I let VS create my model from existing SQL tables using EF 4.3.1. Because the DB tables are not final and may change I don't want to set the validation attributes directly into the model file because it gets overwritten when I update the model.
I want to use the MetadataTypeAttribute approach described here:
Update Model From Database (Database First)
So I created an external file containing this class:
using System.ComponentModel.DataAnnotations;
namespace PDB.Models
{
[MetadataTypeAttribute(typeof(t_scriptingMetadata))]
public partial class t_scripting
{
}
public class t_scriptingMetadata
{
[Required]
public int platform {get; set;}
[Required]
[StringLength(20)]
public string Projectname {get; set;}
}
}
Unfortunately I get these errors in VS:
Duplicate EdmEntityTypeAttribute attribute
Duplicate Serializable attribute
Duplicate DataContractAttribute attribute
My model that has been generated by VS has exactly these attributes the error message mentions:
[EdmEntityTypeAttribute(NamespaceName="CAWI_STDMGTModel", Name="t_scripting")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
public partial class t_scripting : EntityObject
{
//...
}
What am I doing wrong?
Your t_scriptingMetadata class have to be into t_scripting not necessarily
[MetadataTypeAttribute(typeof(t_scriptingMetadata))]
public partial class t_scripting
{
public class t_scriptingMetadata
{
[Required]
public int platform {get; set;}
[Required]
[StringLength(20)]
public string Projectname {get; set;}
}
}
And both partial classes must have same namespace.
Hope this help.
Regards
I have found the problem. I had a table in my model that actually is a view containing fields from another table that was also in my model. So the error messages were indeed right. Thank for your help, vfabre!
Related
I have two database classes as defined below:
public class TopDate
{
[Key]
public int DateId { get; set; }
public DateTime Date { get; set; }
}
public class TopSong
{
[Key]
public int SongId { get; set; }
public string Title { get; set; }
public int DateId { get; set; }
}
where DateId is foreign key to TopSong
I am creating a controller through which i can create, delete or edit these database values.
When i right click on controller class and add controller i can only select one of the two classes defined above. Is there a way to make 1 controller to handle database updates to both these tables on one page?
Error Image:
Your controller should not be dealing directly with domain objects (meaning those things that are directly associated with your database). Create a ViewModel that contains the properties that you need, use your service layer to populate the ViewModel and your controller will use that as the Model for its base. An example of your ViewModel could be something like the following given your description above:
public class MusicViewModel
{
public int SongId {get;set;}
public string Title {get;set;}
public IEnumerable<DateTime> TopDates {get;set;}
}
This view model would contain a list of all dates that a specific song was a Top Song.
The objects you showing (code) are database classes (so called domain objects).
What you need to do is to define a view model, a standard ASP MVC practice:
you define a class, that is tailored for specific view and only containing data relevant to that particular view. So you will have a view model for a view that will create a song, another that will update it etc.
Actually situation you describing is classical situation to use view models. Using domain objects in the views, however, is really really bad practice and prone to more problems than you want to deal with.
Hope this helps.
I recently just learned about putting your data annotations in a new partial class so that they persist on edmx updates from the database.
Database-first approach and modifying the database schema
Update Model From Database (Database First)
In one of my models I have two attributes: firstName and lastName.
I had created a virtual property for full name seen below.
public virtual string fullName { get {return firstName + " " + lastName; } }
The fullName property works when it's in the edmx generated .tt model class, but when I put it in my "buddy" partial class that hold my annotations, it doesn't work (ie isn't recognized by the rest of the app as an attribute of my class).
How do I get a aggregate virtual property like the fullName property above that won't be overwritten by a database update to the edmx?
I figured it out. The accompanying partial class for data annotations has a classMetaData class that you use to set the Meta Data for your partial class (ie your annotations go here). The aggregate attribute has to go in the partial class though (not the Meta Data class).
So the second partial class code should look something like this:
namespace MyProject.Models
{
[MetadataType(typeof(PersonMetaData))]
public partial class Person
{
//this is where you put new aggregate properties
public virtual string fullName { get { return firstName + " " + lastName; } }
}
public class PersonMetaData
{
//this is where you put data annotations
[Required]
public string firstName { get; set; }
[Required]
public string lastName { get; set; }
}
}
I am developing MVC application in which , I am trying to create the partial class of class generated by MVC application lets say Location class.
Now I want to create the partial class of Location class in new class file.
The below class code is auto genrated by MVC of Location code.
namespace CRM
{
public partial class Location
{
public int Id { get; set; }
public string Name { get; set; }
public string Remark { get; set; }
}
}
I have added new class file which contain the partial class of above file
namespace CRMEntities.Partial_Class
{
public interface ILocation
{
[StringLength(50, ErrorMessage = "Region can accept maximum 50 characters.")]
string Region { get; set; }
[Key]
int Id { get; set; }
[Required]
string Name { get; set; }
string Remark { get; set; }
}
public partial class Location : ILocation
{
}
}
Its giving the below error...
CRMEntities.Partial_Class.Location' does not implement interface member 'CRMEntities.Partial_Class.ILocation.Name
First, you don't need to do this, what I understand is you are trying to do validation right? Think about, the object generated by EF is not ViewModel, they are domain model. Data annotation should be in View Model, not domain model.
Most of cases, often mis-use is to use domain model as view model, but it is not correct much. Because sometime, view models need more than one domain model to provide data for your UI.
So for separation of concerns, you need to define your View Model different with domain model.
Example: you have Location class, you need to add LocationViewModel class and put data annotation in here.
You can map manually or use AutoMapper for mapping bettween View Model and Domain Model.
Another solution is you can use Fluent Validation, with this way, needless to have more partial class just for validation.
You don't show the definition of ILocation in your question, but the error says that the Location.Name property is declared differently than the ILocation.Name member.
Edit: Your two partial classes appear to be in two different namespaces, hence they are actually two entirely different classes, not two parts of the same class. That would explain the compiler error.
Having said that, I do agree with the other answer (+1!) that you should do your UI validation on a view model instead.
I am working on an mvc3 application and having some problems with getting validation to work as I want.
The application is using buddy classes for the models. (This is something I haven't used in the past and I am a little confused why they are used...anyway)
I want to add required fields to ensure data been submitted is correct. I have tried adding the required field to the buddy class.
When I submit the form no client-side validation takes place and the debugger steps into the entity frameworks generated code. Here is complains that the fields that contain null values are causing are invalid. If I step through all of those it finally gets to the controller where my if (ModelState.IsValid) is showing false.
I have client-side validation switched on.
Am I meant to be applying the data validation at the buddy class level or at the view model?
One other question is why use buddy classes? to me they seem to over complicate things.
Updated added an example of the buddy class
[MetadataType(typeof (CustomerMetaData))]
public partial class Customer
{
public string Priorty
{
get
{
var desc = (Priority) Priority;
return desc.ToString().Replace('_', ' ');
}
}
internal class CustomerMetaData
{
[Required]
[DisplayName("Priorty")]
public string Priorty { get; set; }
Buddy classes are metadata classes to put data annotation attributes when you are not in control of the original class i.e. can't edit it. Typical situation is when the class is generated by an ORM like Entity Framework.
//Can't edit this class
public partial class YourClass{
public string SomeField {get; set;}
}
//Add a partial class
[MetadataType(typeof(YourClassMetadata))]
public partial class YourClass{
}
//And a metadata class
public class YourClassMetadata
{
[Required(ErrorMessage = "Some Field is required")]
public string SomeField {get; set;}
}
are you sure that you have [MetadataType(typeof(YourClassMetadata))]?
More about buddy classes here and here
You would typically use a buddy class when it isn't possible to add meta data to an entity class such as when a model is automatically generated by an ORM tool. In this case any meta data you had applied would be lost.
Therefore, your original (automatically generated) class would be defined as a partial class:
public partial class Customer
{
public string Priority { get; set; }
}
And then you would generate your buddy classes to add the meta data.
[MetadataType(typeof(CustomerMetaData))]
public partial class Customer
{
}
internal class CustomerMetaData
{
[Required]
public string Priority { get; set; }
}
You would then pass the Customer class to the view where the Priority would be set.
In your case i'm not sure if you only have one partial class or two (as the other is not shown but please provide if there is). I'm interested to know how you obtain the priority information from the customer as i'm wondering if this is an issue with how you use ModelState.IsValid? The reason I ask is that no set accessor is declared on the Priority property so i'm wondering how this is set from the view in order to report that it is not valid?
You would also use a buddy class when it isn't possible to add meta data to an entity class such as when a model is automatically generated by an WCF Data Contract.
I used LINQ to SQL to generate a dbml file which contains the database model for my database table. I want to use UIHint to let MVC present some fields as DropDownLists or Checkboxes in edit mode. But if I change the file, it will be lost if it's been regenerated. How should I solve that issue? I'm quite new to MVC and still learning. I've set up a controller with views for all CRUD elements, but now I'm finetuning and I'm running into this problem.
Since Linq-to-SQL auto-generates partial classes, you'll need to create a partial 'buddy class' where you will add your Data Annotations. Your buddy class mirrors portions of the auto-generated class that you need to modify. You tie them together with [MetadataType(typeof(BuddyClassName))] The partial buddy class and the auto-generated partial class will be merged together when you compile your project.
In an example given that:
Your namespace is "Project.Models"
Your Linq-To-Sql class is called "Products"
using System.ComponentModel.DataAnnotations;
namespace Project.Models
{
[MetadataType(typeof(ProductsMeta))]
public partial class Products
{
// You can extend the products class here if desired.
public class ProductsMeta
{
// This is a Linq-to-Sql Buddy Class
// In here you can add DataAnnotations to the auto-generated partial class
[Key]
public int ProductKey { get; set; }
[Display (Name = "Product Name")]
[Required(ErrorMessage = "Product Name Required")]
[StringLength(255, ErrorMessage = "Must be under 255 characters")]
public string ProductName { get; set; }
[UIHint("MultilineText")]
public string Description { get; set; }
}
}
}
These articles were very helpful:
ScottGu: ASP.NET MVC 2: Model Validation
How to: Validate Model Data Using DataAnnotations Attributes
Validating with Data Annotation Validators
If you are going to use the entities directly you should create a partial class and add your annotations there. This way when the model is regenerated you will not lose your annotations.