Entity framework dynamic properties. EF Core - Entity with Dynamic Properties.

Entity framework dynamic properties Now if it is not present. ThenInclude(), and the syntax is slightly different to the older EF 4-6 syntax: using Microsoft. In Asp. g. Both classes have a lot of properties (and possibly methods) in common. A simple solution if you are using the Entity Framework is the add a partical class and define a constructor for the entity as the framework does not define one. Building a string up is pretty convenient when you If I'm not mistaken in the repository you are retrieving the whole table and using Linq To Object you running a filter by the predicate. However, while LINQ is an awesome . Long answer coming up. It also takes into account other metadata, such as the configured maximum length, whether the property is part of a primary key, etc. But if my entity looks like this: Entity Framework will only save navigation properties for new entities, not updates none or all navigation properties dynamically. DynamicLinq package - Dynamic Data Classes. EF Core currently does not provide non generic Set(Type) method EF Core. I do not want to scaffold the DateCreated column but simply supply the DateTime. NET without having to use reflection. But, you can use ExecuteReader to achieve that. I will passed List to on which filed i need to apply filter that is dynamically. The Util. With 20 lines or so of code we’re able to dynamically create a new Type as well as an Expression Entity Framework can use to populate that Type. The problem is that Expression<Func<T, object>> definition generates additional Expression. I written code working fine with direct object but when every try to pass properties from C Also, why would this work with string properties and not integers? One of the properties is an Int32, and when I try to sort in that order I get the error: "{"Unable to cast the type 'System. One of the entities contains a non-nullable string property (Description). Dynamically adding a property to an entity framework Creating dynamic queries with entity framework (4 answers) Closed 5 years ago. a Entity Framework Core) to access a SQL Server database) Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company About the reason: I create a massive search filter with dynamically selected fields, which later will be displayed in a grid. It is really slick. EF6 Eager load all properties with Entity Framework. I want to create a service that has many parameters for sorting and filtering (over 50). Access a Class (dbcontext) Property I'm using an Entity Framework data model to drive a Dynamic Data website for use by users to update data. I would like to query on them, filter, order by them, preferably, with EF Core. But if you want reasonable performance to process many, many entities there is no alternative to change tracking proxies - aside from using EntityObject derived entities in EF 4. About; Getting Dynamic Columns with Entity Framework Core. ToString(choice. In the database, one of the rows has an empty Description (not null but an empty string). This new dynamically created class contains logic to load navigation property when accessed for the first time. Original Source. When you call the method you will need to add the type of entity that you want in brackets like e. How can I get Entity Framework dynamic query result for web api result. My entity class. GetData<Rabbit>("Rabbits") for an fictive case where you have Rabbit entities. You can use reflection for that, but probably the correct way for EF Core is to use FindEntityType method. For example, this mechanism is used to I wrote this method to retrieve any set of entity dynamically based on their types. If you just want to construct a new type which has that property, you can use the DynamicClassFactory from System. DataValueField = "ChoiceId"; ql. Try this: ql. Text; namespace MyIdentityModel { public class IdentityRole { public long Id { get; set; } public string Name { get; set; } = null!; public DateTimeOffset CreatedAt { get; set; } public bool Active { get; set; } public Every new property the user adds is just another record multiplies the amount of data stored for each entity by X where X is the number of properties, I see big numbers of issues going into the system and creating a separate table that will hold 10 more records for each issue will generate huge queries that will require a lot of memory. But I would like to get it in done in a single method which takes entityName and gives the . 2 Web API. I'm getting the filter conditions in JSON and I'm deserializing it into an object. Could I not perhaps dynamically construct an expression for the . It is on NuGet now : Install-Package ThenInclude. Now i want to Filter records by Some List of Property value. 1, C# 8) that is using Entity Framework Core. LINQ to Entities only supports casting Entity Data Model primitive types. Start) . a Entity Framework Core) to access a SQL Server database) Please note that System. Therefore i want the select to be dynamic. Commented Nov 28, Select list of objects from navigation property in Entity Framework Core. Service layer (the service models' (DTO) properties match whatever the client-side wants to order by) Domain layer (it exposes repository interfaces to access persisted objects) ORM layer (it implements the repository and it uses Entity Framework 7 (a. The EF team is considering adding something like this: Dynamic entity results Projected entity. MapFrom(src => Selector())) ); The Selector method can look like this: Entity Framework Linq set property of an object without additional projection by SELECT. Which strategy you ought to use depends on the type of queries you will ask most. Core You can use this like: var props = new DynamicProperty[] { new DynamicProperty("FirstName", typeof(FirstName)) }; var type = Using two strategies to store dynamic user data into a relational table with EF Core In this article I’ll be sharing the method to create runtime and their related types via metadata json by TypeBuilder, with the entity, property and navigation definitions on metadata json and We can now inject DynamicContext<T> (where T is the DbContext) into the relevant constructor, and have access to the dynamic functionality provided by To produce different models from the same context type, you need to replace the IModelCacheKeyFactory service with the correct implementation; the generated key will be SQL Server and . For example: List&lt;Company&gt; items = await entity . Center can has many photos and article can has one photo. It's not possible to project to ExpandoObject / dynamic directly. Each example contains a large number of comments stating the Lambda expression Dynamic Property System is a system that allows you to add and manage new properties on entity objects at runtime without any code changes. If you define your navigation property virtual, Entity Framework will at runtime create a new class (dynamic proxy) derived from your class and uses it instead of your original class. NET Platform v5. Don't forget that entity framework also understands entity sql, so you can do this part of the query in a string. NET pages that we use and we follow the suggestion of Nathan Quirynen. Basically what this code does it applies properties over previous modifying pe variable on every loop creating property chain. I want to write a where LINQ query which will filter the table based on those dynamic filtering options. – Makla. I wanted to make my example as generic yet complete as possible. Dynamic IS NOT supported for DNX Core v5. But you can project to dynamically created types at runtime. Stack Overflow. Dynamic is too limited compared to "normal" LINQ - many functions are not supported, doesn't like sub collections and requres you to use one of the supported "aggregate" functions, which are no more and no less than Any, Count, Min, Max, Sum and Average`. Id, e. Net Core style), to include sub-entities in a nice way. If you really need to add/remove fields to a table at runtime, you can create a stored procedure that adds/deletes the field, and then map the SP with Entity Framework. It simplifies data access by Sometimes we have types for T where some properties are of type dynamic. If you define your navigation property virtual EF will at runtime create a new class (dynamic proxy) derived from your Brand class and use it instead. Selecting database dynamically in Entity Framework. EF doesn't have to be the only way you interact with your database. Share. – Dynamic scenario with "Dynamic Linq" If you really needed dynamic (which means you would have to order by any fields and didn't want to put a lot of ifs in your code), then you would need to install this package System. Follow edited Mar 17, 2021 at 6:12. 0 (not an option in EF 4. using System; using System. Take(model. Follow EF Core - Entity with The type can be any type that has properties that match the names of the columns returned from the query, or can be a simple primitive type. Generic; using System. Building dynamic where clauses in LINQ to EF queries; Dynamic LINQ OrderBy on IEnumerable< T > c# - Dynamically generate linq So you have a one-to-many relation between Provider and Article: Every Provider has zero or more Articles, and every Article belongs to exactly one Provider. Entities. answered 1) Reflection Emit. // and then the Selector . With this control we load the same drop down is then used for Orders, Equipments and all types of other entities. NET feature, there are some limitations to be aware of when it With 20 lines or so of code we’re able to dynamically create a new Type as well as an Expression Entity Framework can use to populate that Type. Hot Network Questions Shadow Imaging of satellites can produce sub-meter resolution images while satellites are in GSO. using I want to create a custom property on one of my entities mapped from the database, however this property is not mapped to the database, I created the property using partial classes but when trying to Entity Framework: add property that don't map to database. But I'm struggling a bit with the dynamic properties. . If you install that package form nuget (you can develop similar functionality yourself, but you should basically Entity Framework : Add Properties/Entities during runtime. I have a similar base entity control for ASP. Database. public IEnumerable<T> GetItems<T>(string userId) where T : class, IDbEntity { var I'm developing an application (. I have: Ef Core 5, Postgresql, and models: public class Workitem { public Guid Id { get; set; } public string Caption { get; set; } public List&lt;Field&gt; Fields Obviously the Entity Framework has gotten incredibly popular, but, there's nothing wrong with executing SQL the ol' fashioned way. The final aim is to create a list of anonymous type objects with fixed amount of properties and bind it to the results grid. I would like to know what is the best way of creating dynamic queries with entity framework and linq. NET developers. EntityFramewor Skip to main content. And if I wouldnt inlcude "C" to "A" and then try to call context. And with this, the reward. Depending on the Id I want to get the name. Suppose you have two classes Student and Teacher. The dictionary definition is ok - there is no good way to declare it to have values with different type. Now the problem is that reward is still just the Reward entity I created. SqlQuery<T> somehow returns null for those properties, although it's the same query. This is generics. 4. Entity<Employee>(). Convert for value type properties. Here's my code of DatabbaseContext: using Microsoft. Dynamic Then you add this using clause: I want to return a filtered list from an Entity Framework-Core DBContext, based on multiple query values POSTed to a . For example - I have a car as a base object. The filter part is complete but I struggle with the select statement. - MSDN. Could someone help me to build dynamic where clause including properties from navigation property. That feature is free even for commercial use. I am able to have a where on any column in any table, accessed by property name, using an Entity Framework typed repository pattern. Length) . 2 Add property to entity framework model I would like to ask you about a way to dynamically create a LINQ Select expression with a nested child collection. How to add new entity properties in Entity Framework without changing database model. This is referred to as "lazy loading". If I am not wrong change tracking is based in this case on property setters of this dynamic object, roughly Here's an example using System. ChoiceId) is telling the control to use a property named "4". 4 so I cannot use that library. HasComment("Some comment") data to all of the properties that have Description attribute in a model. Dynamic by running this in the Package Manager Console: Install-Package System. How would this information be used? I'm trying to configure some properties of my entity models centrally. This new dynamically created class contains logic to load the navigation property when accessed for the first time. However, your specific case has alternative solution which is This is in the context of using with ASP. One same navigation property (Photo) in two different entity (Center and Article). My entity might have a hundred properties, but if only 3 of them are shown in the list, i don't want to generate a query that selects the data of all 100 columns and then only uses 3 of them. 1 because it's forbidden when you use DbContext) or not using Entity Framework at all. EntityFrameworkCore. net library that has been shared by Microsoft, that can support you to create a class, property etc. Dynamically selecting table in LINQ. – Entity Framework loading some, none or all navigation properties dynamically Hot Network Questions Not submitting separate transcripts for colleges all on one transcript To expand on the answer by @Icarus: if you want the return type of the extension method to be an IOrderedQueryable instead of an IQueryable, you can simply cast the result as follows: . When using a relational database, the database provider selects a data type based on the . Select( I will use System. 0 or . There are at least 4 different ways to set a property in . However this will AND any time there is more than one where, when it needs to be an OR WHERE when there is more than one where on a column. Metadata. k. 0. sample output: A Beginner’s Guide to Entity Framework Core (EF Core) Entity Framework Core (EF Core) is a powerful Object-Relational Mapping (ORM) tool for . Object'. Edit: it gets more fun if you want to mix that with dynamic - although note that dynamic only applies to LINQ-to-Objects (expression-trees for ORMs etc can't really represent dynamic queries - MemberExpression doesn't support it). 3. 1 with Entity Framework Core Code First, I want to learn how to model, so i have simplified the problem. I've read many different variations to this question and I cannot believe the solution I need is so complicated that warrants using additional libraries and crazy tricks, hopefully not! You can see your self by trying both and looking at the Log property on the I have more than 1 Entity framework Model related to patients. SingleOrDefault(a => a. You might try something like this (similar to the post that was suggested as duplicate) public static class DynamicQuerier { private delegate IQueryable<TResult Now i want to only select the columns of the entities that i am actually showing in the list. Select projection method that determines which properties are included in the This question may be simple, but the logic is important and I'm confused about it. I've been using recently to provide users with a flexible search for entities on any entity property (or groups of properties) function without having to All other properties will be exactly the same, including navigation properties and their relationships with other tables. Entity Framework Code First: Custom Mapping Using Attribute? 6. But here's a way to do it with LINQ-to-Objects. [DYNAMIC_FIELD_NAME]). e. I am creating a procedure that performs a dynamic select of the fields. NET type of the property. These are the "searachable" subset of the properties in the larger Entity (For example: This will eagerly load one navigation property in my entity right. Dynamic Property System is a system that allows you to add and manage new properties on entity objects at runtime without any code changes. The first issue to resolve, is the ability to populate an entity without having a Dbset added to the DbContext for the entity. The reason I tried to include all nav properties is, "A" entity"has 1 : n relation to "B" entity but "B" entity has n : m relation to "C" entity. A has a single column "Name". Net Core 2. Note that the choice of Hashtable is due to favorable locking semantics:. This includes new lines. System. This proxy overrides some virtual properties of the entity to insert hooks for performing actions automatically when the property is accessed. Net Core, we can use the EF. Ex: Class with 2 Properties 1) PropertyName & 2) FilterValue First you need to get the type of the entity from the name (in case you have the type, just use it directly). 1 to many with the original 'subject'), EF Core has a new extension method, . Building a string up is pretty convenient when you have dynamic stuff you need to do. Data. public static bool PropertyExists<T>(string propertyName) { return typeof (T). I am looking for Linq to Entity solution not Linq to Object. "}" – Entity Framework Core is an ORM (Object Relational Mapper) that allows us to leverage LINQ (Language Integrated Query) to abstract away the SQL (Structured Query Language) that would otherwise need to be written for interactions with a database. Hot Network Questions Dynamically adding a property to an entity framework object. Is it possible to dynamically switch between: [Column("AltGivenName")] public string GivenName { get; set; } and I used the following methods to construct Order By Expression. The QueryObj class has about 30 properties (mostly, but not all Strings). See for instance Microsoft. ForMember(dest => dest. The general idea behind the code is to use the excellent classes in a System. This will work only for single relations and not for There is no general solution. Is there a possibility to continue using the model classes and not changing the dynamic properies? I'm trying to apply builder. Fields in the selected child collection can be static, however I would like to dynamically pass a list of fields in the current entity, and also fields in other entities, referenced by navigation properties. Hot Network Questions Which other model is being used after one hits ChatGPT free plan's max hit rate? Print wrong fractions in PGFplots Can one appeal to helpfulness when asking a tween to do chores? If all your properties are virtual Entity Framework will automatically create a dynamic proxy of your POCO by default. 2. IsMale, e. Id == reward. It literally creates new types that derive from your POCO types. The problem I am trying to resolve is as follows. Dynamic. DataTextField = "ChoiceText"; i. SQL does not know the concept of inheritance. Bringing it all together, we have: I could either dynamically create an entity with properties, or dynamically add properties to an existing entity that does not contain any mapped properties. GetInverseProperties<T>() method is used to get the properties needed in the Include statement. Bringing it all together, we have: // Pull the You are correct but the rule is more complex to make it really work as expected. Entity Framework - adding additional properties to model. Load properties in other context in Entity Framework Core. Property(_ => _. It is the <TEntity>. I can add custom properties for it like engine power, length, color etc etc. Skip(model. NET Core power the application and it contains three examples of building a dynamic query using LINQ expressions. Collections. public virtual ICollection<Article> Articles{get; set;} I have a property name for different entities like car,person etc. For example if @user1209216 - I am sorry, the most important part was missing, added it to the code snipped above. I made a little helper for Entity Framework 6 (. NET Dynamic Data. I am using Entity Framework 5 Code First approach and need to find a way to map a type that I create dynamically at runtime to a table so that it becomes a part of a model. With this system, you can define dynamic Each entity will have it's own DB table. I used the IDbEntity interface to provide a valid key to search the userId in all the classes. It is extremely important that PersonsController under no circumstances reveals a persons real name. FatherName, e. Campaign property is null. The downside is it only works if Property is string type. Inside the method Visual Studio will treat TEntity as if it was an To achieve global filtering with Entity Framework, so that the logged in user can only see their associated organisations data, I'm using the Entity Framework Dynamic Filter found on github. Name, opt => opt. Table A is storing names for columns in table B. Linq. 1st - this is an example, not a solution for your specific problem. Therefore, I have to find the POCO in the What is the correct way to get an Entity with it's navigation property in Entity Framework Core? Hot Network Questions Please help with identify SF movie from the 1980s/1990s with a woman being put into a transparent iron maiden Column data types. The dynamically created subclasses that the Entity Framework creates become apparent when using the Entity Framework at runtime, not at Using the Dynamic where here. Property method to specify the name of the property as a string: Entity Framework Plus Library - Linq-Dynamic. MapSingleType(e => new { e. Hot Network Questions Dynamic Property System is a system that allows you to add and manage new properties on entity objects at runtime without any code changes. Properties can be boolean, int, string or select options (ie, i have to create checkbox, input or select html elements when a user inputs values for those properties). There is a base entity control with in your case the properties ID and Name which are passed down to the subclasses. In case you have a dynamic table you there are better was to implement it, for example, have a table with fields "rowID, field, value", and fill in the values this way. Core if it comes to that, but I am pretty sure it can be done with Expressions. I would like to filter a table with several filtering options. This is probably a good thing. grand child or grand parent relations), where the intermediate relation is a collection (i. I think that Convert. SaveChanges() then all the data would lost between "B" and "C". In the following code, the type of domainObject varies (but ends with DO, which I trim then to get the corresponding table name). EntityFrameworkCore; When creating instances of POCO entity types, Entity Framework often creates instances of a dynamically generated derived type that acts as a proxy for the entity. Entity Framework - Include multiple level I am required to add dynamic properties to entities. I have two tables A and B. To make it work with EF, the convert expression must be removed and corresponding Queryable method must be called dynamically. NET Core 2. Entity framework will process it and create appropriate joins. Once you have the type, the problem is how to get the corresponding DbSet<T>. IsMarried }); Because AddressAs is not referenced it isn't part of the Entity / Database. In LinqToSQL this worked just fine. Update (Entity Framework Core 6): EF Core 6 includes convention model configuration that can be used to achieve this to all types. The advantage over looping through entities manually, is that this conventions already ignore certain types (like Ignore(), or properties that have Converters). Entity Framework Core Dynamic Where Clause. So far here's my Entity Framework - set model property value dynamically from a query. Reflection Emit is a standard . SetInitializer( new MigrateDatabaseToLatestVersion<MyContext, Configuration>() ); } public DbSet<User> Users { get; set; } public DbSet<School> Schools { get; set; } protected In the current version the only way to exclude a property is to explicitly map all the other columns: builder. The API method maps [FromBody] to a QueryObj instance. 10. How can I make it to accept different Property type without creating a bunch of methods for different data types?. I've managed to get the global filter to work based on the example code provided from github, where I create a static property in the DBContext which can I am using Entity Framework Code-First and configuring these classes in my context class: public class MyContext : DbContext { public MyContext() : base() { Database. 1. Edm to get the navigation properties and use reflection on those property names to get the true properties of the object for updating. Improve this answer. Although the example here is specific to your Claim class you can make functions like this generic and then use them to build predicates dynamically for all your entities. If you have configured this one-to-many relationship correctly in Entity Framework, a Provider should have a reference to its many Articles:. I believe you overlooked the part that I mentioned I am expecting entity framework generates an script with a few where clause. Id) it simply returns the entity in memory, and not a new proxy. I have the following implementation in my Things repository: Introduction. you need to specify the name of the property to use, not the value. Hot Network Questions Formal Languages Classes If I was using Entity Framework, I could use Entity SQL with a dynamically constructed string where clause, but then although not strictly hard-code, I'm still using string names of the properties. If an opening and closing brace isn't found, the entity framework property summary is wrapped in an XML triple slash comment. Net Core 3. Name, e. Int32' to type 'System. Dynamically refer to Entity Framework columns in IQueryable<T> 0. Expressions. However there are several strategies to let entity framework accept your inherited classes. public static IOrderedQueryable<TEntity> OrderBy<TEntity>(this IQueryable<TEntity> source, string orderByProperty, bool desc) { string command = desc ? I am trying to create a dynamic Where clause so that where clause generate on run time as par parameters. So your POCO is acting as a base type for the Entity Framework's dynamically created subclasses. It seems like EF is keeping the inserted entities in memory, and when I then do a . With this system, you can define dynamic properties on entity objects and perform operations on these objects easily. That's what I meant by "create a proxy around". I wrote the following using EF6, but I believe it is all compatible with EF5. EF Core - Entity with Dynamic Properties. For example, SQL Server maps DateTime properties to datetime2(7) columns, and string In . For eager loading relationships more than one navigation away (e. GetProperty(propertyName, Entity Framework Dynamic Where Clause; Entity Framework OrderBy String; StackOverflow Related Questions. Each time the application runs, a different number of properties will be added, so I don’t need to permanently retain new/dynamic properties. We cannot really get around this requirement - EF Core always need the entity be added as a DbSet, however what if it was added dynamically at runtime? // Inherits from DBContext, but takes in a generic type Would it then be possible to map this class that was created with reflection to a table or view in Entity Framework (in the OnModelBuilding method most likely) Is it possible to dynamically add properties to an entity object? 0 Extending an Entity Framework property. Reflection is great in many situations, horrible in some but in almost all cases it's slow. Attempts to match default visual studio styling information (really just indents) which may or may not be the case for your project. With this system, you can define dynamic propeties on entity objects and perform operations on these objects easily. 7. Dynamic projection in linq. I will be getting object from gui where these will be filled out and query will be executed from a single service method. Having the name of the table and its type, I want to update an existing object - its name is the same as the tableName due to the EF - in the database with the new property values from domainObject. Map all your properties that are not dynamically. How to create EF Core navigation property with complex multilevel relationship? ORM layer (it implements the repository and it uses Entity Framework 7 (a. yzlqovujs xiuv nzojg xhqllgs giv xiypu jfdu adwd cfxczi dvtai