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• MVVM pattern: ViewModel updates after Model server roundtrip

  - by Pavel Savara

  I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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• How to transform vertical table into horizontal table?

  - by avivo

  Hello, I have one table Person: Id Name 1 Person1 2 Person2 3 Person3 And I have its child table Profile: Id PersonId FieldName Value 1 1 Firstname Alex 2 1 Lastname Balmer 3 1 Email [email protected] 4 1 Phone +1 2 30004000 And I want to get data from these two tables in one row like this: Id Name Firstname Lastname Email Phone 1 Person1 Alex Balmer [email protected] +1 2 30004000 What is the most optimized query to get these vertical (key, value) values in one row like this? Now I have a problem that I done four joins of child table to parent table because I need to get these four fields. Some optimization is for sure possible. I would like to be able to modify this query in easy way when I add new field (key,value). What is the best way to do this? To create some StoreProcedure? I would like to have strongly types in my DB layer (C#) and using LINQ (when programming) so it means when I add some new Key, Value pair in Profile table I would like to do minimal modifications in DB and C# if possible. Actually I am trying to get some best practices in this case.

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• Perl Regex - Condensing groups of find/replace

  - by brydgesk

  I'm using Perl to perform some file cleansing, and am running into some performance issues. One of the major parts of my code involves standardizing name fields. I have several sections that look like this: sub substitute_titles { my ($inStr) = @_; ${$inStr} =~ s/ PHD./ PHD /; ${$inStr} =~ s/ P H D / PHD /; ${$inStr} =~ s/ PROF./ PROF /; ${$inStr} =~ s/ P R O F / PROF /; ${$inStr} =~ s/ DR./ DR /; ${$inStr} =~ s/ D.R./ DR /; ${$inStr} =~ s/ HON./ HON /; ${$inStr} =~ s/ H O N / HON /; ${$inStr} =~ s/ MR./ MR /; ${$inStr} =~ s/ MRS./ MRS /; ${$inStr} =~ s/ M R S / MRS /; ${$inStr} =~ s/ MS./ MS /; ${$inStr} =~ s/ MISS./ MISS /; } I'm passing by reference to try and get at least a little speed, but I fear that running so many (literally hundreds) of specific string replaces on tens of thousands (likely hundreds of thousands eventually) of records is going to hurt the performance. Is there a better way to implement this kind of logic than what I'm doing currently? Thanks Edit: Quick note, not all the replace functions are just removing periods and spaces. There are string deletions, soundex groups, etc.

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• Upload two files at once

  - by Keyo

  I am trying to upload two files at once (two file fields) with codeigniters upload class. Despite having provided the field name codeigniter produces errors on the second field. I this a limitation of codeigniter, php or html or am I simply using the class incorectly? $this->upload->do_upload('video_file') $this->upload->do_upload('image_file') Produces this on the image field: The filetype you are attempting to upload is not allowed. Here are my two functions function upload_image() { $thumb_size = 94; $config['upload_path'] = './assets/uploads/images/'; $config['allowed_types'] = 'jpg|png|gif'; $config['max_size'] = '2048'; $config['file_name'] = 'video_' . rand(999999, 999999999); $this->load->library('upload', $config); if (!$this->upload->do_upload('image_file')) { $error = array('error' => $this->upload->display_errors()); return $error; } else { function upload_video() { $config['upload_path'] = './assets/uploads/videos/'; $config['allowed_types'] = 'flv'; $config['max_size'] = '0'; $config['file_name'] = 'video_' . rand(999999, 999999999); $this->load->library('upload', $config); if (!$this->upload->do_upload('video_file')) { $error = array('error' => $this->upload->display_errors()); return $error; } else {

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• How can I detect if this dictionary key exists in C#?

  - by Adam Tuttle

  I am working with the Exchange Web Services Managed API, with contact data. I have the following code, which is functional, but not ideal: foreach (Contact c in contactList) { string openItemUrl = "https://" + service.Url.Host + "/owa/" + c.WebClientReadFormQueryString; row = table.NewRow(); row["FileAs"] = c.FileAs; row["GivenName"] = c.GivenName; row["Surname"] = c.Surname; row["CompanyName"] = c.CompanyName; row["Link"] = openItemUrl; //home address try { row["HomeStreet"] = c.PhysicalAddresses[PhysicalAddressKey.Home].Street.ToString(); } catch (Exception e) { } try { row["HomeCity"] = c.PhysicalAddresses[PhysicalAddressKey.Home].City.ToString(); } catch (Exception e) { } try { row["HomeState"] = c.PhysicalAddresses[PhysicalAddressKey.Home].State.ToString(); } catch (Exception e) { } try { row["HomeZip"] = c.PhysicalAddresses[PhysicalAddressKey.Home].PostalCode.ToString(); } catch (Exception e) { } try { row["HomeCountry"] = c.PhysicalAddresses[PhysicalAddressKey.Home].CountryOrRegion.ToString(); } catch (Exception e) { } //and so on for all kinds of other contact-related fields... } As I said, this code works. Now I want to make it suck a little less, if possible. I can't find any methods that allow me to check for the existence of the key in the dictionary before attempting to access it, and if I try to read it (with .ToString()) and it doesn't exist then an exception is thrown: 500 The given key was not present in the dictionary. How can I refactor this code to suck less (while still being functional)?

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• Record Disappeared from Mysql Table, How Can I Find Out What Happened?

  - by Jascha

  I got the fire alarm phone call, AIM messages and email today from a client stating "The site is down!, WTF happened?!" Well, after a little digging, it turns out one of the records in a table had been wiped clean, but without removing the row itself. So, I had the representation of data, but a bunch of empty fields. (needless to day I need to write into my code a catch for this.) What my real question is, where can I figure out what happened? I've got access to phpmyadmin and that's about it. I found some access logs on in the root directory of my server, but that just tells me the client was in the admin area I built editing that record, I'd like to know specifically what they did that made all of the data go away. (what query was run etc...) is it possible without real server admin access? is there a neat little php to mysql class that returns data like this? Thanks in advance. -Jascha

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• Why NOT use POST method here?

  - by Camran

  I have a classifieds website. In the main page (index) I have several form fields which the user may or may not fill in, in order to specify a detailed search of classifieds. Ex: Category: Cars Price from: 3000 Price to: 10000 Color: Red Area: California The forms' action is set to a php page: <form action='query_sql.php' method='post'> In query_sql.php I fetch the variables like this: category=$_POST['category']; etc etc... Then query MySql: $query="SELECT........WHERE category='$category' etc etc.... $results = mysql_query($query); Then I simply display the results of the query to the user by creating a table which is filled in dynamically depending on the results set. However, according to an answer by Col. Shrapnel in my previous Q I shouldn't use POST here: http://stackoverflow.com/questions/3004754/how-to-hide-url-from-users-when-submitting-this-form The reason I use post is simply to hide the "one-page-word-document" long URL in the browsers adress bar. I am very confused, is it okay to use POST or not? It is working fine both when I use GET or POST now... And it is already on a production server... Btw, in the linked question, I wasn't referring to make URL invisible (or hide it) I just wanted it too look better (which I have accomplished with mod_rewrite). UPDATE: If I use GET, then how should I make the url better looking (beautiful)? Check this previous Q out: http://stackoverflow.com/questions/3000524/how-to-make-this-very-long-url-appear-short

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• .NET Error with Dynamic T-SQL

  - by Phillip Theriault

  I am trying to create a TableAdapter in .NET using a stored procedure, but I'm getting an error "Incorrect syntax near the keyword 'WHERE'". I have narrowed down the problem in the stored procedure to the following lines: IF @NumRows > 0 SET @SQL += N' WHERE T1.RowNumber BETWEEN 1 and 10' ELSE SET @SQL += N' WHERE T1.RowNumber > 0' @NumRows is an input parameter that defaults to 0. However, if I remove either of those lines everything works fine (both WHERE clauses work fine by themselves when there is no IF/ELSE statement). It almost looks like .NET is ignoring the IF/ELSE and attempting to add the WHERE clause twice. It also works fine if I change it like so: IF @NumRows > 0 SET @SQL += N'' ELSE SET @SQL += N' WHERE T1.RowNumber > 0' One of the WHERE clauses has been removed, and there's no longer a conflict on the .NET side. So I'm pretty sure it has to do with the 2 WHERE clauses, and not with anything else. The sproc runs perfectly fine in SQL Server, and it even runs in .NET despite the error if I click "Preview Data". The only problem is that it won't auto-populate the list of fields, which I need for creating a report. Has anybody seen this before and have a suggestion?

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• Processing XML form input in ASP

  - by Omar Kooheji

  I'm maintaining a legacy application which consists of some ASP.Net pages with c# code behinds and some asp pages. I need to change the way the application accepts it's input from reading a set of parameters from some form fields to reading in one form field which contains contains some XML and parsing to get the parameters out. I've written a C# class that takes an The NameValueCollection from the C# HttpRequest's Form Element. Like so NameValueCollection form = Request.Form; Dictionary<string, string> fieldDictionary = RequestDataExtractor.BuildFieldDictionary(form); The code in the class looks for a particular parameter and if it's there processes the XML and outputs a Dictionary, if its not there it just cycles through the Form parameters and puts them all into the dictionary (Allowing the old method to still work) How would I do this in ASP? Can I use my same class, or a modified version of it? or do I have to write some new code to get this working? If I have to write ASP code Whats the best way to process the XML in ASP? Sorry if this seems like a stupid question but I know next to nothing about ASP and VB.

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• Problem with WHERE columnName = Data in MySQL query in C#

  - by Ryan Sullivan

  I have a C# webservice on a Windows Server that I am interfacing with on a linux server with PHP. The PHP grabs information from the database and then the page offers a "more information" button which then calls the webservice and passes in the name field of the record as a parameter. So i am using a WHERE statement in my query so I only pull the extra fields for that record. I am getting the error: System.Data.SqlClient.SqlException:Invalid column name '42' Where 42 is the value from the name field from the database. my query is string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\""; I do not know if it is a problem with my query or something is wrong with the database, but here is the rest of my code for reference. NOTE: this all works perfectly when I grab all of the records, but I only want to grab the record that I ask my webservice for. public class ktvService : System.Web.Services.WebService { [WebMethod] public string moreInfo(string show) { string connectionStr = "MyConnectionString"; string selectStr = "SELECT name, castNotes, triviaNotes FROM tableName WHERE name =\"" + show + "\""; SqlConnection conn = new SqlConnection(connectionStr); SqlDataAdapter da = new SqlDataAdapter(selectStr, conn); DataSet ds = new DataSet(); da.Fill(ds, "tableName"); DataTable dt = ds.Tables["tableName"]; DataRow theShow = dt.Rows[0]; string response = "Name: " + theShow["name"].ToString() + "Cast: " + theShow["castNotes"].ToString() + " Trivia: " + theShow["triviaNotes"].ToString(); return response; } }

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• How do JVM's implicit memory barriers behave when chaining constructors

  - by Joonas Pulakka

  Referring to my earlier question on incompletely constructed objects, I have a second question. As Jon Skeet pointed out, there's an implicit memory barrier in the end of a constructor that makes sure that final fields are visible to all threads. But what if a constructor calls another constructor; is there such a memory barrier in the end of each of them, or only in one being called from outside? That is, when the "wrong" solution is: public class ThisEscape { public ThisEscape(EventSource source) { source.registerListener( new EventListener() { public void onEvent(Event e) { doSomething(e); } }); } } And the correct one would be a factory method version: public class SafeListener { private final EventListener listener; private SafeListener() { listener = new EventListener() { public void onEvent(Event e) { doSomething(e); } } } public static SafeListener newInstance(EventSource source) { SafeListener safe = new SafeListener(); source.registerListener(safe.listener); return safe; } } Would the following work too, or not? public class MyListener { private final EventListener Listener; private MyListener() { listener = new EventListener() { public void onEvent(Event e) { doSomething(e); } } } public MyListener(EventSource source) { this(); source.register(listener); } }

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• 'Stack level too deep' error in engine-like plugin with globalize

  - by nutsmuggler

  Hello folks. I have built an engine-like plugin thanks to the new features of Rails 2.3. It's a 'Product' module for a CMS, extrapolated from a previously existing (and working) model/controller. The plugin relies on easy_fckeditor and on globalize (description and title field are localised), and I suspect that globalized could be the culprit here... Everything works fine, except for the update action. I get the following error message: (posting just the first lines, all the message is about attribute_methods) stack level too deep /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/attribute_methods.rb:64:in `generated_methods?' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/attribute_methods.rb:241:in `method_missing' /Library/Ruby/Gems/1.8/gems/activerecord-2.3.2/lib/active_record/attribute_methods.rb:249:in `method_missing' For referenze, the full error stack is here: http://pastie.org/596546 I've tried to debug eliminating all the input fields, one by one, but I keep getting the error. fckeditor doesn't seem the culprit (error even without fckeditor) This is the action: def update params[:product][:term_ids] ||= [] @product = Product.find(params[:id]) respond_to do |format| if @product.update_attributes(params[:product]) flash[:notice] = t(:Product_was_successfully_updated) format.html { redirect_to products_path } format.xml { head :ok } else format.html { render :action => "edit" } format.xml { render :xml => @product.errors, :status => :unprocessable_entity } end end end As you see it's quite straightforward. Of course I am not hoping someone to solve this question straightaway, I'd just like to have a head up, a suggestion about where to look to solve this issue. Thanks in advance, Davide

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• Django formset doesn't validate

  - by tsoporan

  Hello, I am trying to save a formset but it seems to be bypassing is_valid() even though there are required fields. To test this I have a simple form: class AlbumForm(forms.Form): name = forms.CharField(required=True) The view: @login_required def add_album(request, artist): artist = Artist.objects.get(slug__iexact=artist) AlbumFormSet = formset_factory(AlbumForm) if request.method == 'POST': formset = AlbumFormSet(request.POST, request.FILES) if formset.is_valid(): return HttpResponse('worked') else: formset = AlbumFormSet() return render_to_response('submissions/addalbum.html', { 'artist': artist, 'formset': formset, }, context_instance=RequestContext(request)) And the template: <form action="" method="post" enctype="multipart/form-data">{% csrf_token %} {{ formset.management_form }} {% for form in formset.forms %} <ul class="addalbumlist"> {% for field in form %} <li> {{ field.label_tag }} {{ field }} {{ field.errors }} </li> {% endfor %} </ul> {% endfor %} <div class="inpwrap"> <input type="button" value="add another"> <input type="submit" value="add"> </div> </form> What ends up happening is I hit "add" without entering a name then HttpResponse('worked') get's called seemingly assuming it's a valid form. I might be missing something here, but I can't see what's wrong. What I want to happen is, just like any other form if the field is required to spit out an error if its not filled in. Any ideas?

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• MVC 2 - Name Attributes on HTML Input Field when using Parent/Child Entities

  - by Click Ahead

  Hi All, I'm pretty new to MVC 2 using the Entity Framework. I have two tables Company {ID int identity PK,Name nvarchar} and User {ID int identity PK,UserName nvarchar,CompanyID int FK}. A Foreign Key exists between User and Company. I generated my ADO.NET Entity Data Model, a Controller and a view to insert a record. My HTML form has the fields Company and UserName and the idea is when I click save a Company and User is inserted into the database. Sounds straight forward right! My question is as follows: I created a strongly-typed view derived from my 'User' entity. I'm using the the html helper Html.TextBoxFor(model = model.Organisation.Name) but the html name attribute for this input field is 'Organisation.Name'. My problem with this is that the dot throws up all sorts of issues in JQuery, which sees this as a property. If I want to change the name I read that I can use DataAnnotations but because I used the Entity Designer this involves using Buddy Classes. Seems like a bit of overkill just to change the html name attribute on this input field. Am I approaching this the right way or am I missing something here? Thanks for the help !

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• Rails Active Record Mysql find query HAVING clause

  - by meetraghu28

  Is there a way to use the HAVING clause in some other way without using group by. I am using rails and following is a sample sccenario of the problem that i am facing. In rails you can use the Model.find(:all,:select,conditions,:group) function to get data. In this query i can specify a having clause in the :group param. But what if i dont have a group by clause but want to have a having clause in the result set. Ex: Lets take a query select sum(x) as a,b,c from y where "some_conditions" group by b,c; This query has a sum() aggregation on one of the fields. No if there is nothing to aggregate then my result should be an empty set. But mysql return a NULL row. So this problem can be solved by using select sum(x) as a,b from y where "some_conditions" group by b having a NOT NULL; but what happens in case i dont have a group by clause?? a query like below select sum(x) as a,b from y where "some_conditions"; so how to specify that sum(x) should not be NULL? Any solution that would return an empty set in this case instead of a NULL row will help and also that solution should be doable in rails. We can use subqueries to get this condition working with sumthin like this select * from ((select sum(x) as b FROM y where "some_condition") as subq) where subq.b is not null; but is there a better way to do this thru sql/rails ??

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• Difference between KeywordQuery, FullTextQuerySearch type for Object Model and Web service Query

  - by Raghu

  Initially I believed these 3 to be doing more or less the same thing with just the notation being different. Until recently, when i noticed that their does exists a big difference between the results of the KeyWordQuery/FullTextQuerySearch and Web service Query. I used both KeywordQuery and FullText method to search of the the value of a customColumn XYZ with value (ASDSADA-21312ASD-ASDASD):- When I run this query as:- FullTextSqlQuery:- FullTextSqlQuery myQuery = new FullTextSqlQuery(site); { // Construct query text String queryText = "Select title, path, author, isdocument from scope() where freetext('ASDSADA-21312ASD-ASDASD') "; myQuery.QueryText = queryText; myQuery.ResultTypes = ResultType.RelevantResults; }; // execute the query and load the results into a datatable ResultTableCollection queryResults = myQuery.Execute(); ResultTable resultTable = queryResults[ResultType.RelevantResults]; // Load table with results DataTable queryDataTable = new DataTable(); queryDataTable.Load(resultTable, LoadOption.OverwriteChanges); I get the following result representing the document. * Title: TestPDF * path: http://SharepointServer/Shared Documents/Forms/DispForm.aspx?ID=94 * author: null * isDocument: false Do note the Path and isDocument fields of the above result. Web Service Method Then I tried a Web Service Query method. I used Sharepoint Search Service Tool available at http://sharepointsearchserv.codeplex.com/ and ran the same query i.e. Select title, path, author, isdocument from scope() where freetext('ASDSADA-21312ASD-ASDASD'). This time I got the following results:- * Title: TestPDF * path: http://SharepointServer/Shared Documents/TestPDF.pdf * author: null * isDocument: true Again note the path. While the search results from 2nd method are useful as they provide me the file path exactly, I can't seem to understand why is the method 1 not giving me the same results? Why is there a discrepancy between the two results?

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• Need help writing jQuery to loop through table and inject markers into google map?

  - by abemonkey

  I am new to jQuery. I've done some simple things with it but what I am attempting now is a over my head and I need some help. I am building a locator for all the firearms dealers in the US for a client. I am working within Drupal. I have a proximity search by zip code that works great. If you search by zip a list of paginated results shows up in an html table that can by paged through via ajax. I would like a map to be above this list with markers corresponding to the names and addresses being listed. I already have all the lat and long values in the table results. I want the script to update the markers and automatically zoom to fit the markers in the view when a user changes the sort order of the table or pages through the results. Also, I'd like to have a hover highlight effect over the rows of the table that simultaneously highlight the corresponding marker, and have a click on the table row equal a click on a marker that pops up a marker info window to be populated using jQuery to read the name and address fields of the table. Hope this all makes sense. I know I'm putting a lot out there, I'm not asking for someone to write the whole script, just wanted to give as many details as possible. Thanks for any help. I'm just lost when it comes to looping and moving data around. If you want to check out what I have so far on the project please visit: www.axtsweapons.com and login with the username: "test" and the password: "1234" and then visit this direct link: www.axtsweapons.com/ffllocator. For just a simple page that would be easy to manipulate and play with goto: http://www.axtsweapons.com/maptest.html Thanks!

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• Best way to test a Delphi application

  - by Osama ALASSIRY

  I have a Delphi application that has many dependencies, and it would be difficult to refactor it to use DUnit (it's huge), so I was thinking about using something like AutomatedQA's TestComplete to do the testing from the front-end UI. My main problem is that a bugfix or new feature sometimes breaks old code that was previously tested (manually), and used to work. I have setup the application to use command-line switches to open-up a specific form that could be tested, and I can create a set of values and clicks needed to be done. But I have a few questions before I do anything drastic... (and before purchasing anything) Is it worth it? Would this be a good way to test? The result of the test should in my database (Oracle), is there an easy way in testcomplete to check these values (multiple fields in multiple tables)? I would need to setup a test database to do all the automated testing, would there be an easy way to automate re-setting the test db? Other than drop user cascade, create user,..., impdp. Is there a way in testcomplete to specify command-line parameters for an exe? Does anybody have any similar experiences.

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• ListBox Items Not Visible after DataBinding

  - by SidC

  Good Evening All, I am writing a page that allows users to search a parts table, select quantities and a listbox is to be populated with gridview values. Here's a snippet of my aspx page: <asp:ListBox runat="server" ID="lbItems" Width="155px"> <asp:ListItem></asp:ListItem> <asp:ListItem></asp:ListItem> <asp:ListItem></asp:ListItem> <asp:ListItem></asp:ListItem> <asp:ListItem></asp:ListItem> </asp:ListBox> Here's the relevant contents of codebehind: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 'Define DataTable Columns as incoming gridview fields Dim dtSelParts As DataTable = New DataTable Dim dr As DataRow = dtSelParts.NewRow() dtSelParts.Columns.Add("PartNumber") dtSelParts.Columns.Add("NSN") dtSelParts.Columns.Add("PartName") dtSelParts.Columns.Add("Qty") 'Select those gridview rows that have txtQty <> 0 For Each row As GridViewRow In MySearch.Rows Dim textboxText As String = _ CType(row.FindControl("txtQty"), TextBox).Text If textboxText <> "0" Then 'Create the row dr = dtSelParts.NewRow() 'Fill the row with data dr("PartNumber") = MySearch.DataKeys(row.RowIndex)("PartNumber") dr("NSN") = MySearch.DataKeys(row.RowIndex)("NSN") dr("PartName") = MySearch.DataKeys(row.RowIndex)("PartName") 'Add the row to the table dtSelParts.Rows.Add(dr) End If Next 'Need to send items to Listbox control lbItems lbItems.DataSource = New DataView(dtSelParts) lbItems.DataValueField = "PartNumber" lbItems.DataValueField = "NSN" lbItems.DataValueField = "PartName" lbItems.DataBind() End Sub The page runs fine in that my search functiobnality is intact, and I can input quantity values into my gridview's textbox. When I click Add to Quote the Listbox receives focus, but no list items are visible. I've created several list items in the aspx page, however I don't know how to populate the contents of my datatable in the listbox. Can someone help a newbie with this, seemingly, easy issue? Thanks, Sid

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• Atomic int writes on file

  - by Waneck

  Hello! I'm writing an application that will have to be able to handle many concurrent accesses to it, either by threads as by processes. So no mutex'es or locks should be applied to this. To make the use of locks go down to a minimum, I'm designing for the file to be "append-only", so all data is first appended to disk, and then the address pointing to the info it has updated, is changed to refer to the new one. So I will need to implement a small lock system only to change this one int so it refers to the new address. How is the best way to do it? I was thinking about maybe putting a flag before the address, that when it's set, the readers will use a spin lock until it's released. But I'm afraid that it isn't at all atomic, is it? e.g. a reader reads the flag, and it is unset on the same time, a writer writes the flag and changes the value of the int the reader may read an inconsistent value! I'm looking for locking techniques but all I find is either for thread locking techniques, or to lock an entire file, not fields. Is it not possible to do this? How do append-only databases handle this? Thanks! Cauê

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• How would you code a washing machine?

  - by Dan

  Imagine I have a class that represents a simple washing machine. It can perform following operations in the following order: turn on - wash - centrifuge - turn off. I see two basic alternatives: A) I can have a class WashingMachine with methods turnOn(), wash(int minutes), centrifuge(int revs), turnOff(). The problem with this is that the interface says nothing about the correct order of operations. I can at best throw InvalidOprationException if the client tries to centrifuge before machine was turned on. B) I can let the class itself take care of correct transitions and have the single method nextOperation(). The problem with this on the other hand, is that the semantics is poor. Client will not know what will happen when he calls the nextOperation(). Imagine you implement the centrifuge button’s click event so it calls nextOperation(). User presses the centrifuge button after machine was turned on and ups! machine starts to wash. I will probably need a few properties on my class to parameterize operations, or maybe a separate Program class with washLength and centrifugeRevs fields, but that is not really the problem. Which alternative is better? Or maybe there are some other, better alternatives that I missed to describe?

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• What is jasper report's algorithm for using a data source?

  - by spderosso

  Hi, I have created my custom data source by implementing the interface JRDataSource. This interface looks like this: public interface JRDataSource { /** * Tries to position the cursor on the next element in the data source. * @return true if there is a next record, false otherwise * @throws JRException if any error occurs while trying to move to the next element */ public boolean next() throws JRException; /** * Gets the field value for the current position. * @return an object containing the field value. The object type must be the field object type. */ public Object getFieldValue(JRField jrField) throws JRException; } My question is the following: In what way does jasper report call this functions for obtaining the fields in the .jrxml. E.g: if( next() )){ call getFieldValue for every field present in the page header while( next() ){ call getFieldValue for every field present in detail part } call getFieldValue for every field present the footer } The previous is just an example, experimentally in fact I found out that it is actually not like that. So my question arised. Thanks!

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• Routing problem with calling a new method without an ID

  - by alkaloids

  I'm trying to put together a form_tag that edits several Shift objects. I have the form built properly, and it's passing on the correct parameters. I have verified that the parameters work with updating the objects correctly in the console. However, when I click the submit button, I get the error: ActiveRecord::RecordNotFound in ShiftsController#update_individual Couldn't find Shift without an ID My route for the controller it is calling looks like this looks like this: map.resources :shifts, :collection => { :update_individual => :put } The method in ShiftsController is this: def update_individual Shift.update(params[:shifts].keys, params[:shifts].values) flash[:notice] = "Schedule saved" end The relevant form parts are these: <% form_tag( update_individual_shifts_path ) do %> ... (fields for...) <%= submit_tag "Save" %> <% end %> Why is this not working? If I browse to the url: "http://localhost:3000/shifts/update_individual/5" (or any number that corresponds to an existing shift), I get the proper error about having no parameters set, but when I pass parameters without an ID of some sort, it errors out. How do I make it stop looking for an ID at the end of the URL?

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• Intercepting Xstream conversion while parsing XML

  - by Shane Bell

  Suppose I have a simple Java class like this: public class User { String firstName; String lastName; public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } } Now, suppose I want to parse the following XML: <user> <firstName>Homer</firstName> <lastName>Simpson</lastName> </user> I can do this with no problems in XStream like so: User homer = (User) xstream.fromXML(xml); Ok, all good so far, but here's my problem. Suppose I have the following XML that I want to parse: <user> <fullName>Homer Simpson</fullName> </user> How can I convert this XML into the same User object using XStream? I'd like a way to implement some kind of callback so that when XStream parses the fullName field, I can split the string in two and manually set the first name and last name fields on the user object. Is this possible? Note that I'm not asking how to split the string in two (that's the easy part), I want to know how to intercept the XML parsing so XStream doesn't try to reflectively set the fullName field on the User object (which obviously doesn't exist). I looked at the converters that XStream provides but couldn't figure out how to use it for this purpose. Any help would be appreciated.

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• WebService Stubs WSDL Axis2

  - by tt0686

  Good afternoon in my timezone. I have a wsdl file with the following snippet of code: <schema targetNamespace="http://util.cgd.pt" xmlns="http://www.w3.org/2001/XMLSchema"> <import namespace="http://schemas.xmlsoap.org/soap/encoding/" /> <complexType name="Attribute"> <sequence> <element name="fieldType" nillable="true" type="xsd:string" /> <element name="dataType" nillable="true" type="xsd:string" /> <element name="name" nillable="true" type="xsd:string" /> <element name="value" nillable="true" type="xsd:string" /> </sequence> </complexType> <complexType name="ArrayOffAttribute"> <complexContent> <restriction base="soapenc:Array"> <attribute ref="soapenc:arrayType" wsdl:arrayType="tns3:Attribute[]" /> </restriction> </complexContent> </complexType> When i use jax-rpc or Axis1 to generate the stubs the type Attribute is generated, but when i use Axis2 the type Attribute is not generated and a new type is created ArrayOffAttribute, this new type extends the axis2.databinding.types.soapencoding.Array and permits to add elements through the array.addObject(object), my question is, i am migrating one Java EE application from webservices using jax-rpc to start using Axis2, and the methods are using the Attribute type to fullfill attributes fields, now in Axis2 and do not have attribute type , what should i use in the ArrayOffAttribute.addObject(?) ? Could be something wrong with Axis2 ? i am stop here :( Thanks in advance Best regards

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