Why does this LINQ query (Id is a property of type long in the Structure object): IList<Structure> theStructures = new List<Structure>(); public int GetChildrenSlow(Structure aStructure){ IEnumerable<Structure> childrenQuery = from structure in theStructures where structure.ParentStru...
Using C# what is the best way to sort a List numerically? my list has items 5,7,3 and I would like them sorted 3,5,7. I know some longer ways, but I would imagine linq has a quicker way? sorry this was end of day, my mind is else where it worked, didn't see it change the first time:( ...
I did some profiling on a program that I'm running and the thing that takes the longest time is getting the results from the linq query: var Results = from a in Table group a by a.Value into b select new {Group = b}; foreach(var Result in Results) { //Do calcs } Any ideas on how I can speed this up? ...
I'm building a poll widget. I've 2 tables, call them Polls and PollsCompleted. I need to do a linq query to get all the Polls that do not exist for a given user in PollsCompleted. I have the following sets: For Polls Where Active == True For PollsCompleted Where UserId == ThisUserId Where PollId = Polls.Id Now I need to get all Polls...
What is the difference between ((IEnumerable)source).OfType<T>() and source as IEnumerable<T> For me they look similar, but they are not! source is of type IEnumerable<T>, but it is boxed as an object. Edit Here is some Code: public class PagedList<T> : List<T>, IPagedList { public PagedList(object source, int index, int pageSiz...
In C# 3.0 you can use Expression to create a class with the following syntax: var exp = Expression.New(typeof(MyClass)); var lambda = LambdaExpression.Lambda(exp); object myObj = lambda.Compile().DynamicInvoke(); But how do you use Expression to create an Anonymous class? //anonymousType = typeof(new{ Name="abc", Num=123}); Type anon...
Possible Duplicate: What is the LINQ way to implode/join a string array? Say I have a linq query that returns a generic list containing a single string element: //Actually comes from a linq to sql query so I don't actually have the array. string[] mer = {"cat","dog","fish"}; var k = (from k in mer select k); Is the...
Hi all, I am using DBLinq to access a MySQL DB from C# .NET 3.5 I have created the dbml file for the Visual Studio 2010 ORM, and it loads fine - however when I compile the source I am met with errors regarding the conversion of MySQL timestamp to .NET DateTime. Now this kind of makes sense, because they are 2 'different' types (Though...
Hi all I have a log file in the format below as you can see each log start with a time and ends with pipe delimeter. Put each Log starting with a dateTime and ending with a pipe delimeter in a List How can I parse this text file and put the logs in the collections? I seem to have a problem in determine how can I find the start and ...
Since there is no DeleteAllOnSubmit() method for LINQ to Entities. So I myself create it and named for DeleteAllObjecst as following code. public static void DeleleAllObjects(this ObjectSet objectSet, TEntity[] objects) { foreach(var o in objects) { objectSet.DeleteObject(o); } } However the ...
Hello I am using LinqPad to learn Linq by querying the NetFlix OData source. (BTW I know their is a similar question already on SO...didn't help me). Here is the query I got working which is awesome. from x in Titles //where x.Rating=="PG" where x.Instant.Available==true where x.AverageRating>=4.0 //where x.Rating.StartsWith("TV")...
On every page of my website a token is passed in as a querystring parameter. The server-side code checks to see if the token already exists in the database. (The token is a uniqueidentifider field in the database). If the token exists then it will use the existing one, if not then it will create a new row with the new token. The problem...
Sort of a Linq beginners question, but is there a simple built-in way to optimize this: bool containsItemWithValue42 = items.Where(i => i.Value == 42).Count() > 0; I would like Linq to stop iterating as soon as it found a match. ...
I have a set of model objects that have a public IsVisible boolean property. All I need to do is find if at least one of the set has that value set to TRUE. In other words, if I have 10,000 objects but the second one is true, I don't need to spin through the other 9,998. I already have my answer. Now I know I could write my own itera...
Hi folks, i've got a really simple linq to entites statement :- var query = (from q in Users.Include("UserHistory") select q).Take(20); works great ... except that, for each user .. the history can be n+1. Some users have 100's of UserHistory records. So, can I restrict the the number of UserHistory records to .. 10 or 5...
var x = from y in db.table where y.member_id == 1 select new { y.member_id }; this statement should return only one record. & i want to retrieve that value the statement returns in a string format. like string m = x; how can i do that?! ...
I accept both C# and VB.NET suggestion, even though I'm writing an app in VB.NET I have two lists of intergers List1 {1,2,3,5} List2 {2,4,6,7} I want to have new List3 {4,6,7} which is composed of elements of List2 that are not in List1. I know I can write a nice For Each loop for this but I want it done in LINQ I've been lookin...
How would you go about pivoting data in a datatable where the number of columns varies from? A few columns would always be in the datatable such as ID and Name but the rest could vary. I have been struggling a lot with this and can't seem to come up with an elegant solution. Does anyone have a suggestion? ...
Ok, last edit, promise: With the following class: public partial class MembershipModule : BaseConnection<MembershipModule> { private const string AccessPrivilege = "Access"; public bool Accessible() { return this.Privileges().Any(p => p.Name.Equals(AccessPrivilege)); } public IQueryable<MembershipAction> P...
Hi all, I am trying to retrieve a list of string where it contains "Britney Spears", and this is what I use from p in Objects where p.Title.Contains("Britney Spears") select p That works fine, but if I want to select title which is "Britney Jean Spears", "Britney 'Sexy' Spears" it doesn't work, so my question is how do I insert a wil...