I'm trying to implement hasthags into an application. I've configured the database already and even have a layout for how I'd like the form to look, however I'm not sure if it's possible to do what I want to do with Razor pages. I have the below classes:
public class Person
{
public int PersonId { get; set; }
public string FirstName { get; set; }
public string LastName{ get; set; }
public IList<PersonTag> PersonTags { get; set; }
}
public class Tag
{
public int TagId { get; set; }
public string TagName { get; set; }
public IList<PersonTag> PersonTags { get; set; }
}
public class PersonTag
{
public int PersonTagId { get; set; }
public int PersonId { get; set; }
public Person Person { get; set; }
public int TagId { get; set; }
public Tag Tag { get; set; }
}
And would like the form to look like this, where you see this input while editing a Person. You'd add a new hashtag by typing in the input box--hitting enter there (or pressing a button--not pictured) would create the tag in the Tag table and also create a new PersonTag relationship with the Person being edited, which would be saved on form submission. I guess the Tag could also get created on form submission if that's simpler. Clicking the "x" on one of the tags should also remove the PersonTag relationship
Is this something that's possible with razor pages? To this point I've only ever done simpler inputs (either single values or select lists), but in this case I need the user to have the option to enter free text multiple times. What kind of input would I need for these? Or would I need to do entirely special handling to pull the data on form submit, and just populate the tags with Javascript when the user adds them?
Related
Sorry for newbie questions, i'm brand new to MVC and OOP
I have the following model for my USER db table
namespace MyApp.Models
{
public class User
{
public int user_id { get; set; }
public string username { get; set; }
public string password { get; set; }
public string salt { get; set; }
public string email { get; set; }
public sbyte status { get; set; }
public System.DateTime creation_date { get; set; }
public sbyte type { get; set; }
public virtual Doctor Doctor { get; set; }
public virtual Owner Owner { get; set; }
public virtual UserToken UserToken { get; set; }
public virtual Veterinarian Veterinarian { get; set; }
}
}
Actually in order to recall a particular USER based on the mail or the id i use a specific class called CustomDbFunctions
namespace MyApp.Models.DAL
{
public static class CustomDbFunctions
{
public static User GetUserEntityFromEmail(string email, DbContext db)
{
return db.Users.FirstOrDefault(u => u.email == (string)email);
}
}
}
in that way i use in my code
User user = CustomDbFunctions.GetUserEntityFromEmail(email, db)
and this it 100% OK with me, but i don't know if this kind of approach is correct or not, or if there's a better way like
//select the single user by calling only the class USER
User mySelectedUser = new User(email)
Thank you very much.
Well for understanding how to access your data in your MVC4 application you could read this tutorial from the Asp.Net MVC main page. Read the whole tutorial about MVC4 and you'll get a solid idea on how to work with it.
But I also recommend this tutorial on a good Entityframework design pattern, it's called Repository Pattern, I just a nice way to get all your code ordered (like all other patterns). Let me know.
I have a table in SqlServerDatabase. Table name is User(Id,Name,Paswd) and Im using automapper in Mvc4. Now i want only specific fields or 2 fields from the table instead of whole table, using automapper.how to do??
basically if the 2 objects have the same fields as in the little example
public class User
{
public int Id { get; set; }
public string Name { get; set; }
public string Paswd { get; set; }
}
public class UserDto
{
public int Id { get; set; }
public string Name { get; set; }
public string Paswd { get; set; }
}
You just have to ignore the field
Mapper.CreateMap<User, UserDto>()
.ForMember(o => o.Paswd, m => m.Ignore());
You can find a lot of usefull example and features here
Automapepr Wiki
I have a constructed a model using code first in C#. The model literally represents a container element for a website building application, in other words, the model defines a Div tag or some such HTML element. Like a Div tag which can contain multiple child elements, I have tried to represent this in my model, but the scaffolding to the DB, does not give me what I'd expect.
I should get a new many to many joins table, but instead I only get a single column in the DB which expects a single int data type.
Here is the model:
public class ElementContainer
{
public int ElementContainerID { get; set; }
public int PageId { get; set; }
public int? ParentElementContainerID { get; set; }
public string ElementContainerName { get; set; }
public ElementType ElementType { get; set; }
public string ElementClass { get; set; }
public PageAsset PageAsset { get; set; } // content of container
public List<ElementContainer> NestedContainers { get; set; }
}
The last line is the self-referential attribute which just appears as a column called ElementContainer_ElementContainerID
Thanks in advance!
I agree with Bahman, DB first is easier.
While I haven't tried to do what you are trying, your code looks like a self-Join that would do exactly what you describe.
This is a One-to-Many relationship. EF Navigation will pull a List of all nested children containers.
If you want to create a many-to-many relationship with EF Code-First, you should create another Entity
public class ContainerChildren
{
public int ElementContainerID { get; set; }
public List<ElementContainer> NestedContainers { get; set; }
}
this reference should help you to get the exact idea http://blogs.msdn.com/b/wriju/archive/2011/05/14/code-first-ef-4-1-building-many-to-many-relationship.aspx
I have a simple class hierarchy looking like this:
public class Top
{
public string Id { get; set; }
public string Description { get; set; }
public List<Middle> Middles { get; set; }
}
public class Middle
{
public string Id { get; set; }
public string Description { get; set; }
public List<Bottom> Bottoms { get; set; }
}
public class Bottom
{
public string Id { get; set; }
public string Description { get; set; }
}
The whole thing is saved as entity of type 'Top'. Document is designed to preserve and reflect relationships/hierarchy but half but at time I will, for example, care only about an 'Id' and 'Description' of a given relationship. So, the types of queries I'd want to run are
select all Top,
select all Middle,
select Middle where Top.Id=somevalue
select Bottom where Top.Id=somevalue and Middle.Id=somevalue
I would like the results to be transformed and returned to me like this:
public class Result
{
public int Id { get; set; }
public string Description { get; set; }
}
How can I implement TransformResults (I presume that that's the feature that can be used) to achieve this? I've read quite a few examples but all of the sudden I see parameters/values, which were not declared anywhere and as a result I don't understand what's happening.
TransformResults doesn't have access to the outside world, you can't execute logic based on the query that you run.
You can flatten this structure, sure, but unless you will create multiple indexes with different TransformResults, you can't do this.
Note that this is a strange thing to do in the first place, because it doesn't matches the standard modeling of documents as a transaction boundary.
I have a datamodel like
ModelA which contains a Collection.
ModelB contains a Collection as a backreference. That is failing because of cyclic references if I query with Include("ModelB"). Not good but I solved that via setting ModelB.List=null for each element.
The problem now is submitting a changed ModelA tree: I am adding ModelB-entities to ModelA.ModelB[]. Now the UpdateEntity function is complaining the it could not add elements of type ModelB which are declared static. The JSON deserializer is creating static arrays.
How is it possible with the combination of upshot/MVC4 to submit datamodels which are not completely flat? As it is not possible right now to create your own DTO objects where you might figure out something I am stuck now...
After investigating the error a bit better, I think the problem is the cyclic backreference:
The ModelA->ModelB->ModelA is breaking the storage of the data. "Could not add data of type ModelA to type ModelB".
As I mentioned the backreference was set to Null because the cyclic ref serialisation problem...
I hope the will be some easier way on doing more manually with DTO objects where I have mroe control.
Please see also: MVC 4, Upshot entities cyclic references for the beginning of the journey...
To solve the cyclic backreference, you can use the ignoreDataMember attribute:
public class Customer
{
[Key]
public int CustomerId { get; set; }
public string Name { get; set; }
public string Address { get; set; }
public double Latitude { get; set; }
public double Longitude { get; set; }
public virtual ICollection<Delivery> Deliveries { get; set; }
}
public class Delivery
{
[Key]
public int DeliveryId { get; set; }
public string Description { get; set; }
public bool IsDelivered { get; set; }
[IgnoreDataMember]
public virtual Customer Customer { get; set; }
public virtual int CustomerId { get; set; }
}
I posted a working solution to your problem in a different question: https://stackoverflow.com/a/10010695/1226140