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  • Linq to sql translation to sql of custom method

    - by DJPB
    hi there is there a way to translate an expression to sql to use with linq to sql? for example I have a method that compares two values example: MyComparer.Compare(value1, value2, ">") return value1 > value2 MyComparer.Compare(value1, value2, "=") return value1 == value2 MyComparer.Compare(value1, value2, "<=") return value1 <= value2 and i would like a query like var list = from i in dataContext.items where MyComparer.Compare(i.value, someValue, "some operator") select ... this won't work because, obviously, MyComparer doesn't translate to sql maybe this is a twisted question, but how can i translate this method to sql or is this possible? tks

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  • Linq sql Attach, Update Check set to Never, but still Concurrency conflicts

    - by remdao
    In the dbml designer I've set Update Check to Never on all properties. But i still get an exception when doing Attach: "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." This approach seems to have worked for others on here, but there must be something I've missed. using(TheDataContext dc = new TheDataContext()) { test = dc.Members.FirstOrDefault(m => m.fltId == 1); } test.Name = "test2"; using(TheDataContext dc = new TheDataContext()) { dc.Members.Attach(test, true); dc.SubmitChanges(); }

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  • Templated Control databinding to custom properties

    - by Dan Wray
    Is there some trick that I'm missing here? I've created a templated control, very simple. One single property on it, and I'd like to databind from the (viewmodel/datacontext of the) page in which it's hosted to a custom property on the control. The property will eventually be a vector type object, defining the position of the control, however in an attempt to get this to work I've tried reducing it to a basic string property. Each time I'm faced with "Set property 'SimpleGame.Classes.Sprite.Property' threw an exception.". I can't even catch the exception in a debug session, the set property code is not being executed. Do I need to use a dependency / attached property or something? I wouldn't have thought so...

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  • Current Time Not working in WPF DLL

    - by Anu
    HI, I making one DLL in WPF,C# and im using it in VC++.In that DLL, ihave one textblock to display current time,But when i run the WPF application as WIndows application it shows current time correctly and also updated with new timings.But when i use it as Dll in VC++ applcation,the current time is not get updating.It shows the time when the applcaiton is loaded.thats all.Its not get updated. Code: public Button() { InitializeComponent(); DispatcherTimer dispatcherTimer = new DispatcherTimer(); dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick); dispatcherTimer.Interval = new TimeSpan(0, 0, 1); dispatcherTimer.Start(); } private void dispatcherTimer_Tick(object sender, EventArgs e) { DataContext = DateTime.Now.ToString("g"); } XAML: <TextBlock Margin="0,6,211,0" Name="textBlock1" Text="{Binding}"/>

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  • Binding the property to a control defined inside a listboxitem template

    - by Malcolm
    I have a class called ledgerObject : public class LedgerObject { public ChargeLine ChargeLine{ get; set; } public DelegateCommand Click_hyperbnCommand{ get; private set; } public LedgerObject() { this.Click_hyperbnCommand = new DelegateCommand(click_btn); } private void click_btn(object args) { } } The chargeLine which is the property of this class is itself a class and has some properties in it. So I am binding the datacontext of a listbox to an array of LedgerObject, and I want to bind the textblock control defined inside a listboxitem template to the property of a ChargeLine. Any idea or suggestion will help. I have tried this but not working: <TextBlock Margin="4 0 4 0" Grid.Column="3" Text="{Binding Path=ChargeLine.SimCode}" TextDecorations="Underline" Foreground="Red" />

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  • Compiled Queries and "Parameters cannot be sequences"

    - by David B
    I thought that compiled queries would perform the same query translation as DataContext. Yet I'm getting a run-time error when I try to use a query with a .Contains method call. Where have I gone wrong? //private member which holds a compiled query. Func<DataAccess.DataClasses1DataContext, List<int>, List<DataAccess.TestRecord>> compiledFiftyRecordQuery = System.Data.Linq.CompiledQuery.Compile <DataAccess.DataClasses1DataContext, List<int>, List<DataAccess.TestRecord>> ((dc, ids) => dc.TestRecords.Where(tr => ids.Contains(tr.ID)).ToList()); //this method calls the compiled query. public void FiftyRecordCompiledQueryByID() { List<int> IDs = GetRandomInts(50); //System.NotSupportedException //{"Parameters cannot be sequences."} List<DataAccess.TestRecord> results = compiledFiftyRecordQuery (myContext, IDs); }

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  • WPF Accessing Items inside Listbox which has a UserControl as ItemTemplate

    - by Turker
    I have Window that has a ListBox ListBox(MyListBox) has a DataTable for its DataContext ListBox's ItemSource is : {Binding} Listbox has a UserControl(MyUserControl) as DataTemplate UserControl has RadioButtons and TextBoxes (At first They're filled with values from DataTable and then user can change them) Window has one Submit Button What I want to do is, when user clicks the submit button For each ListBox Item, get the values form UserControl's TextBoxes and RadioButtons. I was using that method for this job : foreach(var element in MyListBox.Items) { var border = MyListBox.ItemContainerGenerator.ContainerFromItem(element)as FrameworkElement; MyUserControl currentControl = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(myBorder,0) as Border,0)as ContentPresenter,0)as MyUserControl; //And use currentControl } I realised nothing when using 3-5 items in Listbox. But when I used much more items, I saw that "var border" gets "null" after some elements looped in foreach function. I found the reason here : http://stackoverflow.com/questions/1675926/listview-itemcontainergenerator-containerfromitemitem-return-null-after-20-item So what can I do now? I want to access all items and get their values sitting on user controls. Thanks

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  • data binding on properties confusion

    - by Xience
    I have a wpf tabitem whose data context is set to my object 'Product'. All the controls on this form get their data from 'Product' object. I have a listview whose ItemsSource property is set to a list in my object 'Product.DetailsList'. Listview columns are bound to object properties in 'Product.DetailsList' Up till here everything works fine. Now I need to bind some of the columns in my listview to the properties in my datacontext object i.e.'Product'. Can someone tell me how can i achieve this?

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  • How to customize tooltip for silverlight control?

    - by KentZhou
    SL provide ToolTipService.ToolTip for simple tooltip. I want to customize tooltip with my own user control. One way is to do something like: <TextBlock Text="Hello" > <ToolTipService.ToolTip> <TextBlock Text="I can help you." /> <!--replace this with user control --> </ToolTipService.ToolTip> </TextBlock> But what I want is: 1) create a style for tooltip, so that it can be set as something like <TextBlock Text="Hello" Style="{StaticResource TextBlockWithToolTip}" > 2) Content for tooltip can be set dynamically from datacontext, such as title, content, etc. How to implement it?

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  • Strange exception while using linq2sql

    - by zerkms
    Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.ArgumentNullException: Value cannot be null. Parameter name: mapping Source Error: Line 45: #endregion Line 46: Line 47: public db() : Line 48: base(global::data.Properties.Settings.Default.nanocrmConnectionString, mappingSource) Line 49: { this is what i get if i implement such class: partial class db { static db _db = new db(); public static db GetInstance() { return _db; } } db is a linq2sql datacontext why this hapenned and how to solve this?

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  • How do I improve the efficiency of the queries executed by this generic Linq-to-SQL data access clas

    - by Lee D
    Hi all, I have a class which provides generic access to LINQ to SQL entities, for example: class LinqProvider<T> //where T is a L2S entity class { DataContext context; public virtual IEnumerable<T> GetAll() { return context.GetTable<T>(); } public virtual T Single(Func<T, bool> condition) { return context.GetTable<T>().SingleOrDefault(condition); } } From the front end, both of these methods appear to work as you would expect. However, when I run a trace in SQL profiler, the Single method is executing what amounts to a SELECT * FROM [Table], and then returning the single entity that meets the given condition. Obviously this is inefficient, and is being caused by GetTable() returning all rows. My question is, how do I get the query executed by the Single() method to take the form SELECT * FROM [Table] WHERE [condition], rather than selecting all rows then filtering out all but one? Is it possible in this context? Any help appreciated, Lee

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  • Rollback in lucene

    - by Petrick Lim
    Is there a rollback in lucene? I'm saving & updating database repository & lucene repository simultaneously so that the lucene index & database are in sync.. ex. CustomerRepository.add(customer); SupplierRepository.add(supplier); CustomerLuceneRepository.add(customer); SupplierLuceneRepository.add(supplier); // If this here fails i cannot rollback the customer above DataContext.SubmitChanges();

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  • How do I return an empty result set from a procedure using T-SQL?

    - by Kivin
    I'm interested in returning an empty result set from SQL Server stored procedures in certain events. The intended behaviour is that a L2SQL DataContext.SPName().SingleOrDefault() will result in CLR null value. I'm presently using the following solution, but I'm unsure whether it would be considered bad practice, a performance hazard (I could not find one by reading the execution plan), or if there is simply a better way: SELECT * FROM [dbo].[TableName] WHERE 0 = 1; The execution plan is a constant scan with a trivial cost associated with it. The reason I am asking this instead of simply not running any SELECTs is because I'm concerned previous SELECT @scalar or SELECT INTO statements could cause unintended result sets to be served back to L2SQL. Am I worrying over nothing?

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  • Updating multiple tables with LinqToSql in one unit of work

    - by zsharp
    Table 1: int ID-a(pk) Table 2: int ID-a(pk), int ID-b(pk) Table 3: int ID-b(pk), string C I have the data to insert into Table 1. But I do not have the ID-a, which is autogenerated. I have many string C to insert in Table 3. I am trying to insert row into Table 1, get the ID-a to insert in Table 2 along with the ID-b that is auto-Generated in Table 3 when I submit each string C, all in one submission to db. Right now I am calling dc.SubmitChanges twice in same call. Is it efficient to have to submit changes twice on same DataContext or can this be combined further?

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  • NerdDinner difficulties

    - by George
    Hello guys, I'm having a problem with the Create method of the NerdDinner tutorial, which is very good BTW. As you can see here http://nerddinnerbook.s3.amazonaws.com/Part5.htm in the Create method, he removed the ID field of the aspx page. I did that too, but I cannot add any dinners because I get a primary key violation. How is NerdDinner controlling the ids of each dinner? I revised the tutorial and could not see any references to identity fields on SQL database. I even created a method to get me the highest id in the table: public int GetHighestDinnerId() { int resultado = (from dinner in dataContext.Dinners select dinner.DinnerId).Max(); return resultado; } which does not work either. Any thoughts? Thank you

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  • StructureMap: Wiring (generic) implementations to an implementation of another type

    - by Jeremy Frey
    If I have an interface: public interface IRepository<T> And an abstract class: public abstract class LinqToSqlRepository<T, TContext> : IRepository<T> where T : class where TContext : DataContext And a whole bunch of implementations of IRepository / LinqToSqlRepository (e.g. AccountRepository, ContactRepository, etc.), what's the best way to to use StructureMap (2.5.3) to generically wire them all up? e.g., I want this code to pass: [Test] public void ShouldWireUpAccountRepositories { var accountRepo = ObjectFactory.GetInstance<IRepository<Account>>(); Assert.IsInstanceOf<AccountRepository>(accountRepo); } Without explicitly writing this: ObjectFactory.Configure(x => x.ForRequestedType<IRepository<Account>>() .TheDefaultIsConcreteType<AccountRepository>()); In the past, we've always created a specific interface on each repository that inherited from the generic one, and used the default scanner to automatically wire all of those instances, but I'd like to be able to ask specifically for an IRepository<Account> without cluttering up the project with additional interfaces / configurations.

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  • .Remove(object) on a List<T> returned from LINQ to SQL compiled query won't delete the Object right

    - by soldieraman
    I am returning two lists from the database using LINQ to SQL compiled query. While looping the first list I remove duplicates from the second list as I dont want to process already existing objects again. eg. //oldCustomers is a List returned by my Compiled Linq to SQL Statmenet that I have added a .ToList() at the end to //Same goes for newCustomers for (Customer oC in oldCustomers) { //Do some processing newCustomers.Remove(newCusomters.Find(nC=> nC.CustomerID == oC.CusomterID)); } for (Cusomter nC in newCustomers) { //Do some processing } DataContext.SubmitChanges() I expect this to only save the changes that have been made to the customers in my processing and not Remove or Delete any of my customers from the database. Correct? I have tried it and it works fine - but I am trying to know if there is any rare case it might actually get removed

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  • LINQ to SQL stored procedures with multiple results in Visual Studio 2008

    - by Jeremy
    I'm using visual studio 2008 and I've created a stored procedure that selects back two different result sets. I drag the stored proc on to a linq to sql dbml datacontext class, causing visual studio to create the following code in the cs file: [Function(Name="dbo.List_MultiSelect")] public ISingleResult<DataAccessLayer.DataEntities.List_MultiSelectResult> List_MultiSelect() { IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod()))); return ((ISingleResult<DataAccessLayer.DataEntities.List_MultiSelectResult>)(result.ReturnValue)); } Shouldn't the designer generate the code to use IMultipleResults? Or do I have to hand code that?

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  • Difference in linq-to-sql query performance using GenericRespositry

    - by Neil
    Given i have a class like so in my Data Layer public class GenericRepository<TEntity> where TEntity : class { [System.ComponentModel.DataObjectMethod(System.ComponentModel.DataObjectMethodType.Select)] public IQueryable<TEntity> SelectAll() { return DataContext.GetTable<TEntity>(); } } I would be able to query a table in my database like so from a higher layer using (GenericRepositry<MyTable> mytable = new GenericRepositry<MyTable>()) { var myresult = from m in mytable.SelectAll() where m.IsActive select m; } is this considerably slower than using the usual code in my Data Layer using (MyDataContext ctx = new MyDataContext()) { var myresult = from m in ctx.MyTable where m.IsActive select m; } Eliminating the need to write simple single table selects in the Data layer saves a lot of time, but will i regret it?

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  • select n largest using LINQ

    - by Mathias
    This is likely a novice question about LINQ, but assuming I have a set of Items with a DateTime property, one date having at most one item, how would I go about selecting the N most recent items from a date of reference, that is, the N items which have a date smaller that the requested date, and the largest date? My naive thought would be to first select items with a date smaller than the reference date, sort by date, and select the N first items from that subset. var recentItems = from item in dataContext.Items where item.Date<=date orderby item.Date descending select item; var mostRecentItems = recentItems.Take(5).ToList(); Is this the "right" way to do it, or are there obviously better ways to achieve my goal?

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  • WPF DataGrid adding extra "ghost" row

    - by hs2d
    Hei, In my application i'm using DataGrid to show some data. To get everything working with threading i'm using AsyncObservableCollection as DataContext of DataGrid. When my application starts it looks for files in some folders and updates AsyncObservableCollection. Now here's where things go bad, when i start the application for some reason i get 2 rows with same data in DataGrid even if there is one item in collection. If i add a delay(Thread.Sleep() 50ms minimum) before executing loading files method then DataGrid show everything correctly (no extra row). Have anybody encountered something similar or is there something else i should try? Thanks in advance!

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  • Put logic behind generated LinqToSql fields

    - by boris callens
    In a database I use throughout several projects, there is a field that should actually be a boolean but is for reasons nobody can explain to me a field duplicated over two tables where one time it is a char ('Y'/'N') and one time an int (1/0). When I generate a datacontext with LinqToSql the fields off course gets these datatypes. It would be nice if I don't have to drag this stupid choice of datatype throughout the rest of my application. Is there a way to give the generated classes a little bit of logic that just return me return this.equals('Y'); and return this==1; Preferably without having to make an EXTRA field in my partial class. It would be a solution to give the generated field a totally different name that can only be accessed through the partial class and then generate the extra field with the original name with my custom logic in the partial class. I don't know how to alter the accesibility level in my generated class though.. Any suggestions?

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  • Declare 2 types inside using statement gives compile error?

    - by citronas
    I want to use this line of code: using (ADataContext _dc = new ADataContext(ConnectionString), BDataContext _dc2 = new BrDataContext(ConnectionString)){ // ...} This gives a compile error: Cannot use more than one type in a for, using, fixed or declartion statement. I thought this was possible? MSDN says it is: http://msdn.microsoft.com/en-us/library/yh598w02%28VS.80%29.aspx In the MSDN sample code Font is used, which is class and thereby a reference type as well as my two DataContext classes. What went wrong here? How does my attempt differ from the MSDN sample?

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  • Possible Performance Considerations using Linq to SQL Repositories

    - by Robert Harvey
    I have an ASP.NET MVC application that uses Linq to SQL repositories for all interactions with the database. To deal with data security, I do trimming to filter data to only those items to which the user has access. This occurs in several places: Data in list views Links in a menu bar A treeview on the left hand side containing links to content Role-based security A special security attribute, inheriting from AuthorizeAttribute, that implements content-based authorization on every controller method. Each of these places instantiates a repository, which opens a Linq to Sql DataContext and accesses the database. So, by my count, each request for a page access opens at least six separate Linq to SQL DataContexts. Should I be concerned about this from a performance perspective, and if so, what can be done to mitigate it?

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  • linq to sql string property from non-null column with default

    - by Barry Fandango
    I have a LINQ to SQL class "VoucherRecord" based on a simple table. One property "Note" is a string that represents an nvarchar(255) column, which is non-nullable and has a default value of empty string (''). If I instantiate a VoucherRecord the initial value of the Note property is null. If I add it using a DataContext's InsertOnSubmit method, I get a SQL error message: Cannot insert the value NULL into column 'Note', table 'foo.bar.tblVoucher'; column does not allow nulls. INSERT fails. Why isn't the database default kicking in? What sort of query could bypass the default anyway? How do I view the generated sql for this action? Thanks for your help!

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