageElementModelare ignored.
Do you have any idea of how I can solve this? I don't want to use strings in my view model and do the parsing by myself as this will break the MVC pattern. Are there some other ways to achieve my goal?
Here are some code snippets:
public abstract class ElementModel
{
public string ElementName { get; set; }
public ElementType ElementType { get; set; }
public abstract double? ElementValue { get; set; }
}
public class PercentageElementModel : ElementModel
{
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:P2}")]
public override double? ElementValue { get; set; }
}
I came up with another solution as my problem is more a matter of display formatting than of validation: I wrote a custom ModelBinder which checks the input string of the text box. If it ends with a trailing '%' sign, I will devide the value by 100. Here's the code.
public class DoubleModelBinder : IModelBinder
{
public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
var modelState = new ModelState { Value = valueResult };
double? actualValue = null;
try
{
// cut trailing '%'
if (valueResult.AttemptedValue.EndsWith("%"))
{
var strValue = valueResult.AttemptedValue.Substring(0, valueResult.AttemptedValue.Length - 1);
actualValue = double.Parse(strValue, valueResult.Culture) / 100;
}
else
{
actualValue = Convert.ToDouble(valueResult.AttemptedValue, CultureInfo.CurrentCulture);
}
}
catch (FormatException e)
{
modelState.Errors.Add(e);
}
bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
return actualValue;
}
}
The rest happens in the view itself. To display the correct format, I use a simple ToString() method with a percentage format string assigned if needed. And if the user enters a numeric value without '%', a jQuery's blur() event will append the '%' sign to the user's input. Perfectly works for me although this is not the best answer for my own question.
Here's the situation, I have a list of about 20 properties (called Attributes) that I've defined in my database. This consists of a name, possible values, an optional regex, a boolean that indicates the field is required, etc.
In my ViewModel I get the list of attributes and in my view as List I have a nice EditorTemplate for AttributeViewModel to show them using Steve Sanderson's cool BeginCollectionItem to make sure the post gets bound back to a list of AttributeViewModel (this works just fine).
My AttributeViewModel looks like this:
public class AttributeViewModel
{
public string Description { get; set; }
public IEnumerable<SelectListItem> Values { get; set; }
public string SelectedValue { get; set; }
public byte RenderAs { get; set; }
public int AttributeID { get; set; }
public int ID { get; set; }
public int RegexValidation { get; set; }
public bool IsRequired { get; set; }
}
My View looks like this (edit.cshtml):
#model Company.Services.ViewModels.StaffMemberViewModel
<h2>Edit</h2>
#using (Html.BeginForm())
{
Some fields here, nothing of interest.
#Html.EditorFor(model => model.AttributeValues)
<input type="submit" value="Send" />
}
Here's the interesting bit though, this is my EditorTemplate for AttributeValues:
#using Company.Web.Helpers // This is where "BeginCollectionItem" lives
#model Company.Services.ViewModels.AttributeViewModel
using (Html.BeginCollectionItem("attributes"))
{
<div class="editor-label">
#Model.Description
</div>
<div class="editor-field">
#Html.DropDownListFor(m => m.SelectedValue, new SelectList(Model.Values, "Value", "Text"), "-- Select --")
#Html.HiddenFor(model => model.AttributeID)
</div>
}
What I would like to do is use the IsRequired and RegexValidation to make sure the SelectedValue for each attribute is valid. How would I go about doing so? If possible, I'd really like to take advantage of the MVC3 validation framework and unobtrusive validation like I "normally" would.
I obviously can't dynamically add a RequiredAttribute or a RegularExpressionAttribute as these differ for each of my attribute objects in the list.
This is untested. You may have to play with this to get your desired result.
First, create your custom DataAnnotationsModelValidatorProvider class:
public class MyModelMetadataValidatorProvider : DataAnnotationsModelValidatorProvider
{
internal static DataAnnotationsModelValidationFactory DefaultAttributeFactory = Create;
internal static Dictionary<Type, DataAnnotationsModelValidationFactory> AttributeFactories =
new Dictionary<Type, DataAnnotationsModelValidationFactory>()
{
{
typeof(RequiredAttribute),
(metadata, context, attribute) => new RequiredAttributeAdapter(metadata, context, (RequiredAttribute)attribute)
},
{
typeof(RegularExpressionAttribute),
(metadata, context, attribute) => new RegularExpressionAttributeAdapter(metadata, context, (RegularExpressionAttribute)attribute)
}
};
internal static ModelValidator Create(ModelMetadata metadata, ControllerContext context, ValidationAttribute attribute)
{
return new DataAnnotationsModelValidator(metadata, context, attribute);
}
protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context, IEnumerable<Attribute> attributes)
{
List<ModelValidator> vals = base.GetValidators(metadata, context, attributes).ToList();
if (metadata.ModelType.Name == "SelectedValue")
{
// get our parent model
var parentMetaData = ModelMetadataProviders.Current.GetMetadataForProperties(context.Controller.ViewData.Model,
metadata.ContainerType);
// get the associated AttributeId
var attributeId = Convert.ToInt32(parentMetaData.FirstOrDefault(p => p.PropertyName == "AttributeId").Model);
// get AttributeViewModel with specified AttributeId from repository
var attributeViewModel = _db.AttributeViewModels.FirstOrDefault(x => x.AttributeId == attributeId);
DataAnnotationsModelValidationFactory factory;
// check if required
if (attributeViewModel.IsRequired)
{
// must be marked as required
var required = new RequiredAttribute();
required.ErrorMessage = attributeViewModel.Description.Trim() +
" is Required";
if (!AttributeFactories.TryGetValue(required.GetType(), out factory))
factory = DefaultAttributeFactory;
vals.Add(factory(metadata, context, required));
}
// check for regex
if (attributeViewModel.RegexValidation > 0)
{
// get regex from repository
var regexValidation = _db.attributeViewModels.
FirstOrDefault(x => x.RegexValidation == attributeViewModel.RegexValidation);
var regex = new RegularExpressionAttribute(regexValidation.Pattern);
regex.ErrorMessage = attributeViewModel.Description.Trim() +
" is not in a valid format";
if (!AttributeFactories.TryGetValue(regex.GetType(), out factory))
factory = DefaultAttributeFactory;
vals.Add(factory(metadata, context, regex));
}
}
return vals.AsEnumerable();
}
}
Then, add the following to Application_Start in Global.asax.cs:
ModelValidatorProviders.Providers.Clear();
ModelValidatorProviders.Providers.Add(new MyModelMetadataValidatorProvider());
Consider using FluentValidation.Net (which is available via NuGet from the following Install-Package FluentValidation.MVC3). It makes any sort of relatively complex data validation far simpler and more intuitive than a declarative style. There is support for client-side validation too.
I hope I am understanding your question correctly. You want to add custom validation attributes, annotation and validation logic to your views?
If so, you want to go to the System.ComponentModel.DataAnnotation namespace. Your validation logic will be placed in a class deriving from ValidationAttribute:
using System.ComponentModel.DataAnnotation;
public class MyValidationAttribute : ValidationAttribute
{
string readonly _validationParameter;
public MyValidationAttribute(string validationParameter)
{
_validationParameter = validationParameter;
}
protected override ValidationResult IsValid(object value,
ValidationContext validationContext)
{
// add validation logic here
if (//not valid)
{
var errorMessage = FormatErrorMessage(validationContext.DisplayName);
return new ValidationResult(errorMessage);
}
return ValidationResult.Success;
}
}
You can apply the attribute to any model property
[Required]
[MyValidationAttribute("parameter", ErrorMessage="Error in {0}")]
public string MyProperty { get; set; }
I hope this helps. See
Professional ASP.NET MVC 3
page 127 for more info.
(couldn't think of a better title, sorry)
So I've got my layout page, on this page there is a searchbar + options. Choosing whatever, should take you through to the search page, with the results etc. Fairly standard. What I've done to get this working is to create a MasterModel class, with a SearchDataModel class member on it. This SearchDataModel contains the various parameters for the search (search term, what fields to search on etc).
I've then strongly typed my layout page to the MasterModel class, and using a Html.BeginForm... I've constructed the search form for it. However all the checkboxes relating to the fields aren't checked by default, even though the default value for all the fields is true (via a private getter/setter setup).
Yet when I submit the form to the SearchController, all the checkboxes are set to true. So I'm a bit confused as to why it knows they should be true, yet not set the checkboxes to be checked?
Putting breakpoints in key places seems to show that the model isn't insantiated on the get requests, only the post to the Search controller?
I may be going about this all wrong, so if so, pointers as to the right way always appreciated.
public class MasterModel {
public SearchDataModel SearchModel { get; set; }
}
public class SearchDataModel{
private bool _OnTags = true;
private bool _OnManufacturers = true;
private bool _OnCountries = true;
[Display(Name= "Tags")]
public bool OnTags {
get { return _OnTags; }
set { _OnTags = value; }
}
[Display(Name= "Manufacturers")]
public bool OnManufacturers {
get { return _OnManufacturers; }
set { _OnManufacturers = value; }
}
[Display(Name= "Countries")]
public bool OnCountries {
get { return _OnCountries; }
set { _OnCountries = value; }
}
[Required]
[Display(Name="Search Term:")]
public string SearchTerm { get; set; }
}
Then in the _layout page:
#Html.CheckBoxFor(m => m.SearchModel.OnTags, new { #class="ddlCheckbox", #id="inpCheckboxTag" })
#Html.LabelFor(m =>m.SearchModel.OnTags)
Make sure you return a MasterModel with initialized SearchModel from your views:
public ActionResult Index()
{
var model = new MasterModel
{
SearchModel = new SearchDataModel()
};
return View(model);
}
Another possibility to implement this functionality than strongly typing your master layout to a view model is yo use Html.Action as shown by Phil Haack in his blog post.