For no apparent reason (of course there must be one), my web project will no longer generate LINQ to SQL classes/data contexts!!!I am going about the usual routine of right clicking the project, adding new item, selected LINQ to SQL classes, then dragging over a table from Server Explorer, saving and build but no...the bloody thing won't appear!!!Does anyone know why this might be happening/what have I done wrong?
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I have been using LINQ to SQL for quite a while (about two years). Every thing was fine until now. As usual, I created LINQ to SQL classes and built the project, then created an aspx page. However, I cannot see the DataClassesDataContext in the code behind file. It is not listed in the intellisense list.
View 5 RepliesI am following the Nerd Dinner tutorial as I'm learning ASP.NET MVC, and I am currently on Step 3: Building the Model. One part of this section discusses how to integrate validation and business rule logic with the model classes. All this makes perfect sense. However, in the case of this source code, the author only validates one class: Dinner.
What I am wondering is, say I have multiple classes that need validation (Dinner, Guest, etc). It doesn't seem smart to me to repeatedly write these two methods in the partial class:
[code]....
This doesn't "feel" right, but I wanted to check with SO to get opinions of individuals smarter than me on this. I also tested it out, and it seems that the partial keyword on the OnValidate method is causing problems (understandably so). This doesn't seem possible to fix (but I could very well be wrong).
I'm trying to use linq to sql for my project (very short deadline), and I'm kind of in a bind. I don't know the best way to have a data context handy per request thread. I want something like a singleton class from which all my repository classes can access the current data context. However, singleton class is static and is not thread-safe and therefore not suitable for web apps. I want something that would create a data context at the beginning of the request and dispose of it along with the request
View 1 Repliesi am working on Linq,as we know to use any table in linq we have to drag and drop it on our datacontext's Designer File,and at run time we got its value,till here no any problem,main point is if any changes in respective data source's schema has made ,then on datacontext we will not get that changes,for it we have to change this datacontext manually by by again drag and drop,it will not happen implicitly when this changes has been made on the data source. how i solve this problem so that datacontext change implicitly without any over head using .net 3.5.
View 2 RepliesSystem.Data.Linq.ChangeConflictException: 2 of X updates failed. at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at PROJECT.Controllers.HomeController.ClickProc(Int32
id, String code, String n)
This is what I get very often. This action is done thousands of times a day, and I get this exception about once every 5 seconds. From what I understand it happens when something changes in the database in the period between creating DataContext and updating it. Am I right?How can I fix it?I just debugged the error and found the following:
[Code]....
The Stats table is updated constantly. So how can I still make LINQsave the changes. With "classical" MS SQL access through SqlDataCommand I never had problems like that.
I have a linq DataSource and a Grid in my htnl and I want to access the DataContext from code behind. Now in the past when I do evrything in code behind I just use...
DataContextName db = new DataContextName();
and I have my reference.
Now I can still do that and it works fine it just seems odd to be making a second class object when there is one that is made from the linq DataSource in the html. But I can't figure out how to get a reference to the DataContext that is created from my html code.
I am trying to return all records from a table using a Linq strongly typed datacontext. I want this in its own dll and accessible via a public method. I am basing this on the following MSDN example:
[URL]
I get no intellisense for appt in the Linq code and I also get a compile error for Table<Appointments>:
The type or namespace name 'Appointments' could not be found (are you missing a using directive or an assembly reference?)
Here is my code:
[Code]....
I'm studing Linq on TheBeerHouse Project,I would create a my Linq Version.I have a big problem with Updating, this i a part of source :
protected static ArticlesDataContext GetContext()
{
return new ArticlesDataContext(Settings.ConnectionString);
[code]...
I am writing an application in C# that uses LINQ to validate a datacontext off a textbox to see if the record exists already. If the record does exist I inserted an if statement to advise the user that the record exists, if the record does not exist I would like to allow the record to be added to the database. If I take out my else statement everything works fine as far as inserting goes, but I do not want to allow inserts in this scenario. I have tried moving the if and else statement to different parts of the code but can't quite figure this one out.
[Code]....
I need my linq to sql datacontext to be available across my business/data layer for all my repository objects to access. However since this is a web app, I want to create and destroy it per request. I'm wondering if having a singleton class that can lazily create and attach the datacontext to current HttpContext would work. My question is: would the datacontext get disposed automatically when the request ends? Below is the code for what I'm thinking. Would this accomplish my purpose: have a thread-safe datacontext instance that is lazily available and is automatically disposed when the request ends?
public class SingletonDC
{
public static NorthwindDataContext Default
{
get
{
NorthwindDataContext defaultInstance = (NorthwindDataContext)System.Web.HttpContext.Current.Items["datacontext"];
if (defaultInstance == null)
{
defaultInstance = new NorthwindDataContext();
System.Web.HttpContext.Current.Items.Add("datacontext", defaultInstance);
}
return defaultInstance;
}
}
}
I'm new to LINQ and have a problem with my query not showing me the Table Collection. I manually created my Cart class and specified the table attributes on each property (works fine for inserting records via LINQ see below). DataContext dc = new DataContext(Conn);
var q = (from c in dc.NOTABLES?? where ((c.UserID == userID)) orderby c.CreateDateTime Based on examples I would expect to see dc.Cart But I don't, so I tried to access it via dc.GetTable<Cart>() which at least gets me data but doesn't seem to convert the rows to my Cart object since this:
foreach (var cart in q) Log.Info("UserID: " + cart.UserID + " CartID: " + cart.ID.ToString());
blows up with a "Specified Cast is Not Valid" exception.
No Problem Inserting Also, I had no problem inserting data into the database:
DataContext dc = new DataContext(Conn);
Table<Cart> Carts = dc.GetTable<Cart>();
Cart aCart = new Cart();
aCart.UserID = userId;
aCart.Description = description;
aCart.CreateDateTime = System.DateTime.Now;
aCart.UpdateDateTime = System.DateTime.Now;
Carts.InsertOnSubmit(aCart);
Carts.Context.SubmitChanges();
I am trying to run a linq query but I need the result as a datatable as I am using that to store records from different queries in the same viewstate object.The 2 versions below compile, but return an empty set. The exact error is "Value cannot be null.Parameter name: source". (and yes I have checked there is data):
MyDatabaseDataContext db = new MyDatabaseDataContext(conn);
IEnumerable<DataRow> queryProjects =
(from DataRow p in db.STREAM_PROJECTs.AsEnumerable()
[code]...
I have a System.Data.Linq.DataContext object and need to know the proper way of closing it out before it goes out of scope in order to prevent the following error when making a bunch of database changes:
Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.
Can I just call obj.Dispose() or do I need to call obj.Connection.Dispose() or obj.Connection.Close()?
I guess what I want to know is will calling obj.Dispose() end up executing the functionality in obj.Connection.Dispose() and obj.Connection.Close(). The MSDN documentation that I found on these functions does not have this information (at least I didn't see it - I could have mistakenly overlooked it).
I want to create a LINQ DataContext Class as per Database Design. I getting a problem in some cases.
the syntax to bulid a LINQ class :
[Code]....
Here Table Name Is HardCoded But I my case my Table Name A Changed as Finicial Year Change.So How I Give The TableName As RunTime
I have a strange problem. I am adding a LinqDatasource object, and set the context:
[Code]....
Then I get this error:The type 'System.Data.Linq.DataContext' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
On web.config I already have this:
<add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
NOTE: The datacontext is in a different project (DLL proect) where I added a refernce to System.Data.Linq.
is there another way adding a refernce to a web project? or only though teh web.config?
Technically I have the Data Annoations working with Linq to SQL classes - the problem is when validation
passes. When UpdateModel() tries to do its thing i can an error:The model of type 'MyProject.Models.Employee' could not be updated.What i did was i created a partial class for Employee (that is generated by linq to sql), then stuck a Meta Data class on top of it for the validation
[Code]....
And in my master page i include
<script type="text/javascript" src="/Scripts/jquery.validate.min.js"></script>
I am updating a project I wrote some time ago. At the time my preference was for DataSets and DataSetTableAdapters, but I've now moved on to use Linq to SQL DataClasses. I would like to convert the project to Linq to SQL, but I am tight on time and it's a big job. My question is, is there any reasons I can't develop new modules using Linq to SQL DataClasses along side DataSets and convert the DataSets overtime?
Apart from the obvious confusion it will cause, are there any technical problems I should be aware of i.e. will there be any performance problems using the two methods?
I'm building a web app that will keep a events in a database and add the event to a Google calendar on insertion.
I have three types of events, PendingEvents, ApprovedEvents, and DeniedEvents. I'm using single table inheritance through LINQ-to-SQL, with the Event class being abstract and the 3 types inheriting from it
Each type of Event is stored in calendars differently. I would like to use an abstract member function in Event called AddToCalendar.
I'm trying to set this up in a separate class file because I'm using the LINQ-to-SQL designer and I don't want these to be overwritten if I change the LINQ diagram.
However, I get an error from all three inherited classes that "'WebCal.ApprovedEvents' does not implement inherited abstract member 'Edu.Northwestern.WebCal.Event.AddEventToCalendar()' WebCalendarWebApplication1App_CodeWebCalDataSource.designer.cs"
It looks like it won't check my outside file and only looks at the designer.
The non-designer partial class file looks something like this:
public partial class WebCalDataSourceDataContext : System.Data.Linq.DataContext
{
Is it possible to create a table class that can be used for multiple tables? For example, if I have some class:
[Code]....
In LINQ to SQL, this maps to a table with a name based on the class name, DBClass. However, suppose I want to use that class for multiple tables, and it could be an arbitrary number of tables. Is this possible
Is there anyway I can extend LINQ classes through different namespaces?Typically in my class libraries I have a namespace for each class object and their associated DAO and service classes in a folder of my project, therefore on the front-end I can only use the namespaces associated with the given page and not clutter my intellisense or load in a bunch of excess stuff.
However, I have found that upon adding my .dbml LINQtoSQL file, whatever namespace that is in, whether it's the project root namespace or a custom one, is the only namespace I can use partial class extension in.I have tried even creating a custom workspace (placing the .dbml file in a folder) and then including a using statement to that namespace and I still cannot extend the partial classes.Is there anyway I can do this? Or to have the .dbml file count as being in every namespace? I don't want to remove all namespaces but the root one either.such when I try doing the partial class from a different namespace I get the following error:
Error 1
'Id' is not a member of 'LCFVB.EntityNS.Entity'.
C:Usersshol726.UILAWDocumentsVisual Studio 2008ProjectsLCFVBEntityNSEntity.vb
10 7
LCFVB
I came across the article few days ago where somebody said that it's possible to automatically break down ClassName.Designer.CS into multiple classes.
So instead of having Customer and Order class definitions in one .CS file I'm going to have 2 .CS files: Customer.Designer.CS and Order.Designer.CS
I can't believe I'm having so much trouble finding this information. I'm endeavouring to learn about creating model classes with Linq to SQL. By default VS2010 wants to use SQL Express, but our organisation has several database servers for development so I'd rather use one of those. PLEASE can somebody tell me how I can configure VS2010 to do that, as all I get is 'A network-related or instance-specific error occurred while establishing a connection to SQL Server ... Verify that the instance name is correct'. Yeah, thanks Microsoft. Actually telling me how to verify the instance name would be a really good move here.
View 1 RepliesI've been developing a ASP.NET page and have been using LINQ to handle talking to MS SQL server. I'm ok at basic SQL, however I'm a lot better with designing queries using LINQ. I know they are similar but I find it easer to design complex queries in LINQ. My question is this: Is there a way to design a query in LINQ and then get the SQL that it generated? I would like to embed the SQL in a stored procedure since multiple pages (outside my control) will need to do the same query.
View 4 RepliesI am new to LINQ. when we drag tables we get a dbml file and designer file.
For example DataClasses1.dbml and DataClasses1.designer.cs.
Once we have them then we can start using our LINQ Queries.
In my company project I do not see this designer files and instead there are .tt files which were used as templates to greate ABC.generated.cs files. Is this same as designer class?
