Grabbing most recent transaction/record
One way would be filtering by startDate, grouping by ID, ordering by date, and grabbing the first element of the group: var res = tx .Where(tx => tx.TransactionDate <= startDate) .GroupBy(tx => tx.Id) .Select(g => g.OrderBy(tx => tx.Date).First()); ...
Add children to XElement via LINQ
Like this: var element = new XElement( "Ou", new XElement("Group", "AAA"), new XElement("Group", "BBB"), new XElement("Group", "CCC"), new XElement("Group", "DDD")); Or from your data structure: var element = new XElement("Ou", from g in _groups select new XElement("Group", g.Name)); ...
orderby () containing numbers and letters
c#,wpf,linq,linq-to-sql,sql-order-by
Given your example data where the first number is always a single digit: allScenes.OrderBy(x => x.SceneNumber).ToList() If you can possibly have multi-digit numbers, please provide them and where you want them in the sort order. This is one way to sort multiple digit numbers: var allScenes = new[]{ new {SceneNumber="4B"},...
Linq update with specific select of column being null
The problem you have is that your model is not identical to you database, if you could select the row directly (you said Linq2SQL and not Linq2Entities) then you could update it again, which you do. If you select an anonymous type then you lose the context connection and cannot...
get string array from another delimited string array
You can use Enumerable.Select along with String.Split string []arr = {"string:1", "string:1", "string:2"}; string [] result = arr.Select(e=>e.Split(':').Last()).ToArray(); To convert it to int array you can use Convert.ToInt32 int []result1 = arr.Select(e=>Convert.ToInt32(e.Split(':')[1].Last())).ToArray(); ...
Casting a list of objects to another one
The return type of Read() is probably something like IEnumerable<Entity> or List<Entity>. That's why you can't cast them to a single Category. If you need a one line solution for this, you could try var categories = categoryDao.Read().OfType<Category>(); or (thanks @Binkan Salaryman) var categories = categoryDao.Read().Cast<Category>(); (the former will return...
Finding an item in a list in c#
You have your condition wrong, you are looking for questionanswers where the question does not match, you should be looking where they do match and checking that the result is null. (switch the != with ==) It should be if (questionnaire.QuestionAnswers.Find(a => a.Question == fataQuestionsAnswers.Question) == null) However I would...
Adding where clause to IEnumerable Select
Per Discosultan in the comments: IEnumerable<int> interestIds = viewModel.ExistingInterests.Where(x => x.selected == true).Select(x => x.InterestId); ...
How to write Nested LINQ for specific scenario
This is a good example of something to do in Linq. You will find that you can do this easily and even more powerful queries if you understand two things: Don't try to overly literally translate from SQL into Linq. Lambdas. The first is easy to understand but hard to...
How to select all objects that have a property value in list of values?
You need to use Where with Contains: var selectedItems = db.Items.Where(x => locationIds.Contains(x.LocationId)); ...
Select XML Elements after last matching Element
Simply select the last meal element: var lastMeal = noIdea.Elements("Meal").Last(); As an aside, you can simply cast an element to DateTime rather than converting the string value - e.g. (DateTime)el.Element("MealTime"). This uses DateTime.Parse internally with the correct styles as allowed in the XML specification....
Get List of Elements in Tree with specific Field Value
vb.net,linq,properties,interface
If i have understood it correctly you want to get all selected parents and all selected children. You could use a recursive method: Public ReadOnly Property checkedList As List(Of TreeSelectorAttributes) Get Return rootList.Where(Function(t) t.SelectedInTreeSelector). SelectMany(Function(root) GetSelectedChildren(root)). ToList() End Get End Property Function GetSelectedChildren(root As TreeSelectorAttributes, Optional includeRoot As Boolean =...
Using LINQ to reference XML local Xelements
You always have the option to create extension methods to find elements by local name. Whether you like it or not, you have to "use an if within the foreach," that's an ovherhead you'll have to accept. This implementation is in terms of LINQ but you could always write it...
Get and add all properties of type Mname from a list of objects and add them dynamically too a drop down
c#,linq,list,object,properties
In a foreach loop the type of your loop variable is the type of the items in the collection, so you want: foreach (Monster m in monsterObjectList) ddlMonsters.Items.Add(new ListItem(m.MonsterName)); You could also bind the list as the data source: ddlMonsters.DataSource = monsterObjectList; ddlMonsters.DataTextField = "MonsterName"; ddlMonsters.DataBind(); ...
Issue displaying LINQ query results in a grid in C#
I solved my own problem. Here is what I did: Created a class for the attributes needed: public class dataRow { public string CenterName { get; set; } public string CenterCode { get; set; } public string NextImport { get; set; } public string NextExport { get; set; } public...
How can I omit NULL values when converting DataRow to a Dictionary in C#?
Why not replace your original function by: Dictionary<string, Dictionary<string, object>> DataTableToDictionary(DataTable dt, string prefix, string id) { var cols = dt.Columns.Cast<DataColumn>().Where(c => c.ColumnName != id); return dt.Rows.Cast<DataRow>() .ToDictionary(r => prefix + r[id].ToString(), r => cols.Where(c => !Convert.IsDBNull(r[c.ColumnName])).ToDictionary(c => c.ColumnName, c => r[c.ColumnName])); } ...
Difference between cast and as inside a select in LINQ
LINQ to Entities is not the same as LINQ to Objects. While LINQ to Objects functions can take any matching delegate and blindly invoke it as normal C# code, LINQ to Entities treats your lambdas as expression trees because it needs to understand the semantics of those lambdas (not just...
WPF, DataGrid, clicked item/row does not highlight (blue background)
Here is the solution that works: private void tabControlOrganizer_SelectionChanged(object sender, SelectionChangedEventArgs e) { if (tabControlOrganizer.SelectedItem != null) { if (e.Source is TabControl) { if (tabItemTrades.IsSelected) { dataGridTrades.ItemsSource = Queries.GetTradeList(dataContext); } SelectionChanged was the problem: In C# WPF, why is my TabControl's SelectionChanged event firing too often? In free time I...
How to convert to LINQ Queries
This should get you started: foreach (var pair in dict.Where(pair => input.DealInputs.ContainsKey(pair.Key))) { input.DealInputs[pair.Key] = pair.Value; } ...
How to call a lambda using LINQ expression trees in C# / .NET
c#,.net,linq,lambda,expression-trees
Don't use Expression.Call(innerLambda.GetMethodInfo(), ...), that's just asking for trouble. Invoke the delegate instead - you have no business messing around with the delegate's "method" - not only do you lose the target (quite important in instance methods), but you're also violating privacy (anonymous methods are internal or private, for example)....
Asp.Net Identity find users not in role
asp.net,linq,entity-framework,asp.net-identity
In c# you can get all users that are not in a certain role like this: var role = context.Roles.SingleOrDefault(m => m.Name == "role"); var usersNotInRole = context.Users.Where(m => m.Roles.All(r => r.RoleId != role.Id)); ...
Find a fixed length string with specific string part in C#
You can use Regular Expressions to filter the result: List<string> sList = new List<string>(){"AB012345", "AB12345", "AB123456", "AB1234567", "AB98765", "AB987654"}; var qry = sList.Where(s=>Regex.Match(s, @"^AB\d{6}$").Success); ...
Using Linq with VB.NET
You're still using c# syntax for your lambda expression. See http://msdn.microsoft.com/en-us/library/bb531253.aspx for details of Lambda expressions in vb. In your case its as simple as val1 = val1.OrderBy(Function (c) c ).ToArray ...
LINQ Group By and not contains usage issue
It's not SQL but C#, so a string has quotes not apostrophes and it's && not and, change it to: where !line[12].Contains("VM") && !line[12].Contains("Voice Mail") ...
Updating entity framework model using Linq
You need to update your SQL server with the following columns: UserActivity_UserID, Orders_UserId. Or in the code remove this two columns(Map again your DB to the edmx file)....
Remove the Parent Node based on Child condition
If I understand you correctly: string first = "John"; string last = "D"; XDocument xd = XDocument.Parse(xml); xd.Root.Element("product").Elements("auto").ToList() .ForEach(x=> { var name = x.Descendants("name").First(); if (name.Element("first").Value != first && name.Element("last").Value != last) x.Remove(); }); Console.WriteLine(xd); Print: <result> <product> <auto> <report> <auto> <admin></admin> <report> <search> <subjects> <subject> <name>...
Convert delimited string to array and group using LINQ in C#
public static void Main() { var input = @"**Albert School**: George Branson, Eric Towson, Nancy Vanderburg; **Hallowed Halls**: Ann Crabtree, Jane Goodall, Rick Grey, Tammy Hudson; **XXX University**: Rick Anderson, Martha Zander;"; var universities = input .Split(';') .Select(ParseUniversity) .ToArray(); } public static University ParseUniversity(string line) { var split = line...
Sort Array by contains specific char count
Use: var myNewArray = myArray.OrderByDescending(u => u.Name.Split(' ').Length).ToList(); To count the number of words...
check if a list contains all the element in an array using linq
You can use Enumerable.All: dim linqMeddata = From m In medicineDataList Where keys.All(Function(k) m.MedicineData.Contains(k)) Order By m.MedicineName Ascending Select m ...
how to parse a rgbColor using c#
Easily accomplished with Regex: string colorStr = "rgb(67,134,215)"; Regex regex = new Regex(@"rgb\((?<r>\d{1,3}),(?<g>\d{1,3}),(?<b>\d{1,3})\)"); Match match = regex.Match(colorStr); if (match.Success) { int r = int.Parse(match.Groups["r"].Value); int g = int.Parse(match.Groups["g"].Value); int b = int.Parse(match.Groups["b"].Value); //// Create your new object with the r, g, b values } ...
Order LINQ query elements by a collection of numbers
.net,vb.net,linq,compare,compareto
Change: OrderBy(Function(x) x.index.CompareTo(lineNumbers(x.index))) To: OrderBy(Function(x) lineNumbers.ToList().IndexOf(x.index)) Alternatively, if you changed the type of the lineNumbers parameter from IEnumerable(Of Integer) to List(Of Integer), then you wouldn't need to call the ToList method. Although, I have to say, while I love LINQ because it makes the code so much more readable, this...
“Left XOR” between two lists with LINQ
Using the Enumerable.Except: List<string> xorred = pIsinList.Except( diplayedBondsList.Select(x => x.isin)).ToList(); Note that this command will do implicitly a Distinct() on pIsinList (something that isn't explained in the MSDN, but that if you look at the source is quite clear), so if you had new[] { "A", "A" } in pIsinList,...
Linq where clause with if condition
Something like this: .Where(m => !m.IsDeleted && (m.Project == null || !m.Project.IsDeleted)) You need to check if Project is null before checking if Project.IsDeleted. If you don't want the ones where project isn't null, then you just need: .Where(m => !m.IsDeleted && m.Project != null && !m.Project.IsDeleted) Remember: Shortcut evaluation...
LINQ Operator '==' cannot be applied to operands of type 'char' and 'string'
you're comparing string and char type replace where r1[4] == "I" / where r1[4] == "O" with where r1[4] == 'I' / where r1[4] == 'O'...
nested IN subquery in linq to sql
Everything is fine in your code there is only one mistake i guess. change select iq.AffiliateId to => iq.LenderId var innerquery = from iq in db.AffiliateLenderRelations where iq.AffiliateId == loggedInUser.UserId select iq.AffiliateId; List<SelectListItem> lenders = db.Users .Where(o => o.AccountTypeId == 1 && o.Deleted == false && innerquery.Contains(o.UserId)) .Select(o => new...
Linq query in C#
Without converting to Lambda expressions, you can do: XElement test = XElement.Load(new StringReader(xml)); var testThing = from thing in test.Descendants("vehicle") where thing.Descendants("vehicleType").FirstOrDefault().Value.ToString() == "Car" select thing; ...
Group by day, time and id in one LINQ
If you just want to group for displaying purposes, you don't need the classes GroupedByDay, GroupedByTime and GroupedById Considering examples is an IEnumerable<Example> var groupedExamples = from example in examples group example by new { example.SomeDate.Date, //Day example.SomeDate.Hour, // Hour example.Id // Id } into g select g; Then you'll...
Can't access any of Linq methods
The non-generic IQueryable interface doesn't have extension methods of Count and ToList(). Only the generic IQueryable<T> does. If you can modify the library to return a suitable IQueryable<T>, I suggest you do so. If you can't, you may need to call Cast<T>() or OfType<T>() to create an appropriate IQueryable<T> with...
Compare if the characters in a string are a subset of a second string in C#
This works for me: public static bool IsContainedWithin(this string @this, string container) { var lookup = container.ToLookup(c => c); return @this.ToLookup(c => c).All(c => lookup[c.Key].Count() >= c.Count()); } I tested it like this: var tests = new [] { "met".IsContainedWithin("meet"), "meet".IsContainedWithin("met"), "git".IsContainedWithin("light"), "pall".IsContainedWithin("lamp"), }; I got these results: True False...
In which cases do I need to create two different extension methods for IEnumerable and IQueryable?
c#,.net,linq,ienumerable,iqueryable
myEnumerable.AsQueryable() returns a custom object: new EnumerableQuery<TElement>(myEnumerable); (source code) This EnumerableQuery class implements IEnumerable<T> and IQueryable<T> When using the EnumerableQuery result of .AsQueryable() as an IEnumerable, the implementation of the interface method IEnumerable<T>.GetIterator() simply returns the original source iterator, so no change and minimal overhead. When using the result of...
Join 2 tables with multiple references in LINQ
Somewhere in the lines of: var query1 = (from t1 in table1s join t2 in table2s on t1.Id equals t2.Id1 where !string.IsNullOrEmpty(t1.Name) select new {t1.Name, t2.Id1, t2.Id2, t2.MatchLevel}); var query2 = (from t1 in table1s join t2 in table2s on t1.Id equals t2.Id2 where !string.IsNullOrEmpty(t1.Name) select new {t1.Name, t2.Id1, t2.Id2,...
joining two collections in C# or JavaScript
javascript,c#,linq,collections
There are couple of ways on how you can achieve that, i am guessing you want to use a json file as a source file, so why not convert everything to objects and deal with them that way, which will provide more flexibility to manipulate them and perform more complication...
C# Refactoring gigantic switch statement for ordering with LINQ
The OrderBy function works by letting you return the property it should sort on, it will be called foreach item in the list. Instead of hardcoding it, we can use reflection instead: public ActionResult Index(AgentReportViewModel vm) { var b = Agent.GetAgents(); vm.Agents = vm.SortAscending ? b.OrderBy(x => GetValueByColumn(x, vm.SortByColumn)) :...
Sort a LINQ with another LINQ in MVC
sql-server,linq,entity-framework,controller
Try this: var materialnumb = (from r in db.MaterialNumber where r.MaterialNumber == 80254842 select r.MaterialNumber).FirstOrDefault(); var query = from r in db.SQLViewFinalTable where r.MaterialNumber == materialnumb select r But I can not get whay are you filtering by 80254842 and selecting the same value? You can do directly: var query...
Please help me convert this sql to LINQ
something in the line of...i didn't test this but you may have to do Datetime.Parse etc if needed... (from r1 in dt.Rows.OfType<DataRow>() from r2 in dt.Rows.OfType<DataRow>() where r1["timestart"] < r2["timeend"] && r2["timestart"] < r1["timeend"] && r1["pfid"] != r2["pfid"] select new {R1=r1, R2=r2}) ...
LINQ pad is showing SUM at end of result
LINQad will return results in its Results tab, any enumeration will have at the top of its blue box something like: IEnumerable<EventLogEntry> (114 items) Depending on the exact type. That count at the end is a LINQPad feature when it serializes the data for display, and it is the count...
Distinct all columns in a datatable and store to another datatable with LINQ
Solution 1: Simplest solution would be DefaultView.ToTable. dt.DefaultView.ToTable(true, "PONumber", "Customer", "Address"); Solution 2 : Another alternative would be using Linq statement to filter distinct rows and then looping them as required. var result = dt.AsEnumerable() .Select(row => new { PONumber = row.Field<string>("PONumber"), Customer = row.Field<string>("Customer"), Address = row.Field<string>("Address") }).Distinct(); Solution...
Linq Conditional DefaultIfEmpty query filter
c#,linq,asp.net-mvc-5,linq-query-syntax
I solved it by adding the filter after the initial query, checking if the e.PractitionerProfiles were null. var query = from e in _repository.GetAll<Entity>() from u in e.Users where (e.AuditQuestionGroupId != null ? e.AuditQuestionGroupId : 0) == this.LoggedInEntity.AuditQuestionGroupId from p in e.PractitionerProfiles.DefaultIfEmpty() select new { entity = e, user =...
“CLR detected an Invalid Program” when compiling a constructor for List
The DeclaredConstructors property will return even the static constructor of List<>. You clearly can't invoke it. Use: ConstructorInfo foundConstructor = objectType.GetTypeInfo().GetConstructor(Type.EmptyTypes); ...
ExecuteQuery returns empty collection when there is only a single result
I don't know the exact issue you have, but it will of course return nothing if there are no table in the database. If you want to select all schemas better use: SELECT schema_id, name FROM sys.schemas ...
Linq join and order by
Try this: var file = (from f in context.Files join fa in context.FileActions on f.FileId equals fa.FileId where fa.ActionTaker == "Jeff" && f.FileStatus == 4 orderby fa.ActionDate descending select f).FirstOrDefault(); ...
VB LINQ - Take one random row from each group
One quick way to shuffle items is to sort by a "random" value - Guid.NewGuid() usually works well enough. Then just pull the first row from each group: Dim query = _ From rows As DataRow In surveyAnswerKeys.Rows _ Order By Guid.NewGuid() _ Group By questionSortKey = rows(answerGroup) _ Into...
Linq implementation of for and if loop
This is effectively the same as the answer from Stephen Kennedy, but I sometimes like this syntax. Usually for more complicated things, but still: foreach (var item in from l in list1 where l == eCode select l) { // Do something with each item } ...
Cannot get data using LINQ in MVC
c#,asp.net-mvc,linq,asp.net-mvc-4
Ensure term matches the case of the data. As all the data is loaded (.ToList() in the DAL), the .Where clause uses .Net comparison rather than SQL comparison: var vehicle = _service.GetAll().Where(c => c.Name.StartsWith(term, StringComparison.OrdinalIgnoreCase)... If, in the future, you want to change this to Contains, you can add an...
Removing items from an IEnumerable which match items in a List using LINQ
So you want to remove all ProductUpdate instances from the sequence which have a match in the string-list according to the date? Since an IEnumerable<T> does not support Remove you have to re-create it: productUpates = productUpates .Where(pu => !datesList // your List<string> .Any(str => pu.DueDateTime == DateTime.Parse(str, CultureInfo.InvariantCulture))); If...
How to add empty value from gridview cell to list?
c#,linq,list,datagridview,datagridviewtextboxcell
Your problem is that your cell values can be string, DBNull.Value or null. null.ToString() throws the object reference not set to instance of an object exception. To avoid that you can first set your object as string to get rid of the DBNull.Value and then use the null-coalescing operator to...
How to assign key and count to two different labels asp.net
Try this lblMonth.Text=months.Month; lblCount.Text=months.Count; Also you have to call FirstOrDefault() or ToList() in order to select data. Currently you code will not select data. var months = dates.GroupBy(x => x.Value.Month).Select(g => new { Month = g.Key, Count = g.Count() }).FirstOrDefault(); OR var months = dates.GroupBy(x => x.Value.Month).Select(g => new {...
How can I select items where there exists a reference between each item and all items in a list?
You need all the keywords to be present, so test keywords.All. Within that test for all, you need there to be a matching relevant keyword-reference, so test keywordReferences.Any: from f in forms where keywords.All( kw => keywordReferences.Any( kr => kr.KeywordId == kw.Id && kr.FormId == f.Id)) select f; ...
Count number of occurrences of each month in db table asp.net linq
c#,asp.net,linq,sql-server-2008
How about this? var dates = Enumerable.Range(1, 5).Select(i=>new DateTime(2015,i%3+1,1)); var grouped = dates.GroupBy(d => d.Month).Select(g => string.Format("{0}={1}", g.Key, g.Count())); // Now grouped will have your desired data (list of occurrences) I have used dummy dates here. You need to Select the date column from the database instead....
sqlite query slow, how to optimize (using linq to entities)
c#,linq,entity-framework,sqlite
The biggest optimization would be changing the Contains to a StartsWith. Which would be equivalent to changing from name like '%search%' to name like 'search%'. Otherwise SQLite can't fully use the indexes you placed on the columns and you are basically searching the whole table. // First Name if (!string.IsNullOrEmpty(firstName))...
how can I add a column to IQueryable object and modify its values
Simple example for using a non-anonymous class. public class MyLovelyClass { public Int32 Number { get; set; } public bool Selection { get; set; } } var packs = from r in new XPQuery<Roll>(session) select new MyLovelyClass() { Number = r.number }; gcPack.DataSource = packs; ...
How to declare var datatype in public scope in c#?
Declare it as a known type (not an anonymous type), like this for example: Dictionary<int, string> results = new Dictionary<int, string>(); Then you could store the results in the Dictionary: results = behzad.GAPERTitles.ToDictionary(x => x.id, x => x.gaptitle); And reference it later: private void button1_Click(object sender, EventArgs e) { //...
Convert SQL to linq statement
Just use Any(), which will return a boolean, true if your query returns anything, else false. var result =(from a in _applicationRepository.GetList(a => a.ID == applicationId) from r in _roleRepository.GetList(r => r.ApplicationId == a.ID && r.Name == rolename) from au in _authorizationRepository.GetList(au => au.ApplicationId == a.ID && r.ID == au.RoleId)...
Passing conditional parameters to Database.SqlQuery
You can edit your query to this SELECT * FROM Product p WHERE p.ProductId = @ProductId AND (@CustomerId IS NULL OR p.CustomerId = @CustomerId) Then you pass DBNull.Value to @CustomerId if it is not used...
Convert DataTable into object[ , ] array with LINQ
You cannot use Linq to create a rectangular array - Linq only operates on single-dimension arrays. You will need to use traditional for loops: object[,] objectArray = new object[dtReportData.Rows.Count, dataTable1.Columns.Count]; for(int row = 0; row < dtReportData.Rows.Count; row++) { for(int col = 0; col < dtReportData.Columns.Count; col++) { objectArray[row, col]...
Error when building an XDocument
You can ignore pretty much all your code, the issue is just this: XDocument people = new XDocument("Persons"); You can't create an XDocument containing a string, you need to add an element: XDocument people = new XDocument( new XElement("Persons", original.XPathSelectElements(xpathFilterDups))); ...
Sorting a dictionary value which is a list of objects by given fields
You can use List.Sort, LINQ doesn't work in this case because you can't modify the dictionary(f.e. Add or using the Value property) during enumeration: foreach(var kv in yourSortedDictionary) { kv.Value.Sort((p1, p2) => { int diff = p1.LastName.CompareTo(p2.LastName); if(diff != 0) return diff; return p1.FirstName.CompareTo(p2.FirstName); }); } This works even if...
CSV File header part is coming parsing by LINQ
You seem to be doing the Skip(1) in the wrong place: var csvLinesData = csvlines.Skip(1).Select(l => l.Split(',').ToArray()); // IEnumerable<string[]> As it stands you're skipping the first column for each row, not the first row....
Linq in C++ CLI
xml,linq,visual-c++,xpath,c++-cli
I was able to rewrite your code in such a way: using namespace System; using namespace System::Collections::Generic; using namespace System::Xml::Linq; using namespace System::Xml::XPath; ref class cROI { public: property int iX ; property int iY ; property int iWidth ; property int iHeight; cROI (int piX, int piY,int piWidth,int piHeight...
DbSortClause expressions must have a type that is order comparable. Parameter name: key
You make an order by on your entity. You should do it on one of the property of your entity orderby s.SupplierName or multiple properties, of course : orderby s.SupplierName, s.SupplierLastName, s.SupplierBirthDate descending ...
C# + linq(concat) rewrite to java
var q = (from edge in this.Edges where edge.Start == v select edge.End) .Concat(from edge in this.Edges where edge.End == v select edge.Start); this is same as var q = ctx.Edges.Where(o => o.Start == v).Select(o => o.End).Union( ctx.Edges.Where(o => o.End == v).Select(o => o.Start)).ToList(); and this would be Stream<Node> q...
Load XML to list using LINQ [duplicate]
Make a base class which will have id,x,y,z, and have Vendors,Bankers and Hospitals extend it. Then you can have a collection of the base class, and add to it the classes that inherit from it....
Why does .Where() with a Func parameter executes the query?
c#,oracle,linq,entity-framework
There is a very important difference between Enumerable.Where and Queryable.Where: Enumerable.Where takes a Func<T, bool>. Queryable.Where takes an Expression. Your filter variable is not an Expression, it is a Func<T, bool>, therefore, the compiler uses Enumerable.Where. What happens then is that all rows of your FOO table are transferred to...
How do I convert this tSQL statement to LINQ using group by in a sub query
I think there is opportunity to rewrite your query, but for information purposes I rewrote your sql into linq verbatim. If you explain what you are trying to achieve we can provide alternative sql / linq var eqnums = new[] { "M0435", "Z0843" }; var testdate = "2008-06-01"; var query...
Database error in web api
c#,sql,linq,asp.net-web-api,odata
It's a common error and there is probably some bug in the ADO.NET EF . In my case the error occurred when the edmx model generated had one of the entities listed in upper case, which in the database is listed in lower case. Strange error to find. I modified...
Selecting Multiple Linq Fields Removing Column Names
What you are seeing is the string representation of the object you asked the view to render. You'll need to render each value separately to get your desired output. @foreach(var col in item.cols) { if (!string.IsNullOrEmpty(col.Col1)) { <div>@col.Col1</div> } if (!string.IsNullOrEmpty(col.Col2)) { <div>@col.Col2</div> } if (!string.IsNullOrEmpty(col.Col3)) { <div>@col.Col3</div> } }...
Update list of items in c#
I would do something like this: (for ordinairy lists) // the current list var currentList = new List<Employee>(); currentList.Add(new Employee { Id = 154, Name = "George", Salary = 10000 }); currentList.Add(new Employee { Id = 233, Name = "Alice", Salary = 10000 }); // new list var newList =...
ForEachAsyc with Result
c#,linq,task-parallel-library,task
Your LINQ query can only ever have the same number of results as the number of partitions - you're just projecting each partition into a single result. If you don't care about the order, you just need to assemble the results of each partition into a list, then flatten them...
How To optimise following linq to object query
c#,asp.net,linq,linq-to-objects
Well, couldn't you use a groupby ? var item3 = items.GroupBy (m => m.SKU) .Select(g => new { SKU = g.Key, colors = string.Join("," , g.Select(m => m.color_class) .Distinct()),//you could do a .OrderBy(m => m) after the distinct sizes = string.Join(",", g.Select(m => m.size) .Distinct())//you could do a .OrderBy(m =>...
How does the Take() method work in LINQ
See Return Or Skip Elements in a Sequence. Take(N) will add TOP N to your SQL and only retrieve N records. For example (using my own SQL Server 2014 with EF 6.1): This LINQ: var query = await dbContext.Lookup .Where(w => w.LookupCd == '1') .Take(10) .ToListAsync(); Generates this SQL: SELECT...
Improve my SQL Select statement to select students who have not fully completed a section
Using a subquery with a group by and having statement you can come up with something similar to this: SELECT * FROM Students WHERE StudentID NOT IN ( SELECT s.StudentID FROM Students s JOIN CourseEnrollment ce ON s.StudentID = ce.StudentID JOIN Courses c ON ce.CourseID = c.CourseID WHERE ce.EnrollmentStatus =...
Check if a List contains specific types (multiple)
You can do the following (if there's typo's, I blame the sidetracking thought of crispy bacon as we near lunch time): var types = new List<Type> { typeof(Smokey), typeof(Rasher), typeof(Danish) }; As mentioned in comments, for every item in your bacon list, you want the first matching corresponding type from...
Linq to XML select descendent of descendant each with specific attribute
There are multiple options here, but I'd suggest the simplest thing is just to check each Grandchild: var grandchildren = doc .Descendants("Grandchild") .Where(x => (string) x.Parent.Parent.Attribute("name") == "Ken" && (string) x.Parent.Attribute("name") == "Lorna"); Or you could find all the relevant Child elements and then retrieves their children: var grandchildren =...
Get a single text value using linq
c#,asp.net-mvc,linq,entity-framework,asp.net-mvc-3
Change your Select to be a Where. Where uses a predicate to filter the data and return the same structure...just a subset. Select on the other hand changes the data structure to be whatever is evaluated in the provided function. In your case you are changing the structure to be...
Dividing an Expression in C# using Expression.AndAlso() causes an Exception
Because where you see a single c parameter, in truth there are two different c parameters (let's call them c1 and c2). So when you merge the two expressions you have: c1 => c1.Something && c2.SomethingElse; And the CLR gets angry because it can't find the c2. Worse, as you...
LINQ: Searching inside child entities
One option would be to use LINQ .Any(): var stringResults = db.Properties.Where(x => x.Address.Contains(id) || /* Other conditions || */ x.BayOptions.Any(g => g.Description.Contains(id))); Here, x.BayOptions.Any(g => g.Description.Contains(id)) will return true if any of the BayOptions values have a description which contains the ID....
Search functionality across many columns
I guess the main question is, how should the value match against a numeric column? For example, if the column has "123" and "2" should match it, then you're essentially treating the column as a string rather than a number. In that case, just treat it like a string: ||...
C# lambda expressions without variable / parameter declaration?
Methods don't accept lambdas as parameters. They accept delegates as parameters. A lambda is just one way of creating a delegate. Another way is supplying a method group, as is done in your second example, which can be converted to a delegate. A similar way is to use the anonymous...
LINQ: How to add multiple fields for grouping
If I understand you well, you need this: from line in csvLinesData group line by new { prop1 = line[12], Time = DateTime.Parse(line[0]).TimeOfDay } into newGroup orderby newGroup.Key.prop1, newGroup.Key.Time select newGroup; Since line[0] is a string (apparently), you have to parse it to a DateTime value. I show the most...
Listing directories by content size using C# [closed]
A small example here: class DirectorySize { public string DirectoryName; public long DirectorySizes; } public class Program { static void Main(string[] args) { string[] cDirectories = Directory.GetDirectories("C:\\"); List<DirectorySize> listSizes = new List<DirectorySize>(); for (int i = 0; i < cDirectories.Length; i++) { long size = GetDirectorySize(cDirectories[i]); if(size != -1) {...
Distinct() How to find unique elements in list of objects
You need to actually pass the IEqualityComparer that you've created to Disctinct when you call it. It has two overloads, one accepting no parameters and one accepting an IEqualityComparer. If you don't provide a comparer the default is used, and the default comparer doesn't compare the objects as you want...
LINQ to Entities Retrieving related Entities or T-SQL
you can try selecting from Vendors and using Any() for ShowId. Vendor[] vendorsInShow = (from v in db_.Vendor .Include("Products.Pics") .Where(m => m.Booths.Any(a => a.ShowID == showId) && m.Products.Count > 0) select v).AsNoTracking().ToArray(); ...