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Search found 12 results on 1 pages for 'predicatebuilder'.

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• How to use PredicateBuilder with nested OR conditionals in Linq

  - by tblank

  I've been very happily using PredicateBuilder but until now have only used it for queries with only either concatenated AND statements or OR statements. Now for the first time I need a pair of OR statements nested along with a some AND statements like this: select x from Table1 where a = 1 AND b = 2 AND (z = 1 OR y = 2) Using the documentation from Albahari, I've constructed my expression like this: Expression<Func<TdIncSearchVw, bool>> predicate = PredicateBuilder.True<TdIncSearchVw>(); // for AND Expression<Func<TdIncSearchVw, bool>> innerOrPredicate = PredicateBuilder.False<TdIncSearchVw>(); // for OR innerOrPredicate = innerOrPredicate.Or(i=> i.IncStatusInd.Equals(incStatus)); innerOrPredicate = innerOrPredicate.Or(i=> i.RqmtStatusInd.Equals(incStatus)); predicate = predicate.And(i => i.TmTec.Equals(tecTm)); predicate = predicate.And(i => i.TmsTec.Equals(series)); predicate = predicate.And(i => i.HistoryInd.Equals(historyInd)); predicate.And(innerOrPredicate); var query = repo.GetEnumerable(predicate); This results in SQL that completely ignores the 2 OR phrases. select x from TdIncSearchVw where ((this_."TM_TEC" = :p0 and this_."TMS_TEC" = :p1) and this_."HISTORY_IND" = :p2) If I try using just the OR phrases like: Expression<Func<TdIncSearchVw, bool>> innerOrPredicate = PredicateBuilder.False<TdIncSearchVw>(); // for OR innerOrPredicate = innerOrPredicate.Or(i=> i.IncStatusInd.Equals(incStatus)); innerOrPredicate = innerOrPredicate.Or(i=> i.RqmtStatusInd.Equals(incStatus)); var query = repo.GetEnumerable(innerOrPredicate); I get SQL as expected like: select X from TdIncSearchVw where (IncStatusInd = incStatus OR RqmtStatusInd = incStatus) If I try using just the AND phrases like: predicate = predicate.And(i => i.TmTec.Equals(tecTm)); predicate = predicate.And(i => i.TmsTec.Equals(series)); predicate = predicate.And(i => i.HistoryInd.Equals(historyInd)); var query = repo.GetEnumerable(predicate); I get SQL like: select x from TdIncSearchVw where ((this_."TM_TEC" = :p0 and this_."TMS_TEC" = :p1) and this_."HISTORY_IND" = :p2) which is exactly the same as the first query. It seems like I'm so close it must be something simple that I'm missing. Can anyone see what I'm doing wrong here? Thanks, Terry

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• C# PredicateBuilder Entities: The parameter 'f' was not bound in the specified LINQ to Entities quer

  - by Neothor

  I needed to build a dynamic filter and I wanted to keep using entities. Because of this reason I wanted to use the PredicateBuilder from albahari. I created the following code: var invoerDatums = PredicateBuilder.True<OnderzoeksVragen>(); var inner = PredicateBuilder.False<OnderzoeksVragen>(); foreach (var filter in set.RapportInvoerFilter.ToList()) { if(filter.IsDate) { var date = DateTime.Parse(filter.Waarde); invoerDatums = invoerDatums.Or(o => o.Van >= date && o.Tot <= date); } else { string temp = filter.Waarde; inner = inner.Or(o => o.OnderzoekType == temp); } } invoerDatums = invoerDatums.And(inner); var onderzoeksVragen = entities.OnderzoeksVragen .AsExpandable() .Where(invoerDatums) .ToList(); When I ran the code there was only 1 filter which wasn't a date filter. So only the inner predicate was filled. When the predicate was executed I got the following error. The parameter 'f' was not bound in the specified LINQ to Entities query expression. While searching for an answer I found the following page. But this is already implemented in the LINQKit. Does anyone else experienced this error and know how to solve it?

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• Generated SQL with PredicateBuilder, LINQPad and operator ANY

  - by Sig. Tolleranza

  I previously asked a question about chaining conditions in Linq To Entities. Now I use LinqKit and everything works fine. I want to see the generated SQL and after reading this answer, I use LinqPad. This is my statement: var predProduct = PredicateBuilder.True<Product>(); var predColorLanguage = PredicateBuilder.True<ColorLanguage>(); predProduct = predProduct.And(p => p.IsComplete); predColorLanguage = predColorLanguage.And(c => c.IdColorEntity.Products.AsQueryable().Any(expr)); ColorLanguages.Where(predColorLanguage).Dump(); The code works in VS2008, compile and produce the correct result set, but in LinqPad, I've the following error: NotSupportedException: The overload query operator 'Any' used is not Supported. How can I see the generated SQL if LINQPad fails?

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• PredicateBuilder "And" Method not working

  - by mikemurf22

  I have downloaded the predicate builder and am having a difficult time getting it to work with the entity framework. Here is my code: v_OrderDetail is the entity var context = new OrdersEntities(); Expression<Func<v_OrderDetail,bool>> whereClause = w => true; var predicate = PredicateBuilder.True<v_OrderDetail>(); predicate.And(w => w.Status == "Work"); var results = context.v_OrderDetail.AsExpandable().Where(predicate); When I look at the results I get back every order. The And predicate doesn't seem to take. When I look at the predicate.parameters.count it only shows 1. I'm not sure, but I would expect it to show 2 after I add the second one. Any help is greatly appreciated.

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• Linq PredicateBuilder with conditional AND, OR and NOT filters.

  - by richeym

  We have a project using LINQ to SQL, for which I need to rewrite a couple of search pages to allow the client to select whether they wish to perform an and or an or search. I though about redoing the LINQ queries using PredicateBuilder and have got this working pretty well I think. I effectively have a class containing my predicates, e.g.: internal static Expression<Func<Job, bool>> Description(string term) { return p => p.Description.Contains(term); } To perform the search i'm doing this (some code omitted for brevity): public Expression<Func<Job, bool>> ToLinqExpression() { var predicates = new List<Expression<Func<Job, bool>>>(); // build up predicates here if (SearchType == SearchType.And) { query = PredicateBuilder.True<Job>(); } else { query = PredicateBuilder.False<Job>(); } foreach (var predicate in predicates) { if (SearchType == SearchType.And) { query = query.And(predicate); } else { query = query.Or(predicate); } } return query; } While i'm reasonably happy with this, I have two concerns: The if/else blocks that evaluate a SearchType property feel like they could be a potential code smell. The client is now insisting on being able to perform 'and not' / 'or not' searches. To address point 2, I think I could do this by simply rewriting my expressions, e.g.: internal static Expression<Func<Job, bool>> Description(string term, bool invert) { if (invert) { return p => !p.Description.Contains(term); } else { return p => p.Description.Contains(term); } } However this feels like a bit of a kludge, which usually means there's a better solution out there. Can anyone recommend how this could be improved? I'm aware of dynamic LINQ, but I don't really want to lose LINQ's strong typing.

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• How do I programmatically translate a LINQ query to readable English text that correctly describes t

  - by eniac

  I am working on a project that uses Albahari's PredicateBuilder library http://www.albahari.com/nutshell/ to create a linq expression dynamically at run time. I would like to find a way to translate this dynamically created linq predicate of type Expression<Func<T, bool>> into a readable english statement at runtime. I'll give a statically created linq statement as an example: from p in Purchases select p where p.Price 100 && p.Description != "Bike". For this linq statement I would want to dynamically generate at runtime an english description along the lines of: "You are searching for purchases where the price is greater than 100 and the description is not bike". Are there any libraries that already exist which accomplish this goal, keep in mind I am using PredicateBuilder to dynamically generate the where predicate. If no solution exists how would you go about building a solution? Thanks!

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• Linq In Clause & Predicate building

  - by Michael G

  I have two tables. Report and ReportData. ReportData has a constraint ReportID. How can I write my linq query to return all Report objects where the predicate conditions are met for ReportData? Something like this in SQL: SELECT * FROM Report as r Where r.ServiceID = 3 and r.ReportID IN (Select ReportID FROM ReportData WHERE JobID LIKE 'Something%') This is how I'm building my predicate: Expression<Func<ReportData, bool>> predicate = PredicateBuilder.True<ReportData>(); predicate = predicate.And(x => x.JobID.StartsWith(QueryConfig.Instance.DataStreamName)); var q = engine.GetReports(predicate, reportsDataContext); reports = q.ToList(); This is my query construction at the moment: public override IQueryable<Report> GetReports(Expression<Func<ReportData, bool>> predicate, LLReportsDataContext reportDC) { if (reportDC == null) throw new ArgumentNullException("reportDC"); var q = reportDC.ReportDatas.Where(predicate).Where(r => r.ServiceID.Equals(1)).Select(r => r.Report); return q; }

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• T-SQL selecting values that match ISNUMERIC and also are within a specified range. (plus Linq-to-sql

  - by Toby

  I am trying to select rows from a table where one of the (NVARCHAR) columns is within a numeric range. SELECT ID, Value FROM Data WHERE ISNUMERIC(Value) = 1 AND CONVERT(FLOAT, Value) < 66.6 Unfortunately as part of the SQL spec the AND clauses don't have to short circuit (and don't on MSSQL Server EE 2008). More info: http://stackoverflow.com/questions/789231/is-the-sql-where-clause-short-circuit-evaluated My next attempt was to try this to see if I could achieve delayed evaluation of the CONVERT SELECT ID, Value FROM Data WHERE (CASE WHEN ISNUMERIC(Value) = 1 THEN CONVERT(FLOAT, Value) < 66.6 ELSE 0 END) but I cannot seem to use a < (or any comparison) with the result of a CONVERT. It fails with the error Incorrect syntax near '<'. I can get away with SELECT ID, CONVERT(FLOAT, Value) AS Value FROM Data WHERE ISNUMERIC(Value) = 1 So the obvious solution is to wrap the whole select statement in another SELECT and WHERE and return the converted values from the inner select and filter in there where of the outer select. Unfortunately this is where my Linq-to-sql problem comes in. I am filtering not only by one range but potentialy by many, or just by the existance of the record (there are some date range selects and comparisons I've left out.) Essentially I would like to be able to generate something like this: SELECT ID, TypeID, Value FROM Data WHERE (TypeID = 4 AND ISNUMERIC(Value) AND CONVERT(Float, Value) < 66.6) OR (TypeID = 8 AND ISNUMERIC(Value) AND CONVERT(Float, Value) > 99) OR (TypeID = 9) (With some other clauses in each of those where options.) This clearly doesn't work if I filter out the non-ISNUMERIC values in an inner select. As I mentioned I am using Linq-to-sql (and PredicateBulider) to build up these queries but unfortunately Datas.Where(x => ISNUMERIC(x.Value) ? Convert.ToDouble(x.Value) < 66.6 : false) Gets converted to this which fails the initial problem. WHERE (ISNUMERIC([t0].[Value]) = 1) AND ((CONVERT(Float,[t0].[Value])) < @p0) My last resort will have to be to outer join against a double select on the same table for each of the comparisons but this isn't really an idea solution. I was wondering if anyone has run into similar issues before?

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• Linqbuilder Query with an OrderBy

  - by Renshai

  I have a 1 : M relationship. I built a dynamic query based on input from users to return the listing of parents entities along with their children (using predicate builder: (done successfully new TDataContext().Ps.Where(predicate) )... but need to order the results by a field found only on the child entities. I'm at a loss: new TDataContext().Ps.Where(predicate).OrderBy(p = p.Cs. ??) where Ps = parents collection relationship with Cs = child entities any help appreciated.

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• How can I generate an Expression tree that queries an object with List<T> as a property?

  - by David Robbins

  Forgive my clumsy explanation, but I have a class that contains a List: public class Document { public int OwnerId { get; set; } public List<User> Users { get; set; } public Document() { } } public class User { public string UserName { get; set; } public string Department { get; set; } } Currently I use PredicateBuilder to perform dynmica queries on my objects. How can I turn the following LINQ statement into an Expression Tree: var predicate= PredicateBuilder.True<User>(); predicate= predicate.And<User>(user => user.Deparment == "HR"); var deptDocs = documents.AsQueryable() .Where(doc => doc.Users .AsQueryable().Count(predicate) > 0) .ToList(); In other words var deptDocs = documents.HasUserAttributes("Department", "HR").ToList();

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• LINQ - IEnumerable.Join on Anonymous Result Set in VB.NET

  - by user337501

  I've long since built a way around this, but it still keeps bugging me... it doesnt help that my grasp of dynamic LINQ queries is still shakey. For the example: Parent has fields (ParentKey, ParentField) Child has fields (ChildKey, ParentKey, ChildField) Pet has fields (PetKey, ChildKey, PetField) Child has a foreign key reference to Parent on Child.ParentKey = Parent.ParentKey Pet has a foreign key reference to Child on Pet.Childkey = Child.ChildKey Simple enough eh? Lets say I have LINQ like this... Dim Q = FROM p in DataContext.Parent _ Join c In DataContext.Child On c.ParentKey = p.ParentKey Consider this a "base query" on which I will perform other filtering actions. Now I want to join the Pet table like this: Q = Q.Join(DataContext.Pet, _ Function(a) a.c.ChildKey, _ Function(p As Pet) p.ChildKey, _ Function(a, p As Pet) p.ChildKey = a.c.ChildKey) The above Join call doesnt work. I sort of understand why it doesnt work, but hopefully it'll show you how I tried to accomplish this task. After all this was done I would have appended a Select to finish the job. Any ideas on a better way to do this? I tried it with the PredicateBuilder with little success. I might not know how to use it right but it felt like it wasnt gonna handle the joining.

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• LINQ to SQL: NOTing a prebuilt expression

  - by ck

  I'm building a library of functions for one of my core L2S classes, all of which return a bool to allow checking for certain situations. Example: Expression<Func<Account, bool>> IsSomethingX = a => a.AccountSupplementary != null && a.AccountSupplementary.SomethingXFlag != null && a.AccountSupplementary.SomethingXFlag.Value; Now to query where this is not true, I CAN'T do this: var myAccounts= context.Accounts .Where(!IsSomethingX); // does not compile However, using the syntax from the PredicateBuilder class, I've come up with this: public static IQueryable<T> WhereNot<T>(this IQueryable<T> items, Expression<Func<T, bool>> expr1) { var invokedExpr = Expression.Invoke(expr1, expr1.Parameters.Cast<Expression>()); return items.Where(Expression.Lambda<Func<T, bool>> (Expression.Not(invokedExpr), expr1.Parameters)); } var myAccounts= context.Accounts .WhereNot(IsSomethingX); // does compile which actually produces the correct SQL. Does this look like a good solution, and is there anything I need to be aware of that might cause me problems in future?

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