Bypass Data Annotations validation on ASP.NET MVC 2 - asp.net

I would like to know if it's possible to bypass the validation of one property which is using Data Annotations. Since I use the model across multiple pages, there's a check I need in some, but not in others, so I would like it to be ignored.
Thaks!

You could use FluentValidation, which uses as external validator class. In this case you would implement a different validator class for each scenario.
http://fluentvalidation.codeplex.com/
Example:
using FluentValidation;
public class CustomerValidator: AbstractValidator<Customer> {
public CustomerValidator() {
RuleFor(customer => customer.Surname).NotEmpty();
RuleFor(customer => customer.Forename).NotEmpty()
.WithMessage("Please specify a first name");
}
}
public class CustomerValidator2: AbstractValidator<Customer> {
public CustomerValidator() {
RuleFor(customer => customer.Surname).NotEmpty();
}
}
Customer customer = new Customer();
CustomerValidator validator = new CustomerValidator();
ValidationResult results = validator.Validate(customer);
CustomerValidator2 validator2 = new CustomerValidator2();
ValidationResult results2 = validator2.Validate(customer);
results would have 2 validation errors
results2 would have 1 validation error for the same customer

I don't believe this is possible with Data Annotations. I know the Microsoft Enterprise Library Validation Application Block has the notion of rule sets to group validations. This allows you to validate an object on several rule sets, for instance the default ruleset and on some pages the extended rule set. Data Annotations does not have something like rule sets.
Here is an example using VAB:
public class Subscriber
{
[NotNullValidator]
[StringLengthValidator(1,200)]
public string Name { get; set; }
[NotNullValidator(Ruleset="Persistence")]
[EmailAddressValidator]
public string EmailAddress { get; set; }
}

Related

Unwanted unique constraint in many to many relationship

I'm trying to set up a Tagging tool for images. Basically I have two tables, one for pictures, and one for tags. Both are connected with a many to many setup. I can already add a single tag to a picture, and the same tag to different pictures. However, when I try to add a second tag to an image I get an exception complaining about a unique constraint that I simply don't see.
public class MediaEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<TagEntity> Tags { get; set; }
}
public class TagEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<MediaEntity> MediaEntities { get; set; }
}
public void updateMedia(MediaEntity model)
{
using (var db = new MediaContext(_dbLocation))
{
db.Update(model);
db.SaveChanges();
}
}
public class MediaContext : DbContext
{
private const string DB_NAME = "PT.db";
private string _path;
public DbSet<MediaEntity> MediaTable { get; set; }
public DbSet<TagEntity> TagTable { get; set; }
public MediaContext(string path)
{
_path = path;
ChangeTracker.AutoDetectChangesEnabled = false;
}
protected override void OnConfiguring(DbContextOptionsBuilder options)
=> options.UseSqlite($"Data Source={Path.Combine(_path, DB_NAME )}");
}
As far as I can tell my setup should create a normal many-to-many relationship, and it the database I also see pretty much this. EF automatically creates a TagTable, MediaTable, and MediaEntityTagEntityTable. But when I try to add a second tag I get this:
SqliteException: SQLite Error 19: 'UNIQUE constraint failed:
MediaEntityTagEntity.MediaEntitiesId, MediaEntityTagEntity.TagsId'.
Data from the table showing I can have the same tag on different pictures:
MediaEntitiesId
TagEntitiesId
1B48E85B-F097-4216-9B7A-0BA34E69CBFF
CF581257-F176-4CDF-BF34-09013DCEAA27
CE33F03F-5C80-492B-88C6-3C40B9BADC6C
CF581257-F176-4CDF-BF34-09013DCEAA27
523178A1-C7F8-4A69-9578-6A599C1BEBD5
0C45C9D1-7576-4C62-A495-F5EF268E9DF8
I don't see where this unique constaint comes in. How can I set up a proper many-to-many relationship?
I suspect the issue you may be running into is with the detached Media and associated Tags you are sending in. You are telling EF to apply an 'Update' to the media, but the DbContext will have no idea about the state of the Tags attached. Assuming some tags may have been newly attached, others are existing relationships. If the Context isn't tracking any of these Tags, it would treat them all as inserts, resulting in index violations (many to many) or duplicate data (many to one / one to many)
When dealing with associations like this, it is generally simpler to define more atomic actions like: AddTag(mediaId, tagId) and RemoveTag(mediaId, tagId)
If you are applying tag changes along with potential media field updates in a single operation I would recommend rather than passing entire entity graphs back and forth, to use a viewModel/DTO for the tag containing a collection of TagIds, from that apply your tag changes against the media server side after determining which tags have been added and removed.
I.e.:
public void updateMedia(MediaViewModel model)
{
using (var db = new MediaContext(_dbLocation))
{
var media = db.Medias.Include(x => x.Tags).Single(x => x.MediaId = model.MedialId);
// Ideally have a Timestamp/row version number to check...
if (media.RowVersion != model.RowVersion)
throw new StaleDataException("The media has been modified since the data was retrieved.");
// copy media fields across...
media.Name = model.Name;
// ... etc.
var existingTagIds = media.Tags
.Select(x => x.TagId)
.ToList();
var tagIdsToRemove = existingTagIds
.Except(model.TagIds)
.ToList();
var tagIdsToAdd = model.TagIds
.Except(existingTagIds)
.ToList();
if(tagIdsToRemove.Any())
media.Tags.RemoveRange(media.Tags.Where(x => tagIdsToRemove.Contains(x.TagId));
if(tagIdsToAdd.Any())
{
var tagsToAdd = db.Tags.Where(x => tagIdsToAdd.Contains(x.TagId)).ToList();
media.Tags.AddRange(tagsToAdd);
}
db.SaveChanges();
}
}
Using this approach the DbContext is never left guessing about the state of the media and associated tags. It helps guard against stale data overwrites and unintentional data tampering (if receiving data from web browsers or other unverifiable sources), and by using view models with the minimum required data, you improve performance by minimzing the amount of data sent over the wire and traps like lazy load hits by serializers.
I always explicitly create the join table. The Primary Key is the combination of the two 1:M FK attributes. I know EF is supposed to map automatically, but since it isn't, you can specify the structure you know you need.

How to require parameters in asp.net actions

How to require/validate parameters for actions. Right now I have lot of actions that looks like this (which is horrible):
public ActionResult DoSomething(string paramA, string paramB, string paramC)
{
if (string.IsNullOrWhiteSpace(paramA))
{
return JsonResult(false, "paramA is missing");
}
if (string.IsNullOrWhiteSpace(paramB))
{
return JsonResult(false, "paramB is missing");
}
if (string.IsNullOrWhiteSpace(paramC))
{
return JsonResult(false, "paramC is missing");
}
//Actual Code
}
How to encapsulte this (potentially "globally")? I know that its possible to wrap parameters to model and use ModelState.IsValid like in this post: https://stackoverflow.com/a/39538103/766304
That is maybe one step forward on same places but generally I don't that it's realistic to wrap all parameters to models everywhere (~1 class definition per 1 action method... how nice is that?).
Also this is again per action ceremony which should be handled somewhere centralized:
if (ModelState.IsValid == false)
{
return BadRequest(ModelState);
}
The easiest way to do it would be to create a model class and use [Required] attributes like this:
public class FooModel
{
[Required]
public string ParamA {get;set;}
[Required]
public string ParamB {get;set;}
[Required]
public string ParamC {get;set;}
}
And then use it in your controller like this:
public ActionResult DoSomething(FooModel model)
{
if (!ModelState.IsValid)
{
// return some errors based on ModelState
}
//Actual Code
}
If you are looking for more global approach, then i believe you could look into Action Filters and use OnActionExecuting filter and handle the validation there (haven't used that myself tho).
Here is how to do it:
How can I centralize modelstate validation in asp.net mvc using action filters?
That way your method would never be called if any of the parameters were missing.
The model annotations with [Required] [Length] and all these attributes is one of the most common ways to validate your model, specially it integrates with the Razor View engine and generates JavaScript validation as well, the same will happen if you are using EntityFramework for your back end, so this way you will have validation at the level of the UI, Controller and Data access.
You can also use Code Contracts which allows you to put pre and post conditions for your method in a nice way https://msdn.microsoft.com/en-us/library/dd264808(v=vs.110).aspx
If none of the above is still not enough, then you can add some checks in either your controller action or in your business domain service to make some business validation and return an error code if any errors found

ViewModel type architecture from Controller to View

I have a fairly complex class of Policies, of which I display a checkbox list of them, the user checks which one they want, and returns back to the server via ajax. The class is fairly complex:
public class Policy {
public int PolicyId { get; set; }
public string PolicyName { get; set; }
... another 15 properties ...
}
To display the list of checkboxes I really only need the Id and Name, so I've created a lightweight class PolicyViewModel that is simply:
public class PolicyViewModel {
public int PolicyId { get; set; }
public string PolicyName { get; set; }
}
So I then pass a List to the View and get a List back containing the selected Policies.
Another developer on my team said that he doesn't necessarily want to translate from the ViewModel to the Policy class on the Ajax call to save the selected policies, but I'm resistant to send a List of policies due to how heavy they are to send to the view, retrieving all the properties, etc.
EDIT: For clarification, on the Ajax save method, to persist to the DB, the call needs a list of the full Policy class.
What is the best way to display this list and get back the values? Is there a better way than I am proposing?
Usually, you wouldn't need a separate model when serializing to json. Simply pluck out what you need from the domain object into an anonymous object.
return policies.Select(x => new { PolicyId = x.PolicyId, Name = x.PolicyName});
on the return trip, you shouldn't have to send anything more than the Ids of the policies that the user selected. Those can be easily mapped back to your policy objects.
public Whatever PostPolicyChoices(IEnumerable<int> ids)
{
var checked = _context.Policies.Where(x => returnIds.Contains(x.PolicyId));
// snip
boom. done.
I will recommend you not to work with Domain objects in your mvc application . You must work just with ViewModels, I think this is best practice for mvc projects. Take a look at Automapper and use it in your project, this will simplify your work, so this should look something like this :
in your [HttpGet] method you will have :
var model =Mapper.Map<IList<Policy>,IList<VmSysPolicy>>(yourlist)
And in your [HttpPost] method you will have :
var domainList=Mapper.Map<IList<VmSysPolicy>,IList<Policy>>(modelList);
And in your mapping configuration you will do :
Mapper.CreateMap<Policy,PolicyVmSysPolicy,>()
.ForMemeber()//Your mapping here
and
Mapper.CreateMap<VmSysPolicy,Policy>()
.ForMemeber//mapping here

How to add custom ClientValidationRules (unobtrusive validation) for a complex type on a model?

Say I have a custom validation attribute ValidateFooIsCompatibleWith model like so:
public class FooPart
{
public string Foo { get; set; }
public string Eey { get; set; }
}
public class FooableViewModel
{
public FooPart Foo1 { get; set; }
[ValidateFooIsCompatibleWith("Foo1")]
public FooPart Foo2 { get; set; }
}
Let's say I also have custom EditorTemplates defined for FooPart:
#Html.TextBoxFor(m => m.Foo)
#Html.TextBoxFor(m => m.Eey)
And thus my view is essentially:
#Html.EditorFor(m => m.Foo1)
#Html.EditorFor(m => m.Foo2)
Server side, the validation works fine. However, no matter what I try, I can't get the rendered html to add the rule.
If I implement IClientValidatable, it turns out that GetClientValidationRules() never gets called. (I have successfully used IClientValidatable with "simple" fields before).
I also tried registering my own custom adapter by inheriting from DataAnnotationsModelValidator<TAttribute> and registering it in the global.asax with DataAnnotationsModelValidatorProvider.RegisterAdapter(...) That approach too fails to call GetClientValidationRules().
** Update **
If a add both a custom ModelMetadataProvider and a custom ModelValidatorProvider so that I can set breakpoints, I notice an interesting bit of behavior:
a request is made to the ModelMetadataProvider for metadata with a ContainerType of FooableViewModel and a ModelType of FooPart. However, no corresponding request is made to the ModelValidatorProvider, so I can't insert my custom client validation rules there.
requests are made to the ModelValidatorProvider with a ContainerType of FooPart and a ModelType of string for both the Foo and Eey properties. But at this level, I don't know the attributes applied to the FooPart property.
How can I get the MVC framework to register my custom client validation rules for complex types?
I found a solution:
First, Create a custom model metadata provider (see https://stackoverflow.com/a/20983571/24954) that checks the attributes on the complex type, and stores a client validatable rule factory in the AdditionalValues collection, e.g. in the CreateMetadataProtoype override of the CachedDataAnnotationsModelMetadataProvider
var ruleFactories = new List<Func<ModelMetadata, ControllerContext, IEnumerable<ModelClientValidationRules>>>();
...
var clientValidatable = (IClientValidatable)attribute;
ruleFactories.Add(clientValidatable.GetClientValidationRules);
...
result.AdditionalValues.Add("mycachekey", ruleFactories);
Next, register this as the default metadata provider in the global.asax
protected void Application_Start()
{
ModelMetadataProviders.Current = new MyCustomModelMetadataProvider();
....
}
Then I created an html helper that would process the modelmetata and create/merge the "data-val*" html attributes from each of AdditionalValues collection.
public static IDictionary<string, Object> MergeHtmlAttributes<TModel>(this HtmlHelper<TModel>, object htmlAttributes = null)
{
var attributesDictionary = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes);
//ensure data dictionary has unobtrusive validation enabled for the element
attributesDictionary.Add("data-val", "true");
//loop through all the rule factories, and execute each factory to get all the rules
var rules = ruleFactory(helper.Html.ViewData.ModelMetadata, helper.Html.ViewContext);
//loop through and execute all rules in the ruleFactory collection in the AdditionalValues
//and add the data-val attributes for those.
attributesDictionary.add("data-val-" + rule.ValidationType, ruleErrorMessage);
//similarly for anything in the rule.ValidationParameters
attributesDictionary.Add("data-val-" + rule.ValidationType + "-" + parameterName, parameterValue);
}
Finally, in my editor template, call the html helper (which has a model type of `FooPart1) for each complex type property, e.g.
#Html.TextBoxFor(m => m.Foo, Html.MergeHtmlAttributes(new { #class="Bar"}))
#Html.TextBoxFor(m => m.Eey, Html.MergeHtmlAttributes())
I actually ended up creating a second interface (with the same signature as IClientValidatable) that allowed me to customize rules (primarily for error messages) for the individual fields of a complex type. I also extended the helper to take a string argument that could be formatted with my custom rules.
jQuery.validator.setDefaults({
success: "valid"
});
$( "#foo" ).validate({
rules:
{
rule1: {required: true, min: 3},
parent:
{
required: function(element) {return $("#age").val() < 13;}
}
}
});
Complex types seem to hassle me for no good reason so try the Jquery validator. Depending on what you're trying to validate it might get the job done.

MVC2 and two different models using same controller method? Possible?

I don't know if this is the right way of doing this or not, but I am using Jquery and MVC2. I am using a the $.ajax method to make a call back to a controller to do some business logic on a .blur of a textbox.
I have two views that basically do the same thing with the common data, but are using different models. They both use the same controller. It might be easier to explain with code:
So here are the two models:
public class RecordModel {
public string RecordID { get; set; }
public string OtherProperties { get; set; }
}
public class SecondaryModel {
public string RecordID { get; set; }
public string OtherPropertiesDifferentThanOtherModel { get; set; }
}
There are two views that are strongly typed to these models. One is RecordModel, the other SecondaryModel.
Now on these views is a input="text" that is created via:
<%= Html.TextBoxFor(model => model.RecordID) %>
There is jQuery javascript that binds the .blur method to a call:
<script>
$('#RecordID').blur(function() {
var data = new Object();
data.RecordID = $('#RecordID').val();
// Any other stuff needed
$.ajax({
url: '/Controller/ValidateRecordID',
type: 'post',
dataType: 'json',
data: data,
success: function(result) {
alert('success: ' + result);
},
error: function(result) {
alert('failed');
}
});
}
</script>
The controller looks like:
[HttpPost]
public ActionResult ValidateRecordID(RecordModel model) {
// TODO: Do some verification code here
return this.Json("Validated.");
}
Now this works fine if I explicitly name the RecordModel in the controller for the View that uses the RecordModel. However, the SecondaryModel view also tries to call this function, and it fails because it's expecting the RecordModel and not the SecondaryModel.
So my question is this. How can two different strongly typed views use the same Action in a controller and still adhering to the modeling pattern? I've tried abstract classes and interfaces (and changing the view pages to use the Interface/abstract class) and it still fails.
Any help? And sorry for the robustness of the post...
Thanks.
You could define an interface for those classes.
interface IRecord
{
string RecordID { get; set; }
string OtherProperties { get; set; }
}
and make the method receive the model by using that:
[HttpPost]
public ActionResult ValidateRecordID(IRecord model)
{
// TODO: Do some verification code here
return this.Json("Validated.");
}
If you only need the RecordID, you can just have the controller method take int RecordID and it will pull that out of the form post data instead of building the view model back up and providing that to your action method.
[HttpPost]
public ActionResult ValidateRecordID(int RecordID) {
// TODO: Do some verification code here
return this.Json("Validated.");
}
There is no direct way of binding data to a interface/abstract class. The DefaultModelBinder will try to instantiate that type, which is (by definition) impossible.
So, IMHO, you should not use that option. And if you still want to share the same controller action between the two views, the usual way of doing that would be using a ViewModel.
Make your strongly-typed views reference that viewmodel. Make the single shared action receive an instance of it. Inside the action, you will decide which "real" model should be used...
If you need some parameter in order to distinguish where the post came from (view 1 or 2), just add that parameter to the ajax call URL.
Of course, another way is keeping what you have already tried (interface/abstract class), but you'll need a custom Model Binder in that case... Sounds like overcoding to me, but it's your choice.
Edit After my dear SO fellow #Charles Boyung made a gracious (and wrong) comment below, I've come to the conclusion that my answer was not exactly accurate. So I have fixed some of the terminology that I've used here - hope it is clearer now.
In the case above your action could accept two strings instead of a concrete type.
Another possibility is having two actions. Each action taking one of your types. I'm assuming that functionality each type is basically the same. Once the values have been extracted hand them off to a method. In your case method will probably be the same for each action.
public ActionResult Method1(Record record)
{
ProcessAction(record.id, record.Property);
}
public ActionResult Action2(OtherRecord record)
{
ProcessAction(record.id, record.OtherProperty);
}
private void ProcessAction(string id, string otherproperity)
{
//make happen
}

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