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  • How cast in c#/.net 3.5 works? for types with '?'

    - by Inez
    This is my code which works public decimal? Get() { var res = ... return res.Count() > 0 ? res.First() : (decimal?) null; } and this one doesn't work public decimal? Get() { var res = ... return res.Count() > 0 ? res.First() : null; } giving the compilator error: Error 1 Type of conditional expression cannot be determined because there is no implicit conversion between 'decimal' and '' I wonder why? any ideas?

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  • Losing scope for DataContex using LINQToSQL intermediately

    - by greektreat
    I am having a weird Situation with my DataConext. All My code is in C# I have a DLL project for my data access layer and business Layer which and Winforms project for my UI layer. My Data access Layer's Namespace is xxx.Data this is where have my xxx.dbml I also have xxx.Data.BusinessObjects name space of course for my business object in that project In my UI Layer I have these namespaces xxxApp(for Forms), xxxApp.Controls (For Controls) I have lost scope of the DataContext, it was accessible now when I do a Rebuild Solution I sometimes get compile errors saying for example: Error 34 'xxx.Data.xxxDataContext' does not contain a definition for 'SubmitChanges' and no extension method 'SubmitChanges' accepting a first argument of type 'xxx.Data.xxxDataContext' could be found (are you missing a using directive or an assembly reference?) Also intelisense doesn't recognize the methods and table classes from my xxxDataContext anymore I can access all object fine when I am in the DLL project but now in the Winforms project this is very strange. If anyone can help me out I would be extremely grateful!

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  • DataContext to DB

    - by JD
    Hi all, I have designed my DB using the ORM in VS 2008. What is the best way to export this to an SQL server so it will create the tables and relations on SQL Server? Thanks, JD

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  • Caching stored procedure results in Linq'u

    - by itdebeloper
    In our web application we have a lots of stored procedures look like this one: getSomeData(/* 7 diffrent params */) This stored procedure don't make any updates. We are using Linq'u. I know that the date are changing no often than once per day so the results for the same sets of parameters values will be the same. Does Linqu have cache simple solution? I know how to 'manually' write cache mechanism in .net, but I supposed that in Linqu this problem was solved. I'm a lazy guy :) so I'm looking for something realy simple like: Linqu_global_store_procedure_configuration.CacheDuration="600" Linqu_global_store_procedure_configuration.CacheVaryByParam="*" I'm using .net 3.5 but its not any problem to move for 4.0.

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  • data filter using dataloadoptions

    - by Tassadaque
    Using dataloadoptions i have tried the following example Northwnd db = new Northwnd(@"northwnd.mdf"); // Preload Orders for Customer. // One directive per relationship to be preloaded. DataLoadOptions ds = new DataLoadOptions(); ds.LoadWith<Customer>(c => c.Orders); ds.AssociateWith<Customer> (c => c.Orders.Where(p => p.ShippedDate != DateTime.Today)); db.LoadOptions = ds; var custQuery = from cust in db.Customers where cust.City == "London" select cust; foreach (Customer custObj in custQuery) { Console.WriteLine("Customer ID: {0}", custObj.CustomerID); foreach (Order ord in custObj.Orders) { Console.WriteLine("\tOrder ID: {0}", ord.OrderID); foreach (OrderDetail detail in ord.OrderDetails) { Console.WriteLine("\t\tProduct ID: {0}", detail.ProductID); } } } Now i need to ask how can i display Category ID and Category Name of the productID (i am supposing that One product can be in at most one category) by extending the above example Regards

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  • Would you make this method Static or not?

    - by Adam Drummond
    During a code review I presented a method quickly to the team that I had made static and one person agreed that there was no reason for it to not be static and a person disagreed saying that he would not make it static because it wasn't necessary and just to be on the safe side for future modifications and testing. So I did quite a bit of research and obviously it's a specialized case but I would like to know what you would do in this situation and why? (Its basically a helper method I call from a few different methods, a very low traffic page. More for my knowledge and learning on Static.) private IEnumerable<Category> GetCategoryByID(int id, Context context) { var categoryQuery = from selectAllProc in context.SelectAll_sp() where selectAllProc.CategoryID == id select selectAllProc; return categoryQuery; }

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  • How to do rolling balances in Linq2SQL

    - by David Liddle
    Given an account with a list of transactions I would like to output a query that shows each transaction with the rolling balance (just like you would see on an online banking account). TRANSACTIONS - ID - DATE - AMOUNT Here is what I created in T-SQL however was wondering if this can be translated to linq2sql code? select T.ID, convert(char(10), T.DATE, 101) as 'DATE', T.AMOUNT, (select sum(O.AMOUNT) from TRANSACTIONS O where O.DATE < T.DATE or (O.DATE = T.DATE and O.ID <= T.ID)) 'BALANCE' from TRANSACTIONS as T where T.DATE between @pStartDate and @pEndDate order by T.DATE, T.ID Alternatively I guess my other option is to just call a stored procedure for these kind of results. However, I have Services which call Repositories and didn't really want to put the sproc call in the Repository.

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  • asp.net viewdata

    - by mazhar
    public ActionResult AddDinner() { Dinner dinner = dinnerRepository.GetDinner(id); ViewData["dinner"] = repository.AllDinners(); return View(dinner); } 1) First of all both the dinner object and the ViewData["dinner"] is passing to the view? 2) Secondly how would I iterate over the ViewData["dinner"] in the view?

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  • how to find last version no from a list<> in C#

    - by Rohit
    I have a entity class RenderingTemplates. Inside this i have a property List which holds all versions of rendering template. RenderingTemplateVersion has a property VersionName which stores version name as "Version 1.0". I am creating a new version and want to find last version no.so that i can append it by 1 and make new VersionName as "Version 2.0". To accomplish this i have LatestVersion = template.RenderingTemplateVersionList.OrderByDescending(e => e.VersionName.Split(new char[] { ' ', '.' })[1]).First() LatestVersion is a integer. How to convert this to integer.Please help or suggest some other way.

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  • Showing multiple models in a single ListView

    - by Veer
    I've three models (Contacts, Notes, Reminders). I want to search all these and produce the filtered result in a single listview and depending upon the selection I've to display the corresponding view(UserControl) to its right. I want the right way of implementing the design or atleast alternatives to this method that I've tried. Now I've tried it using a IntegratedViewModel having all the properties from all the three models. public class IntegratedViewModel { ContactModel _contactModel; NoteModel _noteModel; public IntegratedViewModel(ContactModel contactModel) { _contactModel = contactModel; } // similarly for other models also public string DisplayTitle // For displaying in ListView { get; //same as set set { If(_contactModel != null) return _contactModel.Name; If(_noteModel != null) return _noteModel.Title; } } // All other properties from the three models includin the Name/Title properties for displaying them in the corresponding views(UserControl) } Now I set the itemsSource as the List<IntegratedViewModel>. I've to now bind the visibility of the views to some properties in the MainViewModel. I tried setting bool properties like IsContactViewSelected, IsNoteViewSelected using the setter of SelectedEntity property which is bound to the ListView's SelectedItem. public SelectedEntity { //get set { oldvalue = _selectedEntity; _selectedEntity = value; // now i find the Type of model selected using oldvalue.ModelType // where ModelType is a property in the IntegratedViewModel // according to the type, i set one of the above bool properties to false // and do the same for _selectedEntity but set the property to true // so that the view corresponding to the selectedEntityType is visible // and others are collapsed } } Here is the problem: For eg: let us say, I selected an item of type ContactModel, the old selection being NoteModel. I set the property IsNoteModelSelected to false according to the oldvalue, it sets the property and then Raises the propertychanged event and does not go and check the remaining if condition where i check for _selectedEntity which is used to set the IsContactModelSelected to true.

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  • How can I check the type of an object against a list of types?

    - by RookieRick
    Given a collection IEnumerable<Type> supportedTypes What's the best way to check whether a given object is one of those types (or a derived type)? My first instinct was to do something like: // object target is a parameter passed to the method in which I'm doing this. if (supportedTypes.Count( supportedType => target is supportedType ) > 0) { // Yay my object is of a supported type!!! } ..but that doesn't seem to be working. Can I not use the "is" keyword in a lambda expression like this?

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  • Matching on search attributes selected by customer on front end

    - by CodeNinja1974
    I have a method in a class that allows me to return results based on a certain set of Customer specified criteria. The method matches what the Customer specifies on the front end with each item in a collection that comes from the database. In cases where the customer does not specify any of the attributes, the ID of the attibute is passed into the method being equal to 0 (The database has an identity on all tables that is seeded at 1 and is incremental). In this case that attribute should be ignored, for example if the Customer does not specify the Location then customerSearchCriteria.LocationID = 0 coming into the method. The matching would then match on the other attributes and return all Locations matching the other attibutes, example below: public IEnumerable<Pet> FindPetsMatchingCustomerCriteria(CustomerPetSearchCriteria customerSearchCriteria) { if(customerSearchCriteria.LocationID == 0) { return repository.GetAllPetsLinkedCriteria() .Where(x => x.TypeID == customerSearchCriteria.TypeID && x.FeedingMethodID == customerSearchCriteria.FeedingMethodID && x.FlyAblityID == customerSearchCriteria.FlyAblityID ) .Select(y => y.Pet); } } The code for when all criteria is specified is shown below: private PetsRepository repository = new PetsRepository(); public IEnumerable<Pet> FindPetsMatchingCustomerCriteria(CustomerPetSearchCriteria customerSearchCriteria) { return repository.GetAllPetsLinkedCriteria() .Where(x => x.TypeID == customerSearchCriteria.TypeID && x.FeedingMethodID == customerSearchCriteria.FeedingMethodID && x.FlyAblityID == customerSearchCriteria.FlyAblityID && x.LocationID == customerSearchCriteria.LocationID ) .Select(y => y.Pet); } I want to avoid having a whole set of if and else statements to cater for each time the Customer does not explicitly select an attribute of the results they are looking for. What is the most succint and efficient way in which I could achieve this?

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  • ToList()-- Does it Create a New List?

    - by Ngu Soon Hui
    Let's say I have a class public class MyObject { public int SimpleInt{get;set;} } And I have a List<MyObject>, and I ToList() it and then change one of the SimpleInt, will my change be propagated back to the original list. In other words, what would be the output of the following method? public void RunChangeList() { var objs = new List<MyObject>(){new MyObject(){SimpleInt=0}}; var whatInt = ChangeToList(objs ); } public int ChangeToList(List<MyObject> objects) { var objectList = objects.ToList(); objectList[0].SimpleInt=5; return objects[0].SimpleInt; } Why? P/S: I'm sorry if it seems obvious to find out. But I don't have compiler with me now...

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  • Merging ILists to bind on datagridview to avoid using a database view

    - by P.Bjorklund
    In the form we have this where IntaktsBudgetsType is a poorly named enum that only specifies wether to populate the datagridview after customer or product (You do the budgeting either after product or customer) private void UpdateGridView() { bs = new BindingSource(); bs.DataSource = intaktsbudget.GetDataSource(this.comboBoxKundID.Text, IntaktsBudgetsType.PerKund); dataGridViewIntaktPerKund.DataSource = bs; } This populates the datagridview with a database view that merge the product, budget and customer tables. The logic has the following method to get the correct set of IList from the repository which only does GetTable<T>.ToList<T> public IEnumerable<IntaktsBudgetView> GetDataSource(string id, IntaktsBudgetsType type) { IList<IntaktsBudgetView> list = repository.SelectTable<IntaktsBudgetView>(); switch (type) { case IntaktsBudgetsType.PerKund: return from i in list where i.kundId == id select i; case IntaktsBudgetsType.PerProdukt: return from i in list where i.produktId == id select i; } return null; } Now I don't want to use a database view since that is read-only and I want to be able to perform CRUD actions on the datagridview. I could build a class that acts as a wrapper for the whole thing and bind the different table values to class properties but that doesn't seem quite right since I would have to do this for every single thing that requires "the merge". Something pretty important (and probably basic) is missing the the thought process but after spending a weekend on google and in books I give up and turn to the SO community.

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  • ASP.NET MVC Inserting object and related object into 2 tables

    - by ile
    I have two tables: Users and UserOwners. Table UserOwners contains list of users that certain user created (list of child-users) - or to be more precise, it contains UserOwnerID and UserID fields. So, now I want to create a new user... in Controller I have something like this: var userOwner = accountRepository.GetUser(User.Identity.Name); var userOwnerID = userOwner.UserID; UserReference userReference = new UserReference(); userReference.UserOwnerID = userOwnerID; if (ModelState.IsValid) { try { //accountRepository.Add(user); //accountRepository.Save(); return View(); } catch { return View(); } } What is the easiest way to add new user to a table Users and matching UserOwner to UserOwners table. Is it suppose to be something like this? public void Add(User user) { db.Users.InsertOnSubmit(user); db.UserReferences.InsertOnSubmit(user.UserReference); } ...or I will have to pass two objects and after adding user I must read it's ID and than assign it to userReference object and add that object to DB? If so, how to read ID of the last object added? Thanks, Ile

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  • How do I use XPath with a default namespace with no prefix?

    - by Scott Stafford
    What is the XPath (in C# API to XDocument.XPathSelectElements(xpath, nsman) if it matters) to query all MyNodes from this document? <?xml version="1.0" encoding="utf-8"?> <configuration> <MyNode xmlns="lcmp" attr="true"> <subnode /> </MyNode> </configuration I tried /configuration/MyNode which is wrong because it ignores the namespace. I tried /configuration/lcmp:MyNode which is wrong because lcmp is the URI, not the prefix. I tried /configuration/{lcmp}MyNode which failed because Additional information: '/configuration/{lcmp}MyNode' has an invalid token. EDIT: I can't use mgr.AddNamespace("df", "lcmp"); as some of the answerers have suggested. That requires that the XML parsing program know all the namespaces I plan to use ahead of time. Since this is meant to be applicable to any source file, I don't know which namespaces to manually add prefixes for. It seems like {my uri} is the XPath syntax, but Microsoft didn't bother implementing that... true?

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  • How do I differentiate between different descendents with the same name?

    - by zotty
    I've got some XML I'm trying to import with c#, which looks something like this: <run> <name = "bob"/> <date = "1958"/> </run> <run> <name = "alice"/> <date = "1969"/> </run> I load my xml using XElement xDoc=XElement.Load(filename); What I want to do is have a class for "run", under which I can store names and dates: public class RunDetails { public RunDetails(XElement xDoc, XNamespace xmlns) { var query = from c in xDoc.Descendants(xmlns + "run").Descendants(xmlns + "name") select c; int i=0; foreach (XElement a in query) { this.name= new NameStr(a, xmlns); // a class for names Name.Add(this.name); //Name is a List<NameStr> i++; } // Here, i=2, but what I want is a new instance of the RunDetails class for each <run> } } How can I set up my code to create a new instance of the RunDetails class for every < run, and to only select the < name and < date inside a given < run?

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  • [C#] How to create a constructor of a class that return a collection of instances of that class?

    - by codemonkie
    My program has the following class definition: public sealed class Subscriber { private subscription; public Subscriber(int id) { using (DataContext dc = new DataContext()) { this.subscription = dc._GetSubscription(id).SingleOrDefault(); } } } ,where _GetSubscription() is a sproc which returns a value of type ISingleResult<_GetSubscriptionResult> Say, I have a list of type List<int> full of 1000 ids and I want to create a collection of subscribers of type List<Subscriber>. How can I do that without calling the constructor in a loop for 1000 times? Since I am trying to avoid switching the DataContext on/off so frequently that may stress the database. TIA.

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  • Write Unit test for sorting

    - by user175084
    I need to write a unit test for a method where I arrange data according to another default list. This is the method. internal AData[] GetDataArrayInInitialSortOrder(ABData aBData) { Dictionary<string,AData > aMap = aBData.ADataArray.ToDictionary(v => v.GroupName, v => v); List<AData> newDataList = new List<AData>(); foreach (AData aData in _viewModel.ADList) newDataList.Add(aMap[aData.GroupName]); return newDataList.ToArray(); } Please help I am new in unit testing and this is not easy for me. Any sample or links are appreciated Thanks

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  • Entity Framework 5 upgrade from 4

    - by user1714591
    I'm having an issue with the Where clause in a search, in my original version EF4 I could add a Where clause with 2 parameters, the where clause (string predicate) and a ObjectParameter list such as var query = context.entities.Where(WhereClause.ToString(), Params.ToArray()); since my upgrade to EF5 I don't seem to have that option am I missing something? This was originally used to build dynamic where clause such as "it.entity_id = @entity_id" then holding the variable value in the ObjectParameter. I'm hoping I don't have to rewrite all the searches that have been built out this way, so any assistance would be greatly appreciated. Cheers

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  • What does P mean in Sort(Expression<Func<T, P>> expr, ListSortDirection direction)?

    - by Grasshopper
    I am attempting to use the answer in post: How do you sort an EntitySet<T> to expose an interface so that I can sort an EntitySet with a Binding list. I have created the class below and I get the following compiler error: "The type or namespace 'P' could not be found (are you missing a using directive or assembly reference?). Can someone tell me what the P means and which namespace I need to include to get the method below to compile? I am very new to delegates and lamba expressions. Also, can someone confirm that if I create a BindingList from my EntitySet that any modifications I make to the BindingList will be made to the EntitySet? Basically, I have an EntitySet that I need to sort and make changes to. Then, I will need to persist these changes using the original Entity that the BindingList came from. public class EntitySetBindingWrapper<T> : BindingList<T> { public EntitySetBindingWrapper(BindingList<T> root) : base(root) { } public void Sort(Expression<Func<T, P>> expr, ListSortDirection direction) { if (expr == null) base.RemoveSortCore(); MemberExpression propExpr = expr as MemberExpression; if (propExpr == null) throw new ArgumentException("You must provide a property", "expr"); PropertyDescriptorCollection descriptorCol = TypeDescriptor.GetProperties(typeof(T)); IEnumerable<PropertyDescriptor> descriptors = descriptorCol.Cast<PropertyDescriptor>(); PropertyDescriptor descriptor = descriptors.First(pd => pd.Name == propExpr.Member.Name); base.ApplySortCore(descriptor, direction); } }

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  • Getting percentages.

    - by user287798
    Hi, i have got a standing answer in this thread. http://stackoverflow.com/questions/2396203/get-the-count-of-elements-where-candidate-has-won But i am failing to get the percentage, what am i doing wrong. I have the code below. var s4 = from can in allCandidates let noDists= ((from d in root.Elements("Provinces") select d.Attribute("Province").Value).Distinct()).Count() let count = (from winner in (from p in root.Descendants("Province_Data") let maxVotes = (from c in p.Elements("Candidate") select c) .Max(x => ((int)x.Element("votes"))) select (from c in p.Elements("Candidate") select c).Where(x => ((int)x.Element("votes")) == maxVotes) .First().Element("name").Value ) where winner == can select winner).Count() orderby count descending select new { Candidate = can, NumberOfProvincesWon = count,Percentage= (count/noDists)*100}; foreach (var d in s4) Console.WriteLine(" {0}", d.ToString());

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