I'm currently working on a program that is being used to generate PDF's and documents. There are two different use cases, one being an automated process and the second being a manual process where data can be edited via a front-end app.
The solution has 2 Projects in it, the first for the automated part, and the second for the manual part.
However, since the two processes make use of the same data and templates, I've split the solution into two parts, this will allow me to set it up in a way in which I only need to maintain models/templates once.
My database context looks like this:
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace RefundTracker.Models
{
public class DatabaseContext : DbContext
{
public DatabaseContext()
:base("Prod")
{
}
public DbSet<Referral> Referrals { set; get; }
public DbSet<ReferralAppointment> ReferralAppointments { set; get; }
public DbSet<ReferralPayment> ReferralPayments { set; get; }
public DbSet<BankDetails> BankDetails { set; get; }
public DbSet<ReferralAppointment_History> ReferralAppointment_History { set; get; }
public DbSet<ReferralPayment_History> ReferralPayment_History { set ; get; }
public DbSet<IsInUse> IsInUse { set; get; }
}
}
In terms of projects, I have a project called "RefundTracker" and another called "MailMergeTPA".
The context provided above, together with all of the models, are located in the "RefundTracker" project.
I would like to make use of these models and context in the "MailMargeTPA" project as well.
I referenced the "RefundTracker" in "MailMergeTPA" project, however, no results when using the context here. (When I access a function that get a list of names for instance, I get the full list in "RefundTracker", however, I get no results when I use the same function in "MailMergeTPA".
Code Example:
public BankDetails GetBankDetails(Referral record)
{
string bName = record.bankName.Trim();
try
{
BankDetails bankDetails= new BankDetails();
List<BankDetails> bankDetails = new List<BankDetails>();
using (DatabaseContext db = new DatabaseContext())
{
bankDetails = db.BankDetails.SingleOrDefault(a => a.BankName == bName);
}
return bankDetails;
}
catch(Exception ex)
{
Console.WriteLine(ex.ToString());
return null;
}
I would like to make use of this exact function in both projects.
Could you kindly help me with some advice? (Please go easy on me in the comments, I'm still fairly new to EF)
I've tried referencing the project, no result.
I've read up on interfaces, however, I'm unsure as to how I would incorporate this.
We used DB-first approach to generate models in a .NET core application. DataAnnotations were put in a "buddy" metadata class so as to avoid writing in an autogenerated file. When controller calls TryValidateModel, all works well, Name property is required.
public partial class User
{
public string Name { get; set; }
}
[ModelMetadataType(typeof(UserMetaData))]
public partial class User : IValidatableObject
{
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) { }
}
public class UserMetaData
{
[Required]
public string Name { get; set; }
}
On a service layer of the app, we want to implement additional validation, that also checks if objects are valid in regards to data annotations. This is done via
Validator.TryValidateObject()
which successfully calls Validate method, but disregards data annotations - user is valid, even with an empty name.
TL;DR:
MVC (web project) knows how to consider data annotations put in a "buddy" class via ModelMetadataType attribute, service layer project does not.
I thought i have found the answer here, but it seems that
TypeDescriptor.AddProviderTransparent
does not work for .net core apps.
Any ideas would be greatly appreciated.
I really hoped for a one line solution :)
I abused ashrafs answer to his own question like so:
var metadataAttr = typeof(T).GetCustomAttributes(typeof(ModelMetadataTypeAttribute), true).OfType<ModelMetadataTypeAttribute>().FirstOrDefault();
if (metadataAttr != null)
{
var metadataClassProperties = TypeDescriptor.GetProperties(metadataAttr.MetadataType).Cast<PropertyDescriptor>();
var modelClassProperties = TypeDescriptor.GetProperties(typeof(T)).Cast<PropertyDescriptor>();
var errs =
from metaProp in metadataClassProperties
join modelProp in modelClassProperties
on metaProp.Name equals modelProp.Name
from attribute in metaProp.Attributes.OfType<ValidationAttribute>()
where !attribute.IsValid(modelProp.GetValue(model))
select new ValidationResult(attribute.FormatErrorMessage(Reflector.GetPropertyDisplayName<T>(metaProp.Name)), new[] { metaProp.Name });
validationResults.AddRange(errs);
}
In Luis, I created a simple pattern with a simple entity like this:
list bots {Name}
where "Name" is my entity that I would like to get in C#. The pattern and intent works fine and I am getting that correctly.
I follow the official example and built a IRecognizerConvert class so I can deserialize the result. It deserialize the intent just fine but fail to deserialize the entity.
In the _Entities sub-class, I only have the "Name" variable that I am trying to deserialize and nothing else. I don't have any other partial class.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Bot.Builder;
using Newtonsoft.Json;
using Microsoft.Bot.Builder.AI.Luis;
namespace EmptyBot1.Models
{
public class ChatbotIntent : IRecognizerConvert
{
public string Text;
public string AlteredText;
public enum Intent
{
CreateBot,
ListBots,
ListAllBots,
RunBot,
Cancel,
Greet,
None
};
public Dictionary<Intent, IntentScore> Intents;
public class _Entities
{
public string Name;
}
public _Entities Entities;
[JsonExtensionData(ReadData = true, WriteData = true)]
public IDictionary<string, object> Properties { get; set; }
public void Convert(dynamic result)
{
var _result = JsonConvert.DeserializeObject<ChatbotIntent>(JsonConvert.SerializeObject(result, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore }));
Text = _result.Text;
AlteredText = _result.AlteredText;
Intents = _result.Intents;
Entities = _result.Entities;
Properties = _result.Properties;
}
public (Intent intent, double score) TopIntent()
{
Intent maxIntent = Intent.None;
var max = 0.0;
foreach (var entry in Intents)
{
if (entry.Value.Score > max)
{
maxIntent = entry.Key;
max = entry.Value.Score.Value;
}
}
return (maxIntent, max);
}
}
}
In the previous snippet, the important part is the _Entities class which define how the entities look from coming back from Luis. Since I only have 1 simple string entity "Name", I thought this is sufficient.
public class _Entities
{
public string Name;
}
However when I run it and I give it an utterance like:
"list bots mybots"
Luis would correctly assign Name="mybots" and get the correct intent, but it crash on the JsonConvert.DeserializeObject line saying the json format is incorrect. I assume this is complaining about the class I made? And not the actual JSON result from luis?
What do I need to add to the _Entities class so the luis entity can be successfully deserialzied?
I know this is an old question but I'm facing the same situation now so I want to contribute with the step-by-step that worked for me.
As #ranusharao and Bill said, you need to download LUISGen from GitHub.
Start a CMD, go to your solution's directory
cd C:\MySolutionFolder
and run
luis init
if you haven't done yet.
It will ask you for your App ID and information that you get in luis.ai.
After that, go to luis.ai / Manage / Versions, click on your current version and click Export as Json.
Place your JSON file in your solution's folder.
Once you have done that, run the following command in your console:
LUISGen C:\MyJSONPath\MyBot.json -cs MyClassName -o C:\MySolutionFolder
That -cs stands for C#, but if you are usign Typescript then change it for "-ts".
So there you have it, you can access your class with something like:
var result = await _luisRecognizerService._recognizer.RecognizeAsync<MyClassName>(turnContext, cancellationToken);
Console.WriteLine(result.Entities.Producto);
_luisRecognizerService is my instance of LuisRecognizer (dependency injection)
As recommended by #ranusharao, using LUISGen tool, a class will automatically be generated that works with the bot framework.
I am working with ASP.NET MVC 5 Web Api. I want consult all my users.
I wrote api/users and I receive this:
"The 'ObjectContent`1' type failed to serialize the response body for content type 'application/json; charset=utf-8'"
In WebApiConfig, already I added these lines:
HttpConfiguration config = new HttpConfiguration();
config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType);
config.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
But it still doesn't work.
My function for return data is this:
public IEnumerable<User> GetAll()
{
using (Database db = new Database())
{
return db.Users.ToList();
}
}
If you are working with EF, besides adding the code below on Global.asax
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings
.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters
.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
Dont`t forget to import
using System.Data.Entity;
Then you can return your own EF Models
Simple as that!
When it comes to returning data back to the consumer from Web Api (or any other web service for that matter), I highly recommend not passing back entities that come from a database. It is much more reliable and maintainable to use Models in which you have control of what the data looks like and not the database. That way you don't have to mess around with the formatters so much in the WebApiConfig. You can just create a UserModel that has child Models as properties and get rid of the reference loops in the return objects. That makes the serializer much happier.
Also, it isn't necessary to remove formatters or supported media types typically if you are just specifying the "Accepts" header in the request. Playing around with that stuff can sometimes make things more confusing.
Example:
public class UserModel {
public string Name {get;set;}
public string Age {get;set;}
// Other properties here that do not reference another UserModel class.
}
Given right answer is one way to go, however it is an overkill when you can fix it by one config settings.
Better to use it in the dbcontext constructor
public DbContext() // dbcontext constructor
: base("name=ConnectionStringNameFromWebConfig")
{
this.Configuration.LazyLoadingEnabled = false;
this.Configuration.ProxyCreationEnabled = false;
}
Asp.Net Web API Error: The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'
Add this code to global.asax below on Application_Start:
Update from .Ignore to .Serialize . It must work.
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Serialize;
GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
public class UserController : ApiController
{
Database db = new Database();
// construction
public UserController()
{
// Add the following code
// problem will be solved
db.Configuration.ProxyCreationEnabled = false;
}
public IEnumerable<User> GetAll()
{
return db.Users.ToList();
}
}
I resolved it using this code to WebApiConfig.cs file
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
config.Formatters.Remove(config.Formatters.XmlFormatter);
I don't like this code:
foreach(var user in db.Users)
As an alternative, one might do something like this, which worked for me:
var listOfUsers = db.Users.Select(r => new UserModel
{
userModel.FirstName = r.FirstName;
userModel.LastName = r.LastName;
});
return listOfUsers.ToList();
However, I ended up using Lucas Roselli's solution.
Update: Simplified by returning an anonymous object:
var listOfUsers = db.Users.Select(r => new
{
FirstName = r.FirstName;
LastName = r.LastName;
});
return listOfUsers.ToList();
Adding this in your Application_Start() method of Global.asax file should solve the problem
protected void Application_Start()
{
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings
.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters
.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
// ...
}
METHOD 2: [Not recommended]
If you are working with EntityFramework, you can disable proxy in your DbContext class constructor. NOTE: this code wll be removed if you update the model
public class MyDbContext : DbContext
{
public MyDbContext()
{
this.Configuration.ProxyCreationEnabled = false;
}
}
There's also this scenario that generate same error:
In case of the return being a List<dynamic> to web api method
Example:
public HttpResponseMessage Get()
{
var item = new List<dynamic> { new TestClass { Name = "Ale", Age = 30 } };
return Request.CreateResponse(HttpStatusCode.OK, item);
}
public class TestClass
{
public string Name { get; set; }
public int Age { get; set; }
}
So, for this scenario use the [KnownTypeAttribute] in the return class (all of them) like this:
[KnownTypeAttribute(typeof(TestClass))]
public class TestClass
{
public string Name { get; set; }
public int Age { get; set; }
}
This works for me!
My personal favorite: Just add the code below to App_Start/WebApiConfig.cs. This will return json instead of XML by default and also prevent the error you had. No need to edit Global.asax to remove XmlFormatter etc.
The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8
config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
Just put following lines in global.asax:
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
Import
using System.Data.Entity;
Use AutoMapper...
public IEnumerable<User> GetAll()
{
using (Database db = new Database())
{
var users = AutoMapper.Mapper.DynamicMap<List<User>>(db.Users);
return users;
}
}
Use the following namespace:
using System.Web.OData;
Instead of :
using System.Web.Http.OData;
It worked for me
Add the below line
this.Configuration.ProxyCreationEnabled = false;
Two way to use ProxyCreationEnabled as false.
Add it inside of DBContext Constructor
public ProductEntities() : base("name=ProductEntities")
{
this.Configuration.ProxyCreationEnabled = false;
}
OR
Add the line inside of Get method
public IEnumerable<Brand_Details> Get()
{
using (ProductEntities obj = new ProductEntities())
{
this.Configuration.ProxyCreationEnabled = false;
return obj.Brand_Details.ToList();
}
}
Use [Serializable] for class:
Example:
[Serializable]
public class UserModel {
public string Name {get;set;}
public string Age {get;set;}
}
It worked for me!
Solution that worked for me:
Use [DataContract] for class and [DataMember] attributes for each property to serialize. This is enough to get Json result (for ex. from fiddler).
To get xml serialization write in Global.asax this code:
var xml = GlobalConfiguration.Configuration.Formatters.XmlFormatter;
xml.UseXmlSerializer = true;
Read this article, it helped me to understand serialization:
https://www.asp.net/web-api/overview/formats-and-model-binding/json-and-xml-serialization
To add to jensendp's answer:
I would pass the entity to a user created model and use the values from that entity to set the values in your newly created model. For example:
public class UserInformation {
public string Name { get; set; }
public int Age { get; set; }
public UserInformation(UserEntity user) {
this.Name = user.name;
this.Age = user.age;
}
}
Then change your return type to: IEnumerable<UserInformation>
While all these answers above are correct, one may want to check the InnerException > ExceptionMessage.
If it says something like this "The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.". This could be an issue because of default behavior of the EF.
By assigning LazyLoadingEnabled = false in your DbContext constructor will do the trick.
public class MyDbContext : DbContext
{
public MyDbContext()
{
this.Configuration.LazyLoadingEnabled = false;
}
}
For more detailed reading about EagerLoading and LazyLoading behavior of EF refer this MSDN Article.
In my case I have had similar error message:
The 'ObjectContent`1' type failed to serialize the response body for
content type 'application/xml; charset=utf-8'.
But when I dig deeper in it, the issue was:
Type 'name.SomeSubRootType'
with data contract name
'SomeSubRootType://schemas.datacontract.org/2004/07/WhatEverService'
is not expected. Consider using a DataContractResolver if you are
using DataContractSerializer or add any types not known statically to
the list of known types - for example, by using the KnownTypeAttribute
attribute or by adding them to the list of known types passed to the
serializer.
The way I solved by adding KnownType.
[KnownType(typeof(SomeSubRootType))]
public partial class SomeRootStructureType
This was solved inspired from this answer.
Reference: https://msdn.microsoft.com/en-us/library/ms730167(v=vs.100).aspx
I basically add one line which they are
entities.Configuration.ProxyCreationEnabled = false;
to UsersController.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using UserDataAccess;
namespace SBPMS.Controllers
{
public class UsersController : ApiController
{
public IEnumerable<User> Get() {
using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
entities.Configuration.ProxyCreationEnabled = false;
return entities.Users.ToList();
}
}
public User Get(int id) {
using (SBPMSystemEntities entities = new SBPMSystemEntities()) {
entities.Configuration.ProxyCreationEnabled = false;
return entities.Users.FirstOrDefault(e => e.user_ID == id);
}
}
}
}
You will have to define Serializer Formatter within WebApiConfig.cs available in App_Start Folder like
Adding config.Formatters.Remove(config.Formatters.XmlFormatter);
// which will provide you data in JSON Format
Adding config.Formatters.Remove(config.Formatters.JsonFormatter);
// which will provide you data in XML Format
Another case where I received this error was when my database query returned a null value but my user/view model type was set as non-nullable. For example, changing my UserModel field from int to int? resolved.
This also happens when the Response-Type is not public!
I returned an internal class as I used Visual Studio to generate me the type.
internal class --> public class
Visual Studio 2017 or 2019 is totally unthoughtful on this, because Visual Studio itself requires the output to be in json format, while Visual Studio's default format is "XmlFormat" (config.Formatters.XmlFormatter).
Visual Studio should do this automatically instead of giving developers so much trouble.
To correct this problem, go to the WebApiConfig.cs file, and add
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
config.Formatters.Remove(config.Formatters.XmlFormatter);
after "config.MapHttpAttributeRoutes();" in the Register(HttpConfiguration config) method. This would allow your project to produce json output.
In my case I solved recreating the database.
I made some changes in a model and launching Update-Database in Package Manager Console I got the following Error:
"The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK_dbo.Activities_dbo.Projects_ProjectId". The conflict occurred in database "TrackEmAllContext-20190530144302", table "dbo.Projects", column 'Id'."
In case: If adding code to WebApiConfig.cs or Global.asax.cs doesn't work for you:
.ToList();
Add .ToList() function.
I tried out every solution but following worked for me:
var allShops = context.shops.Where(s => s.city_id == id)**.ToList()**;
return allShops;
I hope, it helps.
in my case, it was fixed when I removed the virtual keyword before my navigation properties,
I mean the reference tables.
so I changed
public virtual MembershipType MembershipType { get; set; }
to:
public MembershipType MembershipType { get; set; }
Are there any ways, besides throwing exceptions, that one can go about using the partial validation methods in LINQ to SQL to cancel the insert of a record?
I can understand that you don't want to throw an exception directly after a property is set with an invalid value. This approach makes it difficult to communicate correctly to the user what actually is wrong. However, I think it's better to keep away from using those partial validation methods. IMO you want to throw an exception when your model is invalid, but only just before you're persisting your model to the database.
I advise you to use a validation framework and integrate it with your LINQ to SQL DataContext class. Here's an example of how to do this with The Enterprise Library Validation Application Block, but the concept will work for every validation framework you pick:
public partial class NorthwindDataContext
{
public override void SubmitChanges(ConflictMode failureMode)
{
ValidationResult[] = this.Validate();
if (invalidResults.Length > 0)
{
// You should define this exception type
throw new ValidationException(invalidResults);
}
base.SubmitChanges(failureMode);
}
private ValidationResult[] Validate()
{
// here we use the Validation Application Block.
return invalidResults = (
from entity in this.GetChangedEntities()
let type = entity.GetType()
let validator = ValidationFactory.CreateValidator(type)
let results = validator.Validate(entity)
where !results.IsValid
from result in results
select result).ToArray();
}
private IEnumerable<object> GetChangedEntities()
{
ChangeSet changes = this.GetChangeSet();
return changes.Inserts.Concat(changes.Updates);
}
}
[Serializable]
public class ValidationException : Exception
{
public ValidationException(IEnumerable<ValidationResult> results)
: base("There are validation errors.")
{
this.Results = new ReadOnlyCollection<ValidationResult>(
results.ToArray());
}
public ReadOnlyCollection<ValidationResult> Results
{
get; private set;
}
}
There are several validation frameworks available, such as DataAnnotations and
the Enterprise Library Validation Application Block (VAB). VAB is very suited for doing this. With LINQ to SQL your entities are generated, so you'll need to use the configuration based approach that VAB offers (don’t try decorating your entities with attributes). By overriding the SubmitChanges method you can make sure the validation gets triggered just before entities are persisted. My SO answers here and here contain useful information about using VAB.
I've written a few interesting articles about integrating VAB with LINQ to SQL here and here. The nice thing about LINQ to SQL (compared to Entity Framework 1.0) is that a lot of useful metadata is generated. When combining this with VAB you can use this metadata to validate your model, without having to hook up every validation manually. Especially validations as maximum string length and not null can be extracted from the model. Read here how to do this.
VAB to the rescue!
Ultimately this indicates that at you last line of defence (before any database constraints, at least) your data was invalid. If you want to do something other than scream loudly, then perhaps verify the data (via any of a multitude of approaches) before adding it to the insert list.
As an additional thought, you could try overriding SubmitChanges (on the data-context); obtain the change-set, verify the inserts and remove (delete-on-submit, which IIRC checks the insert list and drops them) any that you've decided were mistakes. Then call the base.SubmitChanges. But to me this is a bit backwards.
To illustrate, this only does a single insert (not two as requested), but I don't like this approach. At all. As long as we're clear ;-p
namespace ConsoleApplication1 {
partial class DataClasses1DataContext { // extends the generated data-context
public override void SubmitChanges(
System.Data.Linq.ConflictMode failureMode) {
var delta = GetChangeSet();
foreach (var item in delta.Inserts.OfType<IEntityCheck>()) {
if (!item.IsValid()) {
GetTable(item.GetType()).DeleteOnSubmit(item);
}
}
base.SubmitChanges(failureMode);
}
}
public interface IEntityCheck { // our custom basic validation interface
bool IsValid();
}
partial class SomeTable : IEntityCheck { // extends the generated entity
public bool IsValid() { return this.Val.StartsWith("d"); }
}
static class Program {
static void Main() {
using (var ctx = new DataClasses1DataContext()) {
ctx.Log = Console.Out; // report what it does
ctx.SomeTables.InsertOnSubmit(new SomeTable { Val = "abc" });
ctx.SomeTables.InsertOnSubmit(new SomeTable { Val = "def" });
ctx.SubmitChanges();
}
}
}
}