In the book I'm reading "Pro Linq in C# 2010" (APress, Freeman and Ratz) the author states that IQueryable will only be returned from the classes in the Linq to Sql namespace, not in the general Linq namespace. I was surprised by this, since I thought anything that had a Where on the end had to be IQueryable. Turns out I was wrong, Where...
I have three tables and need to write a linq query that pulls from all Activities based on two different joins. I need all Activities where the volunteer exist in ActivityVolunteers I need all Activities where the OrganizationID is in the Activity table and the volunteer belongs to the organizaiton (OrganizationVolunteers) but not in...
I'm pretty new to Linq to SQL & Linq to XML but have cobbled together some code together that put the XML results from a stored proc into an XElement. However, it's started failing, apparently now that the XML data is getting larger (2K+) and my .Parse is reading truncated XML (the XML data comes back in two rows). Before i start fumblin...
I have two IQueryable<> lists. Say one is filled with objects of Class Bottle and the other is of type Cup. Both classes have a Guid called DrinkID. How would I take my Bottle list and find all the items in the Cup list that have a DrinkID that is NOT in the Bottle list? I am looking for something like this: var bottles = _context.A...
Hello: Having a bit of a problem getting my LINQ query to return the object type I want to work with. I'm pretty close just need a little bit of input. I have five tables, Objects, People, Locations, Collections, and CollectionEntries. Object is the base class for People, Locations, and Collections. A Collection has many CollectionEnt...
How come setting OrganizationName = null does not work? I am doing a union and would like to set the value to null. from a in Activities select new { a.ActivityID, a.ActivityName, a.OrganizationID, OrganizationName = null } ...
I'm working with the new EF4 CTP4 although I don't think this has much to do with that. I am trying to set up a system where I can add auditable fields for our database automatically. What I'm trying to do is combine the following two expressions a => new { a.CreatedBy, a.CreatedTime, a.UpdatedBy, a.UpdatedTime } and...
So I have this huge XML file that I am converting to an object by using LINQ. And currently I am doing: var resultStories = from story in resultXML.Descendants("story") select new NewsStory { ArticleFrequency = from tag in story.Descendants("tag") ...
I'm trying to write a linq-to-sql query using || that behaves the same way as the OR in SQL when combined with a LIKE/Contains. SQL: SELECT * FROM Users WHERE GroupNumber = 'A123456' OR (FirstName like 'Bob%' AND LastName like 'Smith%') This will result in everyone with a name like "Bob Smith" as well as everyone with a GroupNumber e...
How can I combine two lambda expressions into one using an OR ? I have tried the following but merging them requires me to pass parameters into the Expression.Invoke calls, however I want the value passed into the new lambda to be passed onto each child-lambda.. Expression<Func<int, bool>> func1 = (x) => x > 5; Expression<Func<int, boo...
Hi All, I'm trying to figure out the difference between Where(Expression) and Single(Expression). Is the Expression passed into single forwarded to a Where function? eg, are these two statements the same? var result = context.Persons.Single(p => p.ID == 5); var result2 = context.Persons.Where(p => p.ID == 5).Single(); ...
I can't make any sense of the MSDN documentation for this overload of the Where method that accepts a predicate that has two arguments where the int, supposedly, represents the index of the source element, whatever that means (I thought an enumerable was a sequence and you couldn't see further than the next item, much less do any indexin...
The following code gives me the error: The best overloaded method match for 'System.Xml.Linq.XElement.XElement(System.Xml.Linq.XName, object)' has some invalid arguments. What do I have to change so I can iterate through my List<Customer> collection with Foreach building the XDocument? using System; using System.Collections.Ge...
Does anyone know where I can get a full list of supported statements for linq to entities, this is statements that will be translated and run on the database...? ...
var yCols = from t in flowPath select new {checkPoint = t["CheckPoint"]}; var test = from x in operations where x["Ops"] = "test" && x["check"].Contains(yCols.Select(y=>y.Variable)) Somehow the contains in where clause part is not right.yCols returns Collection of Checkpoints and if x["Check"] cont...
Why is the following adding an Insert (of the new Address) to the DataContent ChangeSet, and how can I stop it from doing so? var db = new DataClasses1DataContext(); var a = new Address(); a.StateProvince = db.StateProvinces.First(); Console.WriteLine(db.GetChangeSet().Inserts.Count); ...
Hi, I'm struggling to find LINQ orderby examples, where data is ordered by a column index. Is this possible to do? Thank you ...
I'm doing like this: entities.AsParallel().ForAll(o => repository.Insert(o)); is this good, am I going to have more performance with this ? ...
So what I'm doing is using an xml document to determine the order in which certain SQL scripts need to be ran by a database update. The XML follows this format <ScriptRules> <Database databaseName = “string”> <Folder folderPath = “string” executeAllFiles = boolean> <file order=”first or last”>“Filename”</file> ...
Hello all. Struggling a bit today. I have the following method that returns a list of products..lovely. public static List<tblWeight> GetProductInfo(string memberid, string locationid, string basematerial, string source) { MyEntities getproductinfo = new MyEntities (); return (from p in getproductinfo...