C linq select dynamic columns. Using Dynamic Column Names in a Linq Query.

C linq select dynamic columns The way that most (at least relational) databases work, is that they try to cache the most frequently used queries. 6. LINQ Select Dynamic Columns and Values. net C# web application; i have an in-memory datatable named 'table1' having three columns 'country', 'productId' and 'productQuantity'; i want to pivot that table in order to obtain a new table (suppose 'table2') having the first column 'country' as a fixed column and a dynamic number and names of columns 'product_1', 'product_2', , 'product_n' I am trying to figure out how to dynamically specify the properties for my select clause in a linq query. e. 0, there's no dynamic typing in the language. C# Linq SQL select Multiple columns to List. Count") . 2. Share. Categories select c. User() object in the query (rather than a dynamic object), which Linq To Sql doesn't allow, but regular Linq on lists does. (from data in myList select new {DName = data. Key, // CampaignID is not populated here. 72. Hot Network Questions How the Rectocrus walks Stuck bit in a ROM data bus, any method to avoid to desolder all memories connected to that line? Can US employers run credit checks on new hires? When measuring leakage inductance using the short method, are you measuring the sum of the primary and C# 7. CategoryId, m. Dynamically building a LINQ by adding a Where clause or OrderBy clause coming from user input is a very common scenario. I was starting to get the hang of the Expression Tree stuff when I had the idea of using a few NuGet packages (ExpressionTreeViewer was great) that allow you to see a decent debug view of the expressions/tree to see how a linq query put together an expression Disclaimer: I've solved the problem using Expressions from System. So, in my LINQ section I should actually pass variables that hold column names to both group by and aggregate clause. ProductGroupName == productGroupName && c. ModifiedDate }) you're selecting so C# can create an anonymous type for you. 3. You can use a dynamic string expression to select a specific column. DataTextField = I tried finding the Column using the name string in a LINQ. public IOrderedQueryable<ProductDetail> GetProductList(string productGroupName, string productTypeName, Dictionary<string,List<string>> filterDictionary) { var q = from c in db. The following shows the syntax of the Select() method: Dynamic select expression to a compile time known type can easily be build using Expression. (on of the 100 Column) } But in reality, I need to avoid using an anonymous type because it is readonly and select all the properties/columns on my "transaction" item. Dynamic. SaveChanges(); Dynamic Select EntityFramework and System. Run it 1000 times with different values, and other LINQ Dynamically Select Column From Column Name. Entity Framework - LINQ - Dynamic Column Names. Join(db. Database. GetTable<Person>() . Entity Framework: generate dynamic where clause and select custom columns 在大多数 LINQ 查询中，查询的一般形式是在代码中设置的。 可以使用 where 子句筛选项、使用 orderby 对输出集合进行排序、对项进行分组，或者执行一些计算。 代码可能会提供筛选器参数、排序键或查询中的其他表达式。 In any case someone still needs grouping by dynamic columns without Dynamic LINQ and with type safety. Children. I assume that you use distinct like a method call on a list. For instance, if I have a table: The user may request a 1, 2, or more columns and the columns that they request may be different. Dynamic I tried to add it to my solution but unfortunately I already use EntityFramework. – Hello I need to select a column in my query with the name stored in a string variable, something like: string day = "Monday"; result = from w in DataContext. Where(String. Select property by string name using LINQ. For more examples, see this link. Entry(DBobj). Creating a LINQ select from multiple tables. Linq To SQL Select Dynamic Columns. c3 }) And to get the top 50 just use. 0. Entity Framework Core Dynamic Where Clause. Improve this answer. Summary: in this tutorial, you’ll learn how to use the LINQ Select() method to project each element of a sequence into a new form. Distinct(); I think this solves your problem To select the 3 columns in linq just use this. TargetDateFrom==d1 && c. AsQueryable(); foreach (var table in tables. Item1, f. Viewed 205k times 54 . Any ideas? (Before you knee-jerk mark this as a duplicate, know that I did a fair amount of StackOverflow research before posting this question, and if this exact question has been I am trying to get the some specific fields from dynamic object with is actually a list of any class, this class contains various fields out of those fields I want to select some specific fields using LINQ, The fields which I want to select is also passing by the user. * Dynamic column support in querying. Its not really the best scenario if you have to waste a bunch of time figuring it out. c1,x. ToList(); so i'm looking to make select part dynamic . Dynamic string in linq c#. and about your question, if you insist on to use reflection, you have to fetch all of your data from data base first However, the past few versions of . The Select() method is a LINQ extension method. If you create a Filter object that contains criteria for Linq that normally goes in a where clause like this: var myFilterObject = FilterFactory. At run time, the end user will be specifying which properties they would like to see for those employees, so I need to be able to dynamically construct my Linq select clause. We will explore different techniques for creating LINQ queries at runtime, as well as discuss the advantages and potential pitfalls of using dynamic List<MyTable> liDeatil = Db. Also, it supports joining on nullable keys (for both 'Left' and 'Right'). Dynamic Table Query. public class Car { public int Id { get; set; } public string Name { get; set; } public string Brand { get; set; } } Dynamically select column name using Linq to Entities (EF6) 2. Commented Jul 28, 2016 at 14:38 var q = from c in db. . Name == name) . For example: List&lt;Company&gt; items = await entity . ToList(); } You can then call it and retrieve data from it like so: We can tell because there are no specified properties in the Select. var items = listObject. What I have tried: how I can Write an sql string and execute it like EXECUTE You can do this with dynamic code gen (though that could be a bitch) essentially generating the data model class on the fly with the relevant column names and types. Column1, Short answer is to add library System. indeed this solution still had the same problem with the string column names, but this one works with linq to entities. Intersect. Basically I have a bunch of dropdownlists that apply groupings and I don't want to enumerate every combination of groupings. ToList(); From liDetail i want to select column dynamically such as . Child_ID, t2 => t2. Column2, Extra = p. You might filter items using a where clause, sort the output collection using orderby, group items, or perform some computation. And although (and obviously) a working answer would do fine, a 1 Extend Select method of dynamic linq to support generic types. I'm using DynamicLinq on my Net Core Web API. khaled bash 6 Reputation points. However I can't simply use LINQ answers others have suggested, as I don't know columns I have before runtime - user selects them. Related. NET/C# have expanded the role of dynamic objects such as the ExpandoObject and I am wondering if there is a way to basically do this: var listOfFoo = myData. If you run that again, but pass ‘myvalue2’ then that gets cached. id, c. * update release notes and fix implementation * Revert changes to linq2db and move fix to a test * formatting * fix build * Dynamic columns. MCTargets where c. FirstName }"); I'm writing an asp. For various reasons I need to be able to allow the user to select an item from a database based on their choice of columns and values. you can not use this x. 1. Modified; db. Where(e => e. I have looked at these: Create dynamic LINQ expression for Select with FirstOrDefault inside; Linq access property by variable Using a dynamic LINQ library we can do the following, Select statement at runtime (pass select statement as string) Where condition at runtime (pass where statement as string) Here in this article we will first see what happens without using a dynamic LINQ library if we are passing a SELECT Statement at runtime. Use LINQ Dynamic with other methods. However each column will either have an Aggregate function or be included in the group by. var distinctValues = dsValues. The problem is that, if you do something like the query above: “select * from MyTable where Field1 = ‘myvalue’”, that gets cached. Lets say I have Entity company with 15 properties I want to do something like this . This C# example uses the LINQ Select method with a dynamic expression to produce a sequence of just the names of a list of products. ToExpandable() where expr. Is it possible to select dynamic column name with linq. I just can't figure I'm looking for a way to return a dynamic column list from a LINQ join of two datatables. 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. I I am creating a procedure that performs a dynamic select of the fields. In this article, we will dive deep into building dynamic LINQ queries in C#. 0 Dynamic linq query with join. You need to use the result of the query as datasource for your DropDownList, for example by materializing it via ToList. The LINQ SelectDynamic projects each element of a sequence into a new form. But I want specific columns from list in following process. Dynamic Linq Select from String Value. Dynamic as a reference and do: string columnName = "Supplier"; var s1 = Suppliers . AsEnumerable() . List<DashBoard> dashboardlist = (List<DashBoard>)objList; string strColumns = "RecDate,ModifiedDate"; objList = (from obj in dashboardlist select new { strColumns } ). Start) . g. Skip(1)) var joinType = "inner"; query = query. In most LINQ queries, the general shape of the query is set in code. ToList(); } Hi all I am trying to do a very simple dynamic query which will select a column dynamically i. Through this getting started about how to use LINQ Dynamic, we have seen a few methods, Expression — Dynamic Linq expression to select the data The columns will have a Name, Linq Expression, Display Order (since the dictionary results won’t be in any particular order), and a var query = from c in _context. 1 Dynamically select columns in LINQ statement. CategoryName}) . You can feed this IQueryable extension method an anonymous object containing all properties that you might ever want to group by (with matching type!) and a list of property names that you want to use for this group call. I've tried this post Dynamically select columns in runtime using entity framework but it works only for a single record not for a list. Net Core - System. Dynamic LINQ GroupBy Multiple Columns. The problem like I said it that the types are dynamic and the customers are dynamic so I need the columns to be dynamic depending on the types in the system But that's not really a clean solution. AddCondition("Salary", "lessThan", "40000"); var myResult = myRepository. Even though this statement looks more complex it’s only three lines and looks somewhat like a SQL statement. Name,myPlace= data. See first answer here. Result Numbers + 1: 6 5 2 4 10 9 7 8 3 1 Select - Simple 2. 5. costumers select new {c. NET, and is one of the most used features for ORM, such as Entity Framework, but it lacks the flexibility to create a dynamic query. LINQ is a great addition to . ToList(); //1 being the catno parameter obviously } } I definitely DO NOT want to use the Dynamic Linq library as it is not type safe. tblTable . Creating a LINQ Select expression dynamically from string column names. We've already written an extension method that takes an IQueryable<T> and using expression trees applies a filter based on the an array of visible columns. var distinctCategories = product . If you want to avoid this anonymous type here is the simple trick. prop2 }); 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 How to create a LINQ group by query with dynamic columns? Ask Question Asked 2 years, 10 months ago. If I know the columns I need to select beforehand, I can use the answer from David Hoarser at Select distinct rows from datatable in Linq:. it adds them to the end of the existing LINQ Group By a Single Column . Persons . The Dynamic LINQ library is an open-source library that simplifies the process of building dynamic LINQ As a follow up- going down this road helped me out to figure out how to get it done with the Dynamic Linq library. Bind method. WW XXX YYYY 1 A B 2 A B 3 C C 4 C This can be achieved by using Dynamic Linq. LINQ Dynamically Select Column From Column Name. name, cr But your case might be simpler if you always select a string column, do you? – Ivan Stoev. From the 100+ columns 2 Columns will always be there and there will be one more column from the 100+ column. Lets say I have a collection of employee objects. Ask Question Asked 16 years, 8 months ago. Select(x => new { x. how to get all columns from a linq result with a join. Dynamic namespace so they are above is working fine to return columns from list using LINQ. how to get value of a definite Column name in c# / How Create linq query select dynamic custom fileds. Take(1). Caching. string column = 'dob'; // This is dynamic var data = ctx. RecDate, obj. I'm trying to use LINQ to SQL to select a few specific columns from a table and return the result as a strongly typed list of objects. 0 I want to reformat the data without going back to the database and in a dynamic way So that the user can LINQ to Entities does not recognize the method 'System. If you can wait to get your data into C#, you could use LINQ to do this. So it could return columns 'a,b,c,d,e' or it could return columns 'a,b,c,g,m,n' - the first three columns are set, but then there could be any number of additional columns. [Silver], [Gold], [Platinum], [AnotherOne] from ( select c. This LINQ statement will be translated into this SQL statement: How do you plan on using objList?I hope you realize it won't be as simple to access the properties as when you statically define the columns (select new { obj. I found an interesting approach here enter link description here that allows to dynamically generate an object[] array with the columns to be fetched. The Select() method projects or transforms each element of a sequence into a new form. SingleOrDefault(); Unfortunately, this doesn't work. In my c# EF Core 6 application I am looking for a solution to dynamically choose the fetched columns in the SELECT statement. Customers. Columns. Payment, x. Fix #744, fix #507 * [WIP] Dynamic columns * Dynamic columns support in (fluent) metadata. I hope this article convinced you that there is quite reasonable way for building queries dynamically at runtime in LINQ, which is much safer and less error-prone than building a string. IQueryable: Project columns by their names in linq dynamically at runtime. The code could look like: var result = context. While linq is a poor tool choice for this requirement, you should change the select to return all columns. for example if I want to have a DataTime which has 31 days for example be the column names. ProductDetail where c. Column name and search_parameters are unknown they are passed from front end via ajax. Entity Framework - only get specific columns specified dynamically from list. Select(m => new {m. It might be easier to simply keep using the full DashBoard objects and only read the properties specified How can I make Select predicate dynamic to include the specified no of columns of an entity based on user page mode. I have already studied and discarded: C# LINQ list select columns dynamically from a joined dataset. [MyTable]"). Reflection. The Dynamic LINQ library let you execute query with dynamic string and provide some utilities methods such as ParseLambda, Parse, Dynamic Select; Dynamic Where Clause Read More using (var context = new EntityContext()) { var query = context. Linq. Using your example, you could then do something like: IQueryable<Person> query = context. Select("new(Key, Sum(NumberOfReads) AS TotalReads)"); Here is a quick sample of how you could select any two columns using Linq to DataSet: public static void SelectRandomColumns(DataTable dataTable, string col1, string col2) { // Select into an anonymous type here, but you could // select into a custom class var query = from row in dataTable. The SQL would How to perform a LINQ where clause with a dynamic column. GetType() in linq query, because it will not be translated to expression tree, only methods can be used in linq which your provider can translate them to expression tree to run on Data Base side, you can read more about these, from post i added (). Learn the System. This query works great: LINQ join to return dynamic column list. add dynamic anonymous object into linq The Dynamic LINQ version from GroupJoin works the same as the normal strongly typed version of GroupJoin. * Support for materialization of dynamic columns. I want to reformat the data without going back to the database and in a dynamic way So that the user can specify what columns he wants to collect. Select(e) . FirstOrDefault(); DBobj. Modified 2 years, In case you want to use a dynamic linq query for this, you can use System. ColumnName} Inside Method A i want to specify which columns to select, so i dont get all columns right away, like this: query. Where("Orders. ToList(); DropDownList1. How to select DataTable columns with string array 'LINQ' Mansour_Dalir 2,036 Reputation points. Follow answered Feb 6, 2020 at 0:58. Expressions, but I'm still looking for a better/easier way. 89+00:00. Take(50) (System. Table where w. How to use Entity Framework to query a table having dynamic columns? 0. Place}). Customers . This is the Model. – PaulVrugt. ProductTypeName == productTypeName // insert dynamic filter here orderby What's Dynamic LINQ. Basically, a dynamic Select Statement in SQL where the FROM column is a variable defined by the user. OrderBy("Orders. 526 11 Try it online. Let’s say that we just want to group by the names of the Categories, so that we can get a list of them. DataSource = distinctCategories; DropDownList1. GroupBy(). Select(x=> new { x. Julius Limson Julius Limson. 2 Use the Select method (very similar to first line of dahlbyk's answer) Select<dynamic>("new (Key as Group, Sum(Value) as TotalValue)") If you need multiple columns, you can use following: GroupBy(@"new (Fund, Column1, Column2)", "it"). ToList(); Above statement i want get two columns I would like to ask you about a way to dynamically create a LINQ Select expression with a nested child collection. Linq-to-SQL select many columns. MarketingCampaignID into g select new MSReport{ CampaignID = g. The main purpose is to select data based on multiple columns filtered by OR. As of C# 3. Remove( pivotValue. ColumnName ); for example it works for the most part but not what and or how I would have expected. Using the Dynamic LINQ Library. With the help of another post I was able to return 1 column for a different application in the program, and I figured I could apply the same process here, but I'm not seeing how to allow the user to select multiple columns within the same query. So, I would select col X if condition 1 and Y if condition 2. Translating an SQL query with multiple tables and joins to a LINQ query. You can map the Stored Proc in Linq to Sql and it will just return the value you request. State = EntityState. Github issue): // declarative query syntax var result = from x in inMemoryTable group x by (x. Take(model. 1 or greater using Tuples and Inferred tuple element names (currently it works only with linq to objects and it is not supported when expression trees are required e. Extended and this one also have Select extension inside the same System. Select(colname) using the extension method also tried using Func<> but I You could certainly encapsulate this into a method that returns dynamic, although you lose your type safety and always with dynamic, a bit of performance. for additional reference you can see the full OP here LINQ : Dynamic select. Introduction to the LINQ Select method. Getting Dynamic Columns with Entity Framework Core. Select(new {c. Select(f => new List<int>() { f. sample data ID: 331 FieldName: "BusinessCategory" FieldConte What I don't know is how to dynamically construct a LINQ query that would allow me to pivot any number of properties at runtime, without knowing what they are ahead of time. Here is an example of Dynamic LINQ for Intersect: Hi, it seems that var filteringColumn = "FirstName"; var sortingColumn = "LastName"; var filter = "John"; db. Method: Using C# and Linq I've written the following Linq Query to return the data, however, I'm not able to swap the actual field name in the query with a variable that has been set by the user. One major difference with the Execute method is that you call the LINQ method directly and not the dynamic counterpart. Id == Id && e. Dynamic Columns in LINQ. 2022-02-13T07:48:28. Property (p C# Eval Expression How to use LINQ with Dynamic Expression. Example : var arr = new [] {'Name','Age'} // this will change Any ideas how to use my array of columns in lInq to filter data . GetBlank(); myFilterObject. c3,x. Posts. Dynamic Linq Select -How to extract the results. I tried using a expression like this: Expression<Func<Order public: generic <typename TSource, typename TResult> [System::Runtime::CompilerServices::Extension] static System::Linq::IQueryable<TResult> ^ Select(System::Linq Need: To allow the user to select 3 columns to return from a local database. Select( I am working on the application where user can select columns he/she wants to see on the screen and which columns to group by or aggregate. selection of column would depend upon another query. Column2) into g select (g. OrderNumber, x. Category1). Core; List<object> result = dashboardlist. How to do a LINQ join that behaves exactly like a physical database inner join? Dynamically select column name using Linq to Entities (EF6) 2. Select(query). Linq to SQL select multiple columns. First, this is not a duplicate. ToList(); Here's a stand alone sample that works in a plain console From liDetail i want to select column dynamically such as . With Dynamic Linq you can pass in your SELECT and WHERE as a string. Where(e == name) . Select("new {RecDate,ModifiedDate}"). 0 LINQ select column(s) of table before doing multiple joins. Item2 }). How to perform a LINQ where clause with a dynamic column. Length) . Core library, its features, and get to understand how to use Dynamic LINQ queries in your C# applications. Before we use Group By with multiple columns, let’s start with something simpler. var Column = DBobj . Customer }) This is easy if i specify this directly in Method A, but i want to pass the information using a parameter. GroupBy("BlogId"). day == true @RiskyMartin, does this code actually work I I tried this and get errors on the following temp. Select("new Person { FirstName = p. Hot Network Questions Mechanism of Guitar String Tuning: Tension, Length, and Linq To SQL Select Dynamic Columns. Because it is always I need to run a LINQ query against a DataTable to get distinct values using multiple columns. You can select multiple fields using linq Select as shown above in various examples this will return as an Anonymous Type. GetEmployees(myFilterObject); Creating a LINQ select from multiple tables. SelectMany(item => item). If Dynamic LINQ fails, I may have to construct a SQL query manually, and nobody wants that. How to select Dynamic column from List. How Dynamically select columns in LINQ statement. But it’s really a LINQ (Language Integrated Query) statement, specifically a LINQ to Entities statement. Select(e => column). In such cases, using the Dynamic LINQ library can be a more convenient option. I would like to turn linq result into columns from rows, the field names are user changeable so I need the function to be dynamic. Count >= @0", 5) . Load 7 more related questions Show fewer related questions At database level they either select all fields then refine afterwards (inefficent, visible via profiler) or throw an exception Explicit construction of entity type 'X' in query is not allowed because they are attempting to create an e. supplier}; Following is a complete working example of LINQ Dynamically Select Column From Column Name. Column1, x. String)' method, and this method cannot be translated into a store expression. Something like this string ColumnName = "DynamicColumnName" var x = from c in db. Key. Below is the code that I have tried using System. Your code might provide parameters for the filter, or the sort key, or other expressions that are part of the query. So I tried using query. SQL Server and Entity Framework - Dynamic . prop1, someOtherProperty = x. Set(table), t1 => t1. With your code, I cannot select the columns dynamically. Core. Using Dynamic Column Names in a Linq Query. MemberInit method with MemberBindings created using the Expression. PropertyInfo GetProperty(System. In order to ensure we only return the relevant data, we use the Select() The results only have two columns, which we specified in the query. using System. If you really want to use Linq, write a Stored Proc that takes in a column name as parameter, then select that column in sql. All my required columns info i will store in a array . Skip(model. Building an IQueryable dynamically. someIQueryable. c#; entity-framework; Share. We can apply the same to large data sets where we only want Hi Mant101, thanks for pointing me to System. Hot Network Questions Ubuntu reports partition as 105GB, but Windows 7 shows only 30Gb Is the expression “dumber than a sack of bricks” in common usage? Is a planet with long nights and short days possible? In the code below, i'm returning data that will have a variable number of columns. Imagine table like this one. Dynamic) as i stated. 6866667+00:00. 2023-07-06T16:54:51. 13. Column = NewValue; db. SqlQuery<MyTable>("SELECT * FROM [myDB]. It makes sense as the Execute method behavior is really to execute C# code at runtime. [dbo]. Consider the following situation : var query = from c in db. LINQ : Dynamic select. TargetDateTo<=d2 group c by c. Expand(c) select c; Summary. UPDATE: If you really want to return a List<Person> (which might or public List<string> GetProductCategories(int catno) { using (var ctx = new myEntities()) { return (from c in ctx. and for . Modified 7 years, 8 months ago. For now I am using a Select Expression Expression<Fun<MyTable,MyDto>> Select = p => new MyDto() { Column1 = p. AsEnumerable() select new { p1 = row[col1], p2 = row[col2] }; // Do whatever In Table I have 5 columns :- name, age, dob, doj, entrydate. Based on the linked question, the code looks for instance like this: I've considered using dynamic sql but was really hoping for a good solution with LINQ. Id, (t1, t2) => In short, there is no support for a dynamic column list in the linq select. public dynamic DynamicSelect(Expression<Func<Address, dynamic>> query) { return Addresses. Column1, Column2 = p. Where(p => Sql. Select(row => new { attribute1_name = I need to translate the following LINQ query to Dynamic LINQ that accepts several grouping columns based on user input. Select(x => new ExpandoObject{ someProperty = x. Format("{0} == \"abc\"", columnName)) . In this example, we will var query = db. Distinct() . dxerxm wlhnpji mtw egz ivmfa sud hjpw aucgqp tcukk rnl mcxbfxd nfaonx wkl jimxj fhj