I am still just a couple days into ASP.NET and WebAPI frameworks so I must be missing out something really simple.
I have a model that has a couple properties and ID (as a property, which has a private setter but that didn't help).
public long ID { get; private set; }
[Required(ErrorMessage = "Location coordinate X is required.")]
public double X { get; set; }
[Required(ErrorMessage = "Location coordinate Y is required.")]
public double Y { get; set; }
And then I have a controller method post:
public HttpResponseMessage Post(MyModel model)
When I start the project and go to auto-generated API documentation, I can see that samples include ID as an input field. I want API to ignore ID input field. I could just ignore it myself but I don't like such must-remember-not-to-use things in my code.
One option would be to create a separate model just for the input but it would mean I have to maintain two classes instead of one.
Is there any data annotation to ignore this property entirely?
Try with:
[ScaffoldColumn(false)]
The ID property will no longer be seen by the html helpers. However, the model binder might still try to move a value into the ID property if it sees a matching value in the request.
So you decorate it with Exclude to avoid property to be binded:
[Exclude]
public long ID { get; set; }
You can also , (inside your Post function) remove the property from state:
ModelState.Remove("Id"); // Key removal
if (ModelState.IsValid)
{
}
}
Related
In the tutorials I've walked through around creating an API in C#, I've gone through creating an HTTP PUT command for updating records in a table contained in a database.
The examples I've seen, essentially, I create a DTO around the fields that can be updated in that table. For example, I have a class that looks like the following:
public class UpdateTablenameDTO
{
public int ID { get; set; }
public int IsActive { get; set; }
public int IsDeleted { get; set;}
...
I then built a controller and all of the fields in my UpdateTablenameDTO appear as elements expected when I do an update.
What I wanted to know is there a proper approach to not requiring all of the elements in the Update DTO when doing the Update call? When I send my payload to include only ID and IsActive, it complained that it needed the rest of my fields. When I think this through, there could be a situation that a user is sitting on a screen with an old state but with a specific update that they want to send through (i.e. make the record inactive).
I don't necessarily want to update all of the elements, really only the specific changes, which would be the only thing I would want to send, along with the ID for identification. I suppose the way I could do this is to check if the record has changed since the user last viewed it upon updating, but I wanted to make sure I wasn't missing something obvious for this kind of scenario.
You can use Nullable value types to indicate that a property is "optional". The deserializer on the webapi side will keep the property as null when no value is provided. You can define the receiving DTO as follow:
public class UpdateTablenameDTO
{
public int ID { get; set; } // still required
public int? IsActive { get; set; } // now it's optional
public int? IsDeleted { get; set;} // optional as well
}
When you provide the JSON body as {"ID":5, "IsActive": 20} then you get an UpdateTablenameDTO instance as follow:
new UpdateTablenameDTO {
ID = 5,
IsActive = 20,
// IsDeleted = null
}
When you receive such an object, you can simply do a check against null or check the HasValue property to see, if there was a value in the request.
if (data.IsActive.HasValue) {
// do something with "data.IsActive.Value"
}
I'm building a web api microservice using Core 3. I have a class defined as follows:
public class UserSourceList
{
[JsonIgnore]
public string UserId { get; set; }
[JsonIgnore]
public string ListId { get; set; }
public string Name { get; set; }
[JsonConverter(typeof(StringEnumConverter))]
public ListTypes ListType { get; set; }
public List<string> Ids { get; set; }
public DateTimeOffset CreationTime { get; set; }
}
When the framework attempts to bind the data provided by a HTTP PUT, it will not populate the UserId and ListId fields. As a result, model binding is failing during validation and returning a HTTP 400, stating that UserId and ListId are required.
The controller's action method is defined as follows:
[HttpPut("{userId:userid}/{listId:listid}", Name = "ReplaceUserList")]
public ActionResult Replace(string userId, string listId, UserSourceList model)
{
return Ok(_listManager.ReplaceUserList(model.UserId, model.ListId, model));
}
A typical call to the API would look similar to this:
PUT /api/v1/listmgmt/abc123def456/c788f2f7b7984424910726d4a290be26
PUT Body
{
"name": "Test",
"listType": "Eans",
"ids": ["97814571867716", "9781430257615", "9780982550670"],
"userId":"abc123def456",
"listId":"c788f2f7b7984424910726d4a290be26"
}
If I removed the JsonIgnore Attribute from the UserId and ListId properties of the model, everything binds as expected.
Is it expected behavior that model binding will ignore fields flagged with JsonIgnore?
I know I can work around it by changing how my validation code works or I can split my model. I would like to understand the current behavior as it is different from what I expected and experienced with ASP.NET MVC 4 and WebApi 2.
Thanks
Short answer, Newtonsoft Json.Net is being used to deserialize the post/put body when the content type is application/json. Therefore, the userId and listId parameters are being ignored during deserialization, but evaluated during model validation.
I removed the JsonIgnore Attribute as well as all the Data Annotations, and changed to the FluentValidation package which provided the ability at runtime to configure how the body should be validated based up the type of call made.
I think the reason is because of this:
[HttpPut("{userId:userid}/{listId:listid}", Name = "ReplaceUserList")]
userId and listId are required and cannot be ignored because they are defined in the annotation HttpPut. I think you need to remove them from HttpPut's parameters and find another way to get around this.
Hope this helps!
I'm currently working on a content editor that can be used for multiple types of content, where a developer could specify their own model. For example, a model might look like this:
public class ImageWithCopyWidgetModel : WidgetModel, IWidgetModel
{
public string ImageUrl { get; set; }
public string ImageAltText { get; set; }
public string HeaderText { get; set; }
public string BodyContent { get; set; }
}
On the editor side, I have a view model that looks like:
public class EditContentViewModel<TModel> where TModel : IWidgetModel
{
public int Id { get; set; }
public string Name { get; set; }
public TModel WidgetModel { get; set; }
}
I have the binding on the GET/form display side working fine. My issue comes with getting the model binder to accept the data on the POST? I've tried the following, but each returns null for model.WidgetModel:
// Option 1
EditContent(int pageId, int id, EditContentViewModel<dynamic> model)
// Option 2
EditContent(int pageId, int id, EditContentViewModel<object> model)
// Option 3
EditContent(int pageId, int id, EditContentViewModel<IWidgetModel> model)
Note, for testing purposes, I tried explicitly setting the type of WidgetModel to a concrete class (the ImageWithCopyWidgetModel noted above) and that works.
I'm really trying to avoid having to use Request.Form here as its going to limit future plans for this implementation.
What you're wanting is not possible, at least out of the box. On post, all the modelbinder has is a bunch of key-value pair string. What informs its decision about how to bind those values to something useful is the action param(s). Specifically, it has no way of knowing that it should actually create an instance of ImageWithCopyWidgetModel when you're binding to EditContentViewModel.
Also, the modelbinder is designed to discard values it doesn't know what to do with. That means that it's unfortunately not even possible to cast to ImageWithCopyWidgetModel after the fact, because all properties not present on EditCopyViewModel would have been discarded by that point.
Your best bet is a custom model binder, but the implementation of that is too broad for the scope of Stack Overflow. I suggest you refer to the documentation.
I have an ASP.NET MVC 3 project that uses .Net 4.0 Framework and Entity Framework 4.4. I am using the code first w/ migrations approach for the Entity Framework.
I have an object A that has a property of object B. object A really just needs to know the id for object B, but MVC is enforcing all annotation validations on object B as I've marked it required in object A (which it is). ModelState.IsValid is always returning false because some validations are failing on object B when the form is submitted.
Example:
public class FormField
{
public int Id { get; set; }
[MaxLength(50)]
[Required]
[DisplayName("Field Name")]
public string Name { get; set; }
[Required]
public Form Form { get; set; }
}
public class Form
{
public Form()
{
Fields = new List<FormField>();
}
public int Id { get; set; }
[Required]
public string Name { get; set; }
public List<FormField> Fields { get; set; }
}
This isn't a problem when editing an existing FormField as I can just put a hidden field with the Form.Name property on the page (this still strikes me as something that should be unnecessary). The issue arises when creating a new FormField. I display a drop down list of forms (this is populated from my view model), and make that field point to the FormField.Form.Id property. ASP .NET MVC is still expecting formField.Form.Name (as this was marked as required on the Form object).
If I remove the "[Required]" annotation from the Form field of the FormField object, the validations wouldn't fire, but this would make the foreign key to Form.Id nullable in the database, which it shouldn't be.
Any thoughts? I'm probably doing something wrong here but I'm not entirely sure what.
I removed the [Required] annotation on FormField.Form. That didn't fix the issue. I tried adding "[Bind(Exclude = "vm.FormField.Form")]" to the parameter being posted. This stops the binding, but ensures I'm still left with the validation errors in ModelState.
Ultimately, I had to do:
ModelState.Remove("FormField.Form.Id");
ModelState.Remove("FormField.Form.Name");
And this prevented the ModelState errors I was getting. As I really only need the Form.Id, I had a property in my ViewModel "SelectedForm" and use this property for that value.
So...this works, but...this seems a pretty tedious solution as if I had more required fields on the FormField.Form object, I would have to list each one as well as hard code the property name in a string form.
Can anyone think of a way to refine this approach?
Maybe you could remove the [Required] attribute and instead use the EF fluent API to configure this:
modelBuilder.Entity<FormField>().Property(ff => ff.Form).IsRequired();
I'm new at ASP.NET MVC web framework. My database is compound of a single model class("Movie"). I need to validate user's from entering existing data, for instance, a database row could be:
Title - "Indiana Jones and the lost Arc"
Price - $10.00
If another user tries to insert into the database the same data above, provide an error message and prevent from submitting the form collection.
First of all, I think that your question need a "program as answer" but I'll try to suggest you from where to start for working with validation. Suppose you have this model:
class Movie {
public Guid Id { get; set; }
[Required(ErrorMessage="Title is required.")]
[Remote("UniqueTitle", "Validation")]
public String Title { get; set; }
[Required(ErrorMessage="Price is required.")]
public float Price { get; set; }
}
You can decorate it for "simple validation" using Data Annotation. I've used a specific attribute, called Remote.
This attribute allow you to define a custom, server-side, logic to validate the model.
Now, you can create a validation controller where check that provided value is not already in use:
class ValidationController : Controller {
private IDbContext db = ...;
public ActionResult UniqueTitle(String title) {
var item = db.Movies.FirstOrDefault(m => m.Title.Equals(title));
return Json(item == null, JsonRequestBehavior.AllowGet);
}
}
Now you are ready to validate your model.
I hope this can help.