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  • when to clear or make null asp .net mvc models?

    - by SARAVAN
    HI, I am working in an asp .net mvc application. I am using the model and storing some of the values which i need to preserve between the page posts, in the form of datacontexts. Say my model looks something like this: public SelectedUser SelectedUserDetails { //get and set has //this.datacontext.data.SelectedUser = ..... //return this.datacontext.data..... } Now when this model needs to be cleared? I have many such models with many properties and datacontext. But I don't have an idea on when to clear it. Is there a way or an event that can be triggered automatically when the model is not used for a long time? Oneway I thought is when i navigate away from a page which uses my underlying model, I can clear that model if its no longer used anywhere and initialise it back as needed. But I need to clear almost many models at many points. Is there an automatic way that can clear models when it is no longer used beacuse care can be taken by my code to initialise them when I need them, but I don't know when to clear them when I no longer need them. I need this to get rid of any memory related issues. Any thoughts or comments?

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  • How to handle null return from custom HttpHandler in asp.net?

    - by Campos
    I'm using a custom ashx HttpHandler to retrieve gif images from a database and show it on a website - when the image exists, it works great. However, there are cases when the image will not exist, and I'd like to have the html table holding the image to become invisible so the "image not found" icon is not shown. But since the HttpHandler is not synchronous, all my attempts checking for image size at Page_Load were frustrated. Any ideas on how this can be accomplished?

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  • Getting Oracle Exception: ORA-1017: invalid username/password; logon denied

    - by Paks
    I have tried so many thing but i can't resolve that Error. I can connect with my username and password to: Database in SQLDeveloper, in SQL-Plus, in Server-Explorer (Visual Studio 2008) and all works fine. But if i Compile my Project i get that Error. Why is that? I tried to set case_sensitive to false, but the same error appears. I dont know what else to do. My Oracle version: Oracle Database 11g Express Edtiton Release 11.2.0.2.0 - Production PL/SQL Release 11.2.0.2.0 - Production CORE 11.2.0.2.0 Production TNS for 32-bit Windows: Version 11.2.0.2.0 - Production NLSRTL Version 11.2.0.2.0 - Production

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  • What is the ISO C++ way to directly define a conversion function to reference to array?

    - by ben
    According to the standard, a conversion function has a function-id operator conversion-type-id, which would look like, say, operator char(&)[4] I believe. But I cannot figure out where to put the function parameter list. gcc does not accept either of operator char(&())[4] or operator char(&)[4]() or anything I can think of. Now, gcc seems to accept (&operator char ())[4] but clang does not, and I am inclined to not either, since it does not seem to fit the grammar as I understand it. I do not want to use a typedef because I want to avoid polluting the namespace with it.

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  • How to write these two queries for a simple data warehouse, using ANSI SQL?

    - by morpheous
    I am writing a simple data warehouse that will allow me to query the table to observe periodic (say weekly) changes in data, as well as changes in the change of the data (e.g. week to week change in the weekly sale amount). For the purposes of simplicity, I will present very simplified (almost trivialized) versions of the tables I am using here. The sales data table is a view and has the following structure: CREATE TABLE sales_data ( sales_time date NOT NULL, sales_amt double NOT NULL ) For the purpose of this question. I have left out other fields you would expect to see - like product_id, sales_person_id etc, etc, as they have no direct relevance to this question. AFAICT, the only fields that will be used in the query are the sales_time and the sales_amt fields (unless I am mistaken). I also have a date dimension table with the following structure: CREATE TABLE date_dimension ( id integer NOT NULL, datestamp date NOT NULL, day_part integer NOT NULL, week_part integer NOT NULL, month_part integer NOT NULL, qtr_part integer NOT NULL, year_part integer NOT NULL, ); which partition dates into reporting ranges. I need to write queries that will allow me to do the following: Return the change in week on week sales_amt for a specified period. For example the change between sales today and sales N days ago - where N is a positive integer (N == 7 in this case). Return the change in change of sales_amt for a specified period. For in (1). we calculated the week on week change. Now we want to know how that change is differs from the (week on week) change calculated last week. I am stuck however at this point, as SQL is my weakest skill. I would be grateful if an SQL master can explain how I can write these queries in a DB agnostic way (i.e. using ANSI SQL).

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  • converting ID to column name and also replacing NULL with last known value.

    - by stackoverflowuser
    TABLE_A Rev ChangedBy ----------------------------- 1 A 2 B 3 C TABLE_B Rev Words ID ---------------------------- 1 description_1 52 1 history_1 54 2 description_2 52 3 history_2 54 Words column datatype is ntext. TABLE_C ID Name ----------------------------- 52 Description 54 History OUTPUT Rev ChangedBy Description History ------------------------------------------------ 1 A description_1 history_1 2 B description_2 history_1 3 C description_2 history_2 Description and History column will have the previous known values if they dont have value for that Rev no. i.e. Since for Rev no. 3 Description does not have an entry in TABLE_B hence the last known value description_2 appears in that column for Rev no. 3 in the output.

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  • When is it safe to do a Response.Redirect() without throwing an exception?

    - by DDechant
    I have an intermediary class extending System.Web.UI.Page for all of my pages that require authentication. The class mostly does custom authentication handling. When a user with insufficient access attempts to visit a page, I try to redirect the user back to the login page while preventing any further page events from being executed (ie. Page_load). The first solution that came to mind was the default implementation of Response.Redirect. Of course the downside to this is the possibility of ThreadAbortExceptions being thrown. So my question is this: When (if at all) during the page life cycle is it actually safe to execute Response.Redirect() without ThreadAbortException ever being thrown? public class CustomPage : System.Web.UI.Page { protected override void OnInit(EventArgs e) { base.OnInit(e); if (!IsValid()) Response.Redirect("login.aspx", true); } }

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  • Is foreign key reference from two different primary key from two different tables valid?

    - by arundex
    I have a foreign key that has to refer primary keys of two different tables. Table 1: animal animal_ id (primary key) Table 2: bird bird_ id (primary key) Table 3: Pet_info pet_id, type ENUM ('bird', 'animal') foreign key (pet_ id) references animal(animal_id), bird(bird_id) So, I need to check for pet_id either from animal or bird table depending on the need. Is this valid? Or should I go for some restructuring . . . NOTE: I referred this . . but I'm not sure whether I have to change my existing design

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  • Io exception: There is no process to read data written to a pipe.

    - by Srikanth
    I'm using Hibernate3.2+Websphere6.0+struts1.3.. After deploying ,application works fine. After some idle time ,i will get this type of error repeatedly,am not able to login at all. Im not using any connection pooling. i feel after idle time its not able to connect to the database again..if i restart the server everything works fine for some time...after that same story.. please help me out

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  • How much does an InnoDB table benefit from having fixed-length rows?

    - by Philip Eve
    I know that dependent on the database storage engine in use, a performance benefit can be found if all of the rows in the table can be guaranteed to be the same length (by avoiding nullable columns and not using any VARCHAR, TEXT or BLOB columns). I'm not clear on how far this applies to InnoDB, with its funny table arrangements. Let's give an example: I have the following table CREATE TABLE `PlayerGameRcd` ( `User` SMALLINT UNSIGNED NOT NULL, `Game` MEDIUMINT UNSIGNED NOT NULL, `GameResult` ENUM('Quit', 'Kicked by Vote', 'Kicked by Admin', 'Kicked by System', 'Finished 5th', 'Finished 4th', 'Finished 3rd', 'Finished 2nd', 'Finished 1st', 'Game Aborted', 'Playing', 'Hide' ) NOT NULL DEFAULT 'Playing', `Inherited` TINYINT NOT NULL, `GameCounts` TINYINT NOT NULL, `Colour` TINYINT UNSIGNED NOT NULL, `Score` SMALLINT UNSIGNED NOT NULL DEFAULT 0, `NumLongTurns` TINYINT UNSIGNED NOT NULL DEFAULT 0, `Notes` MEDIUMTEXT, `CurrentOccupant` TINYINT UNSIGNED NOT NULL DEFAULT 0, PRIMARY KEY (`Game`, `User`), UNIQUE KEY `PGR_multi_uk` (`Game`, `CurrentOccupant`, `Colour`), INDEX `Stats_ind_PGR` (`GameCounts`, `GameResult`, `Score`, `User`), INDEX `GameList_ind_PGR` (`User`, `CurrentOccupant`, `Game`, `Colour`), CONSTRAINT `Constr_PlayerGameRcd_User_fk` FOREIGN KEY `User_fk` (`User`) REFERENCES `User` (`UserID`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `Constr_PlayerGameRcd_Game_fk` FOREIGN KEY `Game_fk` (`Game`) REFERENCES `Game` (`GameID`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=INNODB CHARACTER SET utf8 COLLATE utf8_general_ci The only column that is nullable is Notes, which is MEDIUMTEXT. This table presently has 33097 rows (which I appreciate is small as yet). Of these rows, only 61 have values in Notes. How much of an improvement might I see from, say, adding a new table to store the Notes column in and performing LEFT JOINs when necessary?

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  • Can I get a reference to an object created in a jQuery plugin?

    - by gargantaun
    Perhaps my brain is fried, but I'm writing a plugin that created an tweaks an element, but also creates an object that i'd like access to. So the plugin looks like this (function ($) { $.fn.myPlugin = function () { return this.each(function () { // do some stuff to the element... this.objectInstance = new usefulObject(); }); }; })(jQuery); function usefulObject(){ // useful object properties and methods.... this.doSomething = function(){ alert("Don't google Google. You'll break the internet."); } } so when I call the plugin, I also want to be able to get access to that usefulObject that I created. I thought something like this might work.... tweakedElement = $("#someDiv").myPlugin(); tweakedElement.objectInstance.doSomething(); ... but that's not working. How can I achieve this? Can I achieve this? Answers on a postcard, or down below, whichever suits you.

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  • How to do a back-reference on Google Webapp?

    - by jCuga
    I'm trying to access an object that is linked to by a db.ReferenceProperty in Google app engine. here's the model's code: class InquiryQuestion(db.Model): inquiry_ref = db.ReferenceProperty(reference_class=GiftInquiry, required=True, collection_name="inquiry_ref") And I am trying to access it in the following way: linkedObject = question.inquiry_ref and then linkedKey = linkedObject.key but it's not working. Can anyone please help?

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  • Where can I find "reference barcodes" to verify barcode library output?

    - by mjustin
    This question is not about 'best' barcode library recommendation, we use various products on different platforms, and need a simple way to verify if a given barcode is correct (according to its specification). There are some free online bar code generators in the Internet, and I found many differences between their output and our library output regarding graphics and text field below the code. Now I am not sure which one is wrong, and before filing bug report I want to make sure how the correct barcode should look like. We mainly need Code128 and UCC/EAN-128 with A/B/C subcodes. Which resource would you suggest?

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  • Is it ok to throw NotImplemented exception in virtual methods?

    - by Axarydax
    I have a base class for some plugin-style stuff, and there are some methods that are absolutely required to be implemented. I currently declare those in the base class as virtual, for example public virtual void Save { throw new NotImplementedException(); } and in the descendand I have a public override void Save() { //do stuff } Is it a good practice to throw a NotImplementedException there? The descendand classes could for example be the modules for handling different file formats. Thanks

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  • What is the purpose of this delegate usage?

    - by Kev
    Whilst poking around some code in .NET Reflector in an app I don't have the source code for I found this: if (DeleteDisks) { using (List<XenRef<VDI>>.Enumerator enumerator3 = list.GetEnumerator()) { MethodInvoker invoker2 = null; XenRef<VDI> vdiRef; while (enumerator3.MoveNext()) { vdiRef = enumerator3.Current; if (invoker2 == null) { // // Why do this? // invoker2 = delegate { VDI.destroy(session, vdiRef.opaque_ref); }; } bestEffort(ref caught, invoker2); } } } if (caught != null) { throw caught; } private static void bestEffort(ref Exception caught, MethodInvoker func) { try { func(); } catch (Exception exception) { log.Error(exception, exception); if (caught == null) { caught = exception; } } } Why not call VDI.destroy() directly. Is this just a way of wrapping the same pattern of try { do something } catch { log error } if it's used a lot?

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  • What's the best way to generate an API reference document using a Rails routes.rb file?

    - by RNHurt
    I am trying to document the API for my Rails application and I can't help but wonder if there is a better way to generate an XML file based on my routes.rb file. I'm envisioning something similar to the output of rake routes but in a more friendly, XML type format. Corey has some interesting ideas about using reflection/introspection on the routes file here but it's not quite what I need. Please tell me this is a solved problem and I'm not the first one to think of this. :)

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  • Is it possible to reference a file stored in Isolated Storage by its URI?

    - by Joel
    Using this previous question as motivation, I would like to temporarily store images and videos in Isolated Storage. My application (written in WPF/C#) will allow a user to review these temporarily stored items by viewing their contents in a MediaElement. I was hoping to set the MediaElement's Source Property to a video or image's URI stored in IsolatedStorage but I cannot figure out how to dynamically create a URI since it doesn't appear to be naively supported by IsolatedStorage. Any help would be greatly appreciated - thank you in advance! Update - 1/21/09 After battling the issue for a day, I concluded that the Isolated Storage approach is not practical for storing large video files that need to be referenced by a Uri.

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  • A file is being http posted, how can I reference the parameter by index?

    - by Blankman
    An XML file is being posted to a url that my spring mvc is responding to. In .NET, I could do this: request.Form[0] request.Form["abc"] or request.QueryString[0] request.QueryString["some_key"] Now with spring/servlets it seems I can only do this: request.getParameter("some_key") or get all the names or values. When someone is posting a file to a url, using http post, won't this be just a single request parameter then? Can I get the parameter using index with servlets?

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