ms expression - Page 147

Is it possible to exclude some elements from parsing when using regular expression and .replace()?

- by Fletus Mefitis

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Does the API call ExitProcess() work OK in VB6 if you follow the MS caveats?

- by Clay Nichols

Microsoft indicates that VB6 doesn't support ExitProcess (to exit and return a value). However, it indicates that this call can fail under certain circumstances (if a thread hasn't been completed, etc.) so I'm wondering whether this call will work OK (consistently :-) as long as you obey the caveats in the article. I could go a step further and call ExitProcess() from the Sub Main or Form which stared the app. Update: after some more reading (I really did research this a bit before asking ) I found a suggestion to use the TerminateProcess API instead. I'm investigating that option. Any thoughts?

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Implementing a generic repository for WCF data services

- by cibrax

The repository implementation I am going to discuss here is not exactly what someone would call repository in terms of DDD, but it is an abstraction layer that becomes handy at the moment of unit testing the code around this repository. In other words, you can easily create a mock to replace the real repository implementation. The WCF Data Services update for .NET 3.5 introduced a nice feature to support two way data bindings, which is very helpful for developing WPF or Silverlight based application but also for implementing the repository I am going to talk about. As part of this feature, the WCF Data Services Client library introduced a new collection DataServiceCollection<T> that implements INotifyPropertyChanged to notify the data context (DataServiceContext) about any change in the association links. This means that it is not longer necessary to manually set or remove the links in the data context when an item is added or removed from a collection. Before having this new collection, you basically used the following code to add a new item to a collection. Order order = new Order { Name = "Foo" }; OrderItem item = new OrderItem { Name = "bar", UnitPrice = 10, Qty = 1 }; var context = new OrderContext(); context.AddToOrders(order); context.AddToOrderItems(item); context.SetLink(item, "Order", order); context.SaveChanges(); Now, thanks to this new collection, everything is much simpler and similar to what you have in other ORMs like Entity Framework or L2S. Order order = new Order { Name = "Foo" }; OrderItem item = new OrderItem { Name = "bar", UnitPrice = 10, Qty = 1 }; order.Items.Add(item); var context = new OrderContext(); context.AddToOrders(order); context.SaveChanges(); In order to use this new feature, you first need to enable V2 in the data service, and then use some specific arguments in the datasvcutil tool (You can find more information about this new feature and how to use it in this post). DataSvcUtil /uri:"http://localhost:3655/MyDataService.svc/" /out:Reference.cs /dataservicecollection /version:2.0 Once you use those two arguments, the generated proxy classes will use DataServiceCollection<T> rather than a simple ObjectCollection<T>, which was the default collection in V1. There are some aspects that you need to know to use this feature correctly. 1. All the entities retrieved directly from the data context with a query track the changes and report those to the data context automatically. 2. A entity created with “new” does not track any change in the properties or associations. In order to enable change tracking in this entity, you need to do the following trick. public Order CreateOrder() { var collection = new DataServiceCollection<Order>(this.context); var order = new Order(); collection.Add(order); return order; } You basically need to create a collection, and add the entity to that collection with the “Add” method to enable change tracking on that entity. 3. If you need to attach an existing entity (For example, if you created the entity with the “new” operator rather than retrieving it from the data context with a query) to a data context for tracking changes, you can use the “Load” method in the DataServiceCollection. var order = new Order { Id = 1 }; var collection = new DataServiceCollection<Order>(this.context); collection.Load(order); In this case, the order with Id = 1 must exist on the data source exposed by the Data service. Otherwise, you will get an error because the entity did not exist. These cool extensions methods discussed by Stuart Leeks in this post to replace all the magic strings in the “Expand” operation with Expression Trees represent another feature I am going to use to implement this generic repository. Thanks to these extension methods, you could replace the following query with magic strings by a piece of code that only uses expressions. Magic strings, var customers = dataContext.Customers .Expand("Orders") .Expand("Orders/Items") Expressions, var customers = dataContext.Customers .Expand(c => c.Orders.SubExpand(o => o.Items)) That query basically returns all the customers with their orders and order items. Ok, now that we have the automatic change tracking support and the expression support for explicitly loading entity associations, we are ready to create the repository. The interface for this repository looks like this,public interface IRepository { T Create<T>() where T : new(); void Update<T>(T entity); void Delete<T>(T entity); IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties); IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties); void Attach<T>(T entity); void SaveChanges(); } The Retrieve and RetrieveAll methods are used to execute queries against the data service context. While both methods receive an array of expressions to load associations explicitly, only the Retrieve method receives a predicate representing the “where” clause. The following code represents the final implementation of this repository.public class DataServiceRepository: IRepository { ResourceRepositoryContext context; public DataServiceRepository() : this (new DataServiceContext()) { } public DataServiceRepository(DataServiceContext context) { this.context = context; } private static string ResolveEntitySet(Type type) { var entitySetAttribute = (EntitySetAttribute)type.GetCustomAttributes(typeof(EntitySetAttribute), true).FirstOrDefault(); if (entitySetAttribute != null) return entitySetAttribute.EntitySet; return null; } public T Create<T>() where T : new() { var collection = new DataServiceCollection<T>(this.context); var entity = new T(); collection.Add(entity); return entity; } public void Update<T>(T entity) { this.context.UpdateObject(entity); } public void Delete<T>(T entity) { this.context.DeleteObject(entity); } public void Attach<T>(T entity) { var collection = new DataServiceCollection<T>(this.context); collection.Load(entity); } public IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query.Where(predicate); } public IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query; } public void SaveChanges() { this.context.SaveChanges(SaveChangesOptions.Batch); } } For instance, you can use the following code to retrieve customers with First name equal to “John”, and all their orders in a single call. repository.Retrieve<Customer>( c => c.FirstName == “John”, //Where c => c.Orders.SubExpand(o => o.Items)); In case, you want to have some pre-defined queries that you are going to use across several places, you can put them in an specific class. public static class CustomerQueries { public static Expression<Func<Customer, bool>> LastNameEqualsTo(string lastName) { return c => c.LastName == lastName; } } And then, use it with the repository. repository.Retrieve<Customer>( CustomerQueries.LastNameEqualsTo("foo"), c => c.Orders.SubExpand(o => o.Items));

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Investigation: Can different combinations of components effect Dataflow performance?

- by jamiet

Introduction The Dataflow task is one of the core components (if not the core component) of SQL Server Integration Services (SSIS) and often the most misunderstood. This is not surprising, its an incredibly complicated beast and we’re abstracted away from that complexity via some boxes that go yellow red or green and that have some lines drawn between them. Example dataflow In this blog post I intend to look under that facade and get into some of the nuts and bolts of the Dataflow Task by investigating how the decisions we make when building our packages can affect performance. I will do this by comparing the performance of three dataflows that all have the same input, all produce the same output, but which all operate slightly differently by way of having different transformation components. I also want to use this blog post to challenge a common held opinion that I see perpetuated over and over again on the SSIS forum. That is, that people assume adding components to a dataflow will be detrimental to overall performance. Its not surprising that people think this –it is intuitive to think that more components means more work- however this is not a view that I share. I have always been of the opinion that there are many factors affecting dataflow duration and the number of components is actually one of the less important ones; having said that I have never proven that assertion and that is one reason for this investigation. I have actually seen evidence that some people think dataflow duration is simply a function of number of rows and number of components. I’ll happily call that one out as a myth even without any investigation! The Setup I have a 2GB datafile which is a list of 4731904 (~4.7million) customer records with various attributes against them and it contains 2 columns that I am going to use for categorisation: [YearlyIncome] [BirthDate] The data file is a SSIS raw format file which I chose to use because it is the quickest way of getting data into a dataflow and given that I am testing the transformations, not the source or destination adapters, I want to minimise external influences as much as possible. In the test I will split the customers according to month of birth (12 of those) and whether or not their yearly income is above or below 50000 (2 of those); in other words I will be splitting them into 24 discrete categories and in order to do it I shall be using different combinations of SSIS’ Conditional Split and Derived Column transformation components. The 24 datapaths that occur will each input to a rowcount component, again because this is the least resource intensive means of terminating a datapath. The test is being carried out on a Dell XPS Studio laptop with a quad core (8 logical Procs) Intel Core i7 at 1.73GHz and Samsung SSD hard drive. Its running SQL Server 2008 R2 on Windows 7. The Variables Here are the three combinations of components that I am going to test: One Conditional Split - A single Conditional Split component CSPL Split by Month of Birth and income category that will use expressions on [YearlyIncome] & [BirthDate] to send each row to one of 24 outputs. This next screenshot displays the expression logic in use: Derived Column & Conditional Split - A Derived Column component DER Income Category that adds a new column [IncomeCategory] which will contain one of two possible text values {“LessThan50000”,”GreaterThan50000”} and uses [YearlyIncome] to determine which value each row should get. A Conditional Split component CSPL Split by Month of Birth and Income Category then uses that new column in conjunction with [BirthDate] to determine which of the same 24 outputs to send each row to. Put more simply, I am separating the Conditional Split of #1 into a Derived Column and a Conditional Split. The next screenshots display the expression logic in use: DER Income Category CSPL Split by Month of Birth and Income Category Three Conditional Splits - A Conditional Split component that produces two outputs based on [YearlyIncome], one for each Income Category. Each of those outputs will go to a further Conditional Split that splits the input into 12 outputs, one for each month of birth (identical logic in each). In this case then I am separating the single Conditional Split of #1 into three Conditional Split components. The next screenshots display the expression logic in use: CSPL Split by Income Category CSPL Split by Month of Birth 1& 2 Each of these combinations will provide an input to one of the 24 rowcount components, just the same as before. For illustration here is a screenshot of the dataflow containing three Conditional Split components: As you can these dataflows have a fair bit of work to do and remember that they’re doing that work for 4.7million rows. I will execute each dataflow 10 times and use the average for comparison. I foresee three possible outcomes: The dataflow containing just one Conditional Split (i.e. #1) will be quicker There is no significant difference between any of them One of the two dataflows containing multiple transformation components will be quicker Regardless of which of those outcomes come to pass we will have learnt something and that makes this an interesting test to carry out. Note that I will be executing the dataflows using dtexec.exe rather than hitting F5 within BIDS. The Results and Analysis The table below shows all of the executions, 10 for each dataflow. It also shows the average for each along with a standard deviation. All durations are in seconds. I’m pasting a screenshot because I frankly can’t be bothered with the faffing about needed to make a presentable HTML table. It is plain to see from the average that the dataflow containing three conditional splits is significantly faster, the other two taking 43% and 52% longer respectively. This seems strange though, right? Why does the dataflow containing the most components outperform the other two by such a big margin? The answer is actually quite logical when you put some thought into it and I’ll explain that below. Before progressing, a side note. The standard deviation for the “Three Conditional Splits” dataflow is orders of magnitude smaller – indicating that performance for this dataflow can be predicted with much greater confidence too. The Explanation I refer you to the screenshot above that shows how CSPL Split by Month of Birth and salary category in the first dataflow is setup. Observe that there is a case for each combination of Month Of Date and Income Category – 24 in total. These expressions get evaluated in the order that they appear and hence if we assume that Month of Date and Income Category are uniformly distributed in the dataset we can deduce that the expected number of expression evaluations for each row is 12.5 i.e. 1 (the minimum) + 24 (the maximum) divided by 2 = 12.5. Now take a look at the screenshots for the second dataflow. We are doing one expression evaluation in DER Income Category and we have the same 24 cases in CSPL Split by Month of Birth and Income Category as we had before, only the expression differs slightly. In this case then we have 1 + 12.5 = 13.5 expected evaluations for each row – that would account for the slightly longer average execution time for this dataflow. Now onto the third dataflow, the quick one. CSPL Split by Income Category does a maximum of 2 expression evaluations thus the expected number of evaluations per row is 1.5. CSPL Split by Month of Birth 1 & CSPL Split by Month of Birth 2 both have less work to do than the previous Conditional Split components because they only have 12 cases to test for thus the expected number of expression evaluations is 6.5 There are two of them so total expected number of expression evaluations for this dataflow is 6.5 + 6.5 + 1.5 = 14.5. 14.5 is still more than 12.5 & 13.5 though so why is the third dataflow so much quicker? Simple, the conditional expressions in the first two dataflows have two boolean predicates to evaluate – one for Income Category and one for Month of Birth; the expressions in the Conditional Split in the third dataflow however only have one predicate thus they are doing a lot less work. To sum up, the difference in execution times can be attributed to the difference between: MONTH(BirthDate) == 1 && YearlyIncome <= 50000 and MONTH(BirthDate) == 1 In the first two dataflows YearlyIncome <= 50000 gets evaluated an average of 12.5 times for every row whereas in the third dataflow it is evaluated once and once only. Multiply those 11.5 extra operations by 4.7million rows and you get a significant amount of extra CPU cycles – that’s where our duration difference comes from. The Wrap-up The obvious point here is that adding new components to a dataflow isn’t necessarily going to make it go any slower, moreover you may be able to achieve significant improvements by splitting logic over multiple components rather than one. Performance tuning is all about reducing the amount of work that needs to be done and that doesn’t necessarily mean use less components, indeed sometimes you may be able to reduce workload in ways that aren’t immediately obvious as I think I have proven here. Of course there are many variables in play here and your mileage will most definitely vary. I encourage you to download the package and see if you get similar results – let me know in the comments. The package contains all three dataflows plus a fourth dataflow that will create the 2GB raw file for you (you will also need the [AdventureWorksDW2008] sample database from which to source the data); simply disable all dataflows except the one you want to test before executing the package and remember, execute using dtexec, not within BIDS. If you want to explore dataflow performance tuning in more detail then here are some links you might want to check out: Inequality joins, Asynchronous transformations and Lookups Destination Adapter Comparison Don’t turn the dataflow into a cursor SSIS Dataflow – Designing for performance (webinar) Any comments? Let me know! @Jamiet

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How to manually patch Blogger template to use Disqus

- by user317944

I'm trying to add disqus to my blog and I tried following this guide to do so: http://disqus.com/docs/patch-blogger/ However their instructions are completely off with what I have on my custom template. Here is the template: <b:skin><![CDATA[/*----------------------------------------------- Blogger Template Style Name: Picture Window Designer: Josh Peterson URL: www.noaesthetic.com ----------------------------------------------- */ /* Variable definitions ==================== */ /* Content ----------------------------------------------- */ body { font: $(body.font); color: $(body.text.color); } html body .region-inner { min-width: 0; max-width: 100%; width: auto; } .content-outer { font-size: 90%; } a:link { text-decoration:none; color: $(link.color); } a:visited { text-decoration:none; color: $(link.visited.color); } a:hover { text-decoration:underline; color: $(link.hover.color); } .body-fauxcolumn-outer { background: $(body.background); } .content-outer { background: $(content.background); -moz-border-radius: $(content.border.radius); -webkit-border-radius: $(content.border.radius); -goog-ms-border-radius: $(content.border.radius); border-radius: $(content.border.radius); -moz-box-shadow: 0 0 $(content.shadow.spread) rgba(0, 0, 0, .15); -webkit-box-shadow: 0 0 $(content.shadow.spread) rgba(0, 0, 0, .15); -goog-ms-box-shadow: 0 0 $(content.shadow.spread) rgba(0, 0, 0, .15); box-shadow: 0 0 $(content.shadow.spread) rgba(0, 0, 0, .15); margin: $(content.margin) auto; } .content-inner { padding: $(content.padding); } /* Header ----------------------------------------------- */ .header-outer { background: $(header.background.color) $(header.background.gradient) repeat-x scroll top left; _background-image: none; color: $(header.text.color); -moz-border-radius: $(header.border.radius); -webkit-border-radius: $(header.border.radius); -goog-ms-border-radius: $(header.border.radius); border-radius: $(header.border.radius); } .Header img, .Header #header-inner { -moz-border-radius: $(header.border.radius); -webkit-border-radius: $(header.border.radius); -goog-ms-border-radius: $(header.border.radius); border-radius: $(header.border.radius); } .header-inner .Header .titlewrapper, .header-inner .Header .descriptionwrapper { padding-left: $(header.padding); padding-right: $(header.padding); } .Header h1 { font: $(header.font); text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.3); } .Header h1 a { color: $(header.text.color); } .Header .description { font-size: 130%; } /* Tabs ----------------------------------------------- */ .tabs-inner { margin: .5em $(tabs.margin.sides) $(tabs.margin.bottom); padding: 0; } .tabs-inner .section { margin: 0; } .tabs-inner .widget ul { padding: 0; background: $(tabs.background.color) $(tabs.background.gradient) repeat scroll bottom; -moz-border-radius: $(tabs.border.radius); -webkit-border-radius: $(tabs.border.radius); -goog-ms-border-radius: $(tabs.border.radius); border-radius: $(tabs.border.radius); } .tabs-inner .widget li { border: none; } .tabs-inner .widget li a { display: block; padding: .5em 1em; margin-$endSide: $(tabs.spacing); color: $(tabs.text.color); font: $(tabs.font); -moz-border-radius: $(tab.border.radius) $(tab.border.radius) 0 0; -webkit-border-top-left-radius: $(tab.border.radius); -webkit-border-top-right-radius: $(tab.border.radius); -goog-ms-border-radius: $(tab.border.radius) $(tab.border.radius) 0 0; border-radius: $(tab.border.radius) $(tab.border.radius) 0 0; background: $(tab.background); border-$endSide: 1px solid $(tabs.separator.color); } .tabs-inner .widget li:first-child a { padding-$startSide: 1.25em; -moz-border-radius-top$startSide: $(tab.first.border.radius); -moz-border-radius-bottom$startSide: $(tabs.border.radius); -webkit-border-top-$startSide-radius: $(tab.first.border.radius); -webkit-border-bottom-$startSide-radius: $(tabs.border.radius); -goog-ms-border-top-$startSide-radius: $(tab.first.border.radius); -goog-ms-border-bottom-$startSide-radius: $(tabs.border.radius); border-top-$startSide-radius: $(tab.first.border.radius); border-bottom-$startSide-radius: $(tabs.border.radius); } .tabs-inner .widget li.selected a, .tabs-inner .widget li a:hover { position: relative; z-index: 1; background: $(tabs.selected.background.color) $(tab.selected.background.gradient) repeat scroll bottom; color: $(tabs.selected.text.color); -moz-box-shadow: 0 0 $(region.shadow.spread) rgba(0, 0, 0, .15); -webkit-box-shadow: 0 0 $(region.shadow.spread) rgba(0, 0, 0, .15); -goog-ms-box-shadow: 0 0 $(region.shadow.spread) rgba(0, 0, 0, .15); box-shadow: 0 0 $(region.shadow.spread) rgba(0, 0, 0, .15); } /* Headings ----------------------------------------------- */ h2 { font: $(widget.title.font); text-transform: $(widget.title.text.transform); color: $(widget.title.text.color); margin: .5em 0; } /* Main ----------------------------------------------- */ .main-outer { background: $(main.background); -moz-border-radius: $(main.border.radius.top) $(main.border.radius.top) 0 0; -webkit-border-top-left-radius: $(main.border.radius.top); -webkit-border-top-right-radius: $(main.border.radius.top); -webkit-border-bottom-left-radius: 0; -webkit-border-bottom-right-radius: 0; -goog-ms-border-radius: $(main.border.radius.top) $(main.border.radius.top) 0 0; border-radius: $(main.border.radius.top) $(main.border.radius.top) 0 0; -moz-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); -webkit-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); -goog-ms-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); } .main-inner { padding: 15px $(main.padding.sides) 20px; } .main-inner .column-center-inner { padding: 0 0; } .main-inner .column-left-inner { padding-left: 0; } .main-inner .column-right-inner { padding-right: 0; } /* Posts ----------------------------------------------- */ h3.post-title { margin: 0; font: $(post.title.font); } .comments h4 { margin: 1em 0 0; font: $(post.title.font); } .post-outer { background-color: $(post.background.color); border: solid 1px $(post.border.color); -moz-border-radius: $(post.border.radius); -webkit-border-radius: $(post.border.radius); border-radius: $(post.border.radius); -goog-ms-border-radius: $(post.border.radius); padding: 15px 20px; margin: 0 $(post.margin.sides) 20px; } .post-body { line-height: 1.4; font-size: 110%; } .post-header { margin: 0 0 1.5em; color: $(post.footer.text.color); line-height: 1.6; } .post-footer { margin: .5em 0 0; color: $(post.footer.text.color); line-height: 1.6; } blog-pager { font-size: 140% } comments .comment-author { padding-top: 1.5em; border-top: dashed 1px #ccc; border-top: dashed 1px rgba(128, 128, 128, .5); background-position: 0 1.5em; } comments .comment-author:first-child { padding-top: 0; border-top: none; } .avatar-image-container { margin: .2em 0 0; } /* Widgets ----------------------------------------------- */ .widget ul, .widget #ArchiveList ul.flat { padding: 0; list-style: none; } .widget ul li, .widget #ArchiveList ul.flat li { border-top: dashed 1px #ccc; border-top: dashed 1px rgba(128, 128, 128, .5); } .widget ul li:first-child, .widget #ArchiveList ul.flat li:first-child { border-top: none; } .widget .post-body ul { list-style: disc; } .widget .post-body ul li { border: none; } /* Footer ----------------------------------------------- */ .footer-outer { color:$(footer.text.color); background: $(footer.background); -moz-border-radius: $(footer.border.radius.top) $(footer.border.radius.top) $(footer.border.radius.bottom) $(footer.border.radius.bottom); -webkit-border-top-left-radius: $(footer.border.radius.top); -webkit-border-top-right-radius: $(footer.border.radius.top); -webkit-border-bottom-left-radius: $(footer.border.radius.bottom); -webkit-border-bottom-right-radius: $(footer.border.radius.bottom); -goog-ms-border-radius: $(footer.border.radius.top) $(footer.border.radius.top) $(footer.border.radius.bottom) $(footer.border.radius.bottom); border-radius: $(footer.border.radius.top) $(footer.border.radius.top) $(footer.border.radius.bottom) $(footer.border.radius.bottom); -moz-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); -webkit-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); -goog-ms-box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); box-shadow: 0 $(region.shadow.offset) $(region.shadow.spread) rgba(0, 0, 0, .15); } .footer-inner { padding: 10px $(main.padding.sides) 20px; } .footer-outer a { color: $(footer.link.color); } .footer-outer a:visited { color: $(footer.link.visited.color); } .footer-outer a:hover { color: $(footer.link.hover.color); } .footer-outer .widget h2 { color: $(footer.widget.title.text.color); } ]] <b:template-skin> <b:variable default='930px' name='content.width' type='length' value='930px'/> <b:variable default='0' name='main.column.left.width' type='length' value='180px'/> <b:variable default='360px' name='main.column.right.width' type='length' value='180px'/> <![CDATA[ body { min-width: $(content.width); } .content-outer, .region-inner { min-width: $(content.width); max-width: $(content.width); _width: $(content.width); } .main-inner .columns { padding-left: $(main.column.left.width); padding-right: $(main.column.right.width); } .main-inner .fauxcolumn-center-outer { left: $(main.column.left.width); right: $(main.column.right.width); /* IE6 does not respect left and right together */ _width: expression(this.parentNode.offsetWidth - parseInt("$(main.column.left.width)") - parseInt("$(main.column.right.width)") + 'px'); } .main-inner .fauxcolumn-left-outer { width: $(main.column.left.width); } .main-inner .fauxcolumn-right-outer { width: $(main.column.right.width); } .main-inner .column-left-outer { width: $(main.column.left.width); right: $(main.column.left.width); margin-right: -$(main.column.left.width); } .main-inner .column-right-outer { width: $(main.column.right.width); margin-right: -$(main.column.right.width); } #layout { min-width: 0; } #layout .content-outer { min-width: 0; width: 800px; } #layout .region-inner { min-width: 0; width: auto; } ]]> </b:template-skin> <div class='main-cap-bottom cap-bottom'> <div class='cap-left'/> <div class='cap-right'/> </div> </div> <footer> <div class='footer-outer'> <div class='footer-cap-top cap-top'> <div class='cap-left'/> <div class='cap-right'/> </div> <div class='fauxborder-left footer-fauxborder-left'> <div class='fauxborder-right footer-fauxborder-right'/> <div class='region-inner footer-inner'> <macro:include id='footer-sections' name='sections'> <macro:param default='2' name='num' value='3'/> <macro:param default='footer' name='idPrefix'/> <macro:param default='foot' name='class'/> <macro:param default='false' name='includeBottom'/> </macro:include>  <b:section class='foot' id='footer-3' showaddelement='no'> document.body.className = document.body.className.replace('loading', ''); <macro:if cond='data:col.num >= 2'> <table border='0' cellpadding='0' cellspacing='0' mexpr:class='"section-columns columns-" + data:col.num'> <tbody> <tr> <td class='first columns-cell'> <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + "-2-1"'/> </td> <td class='columns-cell'> <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + "-2-2"'/> </td> <macro:if cond='data:col.num >= 3'> <td class='columns-cell'> <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + "-2-3"'/> </td> </macro:if> <macro:if cond='data:col.num >= 4'> <td class='columns-cell'> <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + "-2-4"'/> </td> </macro:if> </tr> </tbody> </table> <macro:if cond='data:col.includeBottom'> <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + "-3"' showaddelement='no'/> </macro:if> </macro

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C#: LINQ vs foreach - Round 1.

- by James Michael Hare

So I was reading Peter Kellner's blog entry on Resharper 5.0 and its LINQ refactoring and thought that was very cool. But that raised a point I had always been curious about in my head -- which is a better choice: manual foreach loops or LINQ? The answer is not really clear-cut. There are two sides to any code cost arguments: performance and maintainability. The first of these is obvious and quantifiable. Given any two pieces of code that perform the same function, you can run them side-by-side and see which piece of code performs better. Unfortunately, this is not always a good measure. Well written assembly language outperforms well written C++ code, but you lose a lot in maintainability which creates a big techncial debt load that is hard to offset as the application ages. In contrast, higher level constructs make the code more brief and easier to understand, hence reducing technical cost. Now, obviously in this case we're not talking two separate languages, we're comparing doing something manually in the language versus using a higher-order set of IEnumerable extensions that are in the System.Linq library. Well, before we discuss any further, let's look at some sample code and the numbers. First, let's take a look at the for loop and the LINQ expression. This is just a simple find comparison: // find implemented via LINQ public static bool FindViaLinq(IEnumerable<int> list, int target) { return list.Any(item => item == target); } // find implemented via standard iteration public static bool FindViaIteration(IEnumerable<int> list, int target) { foreach (var i in list) { if (i == target) { return true; } } return false; } Okay, looking at this from a maintainability point of view, the Linq expression is definitely more concise (8 lines down to 1) and is very readable in intention. You don't have to actually analyze the behavior of the loop to determine what it's doing. So let's take a look at performance metrics from 100,000 iterations of these methods on a List<int> of varying sizes filled with random data. For this test, we fill a target array with 100,000 random integers and then run the exact same pseudo-random targets through both searches. List<T> On 100,000 Iterations Method Size Total (ms) Per Iteration (ms) % Slower Any 10 26 0.00046 30.00% Iteration 10 20 0.00023 - Any 100 116 0.00201 18.37% Iteration 100 98 0.00118 - Any 1000 1058 0.01853 16.78% Iteration 1000 906 0.01155 - Any 10,000 10,383 0.18189 17.41% Iteration 10,000 8843 0.11362 - Any 100,000 104,004 1.8297 18.27% Iteration 100,000 87,941 1.13163 - The LINQ expression is running about 17% slower for average size collections and worse for smaller collections. Presumably, this is due to the overhead of the state machine used to track the iterators for the yield returns in the LINQ expressions, which seems about right in a tight loop such as this. So what about other LINQ expressions? After all, Any() is one of the more trivial ones. I decided to try the TakeWhile() algorithm using a Count() to get the position stopped like the sample Pete was using in his blog that Resharper refactored for him into LINQ: // Linq form public static int GetTargetPosition1(IEnumerable<int> list, int target) { return list.TakeWhile(item => item != target).Count(); } // traditionally iterative form public static int GetTargetPosition2(IEnumerable<int> list, int target) { int count = 0; foreach (var i in list) { if(i == target) { break; } ++count; } return count; } Once again, the LINQ expression is much shorter, easier to read, and should be easier to maintain over time, reducing the cost of technical debt. So I ran these through the same test data: List<T> On 100,000 Iterations Method Size Total (ms) Per Iteration (ms) % Slower TakeWhile 10 41 0.00041 128% Iteration 10 18 0.00018 - TakeWhile 100 171 0.00171 88% Iteration 100 91 0.00091 - TakeWhile 1000 1604 0.01604 94% Iteration 1000 825 0.00825 - TakeWhile 10,000 15765 0.15765 92% Iteration 10,000 8204 0.08204 - TakeWhile 100,000 156950 1.5695 92% Iteration 100,000 81635 0.81635 - Wow! I expected some overhead due to the state machines iterators produce, but 90% slower? That seems a little heavy to me. So then I thought, well, what if TakeWhile() is not the right tool for the job? The problem is TakeWhile returns each item for processing using yield return, whereas our for-loop really doesn't care about the item beyond using it as a stop condition to evaluate. So what if that back and forth with the iterator state machine is the problem? Well, we can quickly create an (albeit ugly) lambda that uses the Any() along with a count in a closure (if a LINQ guru knows a better way PLEASE let me know!), after all , this is more consistent with what we're trying to do, we're trying to find the first occurence of an item and halt once we find it, we just happen to be counting on the way. This mostly matches Any(). // a new method that uses linq but evaluates the count in a closure. public static int TakeWhileViaLinq2(IEnumerable<int> list, int target) { int count = 0; list.Any(item => { if(item == target) { return true; } ++count; return false; }); return count; } Now how does this one compare? List<T> On 100,000 Iterations Method Size Total (ms) Per Iteration (ms) % Slower TakeWhile 10 41 0.00041 128% Any w/Closure 10 23 0.00023 28% Iteration 10 18 0.00018 - TakeWhile 100 171 0.00171 88% Any w/Closure 100 116 0.00116 27% Iteration 100 91 0.00091 - TakeWhile 1000 1604 0.01604 94% Any w/Closure 1000 1101 0.01101 33% Iteration 1000 825 0.00825 - TakeWhile 10,000 15765 0.15765 92% Any w/Closure 10,000 10802 0.10802 32% Iteration 10,000 8204 0.08204 - TakeWhile 100,000 156950 1.5695 92% Any w/Closure 100,000 108378 1.08378 33% Iteration 100,000 81635 0.81635 - Much better! It seems that the overhead of TakeAny() returning each item and updating the state in the state machine is drastically reduced by using Any() since Any() iterates forward until it finds the value we're looking for -- for the task we're attempting to do. So the lesson there is, make sure when you use a LINQ expression you're choosing the best expression for the job, because if you're doing more work than you really need, you'll have a slower algorithm. But this is true of any choice of algorithm or collection in general. Even with the Any() with the count in the closure it is still about 30% slower, but let's consider that angle carefully. For a list of 100,000 items, it was the difference between 1.01 ms and 0.82 ms roughly in a List<T>. That's really not that bad at all in the grand scheme of things. Even running at 90% slower with TakeWhile(), for the vast majority of my projects, an extra millisecond to save potential errors in the long term and improve maintainability is a small price to pay. And if your typical list is 1000 items or less we're talking only microseconds worth of difference. It's like they say: 90% of your performance bottlenecks are in 2% of your code, so over-optimizing almost never pays off. So personally, I'll take the LINQ expression wherever I can because they will be easier to read and maintain (thus reducing technical debt) and I can rely on Microsoft's development to have coded and unit tested those algorithm fully for me instead of relying on a developer to code the loop logic correctly. If something's 90% slower, yes, it's worth keeping in mind, but it's really not until you start get magnitudes-of-order slower (10x, 100x, 1000x) that alarm bells should really go off. And if I ever do need that last millisecond of performance? Well then I'll optimize JUST THAT problem spot. To me it's worth it for the readability, speed-to-market, and maintainability.

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Blending the Sketchflow Action

- by GeekAgilistMercenary

Started a new Sketchflow Prototype in Expression Blend recently and documented each of the steps. This blog entry covers some of those steps, which are the basic elements of any prototype. I will have more information regarding design, prototype creation, and the process of the initial phases for development in the future. For now, I hope you enjoy this short walk through. Also, be sure to check out my last quick entry on Sketchflow. I started off with a Sketchflow Project, just like I did in my previous entry (more specifics in that entry about how to manipulate and build out the Sketchflow Map). Once I created the project I setup the following Sketchflow Map. The CoreNavigation is a ComponentScreen setup solely for the page navigation at the top of the screen. The XAML markup in case you want to create a Component Screen with the same design is included below. <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" xmlns:pb="clr-namespace:Microsoft.Expression.Prototyping.Behavior;assembly=Microsoft.Expression.Prototyping.Interactivity" x:Class="RapidPrototypeSketchScreens.CoreNavigation" d:DesignWidth="624" d:DesignHeight="49" Height="49" Width="624"> <Grid x:Name="LayoutRoot"> <TextBlock HorizontalAlignment="Stretch" Margin="307,3,0,0" Style="{StaticResource TitleCenter-Sketch}" Text="Aütøchart Scorecards" TextWrapping="Wrap"> <i:Interaction.Triggers> <i:EventTrigger EventName="MouseLeftButtonDown"> <pb:NavigateToScreenAction TargetScreen="RapidPrototypeSketchScreens.Screen_1"/> </i:EventTrigger> </i:Interaction.Triggers> </TextBlock> <Button HorizontalAlignment="Left" Margin="164,8,0,11" Style="{StaticResource Button-Sketch}" Width="144" Content="Scorecard"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <pb:NavigateToScreenAction TargetScreen="RapidPrototypeSketchScreens.Screen_1_2"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> <Button HorizontalAlignment="Left" Margin="8,8,0,11" Style="{StaticResource Button-Sketch}" Width="152" Content="Standard Reports"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <pb:NavigateToScreenAction TargetScreen="RapidPrototypeSketchScreens.Screen_1_1"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> </Grid> </UserControl> Now that the CoreNavigation Component Screen is done I built out each of the others. In each of those screens I included the CoreNavigation Screen (all those little green lines in the image) as the top navigation. In order to do that, as I created each of the pages I would hover over the CoreNavigation Object in the Sketchflow Map. When the utilities drawer (the small menu that pops down under a node when you hover over it) shows click on the third little icon and drag it onto the page node you want a navigation screen on. Once I created all the screens I setup the navigation by opening up each screen and right clicking on the objects that needed to point to somewhere else in the prototype. Once I was done with the main page, my Home Navigation Page, it looked something like this in the Expression Blend Designer. I fleshed out each of the additional screens. Once I was done I wanted to try out the deployment package. The way to deploy a Sketchflow Prototype is to merely click on File –> Package SketchFlow Project and a prompt will appear. In the prompt enter what you want the package to be called. I like to see the files generated afterwards too, so I checked the box to see that. When Expression Blend is done generating everything you’ll have a directory like the one shown below, with all the needed files for deployment. Now these files can be copied or moved to any location for viewing. One can even copy them (such as via FTP) to a server location to share with others. Once they are deployed and you run the "TestPage.html" the other features of the Sketchflow Package are available. In the image below I have tagged a few sections to show the Sketchflow Player Features. To the top left is the navigation, which provides a clearly defined area of movement in a list. To the center right is the actual prototype application. I have placed lists of things and made edits. On the left hand side is the highlight feature, which is available in the Feedback section of the lower left. On the right hand list I underlined the Autochart with an orange marker, and marked out two list items with a red marker. In the lower left hand side in the Feedback section is also an area to type in your feedback. This can be useful for time based feedback, when you post this somewhere and want people to provide subsequent follow up feedback. Overall lots of great features, that enable some fairly rapid prototyping with customers. Once one is familiar with the steps and parts of this Sketchflow Prototype Capabilities it is easy to step through an application without even stopping. It really is that easy. So get hold of Expression Blend 3 and get ramped up on Sketchflow, it will pay off in the design phases to do so! Original Entry

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MVC 2 Editor Template for Radio Buttons

- by Steve Michelotti

A while back I blogged about how to create an HTML Helper to produce a radio button list. In that post, my HTML helper was “wrapping” the FluentHtml library from MvcContrib to produce the following html output (given an IEnumerable list containing the items “Foo” and “Bar”): 1: <div> 2: <input id="Name_Foo" name="Name" type="radio" value="Foo" /><label for="Name_Foo" id="Name_Foo_Label">Foo</label> 3: <input id="Name_Bar" name="Name" type="radio" value="Bar" /><label for="Name_Bar" id="Name_Bar_Label">Bar</label> 4: </div> With the release of MVC 2, we now have editor templates we can use that rely on metadata to allow us to customize our views appropriately. For example, for the radio buttons above, we want the “id” attribute to be differentiated and unique and we want the “name” attribute to be the same across radio buttons so the buttons will be grouped together and so model binding will work appropriately. We also want the “for” attribute in the <label> element being set to correctly point to the id of the corresponding radio button. The default behavior of the RadioButtonFor() method that comes OOTB with MVC produces the same value for the “id” and “name” attributes so this isn’t exactly what I want out the the box if I’m trying to produce the HTML mark up above. If we use an EditorTemplate, the first gotcha that we run into is that, by default, the templates just work on your view model’s property. But in this case, we *also* was the list of items to populate all the radio buttons. It turns out that the EditorFor() methods do give you a way to pass in additional data. There is an overload of the EditorFor() method where the last parameter allows you to pass an anonymous object for “extra” data that you can use in your view – it gets put on the view data dictionary: 1: <%: Html.EditorFor(m => m.Name, "RadioButtonList", new { selectList = new SelectList(new[] { "Foo", "Bar" }) })%> Now we can create a file called RadioButtonList.ascx that looks like this: 1: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %> 2: <% 3: var list = this.ViewData["selectList"] as SelectList; 4: %> 5: <div> 6: <% foreach (var item in list) { 7: var radioId = ViewData.TemplateInfo.GetFullHtmlFieldId(item.Value); 8: var checkedAttr = item.Selected ? "checked=\"checked\"" : string.Empty; 9: %> 10: <input type="radio" id="<%: radioId %>" name="<%: ViewData.TemplateInfo.HtmlFieldPrefix %>" value="<%: item.Value %>" <%: checkedAttr %>/> 11: <label for="<%: radioId %>"><%: item.Text %></label> 12: <% } %> 13: </div> There are several things to note about the code above. First, you can see in line #3, it’s getting the SelectList out of the view data dictionary. Then on line #7 it uses the GetFullHtmlFieldId() method from the TemplateInfo class to ensure we get unique IDs. We pass the Value to this method so that it will produce IDs like “Name_Foo” and “Name_Bar” rather than just “Name” which is our property name. However, for the “name” attribute (on line #10) we can just use the normal HtmlFieldPrefix property so that we ensure all radio buttons have the same name which corresponds to the view model’s property name. We also get to leverage the fact the a SelectListItem has a Boolean Selected property so we can set the checkedAttr variable on line #8 and use it on line #10. Finally, it’s trivial to set the correct “for” attribute for the <label> on line #11 since we already produced that value. Because the TemplateInfo class provides all the metadata for our view, we’re able to produce this view that is widely re-usable across our application. In fact, we can create a couple HTML helpers to better encapsulate this call and make it more user friendly: 1: public static MvcHtmlString RadioButtonList<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, params string[] items) 2: { 3: return htmlHelper.RadioButtonList(expression, new SelectList(items)); 4: } 5: 6: public static MvcHtmlString RadioButtonList<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<SelectListItem> items) 7: { 8: var func = expression.Compile(); 9: var result = func(htmlHelper.ViewData.Model); 10: var list = new SelectList(items, "Value", "Text", result); 11: return htmlHelper.EditorFor(expression, "RadioButtonList", new { selectList = list }); 12: } This allows us to simply the call like this: 1: <%: Html.RadioButtonList(m => m.Name, "Foo", "Bar" ) %> In that example, the values for the radio button are hard-coded and being passed in directly. But if you had a view model that contained a property for the collection of items you could call the second overload like this: 1: <%: Html.RadioButtonList(m => m.Name, Model.FooBarList ) %> The Editor templates introduced in MVC 2 definitely allow for much more flexible views/editors than previously available. By knowing about the features you have available to you with the TemplateInfo class, you can take these concepts and customize your editors with extreme flexibility and re-usability.

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Entity Framework 4.0 and DDD patterns

- by Voice

Hi everybody I use EntityFramework as ORM and I have simple POCO Domain Model with two base classes that represent Value Object and Entity Object Patterns (Evans). These two patterns is all about equality of two objects, so I overrode Equals and GetHashCode methods. Here are these two classes: public abstract class EntityObject<T>{ protected T _ID = default(T); public T ID { get { return _ID; } protected set { _ID = value; } } public sealed override bool Equals(object obj) { EntityObject<T> compareTo = obj as EntityObject<T>; return (compareTo != null) && ((HasSameNonDefaultIdAs(compareTo) || (IsTransient && compareTo.IsTransient)) && HasSameBusinessSignatureAs(compareTo)); } public virtual void MakeTransient() { _ID = default(T); } public bool IsTransient { get { return _ID == null || _ID.Equals(default(T)); } } public override int GetHashCode() { if (default(T).Equals(_ID)) return 0; return _ID.GetHashCode(); } private bool HasSameBusinessSignatureAs(EntityObject<T> compareTo) { return ToString().Equals(compareTo.ToString()); } private bool HasSameNonDefaultIdAs(EntityObject<T> compareTo) { return (_ID != null && !_ID.Equals(default(T))) && (compareTo._ID != null && !compareTo._ID.Equals(default(T))) && _ID.Equals(compareTo._ID); } public override string ToString() { StringBuilder str = new StringBuilder(); str.Append(" Class: ").Append(GetType().FullName); if (!IsTransient) str.Append(" ID: " + _ID); return str.ToString(); } } public abstract class ValueObject<T, U> : IEquatable<T> where T : ValueObject<T, U> { private static List<PropertyInfo> Properties { get; set; } private static Func<ValueObject<T, U>, PropertyInfo, object[], object> _GetPropValue; static ValueObject() { Properties = new List<PropertyInfo>(); var propParam = Expression.Parameter(typeof(PropertyInfo), "propParam"); var target = Expression.Parameter(typeof(ValueObject<T, U>), "target"); var indexPar = Expression.Parameter(typeof(object[]), "indexPar"); var call = Expression.Call(propParam, typeof(PropertyInfo).GetMethod("GetValue", new[] { typeof(object), typeof(object[]) }), new[] { target, indexPar }); var lambda = Expression.Lambda<Func<ValueObject<T, U>, PropertyInfo, object[], object>>(call, target, propParam, indexPar); _GetPropValue = lambda.Compile(); } public U ID { get; protected set; } public override Boolean Equals(Object obj) { if (ReferenceEquals(null, obj)) return false; if (obj.GetType() != GetType()) return false; return Equals(obj as T); } public Boolean Equals(T other) { if (ReferenceEquals(null, other)) return false; if (ReferenceEquals(this, other)) return true; foreach (var property in Properties) { var oneValue = _GetPropValue(this, property, null); var otherValue = _GetPropValue(other, property, null); if (null == oneValue && null == otherValue) return false; if (false == oneValue.Equals(otherValue)) return false; } return true; } public override Int32 GetHashCode() { var hashCode = 36; foreach (var property in Properties) { var propertyValue = _GetPropValue(this, property, null); if (null == propertyValue) continue; hashCode = hashCode ^ propertyValue.GetHashCode(); } return hashCode; } public override String ToString() { var stringBuilder = new StringBuilder(); foreach (var property in Properties) { var propertyValue = _GetPropValue(this, property, null); if (null == propertyValue) continue; stringBuilder.Append(propertyValue.ToString()); } return stringBuilder.ToString(); } protected static void RegisterProperty(Expression<Func<T, Object>> expression) { MemberExpression memberExpression; if (ExpressionType.Convert == expression.Body.NodeType) { var body = (UnaryExpression)expression.Body; memberExpression = body.Operand as MemberExpression; } else memberExpression = expression.Body as MemberExpression; if (null == memberExpression) throw new InvalidOperationException("InvalidMemberExpression"); Properties.Add(memberExpression.Member as PropertyInfo); } } Everything was OK until I tried to delete some related objects (aggregate root object with two dependent objects which was marked for cascade deletion): I've got an exception "The relationship could not be changed because one or more of the foreign-key properties is non-nullable". I googled this and found http://blog.abodit.com/2010/05/the-relationship-could-not-be-changed-because-one-or-more-of-the-foreign-key-properties-is-non-nullable/ I changed GetHashCode to base.GetHashCode() and error disappeared. But now it breaks all my code: I can't override GetHashCode for my POCO objects = I can't override Equals = I can't implement Value Object and Entity Object patters for my POCO objects. So, I appreciate any solutions, workarounds here etc.

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Boost Regex unknown number of var

- by Katrin Thielmann

I got a Problem with a regex expression and need help. I have some expressions like these in mein .txt File: 19 = NAND (1, 19) regex expression : http://rubular.com/r/U8rO09bvTO With this regex expression i got seperated matches for the numbers. But now I need a regex expression with a unknown size of numbers in the bracket . For example: 19 = NAND (1, 23, 13, 24) match1: 19 match2: 1 match3: 23 match4: 13 match5: 24 I don't know the number of the numbers. So i need a main expression for min 2 numbers in the bracket till a unknow number. I hope somebody can help me.

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Linq To SQL - Specified cast is not valid - SingleOrDefault()

- by NullReference

I am trying to do the following... Request request = (from r in db.Requests where r.Status == "Processing" && r.Locked == false select r).SingleOrDefault(); It is throwing the following exception... Message: Specified cast is not valid. StackTrace: at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable1 source) at GDRequestProcessor.Worker.GetNextRequest() Can anyone help me? Thanks in advance!

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How to convert an object into a double?

- by george t.

I am working on VS C# on the following code, which converts an user input math expression and computes it. MSScriptControl.ScriptControl sc = new MSScriptControl.ScriptControl(); sc.Language = "VBScript"; sc.ExecuteStatement( "function pi\n" + "pi = 3.14159265\n" + "end function"); sc.ExecuteStatement( "function e\n" + "e = exp(1)\n" + "end function"); expression = textBox1.Text.ToString(); expression = expression.Replace("x", i.ToString()); object y = sc.Eval(expression); string k = y.ToString(); double result = double.Parse(k); While this outputs onto the console with the correct result, I want to use the values to make a graph of the function user inputs and it's not doing it correctly. Thank you for your help.

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xaml nested class path designer issue

- by Vlad Bezden

Hi, I have nested class public class Enums { public enum WindowModeEnum { Edit, New } } In my xaml I reference code: <Style.Triggers> <DataTrigger Binding="{Binding WindowMode}" Value="{x:Static Types1:Enums+WindowModeEnum.Edit}"> <Setter Property="Visibility" Value="Collapsed" /> </DataTrigger> </Style.Triggers> Code compiles and runs properly, however I can't open xaml code in design window. I am getting following error: Type 'Types1:Enums+WindowModeEnum' was not found. at MS.Internal.Metadata.ExposedTypes.ValueSerializers.StaticMemberDocumentValueSerializer.ConvertToDocumentValue(ITypeMetadata type, String value, IServiceProvider documentServices) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlMarkupExtensionPropertyBase.get_Value() at MS.Internal.Design.DocumentModel.DocumentTrees.DocumentPropertyWrapper.get_Value() at MS.Internal.Design.DocumentModel.DocumentTrees.InMemory.InMemoryDocumentProperty..ctor(DocumentProperty property, InMemoryDocumentItem item) at MS.Internal.Design.DocumentModel.DocumentTrees.InMemory.InMemoryDocumentItem.SetUpItem(DocumentItem item) Same error exist in VS2008, VS2010. Does anybody has any idea, how to deal with it so I can open window in design mode. Thanks a lot. Sincerely, Vlad.

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Creating an AST node in Erlang

- by dagda1

Hi, I am playing about with Erlang and I am trying to write a simple arithmetic parser. I want to try and parse the following expression: ((12+3)-4) I want to parse the expression into a stack of AST nodes. When parsing this expression, I would first of all create a binary expression for the (12+3) expression which would look something like this in C#: var binaryStructure = new BinaryStructure(); binaryStructure.Left = IntegerLiteralExpression(12); binaryStructure.Right = IntegerLiteralExpression(4); binaryStructure.Operator = binaryExpression.Operator != BinaryOperatorType.Addition; I am quite new to Erlang and I am wondering how I would go about creating a structure like this in Erlang that I can place on a List that I would use as the stack of expressions. Can anyone suggest how to create such a tree like structure? Would a function be a good fit? Thanks Paul

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Should methods containing LINQ expressions be tested / mocked?

- by Phil.Wheeler

Assuming I have a class with a method that takes a System.Linq.Expressions.Expression as a parameter, how much value is there in unit testing it? public void IEnumerable<T> Find(Expression expression) { return someCollection.Where(expression).ToList(); } Unit testing or mocking these sorts of methods has been a mind-frying experience for me and I'm now at the point where I have to wonder whether it's all just not worth it. How would I unit test this method using some arbitrary expression like List<Animal> = myAnimalRepository.Find(x => x.Species == "Cat");

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Mule Performing a string manipulation

- by user2910309

What is the best way to perform a string manipulation. I wish to perform a substring on a email address to extract the domain detail and populate this to a variable. a java transformer is a possibilty, but i was hoping if i could use a message enricher with a expression to perform this operation. pardon me but i am still a greenhorn on Mule. here is the excerpt from my mule flow which is failing with error cannot resolve method string length. <enricher target="#[flowVars['FromAddressDomain']]" doc:name="Message Enricher"> <expression-transformer expression="#[ payload.fromAddr.substring(payload.fromAddr.lastIndexOf('@')+ 1,payload.fromAddr.lenth())]" doc:name="Expression"></expression-transformer> </enricher>

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linq NullReferenceException while checking for null reference

- by Odrade

I have the following LINQ query: List<FileInputItem> inputList = GetInputList(); var results = from FileInputItem f in inputList where ( Path.GetDirectoryName(f.Folder).ToLower().Trim() == somePath || Path.GetDirectoryName(f.Folder).ToLower().Trim() == someOtherPath ) && f.Expression == null select f; Every time this query is executed, it generates a NullReferenceException. If I remove the condition f.Expression == null or change it to f.Expression != null, the query executes normally (giving the wrong results, of course). The relevant bits of FileInputItem look like this: [Serializable] public class FileInputItem { [XmlElement("Folder")] public string Folder { get; set; } [XmlElement("Expression")] public string Expression { get; set; } /*SNIP. Irrelevant properties */ } I'm new to LINQ to objects, so I'm probably missing something fundamental here. What's the deal?

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LINQ - Select Statement - The null value cannot be assigned to a member with type System.Int32 which

- by thiag0

I am trying to achieve the following... _4S.NJB_Request request = (from r in db.NJB_Requests where r.RequestId == referenceId select r).Take(1).SingleOrDefault(); Getting the following exception... Message: The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type. StackTrace: at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source) at DAL.SqlDataProvider.MarkNJBPCRequestAsComplete(Int32 referenceId, Int32 processState) I have verified that 'referenceId' does have a value. Anyone know why this would happen in a select statement? Thanks!

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Microsoft Sql Server 2008 R2 System Databases

For a majority of software developers little time is spent understanding the inner workings of the database management systems (DBMS) they use to store data for their applications. I personally place myself in this grouping. In my case, I have used various versions of Microsoft’s SQL Server (2000, 2005, and 2008 R2) and just recently learned how valuable they really are when I was preparing to deliver a lecture on "SQL Server 2008 R2, System Databases". Microsoft Sql Server 2008 R2 System DatabasesSo what are system databases in MS SQL Server, and why should I know them? Microsoft uses system databases to support the SQL Server DBMS, much like a developer uses config files or database tables to support an application. These system databases individually provide specific functionality that allows MS SQL Server to function. Name Database File Log File Master master.mdf mastlog.ldf Resource mssqlsystemresource.mdf mssqlsystemresource.ldf Model model.mdf modellog.ldf MSDB msdbdata.mdf msdblog.ldf Distribution distmdl.mdf distmdl.ldf TempDB tempdb.mdf templog.ldf Master DatabaseIf you have used MS SQL Server then you should recognize the Master database especially if you used the SQL Server Management Studio (SSMS) to connect to a user created database. MS SQL Server requires the Master database in order for DBMS to start due to the information that it stores. Examples of data stored in the Master database User Logins Linked Servers Configuration information Information on User Databases Resource DatabaseHonestly, until recently I never knew this database even existed until I started to research SQL Server system databases. The reason for this is due largely to the fact that the resource database is hidden to users. In fact, the database files are stored within the Binn folder instead of the standard MS SQL Server database folder path. This database contains all system objects that can be accessed by all other databases. In short, this database contains all system views and store procedures that appear in all other user databases regarding system information. One of the many benefits to storing system views and store procedures in a single hidden database is the fact it improves upgrading a SQL Server database; not to mention that maintenance is decreased since only one code base has to be mainlined for all of the system views and procedures. Model DatabaseThe Model database as the name implies is the model for all new databases created by users. This allows for predefining default database objects for all new databases within a MS SQL Server instance. For example, if every database created by a user needs to have an “Audit” table when it is created then defining the “Audit” table in the model will guarantees that the table will be located in every new database create after the model is altered. MSDB DatabaseThe MSDBdatabase is used by SQL Server Agent, SQL Server Database Mail, SQL Server Service Broker, along with SQL Server. The SQL Server Agent uses this database to store job configurations and SQL job schedules along with SQL Alerts, and Operators. In addition, this database also stores all SQL job parameters along with each job’s execution history. Finally, this database is also used to store database backup and maintenance plans as well as details pertaining to SQL Log shipping if it is being used. Distribution DatabaseThe Distribution database is only used during replication and stores meta data and history information pertaining to the act of replication data. Furthermore, when transactional replication is used this database also stores information regarding each transaction. It is important to note that replication is not turned on by default in MS SQL Server and that the distribution database is hidden from SSMS. Tempdb DatabaseThe Tempdb as the name implies is used to store temporary data and data objects. Examples of this include temp tables and temp store procedures. It is important to note that when using this database all data and data objects are cleared from this database when SQL Server restarts. This database is also used by SQL Server when it is performing some internal operations. Typically, SQL Server uses this database for the purpose of large sort and index operations. Finally, this database is used to store row versions if row versioning or snapsot isolation transactions are being used by SQL Server. Additionally, I would love to hear from others about their experiences using system databases, tables, and objects in a real world environments.

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Microsoft Sql Server 2008 R2 System Databases

For a majority of software developers little time is spent understanding the inner workings of the database management systems (DBMS) they use to store data for their applications. I personally place myself in this grouping. In my case, I have used various versions of Microsoft’s SQL Server (2000, 2005, and 2008 R2) and just recently learned how valuable they really are when I was preparing to deliver a lecture on "SQL Server 2008 R2, System Databases". Microsoft Sql Server 2008 R2 System DatabasesSo what are system databases in MS SQL Server, and why should I know them? Microsoft uses system databases to support the SQL Server DBMS, much like a developer uses config files or database tables to support an application. These system databases individually provide specific functionality that allows MS SQL Server to function. Name Database File Log File Master master.mdf mastlog.ldf Resource mssqlsystemresource.mdf mssqlsystemresource.ldf Model model.mdf modellog.ldf MSDB msdbdata.mdf msdblog.ldf Distribution distmdl.mdf distmdl.ldf TempDB tempdb.mdf templog.ldf Master DatabaseIf you have used MS SQL Server then you should recognize the Master database especially if you used the SQL Server Management Studio (SSMS) to connect to a user created database. MS SQL Server requires the Master database in order for DBMS to start due to the information that it stores. Examples of data stored in the Master database User Logins Linked Servers Configuration information Information on User Databases Resource DatabaseHonestly, until recently I never knew this database even existed until I started to research SQL Server system databases. The reason for this is due largely to the fact that the resource database is hidden to users. In fact, the database files are stored within the Binn folder instead of the standard MS SQL Server database folder path. This database contains all system objects that can be accessed by all other databases. In short, this database contains all system views and store procedures that appear in all other user databases regarding system information. One of the many benefits to storing system views and store procedures in a single hidden database is the fact it improves upgrading a SQL Server database; not to mention that maintenance is decreased since only one code base has to be mainlined for all of the system views and procedures. Model DatabaseThe Model database as the name implies is the model for all new databases created by users. This allows for predefining default database objects for all new databases within a MS SQL Server instance. For example, if every database created by a user needs to have an “Audit” table when it is created then defining the “Audit” table in the model will guarantees that the table will be located in every new database create after the model is altered. MSDB DatabaseThe MSDBdatabase is used by SQL Server Agent, SQL Server Database Mail, SQL Server Service Broker, along with SQL Server. The SQL Server Agent uses this database to store job configurations and SQL job schedules along with SQL Alerts, and Operators. In addition, this database also stores all SQL job parameters along with each job’s execution history. Finally, this database is also used to store database backup and maintenance plans as well as details pertaining to SQL Log shipping if it is being used. Distribution DatabaseThe Distribution database is only used during replication and stores meta data and history information pertaining to the act of replication data. Furthermore, when transactional replication is used this database also stores information regarding each transaction. It is important to note that replication is not turned on by default in MS SQL Server and that the distribution database is hidden from SSMS. Tempdb DatabaseThe Tempdb as the name implies is used to store temporary data and data objects. Examples of this include temp tables and temp store procedures. It is important to note that when using this database all data and data objects are cleared from this database when SQL Server restarts. This database is also used by SQL Server when it is performing some internal operations. Typically, SQL Server uses this database for the purpose of large sort and index operations. Finally, this database is used to store row versions if row versioning or snapsot isolation transactions are being used by SQL Server. Additionally, I would love to hear from others about their experiences using system databases, tables, and objects in a real world environments.

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LINQ - Linq to Sql - Specified cast is not valid - Please Help!

- by thiag0

I am trying to do the following... Request request = ( from r in db.Requests where r.Status == "Processing" && r.Locked == false select r).SingleOrDefault(); It is throwing the following exception... Message: Specified cast is not valid. StackTrace: at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source) at GDRequestProcessor.Worker.GetNextRequest() The .DBML file schema matches my database table that I am trying to select from so I have no clue why I am having this problem. Can anyone help me? Thanks in advance!

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Parameter is not valid when getting image from stream

- by duka1

Hi guys, I have this code: MemoryStream ms = new MemoryStream(newbytes, 0, newbytes.Length); ms.Position = 0; ms.Write(newbytes, 0, newbytes.Length); Image img = Image.FromStream(ms); img.Save(@"C:\Users\gsira\Pictures\Blue hills5.jpg"); I get this error at the Image.FromStream(ms) call: System.ArgumentException: Parameter is not valid. at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateIma How can I resolve this? A couple of links which solve this problem (one on an MSDN thread) are broken so I am lost.

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Concatenating string with number in Javascript

- by Sparky

I'm trying to create a simple calculator in Javascript. I have an array named expression chunk[0] = 12 chunk[1] = + (the "+" sign) chunk[1] = 5 I used a for loop to loop through the chunks (chunk[]) and join then into a single expression as follows:- equation = ""; // To make var equation a string for(i = 0; i <= length; i++) { equation = equation + expression[i]; alert(expression[i]); } alert(equation); alert(expression[i]) showed values 12, + and 5. But alert(equation) showed 125 (instead of "12+5"). I need the variable equation to be "12+5" so that I can later call eval(equation) and get the value of 12+5. What am I doing wrong here?

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Converting Openfire IM datetime values in SQL Server to / from VARCHAR(15) and DATETIME data types

- by Brian Biales

A client is using Openfire IM for their users, and would like some custom queries to audit user conversations (which are stored by Openfire in tables in the SQL Server database). Because Openfire supports multiple database servers and multiple platforms, the designers chose to store all date/time stamps in the database as 15 character strings, which get converted to Java Date objects in their code (Openfire is written in Java). I did some digging around, and, so I don't forget and in case someone else will find this useful, I will put the simple algorithms here for converting back and forth between SQL DATETIME and the Java string representation. The Java string representation is the number of milliseconds since 1/1/1970. SQL Server's DATETIME is actually represented as a float, the value being the number of days since 1/1/1900, the portion after the decimal point representing the hours/minutes/seconds/milliseconds... as a fractional part of a day. Try this and you will see this is true: SELECT CAST(0 AS DATETIME) and you will see it returns the date 1/1/1900. The difference in days between SQL Server's 0 date of 1/1/1900 and the Java representation's 0 date of 1/1/1970 is found easily using the following SQL: SELECT DATEDIFF(D, '1900-01-01', '1970-01-01') which returns 25567. There are 25567 days between these dates. So to convert from the Java string to SQL Server's date time, we need to convert the number of milliseconds to a floating point representation of the number of days since 1/1/1970, then add the 25567 to change this to the number of days since 1/1/1900. To convert to days, you need to divide the number by 1000 ms/s, then by 60 seconds/minute, then by 60 minutes/hour, then by 24 hours/day. Or simply divide by 1000*60*60*24, or 86400000. So, to summarize, we need to cast this string as a float, divide by 86400000 milliseconds/day, then add 25567 days, and cast the resulting value to a DateTime. Here is an example: DECLARE @tmp as VARCHAR(15) SET @tmp = '1268231722123' SELECT @tmp as JavaTime, CAST((CAST(@tmp AS FLOAT) / 86400000) + 25567 AS DATETIME) as SQLTime To convert from SQL datetime back to the Java time format is not quite as simple, I found, because floats of that size do not convert nicely to strings, they end up in scientific notation using the CONVERT function or CAST function. But I found a couple ways around that problem. You can convert a date to the number of seconds since 1/1/1970 very easily using the DATEDIFF function, as this value fits in an Int. If you don't need to worry about the milliseconds, simply cast this integer as a string, and then concatenate '000' at the end, essentially multiplying this number by 1000, and making it milliseconds since 1/1/1970. If, however, you do care about the milliseconds, you will need to use DATEPART to get the milliseconds part of the date, cast this integer to a string, and then pad zeros on the left to make sure this is three digits, and concatenate these three digits to the number of seconds string above. And finally, I discovered by casting to DECIMAL(15,0) then to VARCHAR(15), I avoid the scientific notation issue. So here are all my examples, pick the one you like best... First, here is the simple approach if you don't care about the milliseconds: DECLARE @tmp as VARCHAR(15) DECLARE @dt as DATETIME SET @dt = '2010-03-10 14:35:22.123' SET @tmp = CAST(DATEDIFF(s, '1970-01-01 00:00:00' , @dt) AS VARCHAR(15)) + '000' SELECT @tmp as JavaTime, @dt as SQLTime If you want to keep the milliseconds: DECLARE @tmp as VARCHAR(15) DECLARE @dt as DATETIME DECLARE @ms as int SET @dt = '2010-03-10 14:35:22.123' SET @ms as DATEPART(ms, @dt) SET @tmp = CAST(DATEDIFF(s, '1970-01-01 00:00:00' , @dt) AS VARCHAR(15)) + RIGHT('000' + CAST(@ms AS VARCHAR(3)), 3) SELECT @tmp as JavaTime, @dt as SQLTime Or, in one fell swoop: DECLARE @dt as DATETIME SET @dt = '2010-03-10 14:35:22.123' SELECT @dt as SQLTime , CAST(DATEDIFF(s, '1970-01-01 00:00:00' , @dt) AS VARCHAR(15)) + RIGHT('000' + CAST( DATEPART(ms, @dt) AS VARCHAR(3)), 3) as JavaTime And finally, a way to simply reverse the math used converting from Java date to SQL date. Note the parenthesis - watch out for operator precedence, you want to subtract, then multiply: DECLARE @dt as DATETIME SET @dt = '2010-03-10 14:35:22.123' SELECT @dt as SQLTime , CAST(CAST((CAST(@dt as Float) - 25567.0) * 86400000.0 as DECIMAL(15,0)) as VARCHAR(15)) as JavaTime Interestingly, I found that converting to SQL Date time can lose some accuracy, when I converted the time above to Java time then converted that back to DateTime, the number of milliseconds is 120, not 123. As I am not interested in the milliseconds, this is ok for me. But you may want to look into using DateTime2 in SQL Server 2008 for more accuracy.

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SharePoint 2010 Sandboxed solution SPGridView

- by Steve Clements

If you didn’t know, you probably will soon, the SPGridView is not available in Sandboxed solutions. To be honest there doesn’t seem to be a great deal of information out there about the whys and what nots, basically its not part of the Sandbox SharePoint API. Of course the error message from SharePoint is about as useful as punch in the face… An unexpected error has been encountered in this Web Part. Error: A Web Part or Web Form Control on this Page cannot be displayed or imported. You don't have Add and Customize Pages permissions required to perform this action …that’s if you have debug=true set, if not the classic “This webpart cannot be added” !! Love that one! but will a little digging you should find something like this… [TypeLoadException: Could not load type Microsoft.SharePoint.WebControls.SPGridView from assembly 'Microsoft.SharePoint, Version=14.900.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c'.] Depending on what you want to do with the SPGridView, this may not help at all. But I’m looking to inherit the theme of the site and style it accordingly. After spending a bit of time with Chrome’s FireBug I was able to get the required CSS classes. I created my own class inheriting from GridView (note the lack of a preceding SP!) and simply set the styles in there. Inherit from the standard GridView public class PSGridView : GridView Set the styles in the contructor… public PSGridView() { this.CellPadding = 2; this.CellSpacing = 0; this.GridLines = GridLines.None; this.CssClass = "ms-listviewtable"; this.Attributes.Add("style", "border-bottom-style: none; border-right-style: none; width: 100%; border-collapse: collapse; border-top-style: none; border-left-style: none;"); this.HeaderStyle.CssClass = "ms-viewheadertr"; this.RowStyle.CssClass = "ms-itmhover"; this.SelectedRowStyle.CssClass = "s4-itm-selected"; this.RowStyle.Height = new Unit(25); } Then as you cant override the Columns property setter, a custom method to add the column and set the style… public PSGridView() { this.CellPadding = 2; this.CellSpacing = 0; this.GridLines = GridLines.None; this.CssClass = "ms-listviewtable"; this.Attributes.Add("style", "border-bottom-style: none; border-right-style: none; width: 100%; border-collapse: collapse; border-top-style: none; border-left-style: none;"); this.HeaderStyle.CssClass = "ms-viewheadertr"; this.RowStyle.CssClass = "ms-itmhover"; this.SelectedRowStyle.CssClass = "s4-itm-selected"; this.RowStyle.Height = new Unit(25); } And that should be enough to get the nicely styled SPGridView without the need for the SPGridView, but seriously….get the SPGridView in the SandBox!!! Technorati Tags: Sharepoint 2010,SPGridView,Sandbox Solutions,Sandbox Technorati Tags: Sharepoint 2010,SPGridView,Sandbox Solutions,Sandbox

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