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  • Bit convector : Get byte array from string

    - by nCdy
    When I have a string like "0xd8 0xff 0xe0" I do Text.Split(' ').Select(part => byte.Parse(part, System.Globalization.NumberStyles.HexNumber)).ToArray(); But if I got string like "0xd8ffe0" I don't know what to do ? also I'm able for recommendations how to write byte array as one string.

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  • VB.NET logical expression evaluator

    - by Tim
    I need to test a logical expression held in a string to see if it evaluate to TRUE or FALSE.(the strig is built dynamically) For example the resulting string may contain "'dog'<'cat' OR (14 AND 4<6)". There are no variables in the string, it will logically evaluate. It will only contain simple operators = < < = <= and AND , OR and Open and Close Brackets, string constants and numbers. (converted to correct syntax && || etc.) I currently acheive this by creating a jscipt function and compiling it into a .dll. I then reference the .dll in my VB.NET project. class ExpressionEvaluator { function Evaluate(Expression : String) { return eval(Expression); } } Is there a simpler method using built in .NET functions or Lamdba expressions.

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  • Is it possible to load an entire SQL Server CE database into RAM?

    - by DanM
    I'm using LinqToSql to query a small SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table via a foreign key, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of the appeal of LinqToSql. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view.

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  • ASP.net MVC3 howto edit sql database

    - by user1662380
    MovieStoreEntities MovieDb = new MovieStoreEntities(); public ActionResult Edit(int id) { //var EditMovie1 = MovieDb AddMovieModel EditMovie = (from M in MovieDb.Movies from C in MovieDb.Categories where M.CategoryId == C.Id where M.Id == id select new AddMovieModel { Name = M.Name, Director = M.Director, Country = M.Country, categorie = C.CategoryName, Category = M.CategoryId }).FirstOrDefault(); //AddMovieModel EditMovie1 = MovieDb.Movies.Where(m => m.Id == id).Select(m => new AddMovieModel {m.Id }).First(); List<CategoryModel> categories = MovieDb.Categories .Select(category => new CategoryModel { Category = category.CategoryName, id = category.Id }) .ToList(); ViewBag.Category = new SelectList(categories, "Id", "Category"); return View(EditMovie); } // // POST: /Default1/Edit/5 [HttpPost] public ActionResult Edit(AddMovieModel Model2) { List<CategoryModel> categories = MovieDb.Categories .Select(category => new CategoryModel { Category = category.CategoryName, id = category.Id }) .ToList(); ViewBag.Category = new SelectList(categories, "Id", "Category"); if (ModelState.IsValid) { //MovieStoreEntities model = new MovieStoreEntities(); MovieDb.SaveChanges(); return View("Thanks2", Model2); } else return View(); } This is the Code that I have wrote to edit Movie details and update database in the sql server. This dont have any compile errors, But It didnt update sql server database.

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  • Creating seed model from data already in DB

    - by Nick Brown
    Is there a way to convert data in an existing database into objects that can easily be put into a seed method? Essentially I'd like to let some people add lines to my DB via a form and then convert that into an object that I can re-seed the DB anytime I need to make changes. The database itself is created via code-first using the following model: public class Combo { public int Id { get; set; } public string MainPrefix { get; set; } public string MainDescriptor { get; set; } public string MainDish { get; set; } public string Connector { get; set; } public string SecondaryDescriptor { get; set; } public string SecondaryDish { get; set; } }

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  • Open Source - EER Modeling Tool

    - by Nick Fergis
    Is there a good open source or reasonably priced EER modeling tool for MySQL besides MySQL Workbench? I find the MySQL Workbench interface to be clunky. I would like to be able to manage my production schema beginning all design changes in the EER and propogating those out to my schema for created and altered tables. Is anyone use a tool they love to manage their environments in this way? Thanks. - Nick

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  • Disabling identity (auto-incrementing) on integer primary key using code first

    - by gw0
    I am using code first approach in a ASP.NET MVC 3 application and all integer primary keys in models (public int Id { get; set; }) are by default configured as an identity with auto-incrementing. How to disable this and enable a way to manually enter the integer for the primary key? The actual situation is that the Id integers have a special meaning and I would therefore like to have them choosable at creation and later editable. It would be ideal if in case the integer is not given at creation time it is auto-incremented, else the specified value is used. But editable primary fields is my primary need. Is there any way to do this elegantly in ASP.NET MVC 3?

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  • How can I bind an Enum to a DbType of bit or int?

    - by uriDium
    Hi I am using Linq2Sql and want to bind an objects field (which is enum) to either a bit or a int type in the database. For example I want have a gender field in my model. I have already edited the DBML and changed the Type to point to my enum. I want to create Radio buttons (which I think I have figured out) for gender and dropdown lists for other areas using the same idea. My enum looks like this public enum Gender { Male, Female } Mapping between DbType 'int' and Type 'Project.Models.Gender' in Column 'Gender' of Type 'Candidate' is not supported. Any ideas on how to do this mapping. Am I missing something on the enums.

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  • Why doesn't this CompiledQuery give a performance improvement?

    - by Grammarian
    I am trying to speed up an often used query. Using a CompiledQuery seemed to be the answer. But when I tried the compiled version, there was no difference in performance between the compiled and non-compiled versions. Can someone please tell me why using Queries.FindTradeByTradeTagCompiled is not faster than using Queries.FindTradeByTradeTag? static class Queries { // Pre-compiled query, as per http://msdn.microsoft.com/en-us/library/bb896297 private static readonly Func<MyEntities, int, IQueryable<Trade>> mCompiledFindTradeQuery = CompiledQuery.Compile<MyEntities, int, IQueryable<Trade>>( (entities, tag) => from trade in entities.TradeSet where trade.trade_tag == tag select trade); public static Trade FindTradeByTradeTagCompiled(MyEntities entities, int tag) { IQueryable<Trade> tradeQuery = mCompiledFindTradeQuery(entities, tag); return tradeQuery.FirstOrDefault(); } public static Trade FindTradeByTradeTag(MyEntities entities, int tag) { IQueryable<Trade> tradeQuery = from trade in entities.TradeSet where trade.trade_tag == tag select trade; return tradeQuery.FirstOrDefault(); } }

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  • MVC 1.0 + EF: Does db.EntitySet.where(something) still return all rows in table?

    - by Dale
    In a repository, I do this: public AgenciesDonor FindPrimary(Guid donorId) { return db.AgenciesDonorSet.Include("DonorPanels").Include("PriceAdjustments").Include("Donors").First(x => x.Donors.DonorId == donorId && x.IsPrimary); } then down in another method in the same repository, this: AgenciesDonor oldPrimary = this.FindPrimary(donorId); In the debugger, the resultsview shows all records in that table, but: oldPrimary.Count(); is 1 (which it should be). Why am I seeing all table entries retrieved, and not just 1? I thought row filtering was done in the DB. If db.EntitySet really does fetch everything to the client, what's the right way to keep the client data-lite using EF? Fetching all rows won't scale for what I'm doing.

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  • em.createQuery keeps returning null

    - by Developer106
    I have this application which i use JSF 2.0 and EclipseLink, i have entities created for a database made in MySQL, Created these entities using netbeans 7.1.2, it gets created automaticly. Then i use session beans to work with these entities, the thing is the em.createQuery always returns a null, though I checked NamedQueries in the entities and they perfectly match a sample from the entities named queries:- @NamedQueries({ @NamedQuery(name = "Users.findAll", query = "SELECT u FROM Users u"), @NamedQuery(name = "Users.findByUserId", query = "SELECT u FROM Users u WHERE u.userId = :userId"), @NamedQuery(name = "Users.findByUsername", query = "SELECT u FROM Users u WHERE u.username = :username"), @NamedQuery(name = "Users.findByEmail", query = "SELECT u FROM Users u WHERE u.email = :email"), notice how i use this findByEmail query in the session bean :- public Users findByEmail(String email){ em.getTransaction().begin(); String find = "Users.findByEmail"; Query query = em.createNamedQuery(find); query.setParameter("email", email); Users user = (Users) query.getSingleResult(); but it always returns null from this em.createNamedQuery, i tried using .createQuery first but it also was no good. the stacktrace of the exception Caused by: java.lang.NullPointerException at com.readme.entities.sessionBeans.UsersFacade.findByEmail(UsersFacade.java:48) at com.readme.user.signup.SignupBean.checkAvailability(SignupBean.java:137) at com.readme.user.signup.SignupBean.save(SignupBean.java:146) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) What Seems To Be The Problem Here ?

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  • Problem in mutiple :dependent=> :destroy when multiple polymorphic is true

    - by piemesons
    I have four models question, answer, comment and vote.Consider it same as stackoverflow. Question has_many comments Answers has_many comments Questions has_many votes answers has_many votes comments has_many votes Here are the models (only relevant things) class Comment < ActiveRecord::Base belongs_to :commentable, :polymorphic => true has_many :votes, :as => :votable, :dependent => :destroy end class Question < ActiveRecord::Base has_many :comments, :as => :commentable, :dependent => :destroy has_many :answers, :dependent => :destroy has_many :votes, :as => :votable, :dependent => :destroy end class Vote < ActiveRecord::Base belongs_to :votable, :polymorphic => true end class Answer < ActiveRecord::Base belongs_to :question, :counter_cache => true has_many :comments, :as => :commentable , :dependent => :destroy end Now the problem is whenever i am trying to delete any question/answer/comment its giving me an error NoMethodError in QuestionsController#destroy undefined method `each' for 0:Fixnum if i remove this line from any of the model (question/answer/comment) has_many :votes, :as => :votable, :dependent => :destroy then it works perfectly. It seems there is a problem while deleting the records active record is not able to find out the proper path because of multiple joins within the tables.

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  • count of last item of the day

    - by frenchie
    I have a query in which one of the fields contains the count of status. The status can change several times a day and the count should be based on the final status of the day. For instance, this is what I have for Status1. CountStatus1 = (from status in MyDataContext.StatusHistories where status.UserID == TheUserID where status.StatusDateTime.Month == TheMonth.Month where status.StatusDateTime.Year == TheMonth.Year where status.NewStatus == 1 // where the LAST STATUS OF THE DAY == 1 select status.StatusID).Count() The problem is that I want to select the last status of the day to be equal to 1, and count those. The status for a day can change from 1 to 4 to 2 to 5 to 3 and then to finally to 1; if I write the query like this, the count will include 2 1's and then the 4,2,5 and 3 will also be counted in CountStatus4, CountStatus3, CountStatus"n". The return data is a monthly report grouped by day, where each day is a row. The structure of the query looks like this: var OutputStatusReport = from w in MyDataContext.WorkHistory where w.UserID == TheUserID where w.WorkDatetime.Month == TheMonth.Month where w.WorkDatetime.Year == TheMonth.Year group w by w.Datetime.Date into daygroups select new MyObjectModel { CountStatus1 = ...., CountStatus2 = ...., CountStatus3 =...... }; So I need the day of the count to match the day of daygroups. I'm struggling to figure this one out and any help is very welcome. Thanks.

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  • Best .NET Solution for Frequently Changed Database

    - by sestocker
    I am currently architecting a small CRUD applicaton. Their database is a huge mess and will be changing frequently over the course of the next 6 months to a year. What would you recommend for my data layer: 1) ORM (if so, which one?) 2) Linq2Sql 3) Stored Procedures 4) Parametrized Queries I really need a solution that will be dynamic enough (both fast and easy) where I can replace tables and add/delete columns frequently. Note: I do not have much experience with ORM (only a little SubSonic) and generally tend to use stored procedures so maybe that would be the way to go. I would love to learn Ling2Sql or NHibernate if either would allow for the situation I've described above.

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  • removing items from a generic List<t>

    - by frosty
    I have the following method, I wish to remove items from my collection that match the product Id. Seems fairly straight forward, but i get an exception. Basically my collection is getting out of sync. So what is the best way to remove an item from a collection. public void RemoveOrderItem(Model.Order currentOrder, int productId) { foreach (var orderItem in currentOrder.OrderItems) { if (orderItem.Product.Id == productId) { currentOrder.OrderItems.Remove(orderItem); } } } Exception Details: System.InvalidOperationException: Collection was modified; enumeration operation may not execute

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  • Are there any pitfalls to having two different Models from two different assemblies? (EF)

    - by Jonn
    I have two projects, both of them data access layers, and both using EF. I have another project calling services related to the two different assemblies. Are there any pitfalls on using two different models on two different databases linked to the same database? I'm asking this because I've been getting this generic "EntitySqlException" could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly., near escaped identifier. that does not appear when are run separately but appear when under the same project.

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  • ASP.NET MVC DataAnnotations different tables. Can it be done?

    - by mazhar kaunain baig
    i have a language table which is as a foreign key in the link table , The link can be in 3 languages meaning there will be 3 rows in the link table every time i enter the record . i am using jQuery tabs to enter the records in 3 languages . OK so that thing is that there will be three text boxes for every field in the table.link name field will have 3 text boxes, description will have 3 text boxes and so on. i am using LINK to SQL with VS2010. i will be creating link class with MetadataType so how will i handle for eg link name attribute 3 times

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  • check existense between two IEnumerable

    - by sunglim
    IEnumerable<String> existedThings = from mdinfo in mdInfoTotal select mdinfo.ItemNo; IEnumerable<String> thingsToSave = from item in lbXReadSuccess.Items.Cast<ListItem>() select item.Value; Here are two IEnumerable. I want to check whether a value in existedThings exist in thingsToSave. O.K. I can do that with 3 line code. bool hasItemNo; foreach(string itemNo in existedThings) hasItemNo= thingsToSave.Contains(itemNo); But, It looks dirty. I just want to know if there better solution.

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  • How to check if string contains a string in string array

    - by Abu Hamzah
    edit: the order might change as you can see in the below example, both string have same name but different order.... How would you go after checking to see if the both string array match? the below code returns true but in a reality its should return false since I have extra string array in the _check what i am trying to achieve is to check to see if both string array have same number of strings. string _exists = "Adults,Men,Women,Boys"; string _check = "Men,Women,Boys,Adults,fail"; if (_exists.All(s => _check.Contains(s))) //tried Equal { return true; } else { return false; }

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  • is it possible to write data to a collection in wpf?

    - by randyc
    Hello. In looking through samples I have seen a number of examples where it is possible to present data within a wpf applicaiton by binding to collections. However I was wondering is it possible to write to a collection from an applicaiton. Say for example i have 2 or more fields such as names and I wanted to have hte ability to add up to three names in my application ( all stored in memory). Will collections serve this purpose. In the past with asp.net I have done this by creating data tables and storing values on the fly or during the session. I am trying to learn WPF and I was wondering if collections work in the same fashion? If so could you please post an example or point me to references that show examples of this? Thank you in advance.

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  • Adding LambaExpression to an instance of IQueryable

    - by Paul Knopf
    ParameterExpression parameter = Expression.Parameter(typeof(Product), "x"); MemberExpression Left = Expression.MakeMemberAccess(parameter, typeof(Product).GetProperty("Name")); ConstantExpression Right = Expression.Constant(value, typeof(String)); BinaryExpression expression = Expression.Equal(Left, Right); LambdaExpression lambada = Expression.Lambda<Func<Product, bool>>(expression, parameter); Now how do I add this lambada to an instance of an IQuerybale, lets say _query _query.Where(lambada.Compile());?

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