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  • How do I refer to a constant URL in my route configuration?

    - by Remnant
    Suppose I have the following within a webpage <% using (Html.BeginForm("ShowData", "Summary")) %> <% { %> <div class="dropdown"><%=Html.DropDownList("CourseSelection", Model.CourseList, new { @class = "dropdown", onchange="this.form.submit();" })%> </div> <% } %> When the user makes a selection from the dropdown the form is submitted and I would like it to link to another page with a URL as follows: http://localhost:1721/Summary I have the following routes: routes.MapRoute(null, "Summary", new { controller = "Summary", action = "ShowData", CourseSelection = (string) null }); routes.MapRoute("Default", "{controller}/{action}/{id}", new { controller = "Login", action = "Index", id = UrlParameter.Optional }); When a user selects an item in the dropdownlist, the URL returned is: http://localhost:1721/Summary/ShowData?CourseSelection = UserSelection Clearly the first route in the list is not being matched. I don't want the URL to show the action name and parameter. I simply want to show "Summary" which is what I have hard coded in the URL. How do I achieve this?

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  • undefined method `user_sessions_path' for #<ActionView::Base:0xdb3158>

    - by mrbernz
    I'm getting this error that's driving me up the wall. I don't see what's going on... I've followed instructions to the T and it's still complaining - help please!! I've got extracts of the error message, controller file, login page and routes file. Error message NoMethodError in User_sessions#new Showing app/views/user_sessions/new.html.erb where line #4 raised: undefined method `user_sessions_path' for # Extracted source (around line #4): 1: 2: User Login 3: 4: <% form_for @user_session do |f| % 5: <%= f.error_messages % 6: 7: controller/user_sessions_controller.rb class UserSessionsController < ApplicationController before_filter :require_no_user, :only = [:new, :create] before_filter :require_user, :only = :destroy def new @user_session = UserSession.new end def create @user_session = UserSession.new(params[:user_session]) if @user_session.save flash[:notice] = "Login successful!" redirect_to root_url #redirect_back_or_default account_url else render :action = :new end end def destroy current_user_session.destroy flash[:notice] = "Logout successful!" redirect_to root_url #redirect_back_or_default account_url end end user_sessions/new.html.erb User Login <% form_for @user_session do |f| % <%= f.error_messages % <%= f.label :Email % <%= f.text_field :email % <%= f.label :Password % <%= f.password_field :password % <%= f.submit "Submit" % <% end % routes.rb file ActionController::Routing::Routes.draw do |map| map.login "login", :controller = "user_sessions", :action = "new" Am I look in in the wrong place??

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  • Optional route parameters in ASP.NET 4 RTM no longer work as before

    - by Simon_Weaver
    I upgraded my project to ASP.NET 4 RTM with ASP.NET MVC 2.0 RTM today. I was previously using ASP.NET 3.5 with ASP.NET MVC 2.0 RTM. Some of my routes don't work suddenly and I don't know why. I'm not sure if something changed between 3.5 and 4.0 - or if this was a regression type issue in the 4.0 RTM. (I never previously tested my app with 4.0). I like to use Url.RouteUrl("route-name", routeParams) to avoid ambiguity when generating URLs. Here's my route definition for a gallery page. I want imageID to be optional (you get a thumbnail page if you don't specify it). // gallery id routes.MapRoute( "gallery-route", "gallery/{galleryID}/{imageID}/{title}", new { controller = "Gallery", action = "Index", galleryID = (string) null, imageID = (string) null, title = (string) null} ); In .NET 3.5 / ASP.NET 2.0 RTM / IIS7 Url.RouteUrl("gallery-route", "cats") => /gallery/cats Url.RouteUrl("gallery-route", "cats", 4) => /gallery/cats/4 Url.RouteUrl("gallery-route", "cats", 4, "tiddles") => /gallery/cats/4/tiddles In .NET 4.0 RTM / ASP.NET 2.0 RTM / IIS7 Url.RouteUrl("gallery-route", "cats") => null Url.RouteUrl("gallery-route", "cats", 4) => /gallery/cats/4 Url.RouteUrl("gallery-route", "cats", 4, "tiddles") => /gallery/cats/4/tiddles Previously I could supply only the galleryID and everything else would be ignored in the generated URL. But now it's looking like I need to specify all the parameters up until title - or it gives up in determining the URL. Incoming URLs work fine for /gallery/cats and that is correctly mapped through this rule with imageID and title both being assigned null in my controller. I also tested the INCOMING routes with http://haacked.com/archive/2008/03/13/url-routing-debugger.aspx and they all work fine.

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  • Using T4MVC in real project

    - by artvolk
    T4MVC is cool, but I have a couple of issues integrating it in my project, any help is really appriciated: I've got such warnings for all my actions (I use SnippetsBaseController as base class for all my controller classes: Warning 26 'Snippets.Controllers.ErrorController.Actions' hides inherited member 'Snippets.Controllers.Base.SnippetsBaseController.Actions'. Use the new keyword if hiding was intended. C:\projects_crisp-source_crisp\crisp-snippets\Snippets\T4MVC.cs 481 32 Snippets Is it possible to have strongly typed names of custom Routes, for example, I have route defined like this: routes.MapRoute( "Feed", "feed/", MVC.Snippets.Rss(), new { controller = "Snippets", action = "Rss" } ); Is it possible to replace: <%= Url.RouteUrl("Feed") %> with something like: <%= Url.RouteUrl(MVC.Routes.Feed) %> Having strongly typed links to static files is really cool, but I use <base /> in my pages, so I don't need any URL processing, can I redefine T4MVCHelpers.ProcessVirtualPath without tweaking the T4MVC.tt itself? T4MVC always generate links with uppercased controller and action names, for example: /Snippets/Add instead of /snippets/add. Is it possible to generate them lowercase?

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  • Ember model is gone when I use the renderTemplate hook

    - by Mickael Caruso
    I have a single template - editPerson.hbs <form role="form"> FirstName: {{input type="text" value=model.firstName }} <br/> LastName: {{input type="text" value=model.lastName }} </form> I want to render this template when the user wants to edit an existing person or create a new person. So, I set up routes: App.Router.map(function(){ this.route("createPerson", { path: "/person/new" }); this.route("editPerson", { path: "/person/:id}); // other routes not show for brevity }); So, I define two routes - one for create and one for edit: App.CreatePersonRoute = Ember.Route.extend({ renderTemplate: function(){ this.render("editPerson", { controller: "editPerson" }); }, model: function(){ return {firstName: "John", lastName: "Smith" }; } }); App.EditPersonRoute = Ember.Route.extend({ model: function(id){ return {firstName: "John Existing", lastName: "Smith Existing" }; } }); So, I hard-code the models. I'm concerned about the createPerson route. I'm telling it to render the editPersonTemplate and to use the editPerson controller (which I don't show because I don't think it matters - but I made one, though.) When I use renderTemplate, I lose the model John Smith, which in turn, won't display on the editTemplate on the web page. Why? I "fixed" this by creating a separate and identical (to editPerson.hbs) createPerson.hbs, and removing the renderTemplate hook in the CreatePerson. It works as expected, but I find it somewhat troubling to have a separate and identical template for the edit and create cases. I looked everywhere for how to properly do this, and I found no answers.

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  • ambient values in mvc2.net routing

    - by Muhammad Adeel Zahid
    Hello Everyone, i have following two routes registered in my global.asax file routes.MapRoute( "strict", "{controller}.mvc/{docid}/{action}/{id}", new { action = "Index", id = "", docid = "" }, new { docid = @"\d+"} ); routes.MapRoute( "default", "{controller}.mvc/{action}/{id}", new { action = "Index", id = "" }, new { docConstraint = new DocumentConstraint() } ); and i have a static "dashboard" link in my tabstrip and some other links that are constructed from values in db here is the code <ul id="globalnav" class = "t-reset t-tabstrip-items"> <li class="bar" id = "dashboard"> <%=Html.ActionLink("dash.board", "Index", pck.Controller, new{docid =string.Empty,id = pck.PkgID }, new { @class = "here" })%> </li> <% foreach (var md in pck.sysModules) { %> <li class="<%=liClass%>"> <%=Html.ActionLink(md.ModuleName, md.ActionName, pck.Controller, new { docid = md.DocumentID}, new { @class = cls })%> </li> <% } %> </ul> Now my launching address is localhost/oa.mvc/index/11 clearly matching the 2nd route. but when i visit any page that has mapped to first route and then come back to dash.board link it shows me localhost/oa.mvc/7/index/11 where 7 is docid and picked from previous Url. now i understand that my action method is after docid and changing it would not clear the docid. my question here is that can i remove docid in this scenario without changing the route. regards adeel

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  • google maps call within a For Loop not returning distance

    - by Richard Reddy
    Hi, I am calling google maps within a for loop in my javascript as I have mulitple routes that need to be costed separately based on distances. Everything works great except that the distance is only returned for one of the routes. I have a feeling that it is something to do with the way I have the items declared within the ajax call for the maps. Any ideas what could be the issue from the code below? for (var i = 1; i <= numJourneys; i++) { var mapContainer = 'directionsMap' + i; var directionContainer = $('#getDistance' + i); $.ajax({ async: false, type: "POST", url: "Journey/LoadWayPoints", data: "{'args': '" + i + "'}", contentType: "application/json; charset=utf-8", dataType: "json", success: function (msg) { if (msg.d != '[]') { var map = new GMap2(document.getElementById(mapContainer)); var distance = directionContainer; var wp = new Array(); //routes var counter = 0; $.each(content, function () { wp[counter] = new GLatLng(this['Lat'], this['Long']); counter = counter + 1; }); map.clearOverlays(); map.setCenter(wp[0], 14); // load directions directions = new GDirections(map); GEvent.addListener(directions, "load", function () { alert(directions.getDistance()); //directionContainer.html(directions.getDistance().html); }); directions.loadFromWaypoints(wp, { getSteps: true }); } } }); }

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  • checking mongo database for data

    - by user1647484
    I'm playing around with this tutorial that uses Sinatra, backbone.js, and mongodb for the database. It's my first time using mongo. As far as I understand it the app uses both local storage and a database. it has these routes for the database. For example, it has these routes get '/api/:thing' do DB.collection(params[:thing]).find.to_a.map{|t| from_bson_id(t)}.to_json end get '/api/:thing/:id' do from_bson_id(DB.collection(params[:thing]).find_one(to_bson_id(params[:id]))).to_json end post '/api/:thing' do oid = DB.collection(params[:thing]).insert(JSON.parse(request.body.read.to_s)) "{\"_id\": \"#{oid.to_s}\"}" end After turning the server off and then on, I could see in the server getting data from the database routes 127.0.0.1 - - [17/Sep/2012 08:21:58] "GET /api/todos HTTP/1.1" 200 430 0.0033 My question is, how can I check from within the mongo shell whether the data's in the database? I started the mongo shell ./bin/mongo I selected the database 'use mydb' and then looking at the docs (http://www.mongodb.org/display/DOCS/Tutorial) I tried commands such as > var cursor = db.things.find(); > while (cursor.hasNext()) printjson(cursor.next()); but they didn't return anything.

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  • RoR routing problem. Calling custom action, but getting redirected to show action

    - by conorgil
    I am working on a project in ruby on rails and I am having a very difficult time with a basic problem. I am trying to call a custom action in one of my controllers, but the request is somehow getting redirected to the default 'show' action and I cannot figure out why. link in edit.html.erb: <%= link_to 'Mass Text Entry', :action=>"create_or_add_food_item_from_text" %> Error from development.log: ActiveRecord::RecordNotFound (Couldn't find Menu with ID=create_or_add_food_item_from_text): app/controllers/menus_controller.rb:20:in `show' routes.rb file: ActionController::Routing::Routes.draw do |map| map.resources :nutrition_objects map.resources :preference_objects map.resources :institutions map.resources :locations map.resources :menus map.resources :food_items map.resources :napkins map.resources :users map.resource :session, :controller => 'session' map.root :controller=>'pages', :action=>'index' map.about '/about', :controller=>'pages', :action=>'about' map.contact '/contact', :controller=>'pages', :action=>'contact' map.home '/home', :controller=>'pages', :action=>'index' map.user_home '/user/home', :controller=>'rater', :action=>'index' map.user_napkins '/user/napkins', :controller=>'rater', :action=>'view_napkins' map.user_preferences '/user/preferences',:controller=>'rater', :action=>'preferences' map.blog '/blog', :controller=>'pages', :action=>'blog' map.signup '/signup', :controller=>'users', :action=>'new' map.login '/login', :controller=>'session', :action=>'new' map.logout '/logout', :controller=>'session', :action=>'destroy' # Install the default routes as the lowest priority. map.connect ':controller/:action' map.connect ':controller/:action/:id' map.connect ':controller/:action/:id.:format' end Menus_controller.rb: class MenusController < ApplicationController ... def create_or_add_food_item_from_text end ... end create_or_add_food_item_from_text.html.erb simply has a div to show a form with a text box in it. I have the rest of my app working fine, but this is stumping me. Any help is appreciated.

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  • xpath php attributes not working?

    - by Jared
    Getting this error Call to a member function attributes() on a non-object I have found multiple answers to this on SO, but none of them seem to solve my problem? Here is the XML: <Routes> <Route type="source" name="incoming"> </Route> <Routes> Here is the PHP: $doc = new SimpleXMLElement('routingConfig.xml', null, true); class traverseXML { function getData() { global $doc; $routeCount = count($doc -> xpath("Route")); //this value returns correctly $routeArr = array(); for ($i = 1; $i <= $routeCount; $i++) { $name = $doc -> Route[$i] -> attributes() -> name; array_push($routeArr, $name); } return $routeArr; } } $traverseXML = new traverseXML; var_dump($traverseXML -> getData()); I understand what the error means, but how is it a non-object? How do I return the name attribute of Routes/Route[1] ?

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  • MVC : Does Code to save data in cache or session belongs in controller?

    - by newbie
    I'm a bit confused if saving the information to session code below, belongs in the controller action as shown below or should it be part of my Model? I would add that I have other controller methods that will read this session value later. public ActionResult AddFriend(FriendsContext viewModel) { if (!ModelState.IsValid) { return View(viewModel); } // Start - Confused if the code block below belongs in Controller? Friend friend = new Friend(); friend.FirstName = viewModel.FirstName; friend.LastName = viewModel.LastName; friend.Email = viewModel.UserEmail; httpContext.Session["latest-friend"] = friend; // End Confusion return RedirectToAction("Home"); } I thought about adding a static utility class in my Model which does something like below, but it just seems stupid to add 2 lines of code in another file. public static void SaveLatestFriend(Friend friend, HttpContextBase httpContext) { httpContext.Session["latest-friend"] = friend; } public static Friend GetLatestFriend(HttpContextBase httpContext) { return httpContext.Session["latest-friend"] as Friend; }

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  • Convert Dynamic to Type and convert Type to Dynamic

    - by Jon Canning
    public static class DynamicExtensions     {         public static T FromDynamic<T>(this IDictionary<string, object> dictionary)         {             var bindings = new List<MemberBinding>();             foreach (var sourceProperty in typeof(T).GetProperties().Where(x => x.CanWrite))             {                 var key = dictionary.Keys.SingleOrDefault(x => x.Equals(sourceProperty.Name, StringComparison.OrdinalIgnoreCase));                 if (string.IsNullOrEmpty(key)) continue;                 var propertyValue = dictionary[key];                 bindings.Add(Expression.Bind(sourceProperty, Expression.Constant(propertyValue)));             }             Expression memberInit = Expression.MemberInit(Expression.New(typeof(T)), bindings);             return Expression.Lambda<Func<T>>(memberInit).Compile().Invoke();         }         public static dynamic ToDynamic<T>(this T obj)         {             IDictionary<string, object> expando = new ExpandoObject();             foreach (var propertyInfo in typeof(T).GetProperties())             {                 var propertyExpression = Expression.Property(Expression.Constant(obj), propertyInfo);                 var currentValue = Expression.Lambda<Func<string>>(propertyExpression).Compile().Invoke();                 expando.Add(propertyInfo.Name.ToLower(), currentValue);             }             return expando as ExpandoObject;         }     }

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  • Code Trivia #6

    - by João Angelo
    It’s time for yet another code trivia and it’s business as usual. What will the following program output to the console? using System; using System.Drawing; using System.Threading; class Program { [ThreadStatic] static Point Mark = new Point(1, 1); static void Main() { Thread.CurrentThread.Name = "A"; MoveMarkUp(); var helperThread = new Thread(MoveMarkUp) { Name = "B" }; helperThread.Start(); helperThread.Join(); } static void MoveMarkUp() { Mark.Y++; Console.WriteLine("{0}:{1}", Thread.CurrentThread.Name, Mark); } }

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  • ResponseStatusLine protocol violation

    - by Tom Hines
    I parse/scrape a few web page every now and then and recently ran across an error that stated: "The server committed a protocol violation. Section=ResponseStatusLine".   After a few web searches, I found a couple of suggestions – one of which said the problem could be fixed by changing the HttpWebRequest ProtocolVersion to 1.0 with the command: 1: HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(strURI); 2: req.ProtocolVersion = HttpVersion.Version10;   …but that did not work in my particular case.   What DID work was the next suggestion I found that suggested the use of the setting: “useUnsafeHeaderParsing” either in the app.config file or programmatically. If added to the app.config, it would be: 1: <!-- after the applicationSettings --> 2: <system.net> 3: <settings> 4: <httpWebRequest useUnsafeHeaderParsing ="true"/> 5: </settings> 6: </system.net>   If done programmatically, it would look like this: C++: 1: // UUHP_CPP.h 2: #pragma once 3: using namespace System; 4: using namespace System::Reflection; 5:   6: namespace UUHP_CPP 7: { 8: public ref class CUUHP_CPP 9: { 10: public: 11: static bool UseUnsafeHeaderParsing(String^% strError) 12: { 13: Assembly^ assembly = Assembly::GetAssembly(System::Net::Configuration::SettingsSection::typeid); //__typeof 14: if (nullptr==assembly) 15: { 16: strError = "Could not access Assembly"; 17: return false; 18: } 19:   20: Type^ type = assembly->GetType("System.Net.Configuration.SettingsSectionInternal"); 21: if (nullptr==type) 22: { 23: strError = "Could not access internal settings"; 24: return false; 25: } 26:   27: Object^ obj = type->InvokeMember("Section", 28: BindingFlags::Static | BindingFlags::GetProperty | BindingFlags::NonPublic, 29: nullptr, nullptr, gcnew array<Object^,1>(0)); 30:   31: if(nullptr == obj) 32: { 33: strError = "Could not invoke Section member"; 34: return false; 35: } 36:   37: FieldInfo^ fi = type->GetField("useUnsafeHeaderParsing", BindingFlags::NonPublic | BindingFlags::Instance); 38: if(nullptr == fi) 39: { 40: strError = "Could not access useUnsafeHeaderParsing field"; 41: return false; 42: } 43:   44: if (!(bool)fi->GetValue(obj)) 45: { 46: fi->SetValue(obj, true); 47: } 48:   49: return true; 50: } 51: }; 52: } C# (CSharp): 1: using System; 2: using System.Reflection; 3:   4: namespace UUHP_CS 5: { 6: public class CUUHP_CS 7: { 8: public static bool UseUnsafeHeaderParsing(ref string strError) 9: { 10: Assembly assembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection)); 11: if (null == assembly) 12: { 13: strError = "Could not access Assembly"; 14: return false; 15: } 16:   17: Type type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal"); 18: if (null == type) 19: { 20: strError = "Could not access internal settings"; 21: return false; 22: } 23:   24: object obj = type.InvokeMember("Section", 25: BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, 26: null, null, new object[] { }); 27:   28: if (null == obj) 29: { 30: strError = "Could not invoke Section member"; 31: return false; 32: } 33:   34: // If it's not already set, set it. 35: FieldInfo fi = type.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance); 36: if (null == fi) 37: { 38: strError = "Could not access useUnsafeHeaderParsing field"; 39: return false; 40: } 41:   42: if (!Convert.ToBoolean(fi.GetValue(obj))) 43: { 44: fi.SetValue(obj, true); 45: } 46:   47: return true; 48: } 49: } 50: }   F# (FSharp): 1: namespace UUHP_FS 2: open System 3: open System.Reflection 4: module CUUHP_FS = 5: let UseUnsafeHeaderParsing(strError : byref<string>) : bool = 6: // 7: let assembly : Assembly = Assembly.GetAssembly(typeof<System.Net.Configuration.SettingsSection>) 8: if (null = assembly) then 9: strError <- "Could not access Assembly" 10: false 11: else 12: 13: let myType : Type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal") 14: if (null = myType) then 15: strError <- "Could not access internal settings" 16: false 17: else 18: 19: let obj : Object = myType.InvokeMember("Section", BindingFlags.Static ||| BindingFlags.GetProperty ||| BindingFlags.NonPublic, null, null, Array.zeroCreate 0) 20: if (null = obj) then 21: strError <- "Could not invoke Section member" 22: false 23: else 24: 25: // If it's not already set, set it. 26: let fi : FieldInfo = myType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic ||| BindingFlags.Instance) 27: if(null = fi) then 28: strError <- "Could not access useUnsafeHeaderParsing field" 29: false 30: else 31: 32: if (not(Convert.ToBoolean(fi.GetValue(obj)))) then 33: fi.SetValue(obj, true) 34: 35: // Now return true 36: true VB (Visual Basic): 1: Option Explicit On 2: Option Strict On 3: Imports System 4: Imports System.Reflection 5:   6: Public Class CUUHP_VB 7: Public Shared Function UseUnsafeHeaderParsing(ByRef strError As String) As Boolean 8:   9: Dim assembly As [Assembly] 10: assembly = [assembly].GetAssembly(GetType(System.Net.Configuration.SettingsSection)) 11:   12: If (assembly Is Nothing) Then 13: strError = "Could not access Assembly" 14: Return False 15: End If 16:   17: Dim type As Type 18: type = [assembly].GetType("System.Net.Configuration.SettingsSectionInternal") 19: If (type Is Nothing) Then 20: strError = "Could not access internal settings" 21: Return False 22: End If 23:   24: Dim obj As Object 25: obj = [type].InvokeMember("Section", _ 26: BindingFlags.Static Or BindingFlags.GetProperty Or BindingFlags.NonPublic, _ 27: Nothing, Nothing, New [Object]() {}) 28:   29: If (obj Is Nothing) Then 30: strError = "Could not invoke Section member" 31: Return False 32: End If 33:   34: ' If it's not already set, set it. 35: Dim fi As FieldInfo 36: fi = [type].GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic Or BindingFlags.Instance) 37: If (fi Is Nothing) Then 38: strError = "Could not access useUnsafeHeaderParsing field" 39: Return False 40: End If 41:   42: If (Not Convert.ToBoolean(fi.GetValue(obj))) Then 43: fi.SetValue(obj, True) 44: End If 45:   46: Return True 47: End Function 48: End Class   Technorati Tags: C++,CPP,VB,Visual Basic,F#,FSharp,C#,CSharp,ResponseStatusLine,protocol violation

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  • Dynamic Tab Implementation in ADF

    - by Vijay Mohan
    Well, this can be a common usecase across apps to open tabs dynamically at runtime based on the request.Well, in order to achieve this you can have a parent container, lets say a panelTab component.Inside panelTab , u can have a showDetailItem inside an af:foreach or an af:iterator binded to a bean static list which will have as many show detail items as you wish to be shown.something like this.private static List = { new showDetailItem("1"),new ShowDetailItem("2") ...};now in the backing bean you can have a method that takes care of rendering and disclosing an specific tab based on the index.public void openMyTab(){List<MyItems> list = refToParentContainer.getChildren();int indexOfTabToBeOpened = //Write a method that will compute the tab index of the next //tab.list.get(index).setRendered(true);list.get(index).setDisclosed(true);similarly you can set other properties too.}Else, instead of having af:foreach/iterator iterating through the SD items , you can go for static SDs in the page with render property set to false and then you can follow the same approach to render/disclose it at runtime.

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  • Why prefer a wildcard to a type discriminator in a Java API (Re: Effective Java)

    - by Michael Campbell
    In the generics section of Bloch's Effective Java (which handily is the "free" chapter available to all: http://java.sun.com/docs/books/effective/generics.pdf), he says: If a type parameter appears only once in a method declaration, replace it with a wildcard. (See page 31-33 of that pdf) The signature in question is: public static void swap(List<?> list, int i, int j) vs public static void swap(List<E> list, int i, int j) And then proceeds to use a static private "helper" function with an actual type parameter to perform the work. The helper function signature is EXACTLY that of the second option. Why is the wildcard preferable, since you need to NOT use a wildcard to get the work done anyway? I understand that in this case since he's modifying the List and you can't add to a collection with an unbounded wildcard, so why use it at all?

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  • How can I host a website on a dynamically-assigned IP address?

    - by nick
    I recently upgraded my internet to the point that it is much faster and more reliable than my current webhost. I would like to move my current domain to be hosted at home, but my IP address is dynamic. As far as I know, I only get a new IP when I restart my modem and or router (which is almost never) or when cable one (my ISP) pushes out a firmware update (rarely). There are a few ways I can see doing this: Convince my ISP to give me a static IP Assign my router my current IP to force a static IP (which might work?) Set my DNS record to my current IP address and update it on the rare occasions that it changes. Obviously I'm hoping that the first one works, but I don't want to pay a lot of extra money (if that's what it takes) to get a static IP address. Which of these options will work most reliably?

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  • SQL ADO.NET shortcut extensions (old school!)

    - by Jeff
    As much as I love me some ORM's (I've used LINQ to SQL quite a bit, and for the MSDN/TechNet Profile and Forums we're using NHibernate more and more), there are times when it's appropriate, and in some ways more simple, to just throw up so old school ADO.NET connections, commands, readers and such. It still feels like a pain though to new up all the stuff, make sure it's closed, blah blah blah. It's pretty much the least favorite task of writing data access code. To minimize the pain, I have a set of extension methods that I like to use that drastically reduce the code you have to write. Here they are... public static void Using(this SqlConnection connection, Action<SqlConnection> action) {     connection.Open();     action(connection);     connection.Close(); } public static SqlCommand Command(this SqlConnection connection, string sql){    var command = new SqlCommand(sql, connection);    return command;}public static SqlCommand AddParameter(this SqlCommand command, string parameterName, object value){    command.Parameters.AddWithValue(parameterName, value);    return command;}public static object ExecuteAndReturnIdentity(this SqlCommand command){    if (command.Connection == null)        throw new Exception("SqlCommand has no connection.");    command.ExecuteNonQuery();    command.Parameters.Clear();    command.CommandText = "SELECT @@IDENTITY";    var result = command.ExecuteScalar();    return result;}public static SqlDataReader ReadOne(this SqlDataReader reader, Action<SqlDataReader> action){    if (reader.Read())        action(reader);    reader.Close();    return reader;}public static SqlDataReader ReadAll(this SqlDataReader reader, Action<SqlDataReader> action){    while (reader.Read())        action(reader);    reader.Close();    return reader;} It has been awhile since I've really revisited these, so you will likely find opportunity for further optimization. The bottom line here is that you can chain together a bunch of these methods to make a much more concise database call, in terms of the code on your screen, anyway. Here are some examples: public Dictionary<string, string> Get(){    var dictionary = new Dictionary<string, string>();    _sqlHelper.GetConnection().Using(connection =>        connection.Command("SELECT Setting, [Value] FROM Settings")            .ExecuteReader()            .ReadAll(r => dictionary.Add(r.GetString(0), r.GetString(1))));    return dictionary;} or... public void ChangeName(User user, string newName){    _sqlHelper.GetConnection().Using(connection =>         connection.Command("UPDATE Users SET Name = @Name WHERE UserID = @UserID")            .AddParameter("@Name", newName)            .AddParameter("@UserID", user.UserID)            .ExecuteNonQuery());} The _sqlHelper.GetConnection() is just some other code that gets a connection object for you. You might have an even cleaner way to take that step out entirely. This looks more fluent, and the real magic sauce for me is the reader bits where you can put any kind of arbitrary method in there to iterate over the results.

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  • creating a pre-menu level select screen

    - by Ephiras
    Hi I am working on creating a tower Defence java applet game and have come to a road block about implementing a title screen that i can select the level and difficulty of the rest of the game. my title screen class is called Menu. from this menu class i need to pass in many different variables into my Main class. i have used different classes before and know how to run them and such. but if both classes extend applet and each has its individual graphics method how can i run things from Main even though it was created in Menu. what i essentially want to do is run the Menu class withits action listeners and graphics until a Difficulty button has been selected, run the main class (which 100% works without having to have the Menu class) and pretty much terminate Menu so that i cannot go back to it, do not see its buttons or graphics menus. can i run one applet annd when i choose a button close that one and launch the other one? IF you would like to download the full project you can find it here, i had to comment out all the code that wasn't working my Menu class import java.awt.*; import java.awt.event.*; import java.applet.*; public class Menu extends Applet implements ActionListener{ Button bEasy,bMed,bHard; Main m; public void init(){ bEasy= new Button("Easy"); bEasy.setBounds(140,200,100,50); add(bEasy); bMed = new Button("Medium");bMed.setBounds(280,200,100,50); add(bMed); bHard= new Button("Hard");bHard.setBounds(420,200,100,50); add(bHard); setLayout(null); } public void actionPerformed(ActionEvent e){ Main m = new Main(20,10,3000,mapMed);//break; switch (e.getSource()){ case bEasy: Main m = new Main(6000,20,"levels/levelEasy.png");break;//enimies tower money world case bMed: Main m = new Main(4000,15,"levels/levelMed.png");break; case bHard: Main m = new Main(2000,10,"levels/levelEasy.png");break; default: break; } } public void paint(){ //m.draw(g) } } and here is my main class initialising code. import java.awt.*; import java.awt.event.*; import java.applet.*; import java.io.IOException; public class Main extends Applet implements Runnable, MouseListener, MouseMotionListener, ActionListener{ Button startButton, UpgRange, UpgDamage; //set up the buttons Color roadCol,startCol,finCol,selGrass,selRoad; //set up the colors Enemy e[][]; Tower t[]; Image towerpic,backpic,roadpic,levelPic; private Image i; private Graphics doubleG; //here is the world 0=grass 1=road 2=start 3=end int world[][],eStartX,eStartY; boolean drawMouse,gameEnd; static boolean start=false; static int gridLength=15; static int round=0; int Mx,My,timer=1500; static int sqrSize=31; int towers=0,towerSelected=-10; static int castleHealth=2000; String levelPath; //choose the level Easy Med or Hard int maxEnemy[] = {5,7,12,20,30,15,50,30,40,60};//number of enimies per round int maxTowers=15;//maximum number of towers allowed static int money =2000,damPrice=600,ranPrice=350,towerPrice=700; //money = the intial ammount of money you start of with //damPrice is the price to increase the damage of a tower //ranPrice is the price to increase the range of a tower public void main(int cH,int mT,int mo,int dP,int rP,int tP,String path,int[] mE)//constructor 1 castleHealth=cH; maxTowers=mT; money=mo; damPrice=dP; ranPrice=rP; towerPrice=tP; String levelPath=path; maxEnemy = mE; buildLevel(); } public void main(int cH,int mT,String path)//basic constructor castleHealth=cH; maxTowers=mT; String levelPath=path; maxEnemy = mE; buildLevel(); } public void init(){ setSize(sqrSize*15+200,sqrSize*15);//set the size of the screen roadCol = new Color(255,216,0);//set the colors for the different objects startCol = new Color(0,38,255); finCol = new Color(255,0,0); selRoad = new Color(242,204,155);//selColor is the color of something when your mouse hovers over it selGrass = new Color(0,190,0); roadpic = getImage(getDocumentBase(),"images/road.jpg"); towerpic = getImage(getDocumentBase(),"images/tower.png"); backpic = getImage(getDocumentBase(),"images/grass.jpg"); levelPic = getImage(getDocumentBase(),"images/level.jpg"); e= new Enemy[maxEnemy.length][];//activates all of the enimies for (int r=0;r<e.length;r++) e[r] = new Enemy[maxEnemy[r]]; t= new Tower[maxTowers]; for (int i=0;i<t.length;i++) t[i]= new Tower();//activates all the towers for (int i=0;i<e.length; i++)//sets all of the enimies starting co ordinates for (int j=0;j<e[i].length;j++) e[i][j] = new Enemy(eStartX,eStartY,world); initButtons();//initialise all the buttons addMouseMotionListener(this); addMouseListener(this); }

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  • Useful Extension Method for ICloneable

    - by DesigningCode
    In the past, I’ve had to put a type specific clone in each cloneable class, but with extension methods you can write a generic T specific clone class Program { static void Main(string[] args) { var b = new Blah() {X = 1, Y = 2}; var bb = b.Clone(); Console.WriteLine(string.Format("{0} {1}", bb.X, bb.Y)); } } public class Blah : ICloneable { public int X; public int Y; object ICloneable.Clone() { return MemberwiseClone(); } } public static class CloneExtension { public static T Clone<T>(this T o) where T : ICloneable { return (T)o.Clone(); } }

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  • Solving 2D Collision Detection Issues with Relative Velocities

    - by Jengerer
    Imagine you have a situation where two objects are moving parallel to one-another and are both within range to collide with a static wall, like this: A common method used in dynamic collision detection is to loop through all objects in arbitrary order, solve for pair-wise collision detection using relative velocities, and then move the object to the nearest collision, if any. However, in this case, if the red object is checked first against the blue one, it would see that the relative velocity to the blue object is -20 m/s (and would thereby not collide this time frame). Then it would see that the red object would collide with the static wall, and the solution would be: And the red object passes through the blue one. So it appears to be a matter of choosing the right order in which you check collisions; but how can you determine which order is correct? How can this passing through of objects be avoided? Is ignoring relative velocity and considering every object as static during pair-wise checks a better idea for this reason?

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  • A Basic Thread

    - by Joe Mayo
    Most of the programs written are single-threaded, meaning that they run on the main execution thread. For various reasons such as performance, scalability, and/or responsiveness additional threads can be useful. .NET has extensive threading support, from the basic threads introduced in v1.0 to the Task Parallel Library (TPL) introduced in v4.0. To get started with threads, it's helpful to begin with the basics; starting a Thread. Why Do I Care? The scenario I'll use for needing to use a thread is writing to a file.  Sometimes, writing to a file takes a while and you don't want your user interface to lock up until the file write is done. In other words, you want the application to be responsive to the user. How Would I Go About It? The solution is to launch a new thread that performs the file write, allowing the main thread to return to the user right away.  Whenever the file writing thread completes, it will let the user know.  In the meantime, the user is free to interact with the program for other tasks. The following examples demonstrate how to do this. Show Me the Code? The code we'll use to work with threads is in the System.Threading namespace, so you'll need the following using directive at the top of the file: using System.Threading; When you run code on a thread, the code is specified via a method.  Here's the code that will execute on the thread: private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written."); } The call to Thread.Sleep(1000) delays thread execution. The parameter is specified in milliseconds, and 1000 means that this will cause the program to sleep for approximately 1 second.  This method happens to be static, but that's just part of this example, which you'll see is launched from the static Main method.  A thread could be instance or static.  Notice that the method does not have parameters and does not have a return type. As you know, the way to refer to a method is via a delegate.  There is a delegate named ThreadStart in System.Threading that refers to a method without parameters or return type, shown below: ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); I'll show you the whole program below, but the ThreadStart instance above goes in the Main method. The thread uses the ThreadStart instance, fileWriterHandlerDelegate, to specify the method to execute on the thread: Thread fileWriter = new Thread(fileWriterHandlerDelegate); As shown above, the argument type for the Thread constructor is the ThreadStart delegate type. The fileWriterHandlerDelegate argument is an instance of the ThreadStart delegate type. This creates an instance of a thread and what code will execute, but the new thread instance, fileWriter, isn't running yet. You have to explicitly start it, like this: fileWriter.Start(); Now, the code in the WriteFile method is executing on a separate thread. Meanwhile, the main thread that started the fileWriter thread continues on it's own.  You have two threads running at the same time. Okay, I'm Starting to Get Glassy Eyed. How Does it All Fit Together? The example below is the whole program, pulling all the previous bits together. It's followed by its output and an explanation. using System; using System.Threading; namespace BasicThread { class Program { static void Main() { ThreadStart fileWriterHandlerDelegate = new ThreadStart(WriteFile); Thread fileWriter = new Thread(fileWriterHandlerDelegate); Console.WriteLine("Starting FileWriter"); fileWriter.Start(); Console.WriteLine("Called FileWriter"); Console.ReadKey(); } private static void WriteFile() { Thread.Sleep(1000); Console.WriteLine("File Written"); } } } And here's the output: Starting FileWriter Called FileWriter File Written So, Why are the Printouts Backwards? The output above corresponds to Console.Writeline statements in the program, with the second and third seemingly reversed. In a single-threaded program, "File Written" would print before "Called FileWriter". However, this is a multi-threaded (2 or more threads) program.  In multi-threading, you can't make any assumptions about when a given thread will run.  In this case, I added the Sleep statement to the WriteFile method to greatly increase the chances that the message from the main thread will print first. Without the Thread.Sleep, you could run this on a system with multiple cores and/or multiple processors and potentially get different results each time. Interesting Tangent but What Should I Get Out of All This? Going back to the main point, launching the WriteFile method on a separate thread made the program more responsive.  The file writing logic ran for a while, but the main thread returned to the user, as demonstrated by the print out of "Called FileWriter".  When the file write finished, it let the user know via another print statement. This was a very efficient use of CPU resources that made for a more pleasant user experience. Joe

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  • IsNullOrEmpty generic method for Array to avoid Re-Sharper warning

    - by Michael Freidgeim
    I’ve used the following extension method in many places. public static bool IsNullOrEmpty(this Object[] myArr) { return (myArr == null || myArr.Length == 0); }Recently I’ve noticed that Resharper shows warning covariant array conversion to object[] may cause an exception for the following codeObjectsOfMyClass.IsNullOrEmpty()I’ve resolved the issue by creating generic extension method public static bool IsNullOrEmpty<T>(this T[] myArr) { return (myArr == null || myArr.Length == 0); }Related linkshttp://connect.microsoft.com/VisualStudio/feedback/details/94089/add-isnullorempty-to-array-class    public static bool IsNullOrEmpty(this System.Collections.IEnumerable source)        {            if (source == null)                return true;            else            {                return !source.GetEnumerator().MoveNext();            }        }http://stackoverflow.com/questions/8560106/isnullorempty-equivalent-for-array-c-sharp

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  • /etc/network/interfaces doesn't always take affect

    - by user1221444
    For some reason my eth0 does not have internet on reboot sometimes. I am using a static ip. I can ping my gateway, but I am unable to ping dns servers, or anything out of my network. It seems that when my internet does work(Usually but just restarting enough times), my /etc/resolv.conf has a nameserver in it. It is empty when I have no internet access. I believe something is overwriting my interfaces settings sometimes on boot. Any help would be appreciated. I am running Ubuntu Server 12.04 64bit /etc/network/interfaces: auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 173.213.192.234 netmask 255.255.255.248 network 173.213.192.232 broadcast 173.213.192.239 gateway 173.213.192.233 dns-nameservers 8.8.8.8 auto eth1 iface eth1 inet static address 10.0.0.106 netmask 255.255.255.0 gateway 10.0.0.1

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  • Hosting a website from a dynamic IP

    - by nick
    I recently upgraded my internet to the point that it is much faster and more reliable than my current webhost. I would like to move my current domain to be hosted at home, but my IP address is dynamic. As far as I know, I only get a new IP when I restart my modem and or router (which is almost never) or when cable one (my ISP) pushes out a firmware update (rarely). There are a few ways I can see doing this 1) convince my ISP to give me a static IP 2) assign my router my current IP to force a static IP (which might work?) 3) set my dns record to my current IP address and update it on the rare occasions that it changes. Obviously I'm hoping that the first one works, but I don't want to pay a lot of extra money (if that's what it takes) to get a static IP address. Has anyone had any luck with something like that?

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