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  • What is a simple way to add a timer to a method

    - by John
    The following is in C#. I'm trying to do something very simple (I think). I have a method that loads an XML document XDocument doc = XDocument.Load(uri); , but I don't want to tie up pc resources if there are issues (connectivity, document size, etc.). So I'd like to be able to add a timeout variable that will cut the method off after a given number of seconds. I'm a newbie when it comes to asynchronous programming and find it confusing that there are so many examples written so many different ways . . . and none of them appear simple. I'd like a simple solution, if possible. Here's my thoughts so far on possible solution paths: 1) A method that wraps the existing load public XDocument LoadXDocument(string uri, int timeout){ //code } 2) A wrapper, but as an extension method XDocument doc = XDocument.LoadWithTimeout(string uri, int timeout); 3) A generic extension method. Object obj = SomeStaticClass.LoadWithTimeout(??? method, int timeout); 3), on its face seems really nice, because it would mean being able to generically add timeouts to many different method calls and not specifically tied to one type of object, but I suspect that it is either i)impossible or ii) very difficult. Please assist. Thanks.

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  • Passing System classes as constructor parameters

    - by mcl
    This is probably crazy. I want to take the idea of Dependency Injection to extremes. I have isolated all System.IO-related behavior into a single class so that I can mock that class in my other classes and thereby relieve my larger suite of unit tests of the burden of worrying about the actual file system. But the File IO class I end up with can only be tested with integration tests, which-- of course-- introduces complexity I don't really want to deal with when all I really want to do is make sure my FileIO class calls the correct System.IO stuff. I don't need to integration test System.IO. My FileIO class is doing more than simply wrapping System.IO functions, every now and then it does contain some logic (maybe this is the problem?). So what I'd like is to be able to test my File IO class to ensure that it makes the correct system calls by mocking the System.IO classes themselves. Ideally this would be as easy as having a constructor like so: public FileIO( System.IO.Directory directory, System.IO.File file, System.IO.FileStream fileStream ) { this.Directory = directory; this.File = file; this.FileStream = fileStream; } And then calling in methods like: public GetFilesInFolder(string folderPath) { return this.Directory.GetFiles(folderPath) } But this doesn't fly since the System.IO classes in question are static classes. As far as I can tell they can neither be instantiated in this way or subclassed for the purposes of mocking.

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  • How do I put all the types matching a particular C# interface in an IDictionary?

    - by Kevin Brassen
    I have a number of classes all in the same interface, all in the same assembly, all conforming to the same generic interface: public class AppleFactory : IFactory<Apple> { ... } public class BananaFactory : IFactory<Banana> { ... } // ... It's safe to assume that if we have an IFactory<T> for a particular T that it's the only one of that kind. (That is, there aren't two things that implement IFactory<Apple>.) I'd like to use reflection to get all these types, and then store them all in an IDictionary, where the key is typeof(T) and the value is the corresponding IFactory<T>. I imagine eventually we would wind up with something like this: _map = new Dictionary<Type, object>(); foreach(Type t in [...]) { object factoryForType = System.Reflection.[???](t); _map[t] = factoryForType; } What's the best way to do that? I'm having trouble seeing how I'd do that with the System.Reflection interfaces.

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  • Why use Intent.URI_INTENT_SCHEME

    - by hks
    while reading Android docs about Widgets I stumbled upon this piece of code whose purpose is to launch a service for retrieving a factory for StackView items. // Set up the intent that starts the StackViewService, which will // provide the views for this collection. Intent intent = new Intent(context, StackWidgetService.class); // Add the app widget ID to the intent extras. intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]); intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); // Instantiate the RemoteViews object for the App Widget layout. RemoteViews rv = new RemoteViews(context.getPackageName(), R.layout.widget_layout); // Set up the RemoteViews object to use a RemoteViews adapter. // This adapter connects // to a RemoteViewsService through the specified intent. // This is how you populate the data. rv.setRemoteAdapter(appWidgetIds[i], R.id.stack_view, intent); You can find it here I have a problem understanding why do you need to call intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); I understand that it gives URI a prefix intent://, but is it necessary here?

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  • Immutability and shared references - how to reconcile?

    - by davetron5000
    Consider this simplified application domain: Criminal Investigative database Person is anyone involved in an investigation Report is a bit of info that is part of an investigation A Report references a primary Person (the subject of an investigation) A Report has accomplices who are secondarily related (and could certainly be primary in other investigations or reports These classes have ids that are used to store them in a database, since their info can change over time (e.g. we might find new aliases for a person, or add persons of interest to a report) If these are stored in some sort of database and I wish to use immutable objects, there seems to be an issue regarding state and referencing. Supposing that I change some meta-data about a Person. Since my Person objects immutable, I might have some code like: class Person( val id:UUID, val aliases:List[String], val reports:List[Report]) { def addAlias(name:String) = new Person(id,name :: aliases,reports) } So that my Person with a new alias becomes a new object, also immutable. If a Report refers to that person, but the alias was changed elsewhere in the system, my Report now refers to the "old" person, i.e. the person without the new alias. Similarly, I might have: class Report(val id:UUID, val content:String) { /** Adding more info to our report */ def updateContent(newContent:String) = new Report(id,newContent) } Since these objects don't know who refers to them, it's not clear to me how to let all the "referrers" know that there is a new object available representing the most recent state. This could be done by having all objects "refresh" from a central data store and all operations that create new, updated, objects store to the central data store, but this feels like a cheesy reimplementation of the underlying language's referencing. i.e. it would be more clear to just make these "secondary storable objects" mutable. So, if I add an alias to a Person, all referrers see the new value without doing anything. How is this dealt with when we want to avoid mutability, or is this a case where immutability is not helpful?

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  • Detect whether or not a specific attribute was valid on the model

    - by Sir Code-A-Lot
    Having created my own validation attribute deriving from System.ComponentModel.DataAnnotations.ValidationAttribute, I wish to be able to detect from my controller, whether or not that specific attribute was valid on the model. My setup: public class MyModel { [Required] [CustomValidation] [SomeOtherValidation] public string SomeProperty { get; set; } } public class CustomValidationAttribute : ValidationAttribute { public override bool IsValid(object value) { // Custom validation logic here } } Now, how do I detect from the controller whether validation of CustomValidationAttribute succeeded or not? I have been looking at the Exception property of ModelError in the ModelState, but I have no way of adding a custom exception to it from my CustomValidationAttribute. Right now I have resorted to checking for a specific error message in the ModelState: public ActionResult PostModel(MyModel model) { if(ModelState.Where(i => i.Value.Errors.Where((e => e.ErrorMessage == CustomValidationAttribute.SharedMessage)).Any()).Any()) DoSomeCustomStuff(); // The rest of the action here } And changed my CustomValidationAttribute to: public class CustomValidationAttribute : ValidationAttribute { public static string SharedMessage = "CustomValidationAttribute error"; public override bool IsValid(object value) { ErrorMessage = SharedMessage; // Custom validation logic here } } I don't like relying on string matching, and this way the ErrorMessage property is kind of misused. What are my options?

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  • Is it getting to be time for C# to support compile-time macros?

    - by Robert Rossney
    Thus far, Microsoft's C# team has resisted adding formal compile-time macro capabilities to the language. There are aspects of programming with WPF that seem (to me, at least) to be creating some compelling use cases for macros. Dependency properties, for instance. It would be so nice to just be able to do something like this: [DependencyProperty] public string Foo { get; set; } and have the body of the Foo property and the static FooProperty property be generated automatically at compile time. Or, for another example an attribute like this: [NotifyPropertyChanged] public string Foo { get; set; } that would make the currently-nonexistent preprocessor produce this: private string _Foo; public string Foo { get { return _Foo; } set { _Foo = value; OnPropertyChanged("Foo"); } } You can implement change notification with PostSharp, and really, maybe PostSharp is a better answer to the question. I really don't know. Assuming that you've thought about this more than I have, which if you've thought about it at all you probably have, what do you think? (This is clearly a community wiki question and I've marked it accordingly.)

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  • Android - save/restore state of custom class

    - by user1209216
    I have some class for ssh support - it uses jsch internally. I use this class on main activity, this way: public class MainActivity extends Activity { SshSupport ssh = new SshSupport(); ..... @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Handle events for ssh ssh.eventHandler = new ISshEvents() { @Override public void SshCommandExecuted(SshCommandsEnum commandType, String result) { } //other overrides here } //Ssh operations on gui item click @Override public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) { if (ssh.IsConnected() == false) { try { ssh.ConnectAsync(/*parameters*/); } catch (Exception e) { e.printStackTrace(); } } try { ssh.ExecuteCommandAsync(SshCommandsEnum.values()[position]); } catch (Exception e) { e.printStackTrace(); } } }); } It works very well. My application connects to ssh, performs all needed operation in background thread and results are reported to gui, via events as shown above. But nothing works after user change device orientation. It's clear for me - activity is re-created and all state is lost. Unfortunately, my SshSupport class object is lost as well. It's pretty easy to store gui state for dynamically changed/added objects (using put/get serializable etc methods). But I have no idea how to prevent my ssh object, ssh connected session being lost. Since my class is not serializable, I can't save it to bundle. Also, even if I make my SshSupport class serializable, jsch objects it uses still are not serializable. So what is the best way to solve this?

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  • Configure nHibernate for multiple-project solution

    - by NoOne
    Hello, Im doing a project with C# winforms. This project is composed by: Client project: Windows Forms where user will do CRUD operations on the models; Server project; Common Project: This project will hold the models (in the image only have the model Item); ListSingleton: Remote Object that will do the operations on the models; I already have all the communication working, but now I need to work on the persistence of the data in a mysql database. I was trying to use nHibernate but I’m having some troubles. My main problem is how to organize my hibernate configuration. In which project do I keep the mapping? Common project? In which project do I keep the hibernate configuration file (App.config)? ListSingleton project? In which project do I do this: Configuration cfg = new Configuration(); cfg.AddXmlFile("Item.hbm.xml"); ISessionFactory factory = cfg.BuildSessionFactory(); ISession session = factory.OpenSession(); ITransaction transaction = session.BeginTransaction(); Item newItem = new Item("BLAA"); // Tell NHibernate that this object should be saved session.Save(newItem); // commit all of the changes to the DB and close the ISession transaction.Commit(); session.Close(); In the ListSingleton project? Altho I had reference to the Common Project in the ListSingleton I keep getting error in the addXml line… My mapping is correct because I tried with a one-project solution and it worked :X

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  • How to convert a rectangle to TRBL CSS rect value?

    - by VLostBoy
    I'm not quite sure how to put this, but here goes... The css clip attribute is defined like so: rect(top, right, bottom, left). However, I'm exploring the use of a custom Rectangle 'class' to encapsulate some operations. The rectangle class has the attributes height, width and x, y. The x and y values are encapsulated in a Point object, and the height and width are encapsulated in a Dimension object, the rectangle being a composite of a point (its top-left location) and a dimension (width and height). So far so good. I though it would be pretty simple on the basis of having the rectangles x, y, width and height values to define the css rect attribute in terms of top, right, bottom, left, but I've become hopelessly confused- I've been googling for a while, and I can't seem to find any documentation as to what the TRBL values actually are or what they represent. For example, should I be thinking in terms of co-ordinates, in which case, surely I can describe the rectangle as a css rect using the rectangles x position for Top, x position + width for Right, the rectangles height + y for Bottom and its y position for Left... but thats a load of BS, surely? Also, surely rect is actually an inset, or have I just inverted my understanding of clip? I'd appreciate some advice. What I want to be able to do is (i) Define a rectangle using x, y, width and height (ii)Express the rectangle in TRBL form so that I can manipulate a divs clipping behaviour (iii)Change x, y, width or height and recalculate in terms of TRBL and goto (ii) I appreciate there are some other factors here, and some intermediary transforms to be done, but I've confused myself pretty badly- Can anyone give me some pointers?

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  • jtable update data not visible

    - by Thomas n
    I am running into a problem similar to what I have read here about inserted data and added data not showing up on jtable. I have tried repaint() and revalidate(), but to no avail. Basically, I have two classes say A and B. A calls a function in class B to add a row of data to the table. Here is the code.(By the way I am using Netbeans 7.1.2 to add a table and then add some code to handle the update.) public void callUpdateTable(){ DefaultTableModel myModel = (DefaultTableModel)jTable1.getModel(); DateFormat dateFormate = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss"); Object[] str = new Object[3]; Date date = new Date(); str[0] = dateFormate.format(date); str[1] = "Robot"; str[2] = "hello"; // myModel.addRow(str); myModel.insertRow(1, str); myModel.setValueAt("Hello", 1, 2); System.out.println("count = " + myModel.getValueAt(1, 2)); jTable1.repaint(); } The funny thing is on system print it prints out the value at the cell(1,2) I set the value, but doesn't show up on the table. Thank you for your help.

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  • Cached data accessed by reference?

    - by arthurdent510
    I am running into an odd problem, and this is the only thing I can think of. I'm storing a list in cache, and I am randomly losing items from my list as users use the site. I have a class that is called that either goes to cache and returns the list from there, or if the cache is over a certain time frame old, it goes to the database and refreshes the cache. So when I pull the data from cache, this is what it looks like.... results = (List<Software>)cache["software"]; And then I return results and do some processing, filter for security, and eventually it winds up on the screen. For each Software record, there can be multiple resources attached to it, and based on how the security goes they may see some, all, or none of the records. So in the security check it will remove some of those resources from the software record. So my question is.... when I return my results list, is it a reference directly to the cache object? So when I remove a resource from the software object, it is really removing from cache as well? If that is the case, is there any way to not return it as a reference? Thanks!

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  • TreeView update bug in the VB.NET

    - by CFP
    Consider the following code: Dim Working As Boolean = False Private Sub TreeView1_AfterCheck(ByVal sender As Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCheck If Working Then Exit Sub Working = True e.Node.Checked = Not e.Node.Checked Working = False End Sub Private Sub TreeView1_MouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseClick If e.Button = Windows.Forms.MouseButtons.Right Then MsgBox("Checked = " & TreeView1.SelectedNode.Checked) End Sub Where TreeView1 is a TreeView added to the form, with CheckBoxes set to true and one node added. The code basically cancel any node checking occuring on the form. Single-clicking the top node to check it works well : your click is immediately canceled. Yet if you double-click the checkbox, it will display a tick. But verifying the check state through a right click will yield a Checked = False dialog. How come? Is it a bug (I'm using the latest .Net Framework 4.0, and he same occurs in 2.0), or am I doing something wrong here? Is there a work around? Thanks! EDIT: Additionally, the MouseDoubleClick event is not raised before you click once again. EDIT 2: Posted a bug report at Microsoft Connect

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  • Remove duplication's from my DropDownList

    - by user2976270
    In my controller i am returning list of my object with specific property: public ActionResult Index() { List<MyObject> list = db.MyObjects.Where(x => x.family == "Web").ToList(); ViewBag.Files = new SelectList(list, "Id", "protocol"); return View(); } This is my object: public class MyObject { public int id { get; set; } public string fileName { get; set; } public string browser { get; set; } public string protocol { get; set; } public string family { get; set; } } Index.cshtml: @Html.DropDownList("File", new SelectList(ViewBag.Files, "Id", "protocol_site"), "Select webmail site", new { style = "vertical-align:middle;" }) And i try to made 2 changes with no succeed: Remove all the duplication protocol from my DropDownListfor exapmle if i have 10 objects : 9 is doc protocol and 1 pdf i wand to see in my DropDownList only 2 items: DOC and PDF and not all the 10 items. Sort this DropDownList in alphabet order

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  • Session does not giving right records?

    - by Jugal
    I want to keep one session, but when I rollback transaction then transaction gets isActive=false, so I can not commit and rollback in next statements by using same transaction. then I need to create new transaction but what is going wrong here ? var session = NHibernateHelper.OpenSession();/* It returns new session. */ var transaction1 = session.BeginTransaction(); var list1 = session.Query<Make>().ToList(); /* It returs 4 records. */ session.Delete(list1[2]); /* After Rollback, transaction is isActive=false so I can not commit * and rollback from this transaction in future. so I need to create new transaction. */ transaction1.Rollback(); var transaction2 = session.BeginTransaction(); /* It returns 3 records. * I am not getting object(which was deleted but after that rollback) here why ? */ var list2 = session.Query<Make>().ToList(); Anyone have idea what is going wrong here ? I am not getting deleted object which was rollback.

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  • Preloading Image Bug in IE6-8

    - by Kevin C.
    Page in question: http://phwsinc.com/our-work/one-rincon-hill.asp In IE6-8, when you click the left-most thumbnail in the gallery, the image never loads. If you click the thumbnail a second time, then it will load. I'm using jQuery, and here's my code that's powering the gallery: $(document).ready(function() { // PROJECT PHOTO GALLERY var thumbs = $('.thumbs li a'); var photoWrapper = $('div.photoWrapper'); if (thumbs.length) { thumbs.click( function(){ photoWrapper.addClass('loading'); var img_src = $(this).attr('href'); // The two lines below are what cause the bug in IE. They make the gallery run much faster in other browsers, though. var new_img = new Image(); new_img.src = img_src; var photo = $('#photo'); photo.fadeOut('slow', function() { photo.attr('src', img_src); photo.load(function() { photoWrapper.removeClass('loading'); photo.fadeIn('slow'); }); }); return false; }); } }); A coworker told me that he's always had problems with the js Image() object, and advised me to just append an <img /> element inside of a div set to display:none;, but that's a little messy for my tastes--I liked using the Image() object, it kept things nice and clean, no unnecessary added HTML markup. Any help would be appreciated. It still works without the image preloading, so if all else fails I'll just wrap the preloading in an if !($.browser.msie){ } and call it a day.

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  • problem with converting simple code from Winform to silverlight app.

    - by Sara
    Hi. I have this code for window form application and I have been attempting to convert it to a Silverlight application but it does not work!. There is a Textbox and I attached KeyDown event handler to it. when the user press the arrow key ( left or right) while the focus on the textbox, it will write . or -. When it is window form i used e.KeyCode and Keys.Right and its works great but when it is silverlight I used e.Key and key.Right and the program doesn't work good because the arrows do the 2 functions moving and write ./-. How I can work this out in Silverlight? (My English not good) The code ( window form): private void textBox1_KeyDown(object sender, KeyEventArgs e) { if (sender is TextBox) { TextBox textBox = (TextBox)sender; if (e.KeyCode == Keys.Left || e.KeyCode == Keys.Right) { e.Handled = true; char insert; if (e.KeyCode == Keys.Left) { insert = '.'; } else { insert = '-'; } int i = textBox.SelectionStart; textBox.Text = textBox.Text.Insert(i, insert.ToString()); textBox.Select(i + 1, 0); } } } (and Silverlight): private void textBox1_KeyDown(object sender, KeyEventArgs e) { if (sender is TextBox) { TextBox textBox = (TextBox)sender; if (e.Key == Key.Left || e.Key == Key.Right) { e.Handled = true; char insert; if (e.Key == Key.Left) { insert = '.'; } else { insert = '-'; } int i = textBox.SelectionStart; textBox.Text = textBox.Text.Insert(i, insert.ToString()); textBox.Select(i + 1, 0); } } } I don't understand, is there huge different effect between using Keycode/Keys and Key/Key or because something else?

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  • How to check if an entityset is populated

    - by TheQ
    How can i check if an entityset of a linq-object is populated or not? Example code below. My model have two methods, one joins data, and the other does not: public static Member GetMemberWithSettings(Guid memberId) { using (DataContext db = new DataContext()) { DataLoadOptions dataLoadOptions = new DataLoadOptions(); dataLoadOptions.LoadWith<Member>(x => x.Settings); db.LoadOptions = dataLoadOptions; var query = from x in db.Members where x.MemberId == memberId select x; return query.FirstOrDefault(); } } public static Member GetMember(Guid memberId) { using (DataContext db = new DataContext()) { var query = from x in db.Members where x.MemberId == memberId select x; return query.FirstOrDefault(); } } Then my control have the following code: Member member1 = Member.GetMemberWithSettings(memberId); Member member2 = Member.GetMember(memberId); Debug.WriteLine(member1.Settings.Count); Debug.WriteLine(member2.Settings.Count); The last line will generate a "Cannot access a disposed object" exception. I know that i can get rid of that exception just by not disposing the datacontext, but then the last line will generate a new query to the database, and i don't want that. What i would like is something like: Debug.WriteLine((member1.Settings.IsPopulated()) ? member1.Settings.Count : -1); Debug.WriteLine((member2.Settings.IsPopulated()) ? member2.Settings.Count : -1); Is it possible?

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  • AJAX Request Erroring

    - by 30secondstosam
    I can not figure out for the life of me why this is erroring - can someone please cast a second pair of eyes over this - it's probably something really stupid, thanks in advance for the help: EDIT Stupidly I was putting the wrong URL in - HOWEVER... Now I have put the correct URL in, the site just hangs and crashes. Any ideas please? HTML: <input id="pc" class="sfc" name="ProdCat[]" type="checkbox" value=""> <input id="psc" class="sfc" name="ProdSubCat[]" type="checkbox" value=""> <input id="bf" class="sfc" name="BrandFil[]" type="checkbox" value=""> JQuery: $('input[type="checkbox"]').change(function(){ var name = $(this).attr("name"); var ProdCatFil = []; var ProdSubCatFil = []; var BrandFil = []; // Loop through the checked checkboxes in the same group // and add their values to an array $('input[type="checkbox"]:checked').each(function(){ switch(name) { case 'ProdCatFil[]': ProdCatFil.push($(this).val()); break; case 'ProdSubCatFil[]': ProdSubCatFil.push($(this).val()); break; case 'BrandFil[]': BrandFil.push($(this).val()); break; } }); $("#loading").ajaxStart(function(){ $(this).show(); $('.content_area').hide(); }); $("#loading").ajaxStop(function(){ $(this).hide(); $('.content_area').show(); }); $.ajax({ type: "GET", url: '../ajax/ajax.php', data: 'ProdCatFil='+ProdCatFil+'&ProdSubCatFil='+ProdSubCatFil+'&BrandFil='+BrandFil, success: function(data) { $('.content_area').html(data); } }).error(function (event, jqXHR, ajaxSettings, thrownError) { $('.content_area').html("<h2>Could not retrieve data</h2>"); //alert('[event:' + event + '], [jqXHR:' + jqXHR + '], [ajaxSettings:' + ajaxSettings + '], [thrownError:' + thrownError + '])'); }); PHP (just to prove it's working): echo '<h1>TEST TEST TEST </h1>'; The errors from JQuery alert box: [event:[object Object]], [jqXHR:error], [ajaxSettings:Not Found], [thrownError:undefined])

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  • A better way of getting a data table with various column types into string array

    - by Vlad
    This should be an easy one, looks like I got myself too confused. I get a table from a database, data ranges from varchar to int to Null values. Cheap and dirty way of converting this into a tab-delimited file that I already have is this (shrunken to preserve space, ugliness is kept on par with original): da.Fill(dt) ' da - DataAdapter ' ' dt - DataTable ' Dim lColumns As Long = dt.Columns.Count Dim arrColumns(dt.Columns.Count) As String Dim arrData(dt.Columns.Count) As Object Dim j As Long = 0 Dim arrData(dt.Columns.Count) As Object For i = 0 To dt.Rows.Count - 1 arrData = dt.Rows(i).ItemArray() For j = 0 To arrData.GetUpperBound(0) - 1 arrColumns(j) = arrData(j).ToString Next wrtOutput.WriteLine(String.Join(strFieldDelimiter, arrColumns)) Array.Clear(arrColumns, 0, arrColumns.GetLength(0)) Array.Clear(arrData, 0, arrData.GetLength(0)) Next Not only this is ugly and inefficient, it is also getting on my nerves. Besides, I want, if possible, to avoid the infamous double-loop through the table. I would really appreciate a clean and safe way of rewriting this piece. I like the approach that is used here - especially that is trying to solve the same problem that I have, but it crashes on me when I apply it to my case directly.

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  • How to lazy load a data structure (python)

    - by Anton Geraschenko
    I have some way of building a data structure (out of some file contents, say): def loadfile(FILE): return # some data structure created from the contents of FILE So I can do things like puppies = loadfile("puppies.csv") # wait for loadfile to work kitties = loadfile("kitties.csv") # wait some more print len(puppies) print puppies[32] In the above example, I wasted a bunch of time actually reading kitties.csv and creating a data structure that I never used. I'd like to avoid that waste without constantly checking if not kitties whenever I want to do something. I'd like to be able to do puppies = lazyload("puppies.csv") # instant kitties = lazyload("kitties.csv") # instant print len(puppies) # wait for loadfile print puppies[32] So if I don't ever try to do anything with kitties, loadfile("kitties.csv") never gets called. Is there some standard way to do this? After playing around with it for a bit, I produced the following solution, which appears to work correctly and is quite brief. Are there some alternatives? Are there drawbacks to using this approach that I should keep in mind? class lazyload: def __init__(self,FILE): self.FILE = FILE self.F = None def __getattr__(self,name): if not self.F: print "loading %s" % self.FILE self.F = loadfile(self.FILE) return object.__getattribute__(self.F, name) What might be even better is if something like this worked: class lazyload: def __init__(self,FILE): self.FILE = FILE def __getattr__(self,name): self = loadfile(self.FILE) # this never gets called again # since self is no longer a # lazyload instance return object.__getattribute__(self, name) But this doesn't work because self is local. It actually ends up calling loadfile every time you do anything.

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  • Rails 3 fields_for agressive loading?

    - by Seth
    Hi all, I'm trying to optimize (limit) queries in a view. I am using the fields_for function. I need to reference various properties of the object, such as username for display purposes. However, this is a rel table, so I need to join with my users table. The result is N sub-queries, 1 for each field in fields_for. It's difficult to explain, but I think you'll understand what I'm asking if I paste my code: <%= form_for @election do |f| %> <%= f.fields_for :voters do |voter| %> <%= voter.hidden_field :id %> <%= voter.object.user.preferred_name %> <% end %> <% end %> I have like 10,000 users, and many times each election will include all 10,000 users. That's 10,000 subqueries every time this view is loaded. I want fields_for to JOIN on users. Is this possible? I'd like to do something like: ... <%= f.fields_for :voters, :joins => :users do |voter| %> ... <% end %> ... But that, of course, doesn't work :(

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  • Problem consuming a dataset via a .NET web service from Flex-ActionScript

    - by DEH
    Hi, I am returning a .NET dataset to Flex Actionscript via a web service. Actionscript snippet as follows: var websvc:WebService = new WebService(); websvc.useProxy=false; websvc.wsdl = "http://localhost:13229/test/mysvc.asmx?WSDL"; websvc.loadWSDL(); var operation:Operation = new Operation(null, "GetData"); operation.arguments.command="xx_gethierdata_"+mode+"_"+identifier; operation.addEventListener(ResultEvent.RESULT, onResultHandler, false, 0, true); operation.addEventListener(FaultEvent.FAULT, onFaultHandler, false, 0, true); operation.resultFormat="object"; websvc.operations = [operation]; operation.send(); Once in the onResultHandler function I have access to the datatable - I then want to grab the column names. The following code outputs my column names: for each (var tcolumn:Object in datatable.Columns){trace('Column:'+tcolumn);} This works ok, but the column names are encoded, so a column name that is actually "1-9" is output as "_x005B_1-9_x005D_" Anyone know the best way to decode the column name? I could replace all the encoding strings, but surely there is a better way? Thanks

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  • NUll exception in filling a querystring by mocing framework

    - by user564101
    There is a simple controller that a querystring is read in constructor of it. public class ProductController : Controller { parivate string productName; public ProductController() { productName = Request.QueryString["productname"]; } public ActionResult Index() { ViewData["Message"] = productName; return View(); } } Also I have a function in unit test that create an instance of this Controller and I fill the querystring by a Mock object like below. [TestClass] public class ProductControllerTest { [TestMethod] public void test() { // Arrange var querystring = new System.Collections.Specialized.NameValueCollection { { "productname", "sampleproduct"} }; var mock = new Mock<ControllerContext>(); mock.SetupGet(p => p.HttpContext.Request.QueryString).Returns(querystring); var controller = new ProductController(); controller.ControllerContext = mock.Object; // Act var result = controller.Index() as ViewResult; // Assert Assert.AreEqual("Index", result.ViewName); } } Unfortunately Request.QueryString["productname"] is null in constructor of ProductController when I run test unit. Is ther any way to fill a querystrin by a mocking and get it in constructor of a control?

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  • Python & Pygame: Updating all elements in a list under a loop during iteration

    - by Unit978
    i am working on a program in Python and using Pygame. this is what the basic code looks like: while 1: screen.blit(background, (0,0)) for event in pygame.event.get(): if event.type == QUIT: pygame.quit() sys.exit() if event.type == KEYDOWN and event.key == K_c: circle_create = True circle_list.append(Circle()) if event.type == MOUSEBUTTONDOWN and circle_create == True: if clicks == 0: circle_list[i].center() clicks += 1 if event.type == MOUSEMOTION and clicks == 1 and circle_create == True: circle_list[i].stretch() these if statements are under the while loop not the for loop since they dont require input from the user if circle_create == True: circle_list[i].draw_circle() if clicks == 2: clicks = 0 i += 1 circle_create = False pygame.display.update() what i want to do is have the object's function of draw_circle() to be constantly updated by the loop so that the drawn circle is shown for all objects in the list, but since the list is iterated it updates the new object added and the objects already appended are not updated. The program, works, it draws the circles upon user input but the update problem is the only issue i need to solve. Is there any possible way to have all elements in the list of objects being updated by the while loop? i have tried for many days and i have not been able to find a good solution. any ideas are appreciated. Thanks

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