Search Results

Search found 37004 results on 1481 pages for 'public static'.

Page 513/1481 | < Previous Page | 509 510 511 512 513 514 515 516 517 518 519 520  | Next Page >

• Why is Apache seg faulting?

  - by Jamie Howard

  We have a production server that seems to Seg Fault a few times every day. The fault is picked up by Apache and logged in the error log - but there seems to be no traffic around the time. If it's a request generating the fault then it looks like it happens before any other logging is made so I can't see how it's happening so it's very hard to debug. Our setup is Linux 64 bit Centos 5.3 Apache is loaded with the following modules apachectl -t -D DUMP_MODULES | more Loaded Modules: core_module (static) mpm_prefork_module (static) http_module (static) so_module (static) auth_basic_module (shared) auth_digest_module (shared) authn_file_module (shared) authn_alias_module (shared) authn_anon_module (shared) authn_dbm_module (shared) authn_default_module (shared) authz_host_module (shared) authz_user_module (shared) authz_owner_module (shared) authz_groupfile_module (shared) authz_dbm_module (shared) authz_default_module (shared) ldap_module (shared) authnz_ldap_module (shared) include_module (shared) log_config_module (shared) logio_module (shared) env_module (shared) ext_filter_module (shared) mime_magic_module (shared) expires_module (shared) deflate_module (shared) headers_module (shared) usertrack_module (shared) setenvif_module (shared) mime_module (shared) dav_module (shared) status_module (shared) autoindex_module (shared) info_module (shared) dav_fs_module (shared) vhost_alias_module (shared) negotiation_module (shared) dir_module (shared) actions_module (shared) speling_module (shared) userdir_module (shared) alias_module (shared) rewrite_module (shared) proxy_module (shared) proxy_balancer_module (shared) proxy_ftp_module (shared) proxy_http_module (shared) proxy_connect_module (shared) cache_module (shared) suexec_module (shared) disk_cache_module (shared) file_cache_module (shared) mem_cache_module (shared) cgi_module (shared) version_module (shared) security2_module (shared) unique_id_module (shared) fcgid_module (shared) php5_module (shared) proxy_ajp_module (shared) ssl_module (shared) Here's an exert from the Apache error log: [Mon Mar 15 06:39:25 2010] [error] [client 213.246.222.74] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 07:41:31 2010] [error] [client 213.246.222.74] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 08:24:16 2010] [error] [client 67.19.250.146] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 08:43:46 2010] [error] [client 213.246.222.74] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 08:54:02 2010] [error] [client 74.208.123.71] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 09:09:51 2010] [notice] child pid 2138 exit signal Segmentation fault (11), possible coredump in /tmp [Mon Mar 15 09:45:27 2010] [error] [client 213.246.222.74] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:) [Mon Mar 15 09:49:05 2010] [error] [client 190.12.113.196] File does not exist: /var/www/vhosts/default/htdocs/phpMyAdmin [Mon Mar 15 09:49:06 2010] [error] [client 190.12.113.196] File does not exist: /var/www/vhosts/default/htdocs/PMA And the Access log around the same time (09:09:51): 213.246.222.74 - - [15/Mar/2010:08:43:46 +0000] "GET /" 400 561 "-" "-" 208.80.193.28 - - [15/Mar/2010:08:52:20 +0000] "GET / HTTP/1.0" 301 313 "-" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; SU 2.009)" 74.208.123.71 - - [15/Mar/2010:08:54:02 +0000] "GET /w00tw00t.at.ISC.SANS.DFind:) HTTP/1.1" 400 298 "-" "-" 81.149.146.231 - - [15/Mar/2010:09:15:18 +0000] "GET /zabbix/ HTTP/1.1" 200 3565 "-" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_2; en-us) AppleWebKit/531.21.8 (KHTML, like Gecko) Version/4.0.4 Safari/531.21.10" 81.158.71.196 - - [15/Mar/2010:09:16:06 +0000] "GET / HTTP/1.1" 301 313 "-" "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9.0.18) Gecko/2010020219 Firefox/3.0.18" 213.246.222.74 - - [15/Mar/2010:09:45:27 +0000] "GET /" 400 561 "-" "-" 213.246.222.74 - - [15/Mar/2010:09:45:27 +0000] "GET /w00tw00t.at.ISC.SANS.DFind:) HTTP/1.1" 400 298 "-" "-" 190.12.113.196 - - [15/Mar/2010:09:49:05 +0000] "GET /phpMyAdmin/main.php HTTP/1.0" 404 295 "-" "-" So As you can see, there's no access logged around the time of the fault!! How annoying :s I enabled core dumps and here is the backtrace: #0 0x00007f9c8c8a858b in memcpy () from /lib64/libc.so.6 No symbol table info available. #1 0x00007f9c8cfb066d in apr_pstrcat (a=<value optimized out>) at strings/apr_strings.c:165 cp = 0x1fa6b "\205¦H\211¦t`¦\003" argp = 0x7f9c9ad790e8 "Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Referer, Re"... res = 0x0 saved_lengths = {129643, 2, 43, 140310399395576, 0, 140310394592712} nargs = <value optimized out> len = <value optimized out> adummy = {{gp_offset = 16, fp_offset = 32668, overflow_arg_area = 0x7fff968a0ec0, reg_save_area = 0x7fff968a0de0}} #2 0x00007f9c8cfb1bf9 in apr_table_merge (t=0x7f9c8f83b148, key=0x7f9c85a465fe "Vary", val=0x7f9c9ad99070 "Referer, Referer, Referer, Referer, Referer") at tables/apr_tables.c:688 next_elt = (apr_table_entry_t *) 0x7f9c8f83b270 end_elt = (apr_table_entry_t *) 0x7f9c8f83b270 checksum = <value optimized out> hash = 22 #3 0x00007f9c85a42cfa in ?? () from /etc/httpd/modules/mod_rewrite.so No symbol table info available. #4 0x00007f9c85a44022 in ?? () from /etc/httpd/modules/mod_rewrite.so No symbol table info available. #5 0x00007f9c8e87bd1a in ap_run_fixups () from /usr/sbin/httpd No symbol table info available. #6 0x00007f9c8e88e8f8 in ap_process_request () from /usr/sbin/httpd No symbol table info available. #7 0x00007f9c8e88bb40 in ?? () from /usr/sbin/httpd No symbol table info available. #8 0x00007f9c8e887ca2 in ap_run_process_connection () from /usr/sbin/httpd No symbol table info available. #9 0x00007f9c8e892849 in ?? () from /usr/sbin/httpd No symbol table info available. #10 0x00007f9c8e892ada in ?? () from /usr/sbin/httpd No symbol table info available. #11 0x00007f9c8e892b90 in ?? () from /usr/sbin/httpd No symbol table info available. #12 0x00007f9c8e89387b in ap_mpm_run () from /usr/sbin/httpd No symbol table info available. #13 0x00007f9c8e86de48 in main () from /usr/sbin/httpd No symbol table info available. Can anyone shed any light on how to move forward with this? I can confirm that the server is operational and doesn't appear to be misbehaving - the failures are so infrequent that I haven't seen it do one while making a request myself. Really appreciate any help! Cheers!

  Read the article

• WPF customer control and direct content support

  - by Mmarquee

  I am fairly new to WPF, and am a bit stuck, so any help would be appreciated. I am trying to write WPF custom control that encapsulates several elements of functionality that I already having working (i.e sorting, filtering, standard menus, etc.), but in a nice neat package to avoid repetition. Anyway I have created the custom control (based on control), and then have the following in the Generic.Xaml <ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:Controls.ListViewExtended"> <Style TargetType="{x:Type local:ListViewExtended}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type local:ListViewExtended}"> <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"> <ListView> <ListView.View> <GridView> <!-- Content goes here --> </GridView> </ListView.View> </ListView> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary> When I try to add GridViewColumns (or any control really), as below ... <elv:ListViewExtended> <GridView> <GridViewColumn Width="140" Header="Column 1" /> <GridViewColumn Width="140" Header="Column 2" /> <GridViewColumn Width="140" Header="Column 3" /> </GridView> </elv:ListViewExtended> I get the "... does not support direct content" error. I have created a dependancy property (again below) that allows the adding of GridView, but it still doesn't work. public static DependencyProperty GridViewProperty; public static string GridViewHeader(DependencyObject target) { return (string)target.GetValue(GridViewProperty); } public static void GridViewHeader(DependencyObject target, string value) { target.SetValue(GridViewProperty, value); } Thanks in advance

  Read the article

• UltiDev Cassini and <system.webServer> web.config settings

  - by Robert Koritnik

  MS Cassini Development Web Server is a nice product that executes web requests in a similar way that IIS7 does. Every request (event for static content) goes through the same .Net pipeline without exception. All custom HttpModule can handle any request. But sometimes you don't want these modules to execute for certain content (most often static content). In this regard, MS Cassini doesn't read/obey <system.webServer> web.config settings like IIS7 does. I'm particularly interested in these settings. <system.webServer> ... <handlers /> <modules /> </syste.webServer> Does UltiDev's Cassini (a separate payable product upgraded from MS Cassini) web server read these settings and execute as the web.config tells it to?

  Read the article

• Bound Command not firing on another viewModel? What Am I doing wrong?

  - by devnet247

  Hi I cannot seem to bind a command to a button.I have a treeview on the left showing Country City etc.. And I tabcontrol on the right. do I This uses 4 viewModels rootviewModel-ContinentViewModel-CountryViewModel-CityViewModel What I am building is based on http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx Now on one of the tabs I have a Toolbar with a button "TestButton" that I have mapped in zaml. This does not fire! The reason is not firing is because I m binding the RootViewModel but the command that is bound in zaml is in the cityViewModel. How Do I pass the datacontext from one view to the other? or how do I make the button fire. I need the command to be in the cityViewModel. Any Suggestions on how I bind it? View "WorldExplorerView" where I bind the main DataContext public partial class WorldExplorerView { public WorldExplorerView() { InitializeComponent(); var continents = Database.GetContinents(); var rootViewModel = new RootViewModel(continents); DataContext = rootViewModel; } } CityViewModel public class CityViewModel : TreeViewItemViewModel { private City _city; private RelayCommand _testCommand; public CityViewModel(City city, CountryViewModel countryViewModel):base(countryViewModel,false) { _city = city; } Properties etc...... public ICommand TestCommand { get { if(_testCommand==null) { _testCommand = new RelayCommand(param => GetTestCommand(), param => CanCallTestCommand); ; } return _testCommand; } } protected bool CanCallTestCommand { get { return true; } } private static void GetTestCommand() { MessageBox.Show("It works"); } } ZAML <DockPanel> <DockPanel LastChildFill="True"> <Label DockPanel.Dock="top" Content="Title " HorizontalAlignment="Center"></Label> <StatusBar DockPanel.Dock="Bottom"> <StatusBarItem Content="Status Bar" ></StatusBarItem> </StatusBar> <Grid DockPanel.Dock="Top"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="2*"/> </Grid.ColumnDefinitions> <TreeView Name="tree" ItemsSource="{Binding Continents}"> <TreeView.ItemContainerStyle> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsExpanded" Value="{Binding IsExpanded,Mode=TwoWay}"/> <Setter Property="IsSelected" Value="{Binding IsSelected,Mode=TwoWay}"/> <Setter Property="FontWeight" Value="Normal"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="FontWeight" Value="Bold"></Setter> </Trigger> </Style.Triggers> </Style> </TreeView.ItemContainerStyle> <TreeView.Resources> <HierarchicalDataTemplate DataType="{x:Type ViewModels:ContinentViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Continent.png"/> <TextBlock Text="{Binding ContinentName}"/> </StackPanel> </HierarchicalDataTemplate> <HierarchicalDataTemplate DataType="{x:Type ViewModels:CountryViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Country.png"/> <TextBlock Text="{Binding CountryName}"/> </StackPanel> </HierarchicalDataTemplate> <DataTemplate DataType="{x:Type ViewModels:CityViewModel}" > <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\City.png"/> <TextBlock Text="{Binding CityName}"/> </StackPanel> </DataTemplate> </TreeView.Resources> </TreeView> <GridSplitter Grid.Row="0" Grid.Column="1" Background="LightGray" Width="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/> <Grid Grid.Column="2" Margin="5" > <TabControl> <TabItem Header="Demo"> <DockPanel LastChildFill="True"> <ToolBar DockPanel.Dock="Top"> <!-- DOES NOT WORK--> <Button Name="btnTest" Command="{Binding TestCommand}" Content="Press me see if works"></Button> </ToolBar> <TextBox></TextBox> </DockPanel> </TabItem> <TabItem Header="Details" DataContext="{Binding Path=SelectedItem.City, ElementName=tree, Mode=OneWay}"> <StackPanel > <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityName}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Area}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Population}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.ClubsCount}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.PubsCount}"/> </StackPanel> </TabItem> </TabControl> </Grid> </Grid> </DockPanel> </DockPanel>

  Read the article

• Correct way to edit and update complex viewmodel objects using asp.net-mvc2 and entity framework

  - by jslatts

  I have a table in my database with a one to many relationship to another table: ParentObject ID Name Description ChildObject ID Name Description ParentObjectID AnotherObjectID The objects are mapped into Entity Framework and exposed through a data access class. It seemed like ViewModels are recommended when the data to be displayed greatly differs from the domain object, so I created a ViewModel as follows: public class ViewModel { public IList<ParentObject> ParentObjects { get; set; } public ParentObject selectedObject { get; set; } public IList<ChildObject> ChildObjects { get; set; } } I have a view that displays a list of ParentObjects and when clicked will allow a ChildObject to be modified saved. <% using (Html.BeginForm()) { %> <table> <% foreach (var parent in Model.ParentObjects) { %> <tr> <td> ObjectID [<%= Html.Encode(parent.ID)%>] </td> <td> <%= Html.Encode(parent.Name)%> </td> <td> <%= Html.Encode(parent.Description)%> </td> </tr> <% } %> </table> <% if (Model.ParentObject != null) { %> <div> Name:<br /> <%= Html.TextBoxFor(model => model.ParentObject.Name) %> <%= Html.ValidationMessageFor(model => model.ParentObject.Name, "*")%> </div> <div> Description:<br /> <%= Html.TextBoxFor(model => model.ParentObject.Description) %> <%= Html.ValidationMessageFor(model => model.ParentObject.Description, "*")%> </div> <div> Child Objects </div> <% for (int i = 0; i < Model.ParentObject.ChildObjects.Count(); i++) { %> <div> <%= Html.DisplayTextFor(sd => sd.ChildObjects[i].Name) %> </div> <div> <%= Html.HiddenFor(sd => sd.ChildObjects[i].ID )%> <%= Html.TextBoxFor( sd => sd.ChildObjects[i].Description) %> <%= Html.ValidationMessageFor(sd => sd.ChildObjects[i].Description, "*") %> </div> <% } } } %> This all works fine. My question is around the best way to update the EF objects and persist the changes back to the database. I initially tried: [HttpPost] public ActionResult Edit(ViewModel viewModel) { ParentObject parent = myRepository.GetParentObjectByID(viewModel.SelectedObject.ID); if ((!ModelState.IsValid) || !TryUpdateModel(parent, "SelectedObject", new[] { "Name", "Description" })) { || !TryUpdateModel(parent.ChildObjects, "ChildObjects", new[] { "Name", "Description" })) { //Code to handle failure and return the current model snipped return View(viewModel); } myRepository.Save(); return RedirectToAction("Edit"); } When I try to save a change to the child object, I get this exception: Entities in 'MyEntities.ChildObject' participate in the 'FK_ChildObject_AnotherObject' relationship. 0 related 'AnotherObject' were found. 1 'AnotherObject' is expected. Investigation on StackOverflow and generally googling led me to this blog post that seems to describe my problem: TryUpdateModel() does not correctly handle nested collections. Apparently, (and stepping through the debugger confirms this) it creates a new ChildObject instead of associating with the EF objects from my instantiated context. My hacky work around is this: if (viewModel.ChildObjects.Count > 0) { foreach (ChildObject modelChildObject in viewModel.ChildObjects) { ChildObject childToUpdate = ParentObject.ChildObject.Where(a => a.ID == modelChildObject.ID).First(); childToUpdate.Name = modelChildObject.Name; } } This seems to work fine. My question to you good folks: Is there correct way to do this? I tried following the suggestion for making a custom model binder per the blog link I posted above but it didn't work (there was an issue with reflection) and I needed to get something going ASAP. PS - I tried to cleanup the code to hide specific information, so beware I may have hosed something up. I mainly just want to know if other people have solved this problem. Thanks!

  Read the article

• Spring ROO issue with UrlRewrite in STS (eclipse)

  - by user224270

  Hi. I'm having trouble figuring out how to solve this issue. I have a file called: "urlrewrite.xml" which was automatically generated by spring ROO after running the "controller" command in ROO Shell. However, I still get the following error: "Referenced file contains errors (http://tuckey.org/res/dtds/urlrewrite3.0.dtd). For more information, right click on the message in the Problems View and select "Show Details..." Here's the content of the urlrewrite.xml file: <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 3.0//EN" "http://tuckey.org/res/dtds/urlrewrite3.0.dtd"> <urlrewrite default-match-type="wildcard"> <rule> <from>/resources/**</from> <to last="true">/resources/$1</to> </rule> <rule> <from>/static/WEB-INF/**</from> <set type="status">403</set> <to last="true">/static/WEB-INF/$1</to> </rule> <rule> <from>/static/**</from> <to last="true">/$1</to> </rule> <rule> <from>/</from> <to last="true">/app/index</to> </rule> <rule> <from>/app/**</from> <to last="true">/app/$1</to> </rule> <rule> <from>/**</from> <to>/app/$1</to> </rule> <outbound-rule> <from>/app/**</from> <to>/$1</to> </outbound-rule> </urlrewrite> Any thoughts on how to get rid of this error?

  Read the article

• Custom HTML Helpers in ASP.NET MVC 2

  - by Interfector

  Hi, I want to create a pagination helper. The only parameters that it needs are currentpage, pagecount and routename. However, I do not know if it is possible to use the return value of another html helper inside the definition of my html helper. I am referring specifically to Html.RouteLink. How can I go about doing something like this in the class definition using System; using System.Web.Mvc; namespace MvcApplication1.Helpers { public static class LabelExtensions { public static string Label(this HtmlHelper helper, string routeName, int currentpage, int totalPages) { string html = ""; //Stuff I add to html //I'd like to generate a similar result as the helper bellow html .= Html.RouteLink( pageNo, routeName, new { page = pageNo - 1 } ); //Other stuff I do the html return html; } } } Thank you.

  Read the article

• why this sql not working?

  - by user295189

  I have a query public static function TestQuery( $start=0, $limit=0){ $sql = " SELECT count(*) AS total FROM db.table1 JOIN db.table2 ON table1.fieldID = {$fieldID} AND table2.assigned = 'N'"; $qry = new SQLQuery; $qry-query($sql); if($row = $qry-fetchRow()){ $total = intval($row-total); } return $total; } which works fine but when I add the limit as below, then it doesnt work and gives me errors public static function TestQuery( $start=0, $limit=0){ $sql = " SELECT count(*) AS total FROM db.table1 JOIN db.table2 ON table1.fieldID = {$fieldID} AND table2.assigned = 'N'"; //this fails if($recordlimit 0) $sql .= "LIMIT {$startRecord}, {$recordLimit} "; // $qry = new SQLQuery; $qry-query($sql); if($row = $qry-fetchRow()){ $total = intval($row-total); } return $total; } Any help will be appreciated

  Read the article

• WPF Using commands to slow to update UI controls

  - by toni

  Hi, I bind a command to a button through command property and doing a command binding in the page it is placed. In execute method I create an instance of a class that contains the background worker and I start it (this is a long task). The background worker (bw) class contains a variable isRunning that it is set to true before DoWork method is executed and to false when RunWorkerCompleted is executed. So from the code behind of the page where button is placed, in CanExecute method I set e.canExecute to true if bw is no running (isRunning = false), and e.canExecute to false if isRunning = true. WHen I press the button, it launch bw process for a long time and the button gets disabled. Ok this is correct, but when background worker (bw) finishes, the button doesn't returns to enabled until I press it again. When it is disabled and I press (when bw is finished) it gets enabled. Why the button is not returning automatically to enabled at the end of the bw? my code snippet: <Page x:Class="GParts.Pages.MyPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes; assembly=PresentationFramework.Aero" xmlns:local="clr-namespace:GParts" Loaded="Page_Loaded" Unloaded="Page_Unloaded" Height="Auto"> <Page.CommandBindings> <CommandBinding Command="{x:Static local:Pages.MyPage.rcmd}" Executed="CommandBinding_Executed" CanExecute="CommandBinding_CanExecute"/> </Page.CommandBindings> <...> <Button Command="{x:Static local:Pages.MyPage.rcmd}" /> <...> </Page> The code behind of the page: namespace GParts.Pages { public partial class MyPage : Page { public static RoutedCommand rcmd = new RoutedCommand(); private cBgWorker bw; <...> // ExecutedRoutedEventHandler for the custom button remove all command. private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e) { // get an isntance of the background worker class bw = new cBgWorker(); // start the long task bw.StartTask(); } // CanExecuteRoutedEventHandler for the custom button remove all command. private void CommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e) { // bw is the instance of background worker class if (bw == null) { e.CanExecute = true; } else { e.CanExecute = !bw.isRunning;// isRunning indicates if bw is //executing now } } <...> } // end class } // end namespace

  Read the article

• Having template function defination in cpp file - Not work for VC6

  - by Yan Cheng CHEOK

  I have the following source code : // main.cpp #include "a.h" int main() { A::push(100); } // a.cpp #include "a.h" template <class T> void A::push(T t) { } template void A::push(int t); // a.h #ifndef A_H class A { public: template <class T> static void push(T t); }; #endif The code compiled charming and no problem under VC2008. But when come to my beloved VC6, it give me error : main.obj : error LNK2001: unresolved external symbol "public: static void __cdecl A::push(int)" (?push@A@@SAXH@Z) Any workaround? I just want to ensure my function definition is re-inside cpp file.

  Read the article

• Will client side performance improve if images/scripts/styles on different subdomains?

  - by Andrey

  Hi, I have a domain specifically for static content, so cookies don't travel along with requests to images/scripts/css. Now, I think I've read somewhere that most browsers only open one download thread for each domain/subdomain, so different static content can't be downloaded in parallel if on the same domain. Will it make difference for browsers if i place scripts in script.mycdn.com, styles in css.mycdn.com and images in images.mycdn.com? Will it allow to let browser download images at the same time as scripts and styles? mycdn.com is of course a made up name :) Thanks! Andrey

  Read the article

• Some instruction needed for PHP OOPS concepts.

  - by Avinash

  Hi, I need to clear some OOPS concepts in PHP. 1) Which is faster $this-method(); or self:method(); 2) I know the concept of static keyword but can you please post the actual Use of it. Since it can not be accessed by the instance, but is there ant benefit for that? 3) what is factory? How can i use it? 4) What is singleton? How can i use that? 5) What is late static binding? http://www.php.net/manual/en/oop5.intro.php I have gone through below link but I am not getting clear with it. Thanks Avinash

  Read the article

• Getting pixel data from an image using java.

  - by Matt

  I'm trying to get the pixel rgb values from a 64 x 48 bit image. I get some values but nowhere near the 3072 (= 64 x 48) values that I'm expecting. I also get: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Coordinate out of bounds! at sun.awt.image.ByteInterleavedRaster.getDataElements(ByteInterleavedRaster.java:301) at java.awt.image.BufferedImage.getRGB(BufferedImage.java:871) at imagetesting.Main.getPixelData(Main.java:45) at imagetesting.Main.main(Main.java:27) I can't find the out of bounds error... Here's the code: package imagetesting; import java.io.IOException; import javax.imageio.ImageIO; import java.io.File; import java.awt.image.BufferedImage; public class Main { public static final String IMG = "matty.jpg"; public static void main(String[] args) { BufferedImage img; try { img = ImageIO.read(new File(IMG)); int[][] pixelData = new int[img.getHeight() * img.getWidth()][3]; int[] rgb; int counter = 0; for(int i = 0; i < img.getHeight(); i++){ for(int j = 0; j < img.getWidth(); j++){ rgb = getPixelData(img, i, j); for(int k = 0; k < rgb.length; k++){ pixelData[counter][k] = rgb[k]; } counter++; } } } catch (IOException e) { e.printStackTrace(); } } private static int[] getPixelData(BufferedImage img, int x, int y) { int argb = img.getRGB(x, y); int rgb[] = new int[] { (argb >> 16) & 0xff, //red (argb >> 8) & 0xff, //green (argb ) & 0xff //blue }; System.out.println("rgb: " + rgb[0] + " " + rgb[1] + " " + rgb[2]); return rgb; } }

  Read the article

• Get Specific part of a String in Javascript

  - by streetparade

  I have a string containing something like this "Hello bla bla bla bla ok, once more bla können. // this is static: it doesn't change This is a text, this also a text. // this is dynamically added text it can change each time My name mysurename // this is also static text www.blabla.com " Now I have content and I have to get the first part of the string and the third part, I want to be able to have 3 parts, I think I have to split it using something like split(); string1 = "Hello bla bla bla bla ok, once more bla können.; string2 = ""; // i have this part string3 ="My name mysurename"; If it helps the first part ends with "können. " and the third part ends with the url above // its a fictional URL

  Read the article

• Generic collection as a Java method argument

  - by Guido

  Is there any way to make this work in Java? public static void change(List<? extends Object> list, int position1, int position2) { Object obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); } The only way I've successfully avoided warnings and errors is this: public static <T> T change(List<T> list, int position1, int position2) { T obj = list.get(position1); list.set(position1, list.get(position2)); list.set(position2, obj); return obj; } but I don't like to be forced to return a value.

  Read the article

• Strange WPF ListBox Behavior

  - by uncle-harvey

  I’m trying to bind a List of items to a listbox in WPF. The items are grouped by one value and each group is to be housed in an expander. Everything works fine when I don’t use any custom styles. However, when I use custom styles (which work properly with non-grouped items and as independent controls) the binding doesn’t display any items. Below is the code I’m executing. Any ideas why the items won’t show up in the Expander? Test.xaml: <Window x:Class="Glossy.Test" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Test" Height="300" Width="300"> <Window.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="..\TestStyles.xaml"/> <ResourceDictionary> <Style x:Key="ContainerStyle" TargetType="{x:Type GroupItem}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate> <Expander Header="{Binding}" IsExpanded="True"> <ItemsPresenter /> </Expander> </ControlTemplate> </Setter.Value> </Setter> </Style> </ResourceDictionary> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Window.Resources> <Grid> <ListBox x:Name="TestList"> <ListBox.GroupStyle> <GroupStyle ContainerStyle="{StaticResource ContainerStyle}"/> </ListBox.GroupStyle> </ListBox> </Grid> Test.xaml.cs: public partial class Test : Window { private List<Contact> _ContactItems; public List<Contact> ContactItems { get { return _ContactItems; } set { _ContactItems = value; } } public Test() { InitializeComponent(); ContactItems = new List<Contact>(); ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 1"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 2"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 3"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 10"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 11"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "ABC"; ContactItems.Last().Name = "Contact 12"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "RST"; ContactItems.Last().Name = "Contact 7"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "RST"; ContactItems.Last().Name = "Contact 8"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "RST"; ContactItems.Last().Name = "Contact 9"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "XYZ"; ContactItems.Last().Name = "Contact 4"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "XYZ"; ContactItems.Last().Name = "Contact 5"; ContactItems.Add(new Contact()); ContactItems.Last().CompanyName = "XYZ"; ContactItems.Last().Name = "Contact 6"; ICollectionView view = CollectionViewSource.GetDefaultView(ContactItems); view.GroupDescriptions.Add(new PropertyGroupDescription("CompanyName")); view.SortDescriptions.Add(new SortDescription("Name", ListSortDirection.Ascending)); TestList.ItemsSource = view; } } public class Contact { public string CompanyName { get; set; } public string Name { get; set; } public override string ToString() { return Name; } } TestStyles.xaml: <Style TargetType="{x:Type ListBox}"> <Setter Property="SnapsToDevicePixels" Value="true"/> <Setter Property="OverridesDefaultStyle" Value="true"/> <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/> <Setter Property="ScrollViewer.CanContentScroll" Value="true"/> <Setter Property="MinWidth" Value="120"/> <Setter Property="MinHeight" Value="95"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ListBox"> <Grid Background="Black"> <Rectangle VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Fill="White"> <Rectangle.OpacityMask> <DrawingBrush> <DrawingBrush.Drawing> <GeometryDrawing Geometry="M65.5,33 L537.5,35 537.5,274.5 C536.5,81 119.5,177 66.5,92" Brush="#11444444"> <GeometryDrawing.Pen> <Pen Brush="Transparent"/> </GeometryDrawing.Pen> </GeometryDrawing> </DrawingBrush.Drawing> </DrawingBrush> </Rectangle.OpacityMask> </Rectangle> <Border Name="Border" Background="Transparent" BorderBrush="Gray" BorderThickness="1" CornerRadius="2"> <ScrollViewer Margin="0" Focusable="false"> <StackPanel Margin="2" IsItemsHost="True" /> </ScrollViewer> </Border> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsEnabled" Value="false"> <Setter TargetName="Border" Property="Background" Value="Gray" /> <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> </Trigger> <Trigger Property="IsGrouping" Value="true"> <Setter Property="ScrollViewer.CanContentScroll" Value="false"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> <Style TargetType="{x:Type ListBoxItem}"> <Setter Property="SnapsToDevicePixels" Value="true"/> <Setter Property="OverridesDefaultStyle" Value="true"/> <Setter Property="Foreground" Value="Gray"/> <Setter Property="Background" Value="Transparent"/> <Setter Property="FontFamily" Value="Verdana"/> <Setter Property="HorizontalAlignment" Value="Stretch"/> <Setter Property="FontSize" Value="11"/> <Setter Property="Margin" Value="3,1,3,1"/> <Setter Property="Padding" Value="0"/> <Setter Property="FontWeight" Value="Normal"/> <Setter Property="VerticalAlignment" Value="Center"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ListBoxItem"> <Border Name="Border" Padding="2" SnapsToDevicePixels="true"> <ContentPresenter /> </Border> <ControlTemplate.Triggers> <Trigger Property="IsSelected" Value="true"> <Setter TargetName="Border" Property="Background" Value="Gray"/> </Trigger> <Trigger Property="IsEnabled" Value="false"> <Setter Property="Foreground" Value="White"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> <ControlTemplate x:Key="ExpanderToggleButton" TargetType="ToggleButton"> <Border Name="Border" CornerRadius="2,0,0,0" Background="Transparent" BorderBrush="LightGray" BorderThickness="0,0,1,0"> <Path Name="Arrow" Fill="Blue" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 4 4 L 8 0 Z"/> </Border> <ControlTemplate.Triggers> <Trigger Property="ToggleButton.IsMouseOver" Value="True"> <Setter TargetName="Border" Property="Background" Value="Gray" /> </Trigger> <Trigger Property="IsPressed" Value="True"> <Setter TargetName="Border" Property="Background" Value="Black" /> </Trigger> <Trigger Property="IsChecked" Value="True"> <Setter TargetName="Arrow" Property="Data" Value="M 0 4 L 4 0 L 8 4 Z" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Border" Property="Background" Value="DimGray" /> <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> <Setter Property="Foreground" Value="LightGray"/> <Setter TargetName="Arrow" Property="Fill" Value="LightBlue" /> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> <Style TargetType="{x:Type Expander}"> <Setter Property="Foreground" Value="White"/> <Setter Property="FontFamily" Value="Verdana"/> <Setter Property="FontSize" Value="11"/> <Setter Property="FontWeight" Value="Normal"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="Expander"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Name="ContentRow" Height="0"/> </Grid.RowDefinitions> <Border Name="Border" Grid.Row="0" Background="Black" BorderBrush="DimGray" BorderThickness="1" Cursor="Hand" CornerRadius="2,2,0,0" > <Grid HorizontalAlignment="Left"> <Grid.RowDefinitions> <RowDefinition Height="23"/> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="20" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <ToggleButton IsChecked="{Binding Path=IsExpanded,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource ExpanderToggleButton}" Background="Black" /> <Label Grid.Column="1" FontSize="14" FontWeight="Normal" Margin="0" VerticalAlignment="Top" Foreground="White" FontFamily="Verdana"> <ContentPresenter Grid.Column="1" Margin="4,3,0,0" HorizontalAlignment="Left" ContentSource="Header" RecognizesAccessKey="True" /> </Label> </Grid> </Border> <Border Name="Content" Background="Black" BorderBrush="DimGray" BorderThickness="1,0,1,1" Grid.Row="1" CornerRadius="0,0,2,2" > <Grid Background="Black"> <Rectangle VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Fill="White"> <Rectangle.OpacityMask> <DrawingBrush> <DrawingBrush.Drawing> <GeometryDrawing Geometry="M65.5,33 L537.5,35 537.5,274.5 C536.5,81 119.5,177 66.5,92" Brush="#11444444"> <GeometryDrawing.Pen> <Pen Brush="Transparent"/> </GeometryDrawing.Pen> </GeometryDrawing> </DrawingBrush.Drawing> </DrawingBrush> </Rectangle.OpacityMask> </Rectangle> <ContentPresenter Margin="4" /> </Grid> </Border> </Grid> <ControlTemplate.Triggers> <Trigger Property="IsExpanded" Value="True"> <Setter TargetName="ContentRow" Property="Height" Value="{Binding ElementName=Content,Path=DesiredHeight}" /> </Trigger> <Trigger Property="IsEnabled" Value="False"> <Setter TargetName="Border" Property="Background" Value="Gray" /> <Setter TargetName="Border" Property="BorderBrush" Value="DimGray" /> <Setter Property="Foreground" Value="White"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style>

  Read the article

• Challenge: Neater way of currying or partially applying C#4's string.Join

  - by Damian Powell

  Background I recently read that .NET 4's System.String class has a new overload of the Join method. This new overload takes a separator, and an IEnumerable<T> which allows arbitrary collections to be joined into a single string without the need to convert to an intermediate string array. Cool! That means I can now do this: var evenNums = Enumerable.Range(1, 100) .Where(i => i%2 == 0); var list = string.Join(",",evenNums); ...instead of this: var evenNums = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .Select(i => i.ToString()) .ToArray(); var list = string.Join(",", evenNums); ...thus saving on a conversion of every item to a string, and then the allocation of an array. The Problem However, being a fan of the functional style of programming in general, and method chaining in C# in particular, I would prefer to be able to write something like this: var list = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .string.Join(","); This is not legal C# though. The closest I've managed to get is this: var list = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .ApplyTo( Functional.Curry<string, IEnumerable<object>, string> (string.Join)(",") ); ...using the following extension methods: public static class Functional { public static TRslt ApplyTo<TArg, TRslt>(this TArg arg, Func<TArg, TRslt> func) { return func(arg); } public static Func<T1, Func<T2, TResult>> Curry<T1, T2, TResult>(this Func<T1, T2, TResult> func) { Func<Func<T1, T2, TResult>, Func<T1, Func<T2, TResult>>> curried = f => x => y => f(x, y); return curried(func); } } This is quite verbose, requires explicit definition of the parameters and return type of the string.Join overload I want to use, and relies upon C#4's variance features because we are defining one of the arguments as IEnumerable rather than IEnumerable. The Challenge Can you find a neater way of achieving this using the method-chaining style of programming?

  Read the article

• Winforms connection strings from App.config

  - by Geo Ego

  I have a Winforms app that I am developing in C# that will serve as a frontend for a SQL Server 2005 database. I rolled the executable out to a test machine and ran it. It worked perfectly fine on the test machine up until the last round of changes that I made. However, now on the test machine, it throws the following exception immediately upon opening: System.NullReferenceException: Object reference not set to an instance of an object. at PSRD_Specs_Database_Administrat.mainMenu.mainMenu_Load(Object sender, EventArgs e) at System.Windows.Forms.Form.OnLoad(EventArgs e) at System.Windows.Forms.Form.OnCreateControl() at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible) at System.Windows.Forms.Control.CreateControl() at System.Windows.Forms.Control.WmShowWindow(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ContainerControl.WndProc(Message& m) at System.Windows.Forms.Form.WmShowWindow(Message& m) at System.Windows.Forms.Form.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) The only thing that I changed in this version that pertains to mainMenu_Load is the way that the connection string to the database is called. Previously, I had set a string with the connection string on every form that I needed to call it from, like: string conString = "Data Source = SHAREPOINT;Trusted_Connection = yes;" + "database = CustomerDatabase;connection timeout = 15"; As my app grew and I added forms to it, I decided to add an App.config to the project. I defined the connection string in it: <connectionStrings> <add name="conString" providerName="System.Data.SqlClient" connectionString="Data Source = SHAREPOINT;Trusted_Connection = yes;database = CustomerDatabase;connection timeout = 15" /> </connectionStrings> I then created a static string that would return the conString: public static string GetConnectionString(string conName) { string strReturn = string.Empty; if (!(string.IsNullOrEmpty(conName))) { strReturn = ConfigurationManager.ConnectionStrings[conName].ConnectionString; } else { strReturn = ConfigurationManager.ConnectionStrings["conString"].ConnectionString; } return strReturn; } I removed the conString variable and now call the connection string like so: PublicMethods.GetConnectionString("conString").ToString() It appears that this is giving me the error. I changed these instances to directly call the connection string from App.config without using GetConnectionString. For instance, in a SQLConnection: using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conString"].ConnectionString)) This also threw the exception. However, when I went back to using the conString variable on each form, I had no issues. What I don't understand is why all three methods work fine on my development machine, while using the App.config directly or via the static string I created throw exceptions.

  Read the article

• The best way to organize WPF projects

  - by Mike

  Hello everybody, I've started recently to develop a new software in WPF, and I still don't know which is the best way to organize the application, to be more productive with Visual Studio and Expression Blend. I noticed 2 annoying things I'd like to solve: I'm using Code Contracts in my projects, and when I run my project with Expression Blend, it launches the static analysis of the code. How can I stop that? Which configuration of the project does Blend use by default? I've tried to disable Code Contracts in a new configuration. It works in VS as the static analysis is not launched, but it has no effects in Blend. I've thinked about splitting the Windows Application in 2 parts: the first one containing the views of the WPF (app.exe) and the second one being the core of the project, with the logic code (app.core.dll), and I would just open the former project in Blend. Any thoughts about that? Thanks in advance Mike

  Read the article

• How to call WCF Service Method Asycroniously from Class file?

  - by stackuser1

  I've added WCF Service reference to my asp.net application and configured that reference to support asncronious calls. From asp.net code behind files, i'm able to call the service methods asyncroniously like the bellow sample code. protected void Button1_Click(object sender, EventArgs e) { PageAsyncTask pat = new PageAsyncTask(BeiginGetDataAsync, EndDataRetrieveAsync, null, null); Page.RegisterAsyncTask(pat); } IAsyncResult BeiginGetDataAsync(object sender, EventArgs e, AsyncCallback async, object extractData) { svc = new Service1Client(); return svc.BeginGetData(656,async, extractData); } void EndDataRetrieveAsync(IAsyncResult ar) { Label1.Text = svc.EndGetData(ar); } and in page directive added Async="true" In this scenario it is working fine. But from UI i'm not supposed to call the service methods directly. I need to call all service methods from a static class and from code behind file i need to invoke the static method. In this scenario what exactlly do i need to do?

  Read the article

• Why does does my stack overflow error occur after 518669 specifically?

  - by David

  I created a java program to count up toward infinity: class up { public static void up (int n) { System.out.println (n) ; up (n+1) ; } public static void main (String[] arg) { up (1) ; } } i didn't actually expect it to get there but the thing that i noticed that was a bit curious was that it stopped at the same number each time: 518669 what is the significance of this number? (or of this number +1 i suppose). (also as a bit of an aside question, I've been told that the way i format my code is bad [indentation and such] what am i doing that isn't desirable?)

  Read the article

• How to outperform this regex replacement?

  - by spender

  After considerable measurement, I have identified a hotspot in one of our windows services that I'd like to optimize. We are processing strings that may have multiple consecutive spaces in it, and we'd like to reduce to only single spaces. We use a static compiled regex for this task: private static readonly Regex regex_select_all_multiple_whitespace_chars = new Regex(@"\s+",RegexOptions.Compiled); and then use it as follows: var cleanString= regex_select_all_multiple_whitespace_chars.Replace(dirtyString.Trim(), " "); This line is being invoked several million times, and is proving to be fairly intensive. I've tried to write something better, but I'm stumped. Given the fairly modest processing requirements of the regex, surely there's something faster. Could unsafe processing with pointers speed things further?

  Read the article

• SortedDictionary and SortedList

  - by Simon Cooper

  Apart from Dictionary<TKey, TValue>, there's two other dictionaries in the BCL - SortedDictionary<TKey, TValue> and SortedList<TKey, TValue>. On the face of it, these two classes do the same thing - provide an IDictionary<TKey, TValue> interface where the iterator returns the items sorted by the key. So what's the difference between them, and when should you use one rather than the other? (as in my previous post, I'll assume you have some basic algorithm & datastructure knowledge) SortedDictionary We'll first cover SortedDictionary. This is implemented as a special sort of binary tree called a red-black tree. Essentially, it's a binary tree that uses various constraints on how the nodes of the tree can be arranged to ensure the tree is always roughly balanced (for more gory algorithmical details, see the wikipedia link above). What I'm concerned about in this post is how the .NET SortedDictionary is actually implemented. In .NET 4, behind the scenes, the actual implementation of the tree is delegated to a SortedSet<KeyValuePair<TKey, TValue>>. One example tree might look like this: Each node in the above tree is stored as a separate SortedSet<T>.Node object (remember, in a SortedDictionary, T is instantiated to KeyValuePair<TKey, TValue>): class Node { public bool IsRed; public T Item; public SortedSet<T>.Node Left; public SortedSet<T>.Node Right; } The SortedSet only stores a reference to the root node; all the data in the tree is accessed by traversing the Left and Right node references until you reach the node you're looking for. Each individual node can be physically stored anywhere in memory; what's important is the relationship between the nodes. This is also why there is no constructor to SortedDictionary or SortedSet that takes an integer representing the capacity; there are no internal arrays that need to be created and resized. This may seen trivial, but it's an important distinction between SortedDictionary and SortedList that I'll cover later on. And that's pretty much it; it's a standard red-black tree. Plenty of webpages and datastructure books cover the algorithms behind the tree itself far better than I could. What's interesting is the comparions between SortedDictionary and SortedList, which I'll cover at the end. As a side point, SortedDictionary has existed in the BCL ever since .NET 2. That means that, all through .NET 2, 3, and 3.5, there has been a bona-fide sorted set class in the BCL (called TreeSet). However, it was internal, so it couldn't be used outside System.dll. Only in .NET 4 was this class exposed as SortedSet. SortedList Whereas SortedDictionary didn't use any backing arrays, SortedList does. It is implemented just as the name suggests; two arrays, one containing the keys, and one the values (I've just used random letters for the values): The items in the keys array are always guarenteed to be stored in sorted order, and the value corresponding to each key is stored in the same index as the key in the values array. In this example, the value for key item 5 is 'z', and for key item 8 is 'm'. Whenever an item is inserted or removed from the SortedList, a binary search is run on the keys array to find the correct index, then all the items in the arrays are shifted to accomodate the new or removed item. For example, if the key 3 was removed, a binary search would be run to find the array index the item was at, then everything above that index would be moved down by one: and then if the key/value pair {7, 'f'} was added, a binary search would be run on the keys to find the index to insert the new item, and everything above that index would be moved up to accomodate the new item: If another item was then added, both arrays would be resized (to a length of 10) before the new item was added to the arrays. As you can see, any insertions or removals in the middle of the list require a proportion of the array contents to be moved; an O(n) operation. However, if the insertion or removal is at the end of the array (ie the largest key), then it's only O(log n); the cost of the binary search to determine it does actually need to be added to the end (excluding the occasional O(n) cost of resizing the arrays to fit more items). As a side effect of using backing arrays, SortedList offers IList Keys and Values views that simply use the backing keys or values arrays, as well as various methods utilising the array index of stored items, which SortedDictionary does not (and cannot) offer. The Comparison So, when should you use one and not the other? Well, here's the important differences: Memory usage SortedDictionary and SortedList have got very different memory profiles. SortedDictionary... has a memory overhead of one object instance, a bool, and two references per item. On 64-bit systems, this adds up to ~40 bytes, not including the stored item and the reference to it from the Node object. stores the items in separate objects that can be spread all over the heap. This helps to keep memory fragmentation low, as the individual node objects can be allocated wherever there's a spare 60 bytes. In contrast, SortedList... has no additional overhead per item (only the reference to it in the array entries), however the backing arrays can be significantly larger than you need; every time the arrays are resized they double in size. That means that if you add 513 items to a SortedList, the backing arrays will each have a length of 1024. To conteract this, the TrimExcess method resizes the arrays back down to the actual size needed, or you can simply assign list.Capacity = list.Count. stores its items in a continuous block in memory. If the list stores thousands of items, this can cause significant problems with Large Object Heap memory fragmentation as the array resizes, which SortedDictionary doesn't have. Performance Operations on a SortedDictionary always have O(log n) performance, regardless of where in the collection you're adding or removing items. In contrast, SortedList has O(n) performance when you're altering the middle of the collection. If you're adding or removing from the end (ie the largest item), then performance is O(log n), same as SortedDictionary (in practice, it will likely be slightly faster, due to the array items all being in the same area in memory, also called locality of reference). So, when should you use one and not the other? As always with these sort of things, there are no hard-and-fast rules. But generally, if you: need to access items using their index within the collection are populating the dictionary all at once from sorted data aren't adding or removing keys once it's populated then use a SortedList. But if you: don't know how many items are going to be in the dictionary are populating the dictionary from random, unsorted data are adding & removing items randomly then use a SortedDictionary. The default (again, there's no definite rules on these sort of things!) should be to use SortedDictionary, unless there's a good reason to use SortedList, due to the bad performance of SortedList when altering the middle of the collection.

  Read the article

• Varnish default.vcl grace period

  - by Vladimir

  These are my settings for a grace period (/etc/varnish/default.vcl) sub vcl_recv { .... set req.grace = 360000s; ... } sub vcl_fetch { ... set beresp.grace = 360000s; ... } I tested Varnish using localhost and nodejs as a server. I started localhost, the site was up. Then I disconnected server and the site got disconnected in less than 2 min. It says: Error 503 Service Unavailable Service Unavailable Guru Meditation: XID: 1890127100 Varnish cache server Could you tell me what could be the problem? sub vcl_fetch { if (beresp.ttl < 120s) { ##std.log("Adjusting TTL"); set beresp.ttl = 36000s; ##120s; } # Do not cache the object if the backend application does not want us to. if (beresp.http.Cache-Control ~ "(no-cache|no-store|private|must-revalidate)") { return(hit_for_pass); } # Do not cache the object if the status is not in the 200s if (beresp.status >= 300) { # Remove the Set-Cookie header #remove beresp.http.Set-Cookie; return(hit_for_pass); } # # Everything below here should be cached # # Remove the Set-Cookie header ####remove beresp.http.Set-Cookie; # Set the grace time ## set beresp.grace = 1s; //change this to minutes in case of app shutdown set beresp.grace = 360000s; ## 10 hour - reduce if it has negative impact # Static assets - browser caches tpiphem for a long time. if (req.url ~ "\.(css|js|.js|jpg|jpeg|gif|ico|png)\??\d*$") { /* Remove Expires from backend, it's not long enough */ unset beresp.http.expires; /* Set the clients TTL on this object */ set beresp.http.cache-control = "public, max-age=31536000"; /* marker for vcl_deliver to reset Age: */ set beresp.http.magicmarker = "1"; } else { set beresp.http.Cache-Control = "private, max-age=0, must-revalidate"; set beresp.http.Pragma = "no-cache"; } if (req.url ~ "\.(css|js|min|)\??\d*$") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ##do not duplicate these settings if (req.url ~ ".css") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".js") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } if (req.url ~ ".min") { set beresp.do_gzip = true; unset beresp.http.expires; set beresp.http.cache-control = "public, max-age=31536000"; set beresp.http.expires = beresp.ttl; set beresp.http.age = "0"; } ## If the request to the backend returns a code other than 200, restart the loop ## If the number of restarts reaches the value of the parameter max_restarts, ## the request will be error'ed. max_restarts defaults to 4. This prevents ## an eternal loop in the event that, e.g., the object does not exist at all. if (beresp.status != 200 && beresp.status != 403 && beresp.status != 404) { return(restart); } if (beresp.status == 302) { return(deliver); } # Never cache posts if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(hit_for_pass); } ##check this setting to ensure that it does not cause issues for browsers with no gzip if (beresp.http.content-type ~ "text") { set beresp.do_gzip = true; } if (beresp.http.Set-Cookie) { return(deliver); } ##if (req.url == "/index.html") { set beresp.do_esi = true; ##} ## check if this is needed or should be used # return(deliver); the object return(deliver); } sub vcl_recv { ##avoid leeching of images call hot_link; set req.grace = 360000s; ##2m ## if one backend is down - use another if (req.restarts == 0) { set req.backend = cache_director; ##we can specify individual VMs } else if (req.restarts == 1) { set req.backend = cache_director; } ## post calls should not be cached - add cookie for these requests if using micro-caching # Pass requests that are not GET or HEAD if (req.request != "GET" && req.request != "HEAD") { return(pass); ## return(pass) goes to backend - not cache } # Don't cache the result of a redirect if (req.http.Referer ~ "redir" || req.http.Origin ~ "jumpto") { return(pass); } # Don't cache the result of a redirect (asking for logon) if (req.http.Referer ~ "post" || req.http.Referer ~ "submit" || req.http.Referer ~ "add" || req.http.Referer ~ "ask") { return(pass); } # Never cache posts - ensure that we do not use these strings in our URLs' that need to be cached if (req.url ~ "\/post\/" || req.url ~ "\/submit\/" || req.url ~ "\/ask\/" || req.url ~ "\/add\/") { return(pass); } ## if (req.http.Authorization || req.http.Cookie) { if (req.http.Authorization) { /* Not cacheable by default */ return (pass); } # Handle compression correctly. Different browsers send different # "Accept-Encoding" headers, even though they mostly all support the same # compression mechanisms. By consolidating these compression headers into # a consistent format, we can reduce the size of the cache and get more hits. # @see: http:// varnish.projects.linpro.no/wiki/FAQ/Compression if (req.http.Accept-Encoding) { if (req.url ~ "\.(jpg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|ico)$") { # No point in compressing these remove req.http.Accept-Encoding; } else if (req.http.Accept-Encoding ~ "gzip") { # If the browser supports it, we'll use gzip. set req.http.Accept-Encoding = "gzip"; } else if (req.http.Accept-Encoding ~ "deflate") { # Next, try deflate if it is supported. set req.http.Accept-Encoding = "deflate"; } else { # Unknown algorithm. Remove it and send unencoded. unset req.http.Accept-Encoding; } } # lookup graphics, css, js & ico files in the cache if (req.url ~ "\.(png|gif|jpg|jpeg|css|.js|ico)$") { return(lookup); } ##added on 0918 - check if it causes issues with user specific content if (req.request == "GET" && req.http.cookie) { return(lookup); } # Pipe requests that are non-RFC2616 or CONNECT which is weird. if (req.request != "GET" && req.request != "HEAD" && req.request != "PUT" && req.request != "POST" && req.request != "TRACE" && req.request != "OPTIONS" && req.request != "DELETE") { ##closing connection and calling pipe return(pipe); } ##purge content via localhost only if (req.request == "PURGE") { if (!client.ip ~ purge) { error 405 "Not allowed."; } return(lookup); } ## do we need this? ## return(lookup); }

  Read the article

• C# TraceSource class in multithreaded application

  - by matti

  msdn: "Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe." it contains only instance methods. How should I use it in a way that all activity gets recorder by TextWriterTraceListener to a text file. Is one static member which all threads use (by calling) TraceEvent-method safe. (I've kind of asked this question in http://stackoverflow.com/questions/1901086/how-to-instantiate-c-tracesources-to-log-multithreaded-asp-net-2-0-web-applica, but I cannot just believe if somebody just says it's OK despite the documentation).

  Read the article

< Previous Page | 509 510 511 512 513 514 515 516 517 518 519 520  | Next Page >