dynamic-linq

问题 I'm using Dynamic Linq and today I wanted to build a slightly more complex nested query: "Composition .Where(((ExpirationDate > DateTime.UtcNow.Date) && (ExpirationDate.Year != 9999))) .OrderBy(\"ExpirationDate ASC\") .Select(ExpirationDate) .FirstOrDefault() == @0" (the breaks are only there for readability in this post, not really there in code) The query is held by a string variable and passed to this: private static Func<IQueryable<T>, object, IQueryable<T>> CreateWhereExpression<T>

问题 I am using Microsoft's Dynamic Linq (System.Linq.Dynamic) library to generate some queries at run time. This has worked great for me, but for one specific scenario. Simplified scenario - I am trying to query all claims which have some specific tags that the user has selected and whose Balance is greater than some number. static void Main(string[] args) { var claims = new List<Claim>(); claims.Add(new Claim { Balance = 100, Tags = new List<string> { "Blah", "Blah Blah" } }); claims.Add(new

问题 I am trying to figure out how to enumerate the results from a dynamic LINQ .Select(string selectors) in .NET 4.5. The dynamic linq comes from the System.Linq.Dynamic namespace. Edit: I am also including System.Linq . I have a method that looks like this: public void SetAaData(List<T> data, List<string> fields) { if (data == null || data.Count == 0) { return; } var dynamicObject = data.AsQueryable().Select("new (" + string.Join(", ", fields) + ")"); _aaData = dynamicObject; } If I step through

问题 I'm trying to grab out formatted values from a project. I have a function declared: public static string GetFormattedLink(string ExtTitleID) { return "Str_" + ExtTitleID; } How would I execute this statement from the Select Statement in Dynamic Linq I tried. using (var Model = new MK3Entities()) { var TOrigin = (Model.Titles.Where("ID > 19632") .Select("new(ID, GetFormattedLink(ExtTitleID))") as System.Collections.IEnumerable) .Cast<dynamic>().Take(10).ToList(); } However this returns the

问题 I'm trying to retrieve SQL records where the rowversion is greater than a certain value. In SQL this is trivial (WHERE RowVersion > x), however not so in Dynamic Linq queries. In my EF model I have applied the Timestamp annotation to the appropriate column. [Timestamp] public byte[] RowVersion { get; set; } And used a static Compare Extension for the byte[] comparison (source: (https://stackoverflow.com/a/42502969/3424480) static class MiscExtension { public static int Compare(this byte[] b1,

问题 I'm trying to retrieve SQL records where the rowversion is greater than a certain value. In SQL this is trivial (WHERE RowVersion > x), however not so in Dynamic Linq queries. In my EF model I have applied the Timestamp annotation to the appropriate column. [Timestamp] public byte[] RowVersion { get; set; } And used a static Compare Extension for the byte[] comparison (source: (https://stackoverflow.com/a/42502969/3424480) static class MiscExtension { public static int Compare(this byte[] b1,

问题 We are building dynamic search expressions using the Dynamic Linq library. We have run into an issue with how to construct a lamba expression using the dynamic linq library for navigation properties that have a one to many relationship. We have the following that we are using with a contains statement- Person.Names.Select(FamilyName).FirstOrDefault() It works but there are two problems. It of course only selects the FirstOrDefault() name. We want it to use all the names for each person. If

问题 Disclaimer: I've solved the problem using Expressions from System.Linq.Expressions, but I'm still looking for a better/easier way. Consider the following situation : var query = from c in db.Customers where (c.ContactFirstName.Contains("BlackListed") || c.ContactLastName.Contains("BlackListed") || c.Address.Contains("BlackListed")) select c; The columns/attributes that need to be checked against the blacklisted term are only available to me at runtime. How do I generate this dynamic where

问题 I need some in-memory filtering with Dynamic Linq. My objects have only a indexer: public object this[int index] { } The access to my data is like: object[0], object[1],... So my query is like this: // get FilterText from user at runtime // eg. filterText can be: [0] > 100 and [1] = "wpf" collection.AsQueryable().where(filterText); Is there any way to do this? 回答1: I have some news for you. It is actually possible... BUT! (Yes, there´s a but). I assume you are using the dynamic Linq library.

问题 I need some in-memory filtering with Dynamic Linq. My objects have only a indexer: public object this[int index] { } The access to my data is like: object[0], object[1],... So my query is like this: // get FilterText from user at runtime // eg. filterText can be: [0] > 100 and [1] = "wpf" collection.AsQueryable().where(filterText); Is there any way to do this? 回答1: I have some news for you. It is actually possible... BUT! (Yes, there´s a but). I assume you are using the dynamic Linq library.