Expression Tree Tutorial - Knowledge Base (KB)
28 results in tag: dynamic-linq
expressive tree-based dynamic query
I have a form in which the user will choose the following from dropdown lists:... table_name columnName_to_sort_by columnName_to_search_in ...The user shall enter ...Search_text... in a text box...The form shall draw data from many tables. I want to ...
asked by user375492
LINQ Querying an Entity with Dynamic Field Names
I have created a dynamic search screen in ASP.NET MVC. I retrieved the field names from the entity through reflection so that I could allow the user to choose which fields they wanted to search on instead of displaying all fields in the view....When the ...
asked by Scott Lance
Linq: Dynamic Query Construction: the query is constructed on the client side.
I've been following with great interest the converstaion here:...Construct Query with Linq rather than SQL strings...with regards to constructing expression trees where even the table name is dynamic....Toward that end, I've created a Extension method, ad...
asked by donundeen
Using unknown types in DynamicExpression
If anyone is very familar with the Linq.Dynamic namespace I could use some help -- couldn't find any indepth resources on the internet....Basically I'm using DynamicExpression.ParseLambda to create an expression where the type is not known at compile time...
asked by sean
Dynamic linq against a non-dbml object
I have been asked to investigate the usefulness of linq to sql for a reporting application we are building. Our reporting table is a sql server wide table with many thousands of columns of different types (String1-500, Int1-500 etc). It holds the results ...
asked by madcapnmckay
allow the user to create dynamic expressions using the GUI wizard
I want to build a gui panel/wizard where my application's users could build custom conditions/expressions using the properties of a strongly typed object model. ...Basically something like this....The structure could be nested (LHS/RHS might consist of ot...
asked by wilsonlarg
WCF DataContract class generated dynamically
Is there any way to return an array of objects of type ...DynamicClass... from WCF method?...I'm using ...Dynamic Linq Library... in my WCF service, so as to ...select... columns of database table , as per the request from clients. The client code should ...
asked by Nawaz
Interval grouping using dynamic linq (DateTime, Numeric)
I search everywhere and didn`t find anwser for this question. I want to group by intervals (DateTime, Numeric) in Dynamic linq (the data will be crated dynamically so i must use dynamic linq)...Lets assume that we have such data:...ID|Date|Price 1|2010-1...
asked by WebDeveloper
Perform a query on an object having members of type "dynamic" using Dynamic Linq.
I am trying to use a dynamic linq query to retrieve an IEnumerable<T> from an object collection (Linq to Object), each of the objects in the collection have an internal collection with another set of objects where the data is stored, these values are acce...
asked by Darsegura
Operator overloads with dynamic linq
Consider the code below:...var vectorTest = new Vector2(1, 2) + new Vector2(3, 4); // Works var x = Expression.Parameter(typeof(Vector2), "x"); var test = System.Linq.Dynamic .DynamicExpression.ParseLambda(new[] { x }, null, "x = x + x")...
asked by George Duckett
In C#, how do you make a dynamic lambda-based Linq expression from a string?
I'm having some difficulty creating Lambda-based Linq expressions from a string. Here is my basic case using this sample object/class:...public class MockClass { public string CreateBy { get; set; } } ...Basically I need to convert a string like this...
asked by jon333
Dynamic Linq searching multiple columns of multiple types including nullable types
I need select my columns dynamically and I do not know the types of the columns ahead of time. I've got a string and I want to search all the columns if they contain that string, converting non-string into string for the comparison....string format = "Con...
asked by Kyle
How to create a property (collection) expression selector from a string?
I wanted to transform the string "...Employee.Orders.OrderID..." in the ...linq expression...: "...employee.Orders.Select(order => order.OrderID)..."....I already know how to do this in simple properties such as "Employee.FirstName" my question is how to ...
asked by Lukian
How to add an AND/OR expression to the following dynamic linq expression
T is a type that may or may not have a specific property, lets say 'City'. For the types that have a property named 'City', I would like to restrict the records such that only residents of the Gotham are returned and they are sorted....public static IQuer...
asked by WPFAbsoluteNewBie
Dynamic Linq query on relationship with foreign key of type Guid
I'm using ...System.Linq.Dynamic... to query an IQueryable datasource dynamically using a where-clause in a string format, like this:...var result = source.Entities.Where("City = @0", new object[] { "London" }); ...The example above works fine. But now I ...
asked by Andreas Zita
Linq Expression Builder datetime.year compare
Currently I am using expression builder for dynamic query generation....I have created dynamic expressions for int, date time, and string operators. Now I am stuck at one point ....I want to compare month part of datetime through expression....We are pass...
asked by Jimesh A Mandaliya
Dynamic Linq Library can’t handling duplicate alias column names
I am trying to collect the data from database by using Dynamic Linq Library ...NeGet.... When I loop through it showing this error ‘The item with identity 'FirstName' already exists in the metadata collection’...Seems like Dynamic Linq Library ...NuGe...
asked by sridharnetha
Expression Trees on DataTable
I am trying to build a DataTable filter with ...ExpressionTrees... now I made a ...QueryBuilder... helper class as shown below. The call would be like so:... var pb = PredicateBuilder.True<DataRowCollection>(); int i = 0; ...
asked by Jester
System.Linq.Dynamic.DynamicExpression parsing expressions with methods
I need to build a system where I have a number of expressions that are stored in a file. These expressions would be read into the program, compiled into linq expressions and evaluated as functions on a number of objects. However, these expressions would c...
asked by Tibi Chelcea
Creating dynamic expression for entity framework
I've created a generic expression builder that builds up a predicate based on collection of conditions. I pass the predicate to a generic method in the repository. I think that expression builder works fine and creates the desired predicate although the S...
asked by ssmsexe
Page 1 of 2