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  • flash as3, fade in/out layering problem

    - by Jackson Smith
    Ok, what im trying to do is make a day to night cycle behind my landscape. There is a sun and a moon, they rotate in a circle on opposite sides. (i.e. the sun is up when the moon is down and vice versa) when the sun is coming up it should fade from the night movieclip to the dawn movieclip, then when the sun is up a little bit more, fade into the day moviclip, this works quite well, but, for some reason, when it gets to the sunset, it just wont work :/ and the same goes for when it goes from the sunset to night :/ any and all healp is greatly appreciated, ive spent 5 hours trying to figure this out and cant! please help! stage.addEventListener(Event.ENTER_FRAME, daynightcycle) //setChildIndex(night, getChildIndex(day)); setChildIndex(sunset, 0); setChildIndex(day, 1); setChildIndex(dawn, 2); setChildIndex(night, 3); function daynightcycle(e:Event):void { if(sun.currentLabel == "dawn") { setChildIndex(sunset, 0); setChildIndex(day, 1); setChildIndex(dawn, 2); setChildIndex(night, 3); stage.addEventListener(Event.ENTER_FRAME, nightTdawn); }else if(sun.currentLabel == "sunset") { setChildIndex(dawn, 0); setChildIndex(night, 1); setChildIndex(sunset, 2); setChildIndex(day, 3); stage.addEventListener(Event.ENTER_FRAME, dayTsunset); }else if(sun.currentLabel == "night") { setChildIndex(day, 0); setChildIndex(dawn, 1); setChildIndex(night, 2); setChildIndex(sunset, 3); stage.addEventListener(Event.ENTER_FRAME, sunsetTnight); }else if(sun.currentLabel == "day") { setChildIndex(night, 0); setChildIndex(sunset, 1); setChildIndex(day, 2); setChildIndex(dawn, 3); stage.addEventListener(Event.ENTER_FRAME, dawnTday); }else if(sun.currentLabel == "switch") { stage.addEventListener(Event.ENTER_FRAME, switchLayers); } } function nightTdawn(e:Event):void { if(night.alpha != 0) { night.alpha -= 0.01; }else { stage.removeEventListener(Event.ENTER_FRAME, nightTdawn); night.alpha = 100; //setChildIndex(night, getChildIndex(sunset)); } } function dayTsunset(e:Event):void { if(day.alpha != 0) { day.alpha -= 0.01; }else { stage.removeEventListener(Event.ENTER_FRAME, dayTsunset); day.alpha = 100; //setChildIndex(day, getChildIndex(dawn)); } //day.visible = false; //sunset.visible = true; } function sunsetTnight(e:Event):void { if(sunset.alpha != 0) { sunset.alpha -= 0.01; }else{ stage.removeEventListener(Event.ENTER_FRAME, sunsetTnight); sunset.alpha = 100; //setChildIndex(sunset, (getChildIndex(day))); } //sunset.visible = false; //night.visible = true; } function dawnTday(e:Event):void { sunset.visible = true; day.visible = true; if(dawn.alpha != 0) { dawn.alpha -= 0.01; }else{ stage.removeEventListener(Event.ENTER_FRAME, dawnTday); dawn.alpha = 100; //setChildIndex(dawn, (getChildIndex(night))); } } function switchLayers(e:Event):void { setChildIndex(dawn, 0); setChildIndex(night, 1); setChildIndex(sunset, 2); setChildIndex(day, 3); night.alpha = 100; sunset.alpha = 100; day.alpha = 100; dawn.alpha = 100; stage.removeEventListener(Event.ENTER_FRAME, switchLayers); }

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  • Unable to find valid certification path to requested target while CAS authentication

    - by Dmitriy Sukharev
    I'm trying to configure CAS authentication. It requires both CAS and client application to use HTTPS protocol. Unfortunately we should use self-signed certificate (with CN that doesn't have anything in common with our server). Also the server is behind firewall and we have only two ports (ssh and https) visible. As far as there're several application that should be visible externally, we use Apache for ajp reverse proxying requests to these applications. Secure connections are managed by Apache, and all Tomcat are not configured to work with SSL. But I obtained exception while authentication, therefore desided to set keystore in CATALINA_OPTS: export CATALINA_OPTS="-Djavax.net.ssl.keyStore=/path/to/tomcat/ssl/cert.pfx -Djavax.net.ssl.keyStoreType=PKCS12 -Djavax.net.ssl.keyStorePassword=password -Djavax.net.ssl.keyAlias=alias -Djavax.net.debug=ssl" cert.pfx was obtained from certificate and key that are used by Apache HTTP Server: $ openssl pkcs12 -export -out /path/to/tomcat/ssl/cert.pfx -inkey /path/to/apache2/ssl/server-key.pem -in /path/to/apache2/ssl/server-cert.pem When I try to authenticate a user I obtain the following exception: Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:174) ~[na:1.6.0_32] at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:238) ~[na:1.6.0_32] at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:318) ~[na:1.6.0_32] Meanwhile I can see in catalina.out that Tomcat see certificate in cert.pfx and it's the same as the one that is used while authentication: 09:11:38.886 [http-bio-8080-exec-2] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Constructing validation url: https://external-ip/cas/proxyValidate?pgtUrl=https%3A%2F%2Fexternal-ip%2Fclient%2Fj_spring_cas_security_proxyreceptor&ticket=ST-17-PN26WtdsZqNmpUBS59RC-cas&service=https%3A%2F%2Fexternal-ip%2Fclient%2Fj_spring_cas_security_check 09:11:38.886 [http-bio-8080-exec-2] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Retrieving response from server. keyStore is : /path/to/tomcat/ssl/cert.pfx keyStore type is : PKCS12 keyStore provider is : init keystore init keymanager of type SunX509 *** found key for : 1 chain [0] = [ [ Version: V1 Subject: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country Signature Algorithm: SHA1withRSA, OID = 1.2.840.113549.1.1.5 Key: Sun RSA public key, 1024 bits modulus: 13??a lot of digits here??19 public exponent: ????7 Validity: [From: Tue Apr 24 16:32:18 CEST 2012, To: Wed Apr 24 16:32:18 CEST 2013] Issuer: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country SerialNumber: [ d??????? ????????] ] Algorithm: [SHA1withRSA] Signature: 0000: 65 Signature is here 0070: 96 . ] *** trustStore is: /jdk-home-folder/jre/lib/security/cacerts Here is a lot of trusted CAs. Here is nothing related to our certicate or our (not trusted) CA. ... 09:11:39.731 [http-bio-8080-exec-4] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Retrieving response from server. Allow unsafe renegotiation: false Allow legacy hello messages: true Is initial handshake: true Is secure renegotiation: false %% No cached client session *** ClientHello, TLSv1 RandomCookie: GMT: 1347433643 bytes = { 63, 239, 180, 32, 103, 140, 83, 7, 109, 149, 177, 80, 223, 79, 243, 244, 60, 191, 124, 139, 108, 5, 122, 238, 146, 1, 54, 218 } Session ID: {} Cipher Suites: [SSL_RSA_WITH_RC4_128_MD5, SSL_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, SSL_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_DES_CBC_SHA, SSL_DHE_RSA_WITH_DES_CBC_SHA, SSL_DHE_DSS_WITH_DES_CBC_SHA, SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA, TLS_EMPTY_RENEGOTIATION_INFO_SCSV] Compression Methods: { 0 } *** http-bio-8080-exec-4, WRITE: TLSv1 Handshake, length = 75 http-bio-8080-exec-4, WRITE: SSLv2 client hello message, length = 101 http-bio-8080-exec-4, READ: TLSv1 Handshake, length = 81 *** ServerHello, TLSv1 RandomCookie: GMT: 1347433643 bytes = { 145, 237, 232, 63, 240, 104, 234, 201, 148, 235, 12, 222, 60, 75, 174, 0, 103, 38, 196, 181, 27, 226, 243, 61, 34, 7, 107, 72 } Session ID: {79, 202, 117, 79, 130, 216, 168, 38, 68, 29, 182, 82, 16, 25, 251, 66, 93, 108, 49, 133, 92, 108, 198, 23, 120, 120, 135, 151, 15, 13, 199, 87} Cipher Suite: SSL_RSA_WITH_RC4_128_SHA Compression Method: 0 Extension renegotiation_info, renegotiated_connection: <empty> *** %% Created: [Session-2, SSL_RSA_WITH_RC4_128_SHA] ** SSL_RSA_WITH_RC4_128_SHA http-bio-8080-exec-4, READ: TLSv1 Handshake, length = 609 *** Certificate chain chain [0] = [ [ Version: V1 Subject: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country Signature Algorithm: SHA1withRSA, OID = 1.2.840.113549.1.1.5 Key: Sun RSA public key, 1024 bits modulus: 13??a lot of digits here??19 public exponent: ????7 Validity: [From: Tue Apr 24 16:32:18 CEST 2012, To: Wed Apr 24 16:32:18 CEST 2013] Issuer: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country SerialNumber: [ d??????? ????????] ] Algorithm: [SHA1withRSA] Signature: 0000: 65 Signature is here 0070: 96 . ] *** http-bio-8080-exec-4, SEND TLSv1 ALERT: fatal, description = certificate_unknown http-bio-8080-exec-4, WRITE: TLSv1 Alert, length = 2 http-bio-8080-exec-4, called closeSocket() http-bio-8080-exec-4, handling exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target I tried to convert our pem certificate to der format and imported it to trustedKeyStore (cacerts) (without private key), but it didn't change anything. But I'm not confident that I did it rigth. Also I must inform you that I don't know passphrase for our servier-key.pem file, and probably it differs from password for keystore created by me. OS: CentOS 6.2 Architecture: x64 Tomcat version: 7 Apache HTTP Server version: 2.4 Is there any way to make Tomcat accepts our certificate?

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  • DataTable to JSON

    - by Joel Coehoorn
    I recently needed to serialize a datatable to JSON. Where I'm at we're still on .Net 2.0, so I can't use the JSON serializer in .Net 3.5. I figured this must have been done before, so I went looking online and found a number of different options. Some of them depend on an additional library, which I would have a hard time pushing through here. Others require first converting to List<Dictionary<>>, which seemed a little awkward and needless. Another treated all values like a string. For one reason or another I couldn't really get behind any of them, so I decided to roll my own, which is posted below. As you can see from reading the //TODO comments, it's incomplete in a few places. This code is already in production here, so it does "work" in the basic sense. The places where it's incomplete are places where we know our production data won't currently hit it (no timespans or byte arrays in the db). The reason I'm posting here is that I feel like this can be a little better, and I'd like help finishing and improving this code. Any input welcome. public static class JSONHelper { public static string FromDataTable(DataTable dt) { string rowDelimiter = ""; StringBuilder result = new StringBuilder("["); foreach (DataRow row in dt.Rows) { result.Append(rowDelimiter); result.Append(FromDataRow(row)); rowDelimiter = ","; } result.Append("]"); return result.ToString(); } public static string FromDataRow(DataRow row) { DataColumnCollection cols = row.Table.Columns; string colDelimiter = ""; StringBuilder result = new StringBuilder("{"); for (int i = 0; i < cols.Count; i++) { // use index rather than foreach, so we can use the index for both the row and cols collection result.Append(colDelimiter).Append("\"") .Append(cols[i].ColumnName).Append("\":") .Append(JSONValueFromDataRowObject(row[i], cols[i].DataType)); colDelimiter = ","; } result.Append("}"); return result.ToString(); } // possible types: // http://msdn.microsoft.com/en-us/library/system.data.datacolumn.datatype(VS.80).aspx private static Type[] numeric = new Type[] {typeof(byte), typeof(decimal), typeof(double), typeof(Int16), typeof(Int32), typeof(SByte), typeof(Single), typeof(UInt16), typeof(UInt32), typeof(UInt64)}; // I don't want to rebuild this value for every date cell in the table private static long EpochTicks = new DateTime(1970, 1, 1).Ticks; private static string JSONValueFromDataRowObject(object value, Type DataType) { // null if (value == DBNull.Value) return "null"; // numeric if (Array.IndexOf(numeric, DataType) > -1) return value.ToString(); // TODO: eventually want to use a stricter format // boolean if (DataType == typeof(bool)) return ((bool)value) ? "true" : "false"; // date -- see http://weblogs.asp.net/bleroy/archive/2008/01/18/dates-and-json.aspx if (DataType == typeof(DateTime)) return "\"\\/Date(" + new TimeSpan(((DateTime)value).ToUniversalTime().Ticks - EpochTicks).TotalMilliseconds.ToString() + ")\\/\""; // TODO: add Timespan support // TODO: add Byte[] support //TODO: this would be _much_ faster with a state machine // string/char return "\"" + value.ToString().Replace(@"\", @"\\").Replace(Environment.NewLine, @"\n").Replace("\"", @"\""") + "\""; } }

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  • How to show form in front in C#

    - by corlettk
    Folks, Please does anyone know how to show a Form from an otherwise invisible application, and have it get the focus (i.e. appear on top of other windows)? I'm working in C# .NET 3.5. I suspect I've taken "completely the wrong approach"... I do not Application.Run(new TheForm ()) instead I (new TheForm()).ShowModal()... The Form is basically a modal dialogue, with a few check-boxes; a text-box, and OK and Cancel Buttons. The user ticks a checkbox and types in a description (or whatever) then presses OK, the form disappears and the process reads the user-input from the Form, Disposes it, and continues processing. This works, except when the form is show it doesn't get the focus, instead it appears behind the "host" application, until you click on it in the taskbar (or whatever). This is a most annoying behaviour, which I predict will cause many "support calls", and the existing VB6 version doesn't have this problem, so I'm going backwards in usability... and users won't accept that (and nor should they). So... I'm starting to think I need to rethink the whole shebang... I should show the form up front, as a "normal application" and attach the remainer of the processing to the OK-button-click event. It should work, But that will take time which I don't have (I'm already over time/budget)... so first I really need to try to make the current approach work... even by quick-and-dirty methods. So please does anyone know how to "force" a .NET 3.5 Form (by fair means or fowl) to get the focus? I'm thinking "magic" windows API calls (I know Twilight Zone: This only appears to be an issue at work, we're I'm using Visual Studio 2008 on Windows XP SP3... I've just failed to reproduce the problem with an SSCCE (see below) at home on Visual C# 2008 on Vista Ulimate... This works fine. Huh? WTF? Also, I'd swear that at work yesterday showed the form when I ran the EXE, but not when F5'ed (or Ctrl-F5'ed) straight from the IDE (which I just put up with)... At home the form shows fine either way. Totaly confusterpating! It may or may not be relevant, but Visual Studio crashed-and-burned this morning when the project was running in debug mode and editing the code "on the fly"... it got stuck what I presumed was an endless loop of error messages. The error message was something about "can't debug this project because it is not the current project, or something... So I just killed it off with process explorer. It started up again fine, and even offered to recover the "lost" file, an offer which I accepted. using System; using System.Windows.Forms; namespace ShowFormOnTop { static class Program { [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); //Application.Run(new Form1()); Form1 frm = new Form1(); frm.ShowDialog(); } } } Background: I'm porting an existing VB6 implementation to .NET... It's a "plugin" for a "client" GIS application called MapInfo. The existing client "worked invisibly" and my instructions are "to keep the new version as close as possible to the old version", which works well enough (after years of patching); it's just written in an unsupported language, so we need to port it. About me: I'm pretty much a noob to C# and .NET generally, though I've got a bottoms wiping certificate, I have been a professional programmer for 10 years; So I sort of "know some stuff". Any insights would be most welcome... and Thank you all for taking the time to read this far. Consiseness isn't (apparently) my forte. Cheers. Keith.

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  • Changing color of HighlighBrushKey in XAML

    - by phil
    Hi, I have the following problem. The background color in a ListView is set LightGreen or White, whether a boolflag is true or false. Example Screen Window1.xaml: <Window.Resources> <Style TargetType="{x:Type ListViewItem}"> <Style.Triggers> <DataTrigger Binding="{Binding Path=BoolFlag}" Value="True"> <Setter Property="Background" Value="LightGreen" /> </DataTrigger> </Style.Triggers> </Style> </Window.Resources> <StackPanel> <ListView ItemsSource="{Binding Path=Personen}" SelectionMode="Single" SelectionChanged="ListViewSelectionChanged"> <ListView.View> <GridView> <GridViewColumn DisplayMemberBinding="{Binding Path=Vorname}" Header="Vorname" /> <GridViewColumn DisplayMemberBinding="{Binding Path=Nachname}" Header="Nachname" /> <GridViewColumn DisplayMemberBinding="{Binding Path=Alter}" Header="Alter" /> <GridViewColumn DisplayMemberBinding="{Binding Path=BoolFlag}" Header="BoolFlag" /> </GridView> </ListView.View> </ListView> </StackPanel> Window1.xaml.cs: public partial class Window1 : Window { private IList<Person> _personen = new List<Person>(); public Window1() { _personen.Add(new Person { Vorname = "Max", Nachname = "Mustermann", Alter = 18, BoolFlag = false, }); _personen.Add(new Person { Vorname = "Karl", Nachname = "Mayer", Alter = 27, BoolFlag = true, }); _personen.Add(new Person { Vorname = "Josef", Nachname = "Huber", Alter = 38, BoolFlag = false, }); DataContext = this; InitializeComponent(); } public IList<Person> Personen { get { return _personen; } } private void ListViewSelectionChanged(object sender, SelectionChangedEventArgs e) { Person person = e.AddedItems[0] as Person; if (person != null) { if (person.BoolFlag) { this.Resources[SystemColors.HighlightBrushKey] = Brushes.Green; } else { this.Resources[SystemColors.HighlightBrushKey] = Brushes.RoyalBlue; } } } } Person.cs: public class Person { public string Vorname { get; set; } public string Nachname { get; set; } public int Alter { get; set; } public bool BoolFlag { get; set; } } Now I want to set the highlight color of the selected item, depending on the boolflag. In Code-Behind I do this with: private void ListViewSelectionChanged(object sender, SelectionChangedEventArgs e) { Person person = e.AddedItems[0] as Person; if (person != null) { if (person.BoolFlag) { this.Resources[SystemColors.HighlightBrushKey] = Brushes.Green; } else { this.Resources[SystemColors.HighlightBrushKey] = Brushes.RoyalBlue; } } } } This works fine, but now I want to define the code above in the XAML-file. With <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="Green" /> I can overwrite the default-value. However, it works, but the color is set to Green for all selected items. I have tried different ways to switch the color of HighlightBrushKey between Green and Blue in XAML, depending on the boolflag, but I didn't succeed. May you can help me and give me some examples?

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  • XSLT transformation by grouping based on 3 elements/attributes

    - by Daniel
    This question is related to http://stackoverflow.com/questions/2863202/xslt-1-0-grouping-to-reformat-element-defined-by-date-into-element-defined-by-tas Just to understand more clearly the trick behind. How would the XSLT look like if we were to group by date, task and shift as below: Input XML; <Person> <name>John</name> <date>June12</date> <shift tier=1> <workTime taskID=1>34</workTime> <workTime taskID=2>12</workTime> </shift> <shift tier=2> <workTime taskID=1>3</workTime> </shift> </Person> <Person> <name>John</name> <date>June13</date> <shift tier=1> <workTime taskID=1>21</workTime> <workTime taskID=2>11</workTime> </shift> <shift tier=2> <workTime taskID=1>2</workTime> </shift> </Person> and similarly, the output would be <Person> <name>John</name> <tier>1</tier> <taskID>1</taskID> <workTime> <date>June12</date> <time>34</time> </worTime> <workTime> <date>June13</date> <time>21</time> </worTime> </Person> <Person> <name>John</name> <tier>1</tier> <taskID>2</taskID> <workTime> <date>June12</date> <time>12</time> </worTime> <workTime> <date>June13</date> <time>11</time> </worTime> </Person> <Person> <name>John</name> <tier>2</tier> <taskID>1</taskID> <workTime> <date>June12</date> <time>3</time> </worTime> <workTime> <date>June13</date> <time>2</time> </worTime> </Person>

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  • I'm trying to handle the updates on 2 related tables in one DetailsView using Jquery and Linq, and h

    - by Ben Reisner
    Given two related tables (reports, report_fields) where there can be many report_fields entries for each reports entry, I need to allow the user to enter new report_fields, delete existing report_fields, and re-arrange the order. Currently I am using a DetailsView to handle the editing of the reports. I added some logic to handle report_fields, and currently it allows you to succesfully re-arrange the order, but i'm a little stumped as to the best way to add new items, or delete existing items. The basic logic I have is that each report_fields is represented by a . It has a description as the text, and a field for each field in the report_fields table. I use JQuery Sortable to allow the user to re-arrange the LIs. Abbreviated Create Table Statements:(foreign key constraint ignored for brevity) create table report( id integer primary key identity, reportname varchar(250) ) create table report_fields( id integer primary key identity, reportID integer, keyname integer, keyvalue integer, field_order integer ) My abbreviated markup: <asp:DetailsView ...> ... <asp:TemplateField HeaderText="Fields"> <EditItemTemplate> <ul class="MySortable"> <asp:Repeater ID="Repeater1" runat="server" DataSource='<%# Eval("report_fields") %>'> <ItemTemplate> <li> <%# Eval("keyname") %>: <%# Eval("keyvalue") %> <input type="hidden" name="keyname[]" value='<%# Eval("keyname") %>' /> <input type="hidden" name="keyvalue[]" value='<%# Eval("keyvalue") %>' /> </li> </ItemTemplate> </asp:Repeater> </ul> </EditItemTemplate> </asp:TemplateField> </asp:DetailsView> <asp:LinqDataSource ID="LinqDataSource2" onupdating="LinqDataSource2_Updating" table=reports ... /> $(function() { $(".MySortable").sortable({ placeholder: 'MySortable-highlight' }).disableSelection(); }); Code Behind Class: public partial class Administration_AddEditReport protected void LinqDataSource2_Updating(object sender, LinqDataSourceUpdateEventArgs e) { report r = (report)e.NewObject; MyDataContext dc = new MyDataContext(); var fields = from f in dc.report_fields where f.reportID == r.id select f; dc.report_fields.DeleteAllOnSubmit(fields); NameValueCollection nvc = Request.Params; string[] keyname = nvc["keyname[]"].Split(','); string[] keyvalue = nvc["keyvalue[]"].Split(','); for (int i = 0; i < keyname.Length; i++) { report_field rf = new report_field(); rf.reportID = r.id; rf.keyname = keyname[i]; rf.keyvalue = keyvalue[i]; rf.field_order = i; dc.report_fields.InsertOnSubmit(rf); } dc.SubmitChanges(); } }

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  • Model Object called in NSOutlineView DataSource Method Crashing App

    - by Alec Sloman
    I have a bewildering problem, hoping someone can assist: I have a model object, called Road. Here's the interface. @@@ @interface RoadModel : NSObject { NSString *_id; NSString *roadmapID; NSString *routeID; NSString *title; NSString *description; NSNumber *collapsed; NSNumber *isRoute; NSString *staff; NSNumber *start; NSArray *staffList; NSMutableArray *updates; NSMutableArray *uploads; NSMutableArray *subRoads; } @property (nonatomic, copy) NSString *_id; @property (nonatomic, copy) NSString *roadmapID; @property (nonatomic, copy) NSString *routeID; @property (nonatomic, copy) NSString *title; @property (nonatomic, copy) NSString *description; @property (nonatomic, copy) NSNumber *collapsed; @property (nonatomic, copy) NSNumber *isRoute; @property (nonatomic, copy) NSString *staff; @property (nonatomic, copy) NSNumber *start; @property (nonatomic, copy) NSArray *staffList; @property (nonatomic, copy) NSMutableArray *updates; @property (nonatomic, copy) NSMutableArray *uploads; @property (nonatomic, copy) NSMutableArray *subRoads; - (id)initWithJSONObject:(NSDictionary *)JSONObject; @end This part is fine. To give you some background, I'm translating a bunch of JSON into a proper model object so it's easier to work with. Now, I'm trying to display this in an NSOutlineView. This is where the problem is. In particular, I have created the table and a datasource. - (id)initWithRoads:(NSArray *)roads { if (self = [super init]) root = [[NSMutableArray alloc] initWithArray:roads]; return self; } - (NSInteger)outlineView:(NSOutlineView *)outlineView numberOfChildrenOfItem:(id)item { if (item == nil) return root.count; return 0; } - (BOOL)outlineView:(NSOutlineView *)outlineView isItemExpandable:(id)item { return NO; } - (id)outlineView:(NSOutlineView *)outlineView child:(NSInteger)index ofItem:(id)item { if (item == nil) item = root; if (item == root) return [root objectAtIndex:index]; return nil; } - (id)outlineView:(NSOutlineView *)outlineView objectValueForTableColumn:(NSTableColumn *)tableColumn byItem:(id)item { return [item title]; } In the final datasource method, it attempts to return the "title" string property of the model object, but for some reason crashes each time. I have checked that the method is taking in the correct object (I checked [item class] description], and it is the right object), but for some reason if I call any of the objects accessors the app immediately crashes. This is totally puzzling because in the init method, I can iterate through root (an array of RoadModel objects), and print any of its properties without issue. It is only when I'm trying to access the properties in any of the datasource methods that this occurs. I wonder if there is something memory-wise that is going on behind the scenes and I am not providing for it. If you can shed some light on to this situation, it would be greatly appreciated! Thanks in advance!

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  • Use QuickCheck by generating primes

    - by Dan
    Background For fun, I'm trying to write a property for quick-check that can test the basic idea behind cryptography with RSA. Choose two distinct primes, p and q. Let N = p*q e is some number relatively prime to (p-1)(q-1) (in practice, e is usually 3 for fast encoding) d is the modular inverse of e modulo (p-1)(q-1) For all x such that 1 < x < N, it is always true that (x^e)^d = x modulo N In other words, x is the "message", raising it to the eth power mod N is the act of "encoding" the message, and raising the encoded message to the dth power mod N is the act of "decoding" it. (The property is also trivially true for x = 1, a case which is its own encryption) Code Here are the methods I have coded up so far: import Test.QuickCheck -- modular exponentiation modExp :: Integral a => a -> a -> a -> a modExp y z n = modExp' (y `mod` n) z `mod` n where modExp' y z | z == 0 = 1 | even z = modExp (y*y) (z `div` 2) n | odd z = (modExp (y*y) (z `div` 2) n) * y -- relatively prime rPrime :: Integral a => a -> a -> Bool rPrime a b = gcd a b == 1 -- multiplicative inverse (modular) mInverse :: Integral a => a -> a -> a mInverse 1 _ = 1 mInverse x y = (n * y + 1) `div` x where n = x - mInverse (y `mod` x) x -- just a quick way to test for primality n `divides` x = x `mod` n == 0 primes = 2:filter isPrime [3..] isPrime x = null . filter (`divides` x) $ takeWhile (\y -> y*y <= x) primes -- the property prop_rsa (p,q,x) = isPrime p && isPrime q && p /= q && x > 1 && x < n && rPrime e t ==> x == (x `powModN` e) `powModN` d where e = 3 n = p*q t = (p-1)*(q-1) d = mInverse e t a `powModN` b = modExp a b n (Thanks, google and random blog, for the implementation of modular multiplicative inverse) Question The problem should be obvious: there are way too many conditions on the property to make it at all usable. Trying to invoke quickCheck prop_rsa in ghci made my terminal hang. So I've poked around the QuickCheck manual a bit, and it says: Properties may take the form forAll <generator> $ \<pattern> -> <property> How do I make a <generator> for prime numbers? Or with the other constraints, so that quickCheck doesn't have to sift through a bunch of failed conditions? Any other general advice (especially regarding QuickCheck) is welcome.

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  • Background custom button animation using WPF

    - by ajtp
    Hi, I am using Resources dictionaries to customize my controls and apply them as themes to my WPF application so I have implemented one for the button control. A code snippet for my custom Button.xaml is (its namespace is MyWPFApp.Themes): <ResourceDictionary ...> ... <LinearGradientBrush x:Key="NormalBackground" EndPoint="0,1" StartPoint="0,0"> <GradientStop Color="sc#1.000000, 0.250141, 0.333404, 0.884413" Offset="0"/> <GradientStop Color="#ccffffff" Offset="1"/> </LinearGradientBrush> <LinearGradientBrush x:Key="OverBackground" EndPoint="0,1" StartPoint="0,0"> <GradientStop Color="#da5e69" Offset="0"/> <GradientStop Color="#d12e27" Offset="1"/> </LinearGradientBrush> <LinearGradientBrush x:Key="ClickBackground" EndPoint="0,1" StartPoint="0,0"> <GradientStop Color="#d22828" Offset="1"/> <GradientStop Color="#b00000" Offset="0"/> </LinearGradientBrush> ... <Style TargetType="{x:Type Button}"> ... <Setter Property="Background" Value="{StaticResource NormalBackground}"/> ... </Style> </ResourceDictionary> and I apply it by doing the following from my main Application.xaml: <Application ...> <Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="Themes/Button.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Application.Resources> </Application> What I try to do is to change background color, for example, from White to Lime for 6 seconds by doing this from one of my pages, MyPage1.xaml, using StoryBoard: <Page x:Class="MyWPFApp.Pages.MyPage1" ...> <Page.Resources> ... <Storyboard x:Key="sbBtnResetHC" Storyboard.TargetName="BtnResetHC" Storyboard.TargetProperty="(Background). (SolidColorBrush.Color)"> <ColorAnimation From="Pink" To="Green" By="Blue" Duration="0:0:6" RepeatBehavior="3x" AutoReverse="True" /> </Storyboard> ... </Page.Resources> ... <Button x:Name="BtnResetHC" Click="BtnResetHC_Click" Width="90" Visibility="Collapsed" /> ... </Page> and from code behind MyPage1.xaml.cs I start animation by doing this: Storyboard sb = (Storyboard)FindResource("sbBtnResetHC"); sb.Begin(); when the button is visible, but it doesn't work for me. Any ideas what's wrong? Maybe another possibility, as I want the animation starts on button visible is to do a trigger for the button over Visibility property, Is it a better solution? Thanks a lot!

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  • Random Complete System Unresponsiveness Running Mathematical Functions

    - by Computer Guru
    I have a program that loads a file (anywhere from 10MB to 5GB) a chunk at a time (ReadFile), and for each chunk performs a set of mathematical operations (basically calculates the hash). After calculating the hash, it stores info about the chunk in an STL map (basically <chunkID, hash>) and then writes the chunk itself to another file (WriteFile). That's all it does. This program will cause certain PCs to choke and die. The mouse begins to stutter, the task manager takes 2 min to show, ctrl+alt+del is unresponsive, running programs are slow.... the works. I've done literally everything I can think of to optimize the program, and have triple-checked all objects. What I've done: Tried different (less intensive) hashing algorithms. Switched all allocations to nedmalloc instead of the default new operator Switched from stl::map to unordered_set, found the performance to still be abysmal, so I switched again to Google's dense_hash_map. Converted all objects to store pointers to objects instead of the objects themselves. Caching all Read and Write operations. Instead of reading a 16k chunk of the file and performing the math on it, I read 4MB into a buffer and read 16k chunks from there instead. Same for all write operations - they are coalesced into 4MB blocks before being written to disk. Run extensive profiling with Visual Studio 2010, AMD Code Analyst, and perfmon. Set the thread priority to THREAD_MODE_BACKGROUND_BEGIN Set the thread priority to THREAD_PRIORITY_IDLE Added a Sleep(100) call after every loop. Even after all this, the application still results in a system-wide hang on certain machines under certain circumstances. Perfmon and Process Explorer show minimal CPU usage (with the sleep), no constant reads/writes from disk, few hard pagefaults (and only ~30k pagefaults in the lifetime of the application on a 5GB input file), little virtual memory (never more than 150MB), no leaked handles, no memory leaks. The machines I've tested it on run Windows XP - Windows 7, x86 and x64 versions included. None have less than 2GB RAM, though the problem is always exacerbated under lower memory conditions. I'm at a loss as to what to do next. I don't know what's causing it - I'm torn between CPU or Memory as the culprit. CPU because without the sleep and under different thread priorities the system performances changes noticeably. Memory because there's a huge difference in how often the issue occurs when using unordered_set vs Google's dense_hash_map. What's really weird? Obviously, the NT kernel design is supposed to prevent this sort of behavior from ever occurring (a user-mode application driving the system to this sort of extreme poor performance!?)..... but when I compile the code and run it on OS X or Linux (it's fairly standard C++ throughout) it performs excellently even on poor machines with little RAM and weaker CPUs. What am I supposed to do next? How do I know what the hell it is that Windows is doing behind the scenes that's killing system performance, when all the indicators are that the application itself isn't doing anything extreme? Any advice would be most welcome.

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  • can you simlify and generalize this useful jQuery function?

    - by user199368
    Hi, I'm doing an eshop with goods displayed as "tiles" in grid as usual. I just want to use various sizes of tiles and make sure (via jQuery) there are no free spaces. In basic situation, I have a 960px wrapper and want to use 240x180px (class .grid_4) tiles and 480x360px (class .grid_8) tiles. See image (imagine no margins/paddings there): Problems without jQuery: - when the CMS provides the big tile as 6th, there would be a free space under the 5th one - when the CMS provides the big tile as 7th, there would be a free space under 5th and 6th - when the CMS provides the big tile as 8th, it would shift to next line, leaving position no.8 free My solution so far looks like this: $(".grid_8").each(function(){ //console.log("BIG on position "+($(this).index()+1)+" which is "+(($(this).index()+1)%2?"ODD":"EVEN")); switch (($(this).index()+1)%4) { case 1: // nothing needed //console.log("case 1"); break; case 2: //need to shift one position and wrap into 240px div //console.log("case 2"); $(this).insertAfter($(this).next()); //swaps this with next $(this).prevAll(":nth(0), :nth(1)").wrapAll("<div class=\"grid_4\" />"); break; case 3: //need to shift two positions and wrap into 480px div //console.log("case 3"); $(this).prevAll(":nth(0), :nth(1)").wrapAll("<div class=\"grid_4\" />"); //wraps previous two - forcing them into column $(this).nextAll(":nth(0), :nth(1)").wrapAll("<div class=\"grid_4\" />"); //wraps next two - forcing them into column $(this).insertAfter($(this).next()); //moves behind the second column break; case 0: //need to shift one position //console.log("case 4"); $(this).insertAfter($(this).next()); //console.log("shifted to next line"); break; } }); It should be obvious from the comments how it works - generally always makes sure that the big tile is on odd position (count of preceding small tiles is even) by shifting one position back if needed. Also small tiles to the left from the big one need to be wrapped in another div so that they appear in column rather than row. Now finally the questions: how to generalize the function so that I can use even more tile dimensions like 720x360 (3x2), 480x540 (2x3), etc.? is there a way to simplify the function? I need to make sure that big tile counts as a multiple of small tiles when checking the actual position. Because using index() on the tile on position 12 (last tile in 3rd row) would now return 7 (position 8) because tiles on positions 5 and 9 are wrapped together in one culumn and the big tile is also just a single div, but spans 2x2 positions. any clean way to ensure this? Thank you very much for any hints. Feel free to reuse the code, I think it can be useful. Josef

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  • OpenVPN Server Ethernet Bridging Question

    - by Hooplad
    Hello All, I am having a difficult time properly configuring an ethernet bridge using OpenVPN 2.0.9 install on CentOS 5 ( VPN server ). The goal that I am trying to complete is to connect a VM ( instance running on the same CentOS machine ) acting as a Microsoft Business Contact Manager server. I would then like this "BCM server" to serve Windows XP clients on 192.168.1.0/24 network as well as clients connecting from VPN ( 10.8.0.0/24 ). The setup as it is now was based off a known working configuration. The problem with the working configuration was that it would allow to the client to connect and access everything running on the VPN server ( SVN, Samba, VM Server ) but not any computers on the 192.168.1.0/24 network. I must disclose that the VPN server is behind a router/firewall. Ports are being forwarded correctly ( again, clients were able to connect to the VPN server with no problem. netcat confirms the udp port is open as well ). current ifconfig output br0 Link encap:Ethernet HWaddr 00:21:5E:4D:3A:C2 inet addr:192.168.1.169 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::221:5eff:fe4d:3ac2/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:846890 errors:0 dropped:0 overruns:0 frame:0 TX packets:3072351 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:42686842 (40.7 MiB) TX bytes:4540654180 (4.2 GiB) eth0 Link encap:Ethernet HWaddr 00:21:5E:4D:3A:C2 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:882641 errors:0 dropped:0 overruns:0 frame:0 TX packets:1781383 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:82342803 (78.5 MiB) TX bytes:2614727660 (2.4 GiB) Interrupt:169 eth1 Link encap:Ethernet HWaddr 00:21:5E:4D:3A:C3 UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1 RX packets:650 errors:0 dropped:0 overruns:0 frame:0 TX packets:1347223 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:67403 (65.8 KiB) TX bytes:1959529142 (1.8 GiB) Interrupt:233 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:17452058 errors:0 dropped:0 overruns:0 frame:0 TX packets:17452058 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:94020256229 (87.5 GiB) TX bytes:94020256229 (87.5 GiB) tap0 Link encap:Ethernet HWaddr DE:18:C6:D7:01:63 inet6 addr: fe80::dc18:c6ff:fed7:163/64 Scope:Link UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:3086 errors:0 dropped:166 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:0 (0.0 b) TX bytes:315099 (307.7 KiB) vmnet1 Link encap:Ethernet HWaddr 00:50:56:C0:00:01 inet addr:192.168.177.1 Bcast:192.168.177.255 Mask:255.255.255.0 inet6 addr: fe80::250:56ff:fec0:1/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:4224 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) vmnet8 Link encap:Ethernet HWaddr 00:50:56:C0:00:08 inet addr:192.168.55.1 Bcast:192.168.55.255 Mask:255.255.255.0 inet6 addr: fe80::250:56ff:fec0:8/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:4226 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) current route table Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.55.0 * 255.255.255.0 U 0 0 0 vmnet8 192.168.177.0 * 255.255.255.0 U 0 0 0 vmnet1 192.168.1.0 * 255.255.255.0 U 0 0 0 br0 current iptables output Chain INPUT (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere ACCEPT all -- anywhere anywhere Chain FORWARD (policy ACCEPT) target prot opt source destination ACCEPT all -- anywhere anywhere Chain OUTPUT (policy ACCEPT) target prot opt source destination server_known_working.conf local banshee port 1194 proto udp dev tap0 ca ca.crt cert banshee_server.crt key banshee_server.key dh dh1024.pem server 10.8.0.0 255.255.255.0 ifconfig-pool-persist ipp.txt push "route 192.168.1.0 255.255.255.0" client-to-client keepalive 10 120 tls-auth ta.key 0 user nobody group nobody persist-key persist-tun status openvpn-status.log verb 4 The following is the current CentOS server config file. server_ethernet_bridged.conf ( current ) local 192.168.1.169 port 1194 proto udp dev tap0 ca ca.crt cert server.crt key server.key dh dh1024.pem ifconfig-pool-persist ipp.txt server-bridge 192.168.1.169 255.255.255.0 192.168.1.200 192.168.1.210 push "route 192.168.1.0 255.255.255.0 192.168.1.1" client-to-client keepalive 10 120 tls-auth ta.key 0 user nobody group nobody persist-key persist-tun status openvpn-status.log verb 6 The following is one of the client's config file that was used with the known working configuration. client.opvn client dev tap proto udp remote XXX.XXX.XXX 1194 resolv-retry infinite nobind persist-key persist-tun ca client.crt cert client.crt key client.key tls-auth client.key 1 verb 3 I have tried the HOWTO provided by OpenVPN as well as others http://www.thebakershome.net/openvpn%5Ftutorial?page=1 with no success. Any help or suggestions would be appreciated.

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  • surfaceDestroyed called out of turn

    - by Avasulthiris
    I'm currently developing on minimum sdk version 3 (Android 1.5 - cupcake) and I'm having a strange unexplained issue that I have not been able to solve on my own. It is now becoming a rather urgent issue as I've already missed 1 deadline... I'm writing a high-level library to make long term android development easier and quicker. The one specific module has to capture images for a application... I've gotten everything right so far over the last couple months, except this one little thing and I don't know what to do any more: When I use the Camera object and implement a SurfaceHolder.Callback, the methods surfaceCreated() and surfaceChanged() are called one after the other. Then when the activity finishes, surfaceDestroyed() is called. This is how it should be, but when I stick the exact same code in my library (plain Java library that references the Android API - not in an activity), surfaceDestroyed() is called directly after created and changed. As a result - the camera object is closed before I can use it and the application force closes. What a pain. I can't do anything! This method call is controlled by the device.. Why does the surface close for no reason? Even when I post it to run on the activity thread through my own invokeAndWait(Runnable) method, like I do for many other things. I have 5 different working examples of different ways and implementations of capturing images in android but I still get the same issue when I plug it into my library. I don't understand what the difference is. The code is pretty much the same - and I post all the related code to the UI thread so its not a thread handling issue or anything like that. I've rewritten it about 20 times in different ways - same issue every time.. The only other way to approach it that I know of is creating a new Camera and setting it to the VideoView. The android source (c++ native code) however provides no Camera constructor, only an open() method which automatically forwards the camera's state to 'prepared' but I can only set the camera to the VideoView from the 'initialized' state. Pretty silly, I know, but there is no way around it unless I modify the Android library source code haha. not an option! The API does not allow for this method - you are expected to use it like my first example. So essentially - i just need to understand exactly why surfaceDestroyed() is called out of turn and if there is anything I can do to avoid it closing? If i can just understand the exact logic behind it and how it works! The documentation isn't much help! Secondly, if someone knows of any alternative ways to do it, as my second example, but hopefully one which the API actually allows for? haha Thanks guys. I would post code, but its fairly complicated, a couple thousand lines for this specific class and it would probably take a couple days to explain with all the threading and event listeners and what not. I just need help with this 1 single thing. Please let me know if you have any questions.

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  • <optgroup> Not working in jQuery Dropdown

    - by Santhosh Kumar
    I have a asp:dropdownlist which i have changed to jQuery multiselect. I have to group the data inside the dropdown. I am grouping this in runtime.If it is a normal asp dropdown its working. When applying jquery Multiselect its dosen't. Source: <link rel="stylesheet" type="text/css" href="Styles/jquery.multiselect.css" /> <link rel="stylesheet" type="text/css" href="Styles/jquery.multiselect.filter.css" /> <link rel="stylesheet" type="text/css" href="Styles/style.css" /> <link rel="stylesheet" type="text/css" href="Styles/prettify.css" /> <%--<script src="Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>--%> <script src="Scripts/jquery-1.4.1.js" type="text/javascript"></script> <link rel="stylesheet" type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1/themes/ui-lightness/jquery-ui.css" /> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js"></script> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1/jquery-ui.min.js"></script> <script type="text/javascript" src="Scripts/jquery.multiselect.js"></script> <script type="text/javascript" src="Scripts/jquery.multiselect.filter.js"></script> <script type="text/javascript" src="Scripts/prettify.js"></script> <script type="text/javascript"> $(document).ready(function () { //Create groups for dropdown list $("option[classification='LessThanFive']").wrapAll("<optgroup label='Less Than Five' />"); $("option[classification='GreaterThanFive']").wrapAll("<optgroup label='Greater Than five' />"); }); </script> <asp:DropDownList ID="MobileData" runat="server" OnDataBound="ddl_DataBound"> </asp:DropDownList> //Code Behind: protected void ddl_DataBound(object sender, EventArgs e) { foreach (ListItem item in ((DropDownList)sender).Items) { if (System.Int32.Parse(item.Value) < 2) item.Attributes.Add("classification", "LessThanFive"); else item.Attributes.Add("classification", "GreaterThanFive"); } } protected void Page_Load(object sender, EventArgs e) { ListItemCollection list = new ListItemCollection(); list.Add(new ListItem("1", "1")); list.Add(new ListItem("2", "2")); list.Add(new ListItem("3", "3")); list.Add(new ListItem("4", "4")); list.Add(new ListItem("5", "5")); list.Add(new ListItem("6", "6")); list.Add(new ListItem("7", "7")); list.Add(new ListItem("8", "8")); list.Add(new ListItem("9", "9")); list.Add(new ListItem("10", "10")); MobileData.DataSource = list; MobileData.DataBind(); } Where i'm wrong?

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  • What does the `forall` keyword in Haskell/GHC do?

    - by JUST MY correct OPINION
    I've been banging my head on this one for (quite literally) years now. I'm beginning to kinda/sorta understand how the foreach keyword is used in so-called "existential types" like this: data ShowBox = forall s. Show s => SB s (This despite the confusingly-worded explanations of it in the fragments found all around the web.) This is only a subset, however, of how foreach is used and I simply cannot wrap my mind around its use in things like this: runST :: forall a. (forall s. ST s a) -> a Or explaining why these are different: foo :: (forall a. a -> a) -> (Char,Bool) bar :: forall a. ((a -> a) -> (Char, Bool)) Or the whole RankNTypes stuff that breaks my brain when "explained" in a way that makes me want to do that Samuel L. Jackson thing from Pulp Fiction. (Don't follow that link if you're easily offended by strong language.) The problem, really, is that I'm a dullard. I can't fathom the chicken scratchings (some call them "formulae") of the elite mathematicians that created this language seeing as my university years are over two decades behind me and I never actually had to put what I learnt into use in practice. I also tend to prefer clear, jargon-free English rather than the kinds of language which are normal in academic environments. Most of the explanations I attempt to read on this (the ones I can find through search engines) have these problems: They're incomplete. They explain one part of the use of this keyword (like "existential types") which makes me feel happy until I read code that uses it in a completely different way (like runST, foo and bar above). They're densely packed with assumptions that I've read the latest in whatever branch of discrete math, category theory or abstract algebra is popular this week. (If I never read the words "consult the paper whatever for details of implementation" again, it will be too soon.) They're written in ways that frequently turn even simple concepts into tortuously twisted and fractured grammar and semantics. (I suspect that the last two items are the biggest problem. I wouldn't know, though, since I'm too much a dullard to comprehend them.) It's been asked why Haskell never really caught on in industry. I suspect, in my own humble, unintelligent way, that my experience in figuring out one stupid little keyword -- a keyword that is increasingly ubiquitous in the libraries being written these days -- are also part of the answer to that question. It's hard for a language to catch on when even its individual keywords cause years-long quests to comprehend. Years-long quests which end in failure. So... On to the actual question. Can anybody completely explain the foreach keyword in clear, plain English (or, if it exists somewhere, point to such a clear explanation which I've missed) that doesn't assume I'm a mathematician steeped in the jargon?

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  • Selecting unique records in XSLT/XPath

    - by Daniel I-S
    I have to select only unique records from an XML document, in the context of an <xsl:for-each> loop. I am limited by Visual Studio to using XSL 1.0. <availList> <item> <schDate>2010-06-24</schDate> <schFrmTime>10:00:00</schFrmTime> <schToTime>13:00:00</schToTime> <variousOtherElements></variousOtherElements> </item> <item> <schDate>2010-06-24</schDate> <schFrmTime>10:00:00</schFrmTime> <schToTime>13:00:00</schToTime> <variousOtherElements></variousOtherElements> </item> <item> <schDate>2010-06-25</schDate> <schFrmTime>10:00:00</schFrmTime> <schToTime>12:00:00</schToTime> <variousOtherElements></variousOtherElements> </item> <item> <schDate>2010-06-26</schDate> <schFrmTime>13:00:00</schFrmTime> <schToTime>14:00:00</schToTime> <variousOtherElements></variousOtherElements> </item> <item> <schDate>2010-06-26</schDate> <schFrmTime>10:00:00</schFrmTime> <schToTime>12:00:00</schToTime> <variousOtherElements></variousOtherElements> </item> </availList> The uniqueness must be based on the value of the three child elements: schDate, schFrmTime and schToTime. If two item elements have the same values for all three child elements, they are duplicates. In the above XML, items one and two are duplicates. The rest are unique. As indicated above, each item contains other elements that we do not wish to include in the comparison. 'Uniqueness' should be a factor of those three elements, and those alone. I have attempted to accomplish this through the following: availList/item[not(schDate = preceding:: schDate and schFrmTime = preceding:: schFrmTime and schToTime = preceding:: schToTime)] The idea behind this is to select records where there is no preceding element with the same schDate, schFrmTime and schToTime. However, its output is missing the last item. This is because my XPath is actually excluding items where all of the child element values are matched within the entire preceding document. No single item matches all of the last item's child elements - but because each element's value is individually present in another item, the last item gets excluded. I could get the correct result by comparing all child values as a concatenated string to the same concatenated values for each preceding item. Does anybody know of a way I could do this?

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  • Appropriate programming design questions.

    - by Edward
    I have a few questions on good programming design. I'm going to first describe the project I'm building so you are better equipped to help me out. I am coding a Remote Assistance Tool similar to TeamViewer, Microsoft Remote Desktop, CrossLoop. It will incorporate concepts like UDP networking (using Lidgren networking library), NAT traversal (since many computers are invisible behind routers nowadays), Mirror Drivers (using DFMirage's Mirror Driver (http://www.demoforge.com/dfmirage.htm) for realtime screen grabbing on the remote computer). That being said, this program has a concept of being a client-server architecture, but I made only one program with both the functionality of client and server. That way, when the user runs my program, they can switch between giving assistance and receiving assistance without having to download a separate client or server module. I have a Windows Form that allows the user to choose between giving assistance and receiving assistance. I have another Windows Form for a file explorer module. I have another Windows Form for a chat module. I have another Windows Form form for a registry editor module. I have another Windows Form for the live control module. So I've got a Form for each module, which raises the first question: 1. Should I process module-specific commands inside the code of the respective Windows Form? Meaning, let's say I get a command with some data that enumerates the remote user's files for a specific directory. Obviously, I would have to update this on the File Explorer Windows Form and add the entries to the ListView. Should I be processing this code inside the Windows Form though? Or should I be handling this in another class (although I have to eventually pass the data to the Form to draw, of course). Or is it like a hybrid in which I process most of the data in another class and pass the final result to the Form to draw? So I've got like 5-6 forms, one for each module. The user starts up my program, enters the remote machine's ID (not IP, ID, because we are registering with an intermediary server to enable NAT traversal), their password, and connects. Now let's suppose the connection is successful. Then the user is presented with a form with all the different modules. So he can open up a File Explorer, or he can mess with the Registry Editor, or he can choose to Chat with his buddy. So now the program is sort of idle, just waiting for the user to do something. If the user opens up Live Control, then the program will be spending most of it's time receiving packets from the remote machine and drawing them to the form to provide a 'live' view. 2. Second design question. A spin off question #1. How would I pass module-specific commands to their respective Windows Forms? What I mean is, I have a class like "NetworkHandler.cs" that checks for messages from the remote machine. NetworkHandler.cs is a static class globally accessible. So let's say I get a command that enumerates the remote user's files for a specific directory. How would I "give" that command to the File Explorer Form. I was thinking of making an OnCommandReceivedEvent inside NetworkHandler, and having each form register to that event. When the NetworkHandler received a command, it would raise the event, all forms would check it to see if it was relevant, and the appropriate form would take action. Is this an appropriate/the best solution available? 3. The networking library I'm using, Lidgren, provides two options for checking networking messages. One can either poll ReadMessage() to return null or a message, or one can use an AutoResetEvent OnMessageReceived (I'm guessing this is like an event). Which one is more appropriate?

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  • Rails unknown action suddenly everywhere

    - by Joe
    The weird thing is that my app was working perfectly on Sat, and when I check it out on Monday (after doing nothing to it) I kept getting this problem: This behaviour is only happening on my production server. When I try to login or create a new user or do something that interacts with a form I am getting an unknown action error. A simple retrieval of rows does not throw this error however. I don't have all CRUD operations in most of my controllers because it's not necessary - but Rails always looks for the one that doesn't exist - it seams so anyway. If I make a mistake in the form that would normally throw a validation message to the user it will throw this error too, does that mean it has something to do with the model too (I'm not too Rails experienced and didn't know if that would be the case or not)? This is a general error I am getting - I have super_exception_notifier gem installed, so that's what all the extra params are. Processing SessionsController#new (for OMITTED at 2010-04-12 09:11:12) [GET] Rendering template within layouts/application Rendering sessions/new Completed in 3ms (View: 2, DB: 0) | 200 OK [http://OMITTED.com/session/new] Processing SessionsController#show (for OMITTED at 2010-04-12 09:11:14) [GET] ActionController::UnknownAction (No action responded to show. Actions: create, destroy, error_class_status_codes, error_class_status_codes=, error_layout, error_layout=, exception_notifiable_notification_level, exception_notifiable_notification_level=, exception_notifiable_silent_exceptions, exception_notifiable_silent_exceptions=, exception_notifiable_verbose, exception_notifiable_verbose=, http_status_codes, http_status_codes=, and new): dragonfly (0.5.3) lib/dragonfly/middleware.rb:13:in `call' passenger (2.2.9) lib/phusion_passenger/rack/request_handler.rb:92:in `process_request' passenger (2.2.9) lib/phusion_passenger/abstract_request_handler.rb:207:in `main_loop' passenger (2.2.9) lib/phusion_passenger/railz/application_spawner.rb:400:in `start_request_handler' passenger (2.2.9) lib/phusion_passenger/railz/application_spawner.rb:351:in `handle_spawn_application' passenger (2.2.9) lib/phusion_passenger/utils.rb:184:in `safe_fork' passenger (2.2.9) lib/phusion_passenger/railz/application_spawner.rb:349:in `handle_spawn_application' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:352:in `__send__' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:352:in `main_loop' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:196:in `start_synchronously' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:163:in `start' passenger (2.2.9) lib/phusion_passenger/railz/application_spawner.rb:209:in `start' passenger (2.2.9) lib/phusion_passenger/spawn_manager.rb:262:in `spawn_rails_application' passenger (2.2.9) lib/phusion_passenger/abstract_server_collection.rb:126:in `lookup_or_add' passenger (2.2.9) lib/phusion_passenger/spawn_manager.rb:256:in `spawn_rails_application' passenger (2.2.9) lib/phusion_passenger/abstract_server_collection.rb:80:in `synchronize' passenger (2.2.9) lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize' passenger (2.2.9) lib/phusion_passenger/spawn_manager.rb:255:in `spawn_rails_application' passenger (2.2.9) lib/phusion_passenger/spawn_manager.rb:154:in `spawn_application' passenger (2.2.9) lib/phusion_passenger/spawn_manager.rb:287:in `handle_spawn_application' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:352:in `__send__' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:352:in `main_loop' passenger (2.2.9) lib/phusion_passenger/abstract_server.rb:196:in `start_synchronously' This is what one of my forms looks like (nothing special) <% form_tag session_path do -%> <p><%= label_tag 'Username' %><br /> <%= text_field_tag 'login', @login %></p> <p><%= label_tag 'password' %><br/> <%= password_field_tag 'password', nil %></p> <p><%= label_tag 'remember_me', 'Remember me' %> <%= check_box_tag 'remember_me', '1', @remember_me %></p> <p><%= submit_tag 'Log in' %></p> <% end -%> It looks like dragonfly is the culprit doesn't it, here's the section from the gem files it says is being naughty: module Dragonfly class Middleware def initialize(app, dragonfly_app_name) @app = app @dragonfly_app_name = dragonfly_app_name end def call(env) response = endpoint.call(env) if response[0] == 404 13 -->> @app.call(env) else response end end I don't know what goes on behind the scenes here so I probably haven't been looking in the right place to fix this issue. Like I said it only throws this in a production environment, which guess is what the 'env' variable is referencing. Thank you for your time! I've spent nearly my whole day trying to figure this out! :(

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  • Languages and VMs: Features that are hard to optimize and why

    - by mrjoltcola
    I'm doing a survey of features in preparation for a research project. Name a mainstream language or language feature that is hard to optimize, and why the feature is or isn't worth the price paid, or instead, just debunk my theories below with anecdotal evidence. Before anyone flags this as subjective, I am asking for specific examples of languages or features, and ideas for optimization of these features, or important features that I haven't considered. Also, any references to implementations that prove my theories right or wrong. Top on my list of hard to optimize features and my theories (some of my theories are untested and are based on thought experiments): 1) Runtime method overloading (aka multi-method dispatch or signature based dispatch). Is it hard to optimize when combined with features that allow runtime recompilation or method addition. Or is it just hard, anyway? Call site caching is a common optimization for many runtime systems, but multi-methods add additional complexity as well as making it less practical to inline methods. 2) Type morphing / variants (aka value based typing as opposed to variable based) Traditional optimizations simply cannot be applied when you don't know if the type of someting can change in a basic block. Combined with multi-methods, inlining must be done carefully if at all, and probably only for a given threshold of size of the callee. ie. it is easy to consider inlining simple property fetches (getters / setters) but inlining complex methods may result in code bloat. The other issue is I cannot just assign a variant to a register and JIT it to the native instructions because I have to carry around the type info, or every variable needs 2 registers instead of 1. On IA-32 this is inconvenient, even if improved with x64's extra registers. This is probably my favorite feature of dynamic languages, as it simplifies so many things from the programmer's perspective. 3) First class continuations - There are multiple ways to implement them, and I have done so in both of the most common approaches, one being stack copying and the other as implementing the runtime to use continuation passing style, cactus stacks, copy-on-write stack frames, and garbage collection. First class continuations have resource management issues, ie. we must save everything, in case the continuation is resumed, and I'm not aware if any languages support leaving a continuation with "intent" (ie. "I am not coming back here, so you may discard this copy of the world"). Having programmed in the threading model and the contination model, I know both can accomplish the same thing, but continuations' elegance imposes considerable complexity on the runtime and also may affect cache efficienty (locality of stack changes more with use of continuations and co-routines). The other issue is they just don't map to hardware. Optimizing continuations is optimizing for the less-common case, and as we know, the common case should be fast, and the less-common cases should be correct. 4) Pointer arithmetic and ability to mask pointers (storing in integers, etc.) Had to throw this in, but I could actually live without this quite easily. My feelings are that many of the high-level features, particularly in dynamic languages just don't map to hardware. Microprocessor implementations have billions of dollars of research behind the optimizations on the chip, yet the choice of language feature(s) may marginalize many of these features (features like caching, aliasing top of stack to register, instruction parallelism, return address buffers, loop buffers and branch prediction). Macro-applications of micro-features don't necessarily pan out like some developers like to think, and implementing many languages in a VM ends up mapping native ops into function calls (ie. the more dynamic a language is the more we must lookup/cache at runtime, nothing can be assumed, so our instruction mix is made up of a higher percentage of non-local branching than traditional, statically compiled code) and the only thing we can really JIT well is expression evaluation of non-dynamic types and operations on constant or immediate types. It is my gut feeling that bytecode virtual machines and JIT cores are perhaps not always justified for certain languages because of this. I welcome your answers.

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  • [C#][Design] Appropriate programming design questions.

    - by Edward
    I have a few questions on good programming design. I'm going to first describe the project I'm building so you are better equipped to help me out. I am coding a Remote Assistance Tool similar to TeamViewer, Microsoft Remote Desktop, CrossLoop. It will incorporate concepts like UDP networking (using Lidgren networking library), NAT traversal (since many computers are invisible behind routers nowadays), Mirror Drivers (using DFMirage's Mirror Driver (http://www.demoforge.com/dfmirage.htm) for realtime screen grabbing on the remote computer). That being said, this program has a concept of being a client-server architecture, but I made only one program with both the functionality of client and server. That way, when the user runs my program, they can switch between giving assistance and receiving assistance without having to download a separate client or server module. I have a Windows Form that allows the user to choose between giving assistance and receiving assistance. I have another Windows Form for a file explorer module. I have another Windows Form for a chat module. I have another Windows Form form for a registry editor module. I have another Windows Form for the live control module. So I've got a Form for each module, which raises the first question: 1. Should I process module-specific commands inside the code of the respective Windows Form? Meaning, let's say I get a command with some data that enumerates the remote user's files for a specific directory. Obviously, I would have to update this on the File Explorer Windows Form and add the entries to the ListView. Should I be processing this code inside the Windows Form though? Or should I be handling this in another class (although I have to eventually pass the data to the Form to draw, of course). Or is it like a hybrid in which I process most of the data in another class and pass the final result to the Form to draw? So I've got like 5-6 forms, one for each module. The user starts up my program, enters the remote machine's ID (not IP, ID, because we are registering with an intermediary server to enable NAT traversal), their password, and connects. Now let's suppose the connection is successful. Then the user is presented with a form with all the different modules. So he can open up a File Explorer, or he can mess with the Registry Editor, or he can choose to Chat with his buddy. So now the program is sort of idle, just waiting for the user to do something. If the user opens up Live Control, then the program will be spending most of it's time receiving packets from the remote machine and drawing them to the form to provide a 'live' view. 2. Second design question. A spin off question #1. How would I pass module-specific commands to their respective Windows Forms? What I mean is, I have a class like "NetworkHandler.cs" that checks for messages from the remote machine. NetworkHandler.cs is a static class globally accessible. So let's say I get a command that enumerates the remote user's files for a specific directory. How would I "give" that command to the File Explorer Form. I was thinking of making an OnCommandReceivedEvent inside NetworkHandler, and having each form register to that event. When the NetworkHandler received a command, it would raise the event, all forms would check it to see if it was relevant, and the appropriate form would take action. Is this an appropriate/the best solution available? 3. The networking library I'm using, Lidgren, provides two options for checking networking messages. One can either poll ReadMessage() to return null or a message, or one can use an AutoResetEvent OnMessageReceived (I'm guessing this is like an event). Which one is more appropriate?

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  • Why is the this-pointer needed to access inherited attributes?

    - by Shadow
    Hi, assume the following class is given: class Base{ public: Base() {} Base( const Base& b) : base_attr(b.base_attr) {} void someBaseFunction() { .... } protected: SomeType base_attr; }; When I want a class to inherit from this one and include a new attribute for the derived class, I would write: class Derived: public Base { public: Derived() {} Derived( const Derived& d ) : derived_attr(d.derived_attr) { this->base_attr = d.base_attr; } void SomeDerivedFunction() { .... } private: SomeOtherType derived_attr; }; This works for me (let's ignore eventually missing semicolons or such please). However, when I remove the "this-" in the copy constructor of the derived class, the compiler complains that "'base_attr' was not declared in this scope". I thought that, when inheriting from a class, the protected attributes would then also be accessible directly. I did not know that the "this-" pointer was needed. I am now confused if it is actually correct what I am doing there, especially the copy-constructor of the Derived-class. Because each Derived object is supposed to have a base_attr and a derived_attr and they obviously need to be initialized/set correctly. And because Derived is inheriting from Base, I don't want to explicitly include an attribute named "base_attr" in the Derived-class. IMHO doing so would generally destroy the idea behind inheritance, as everything would have to be defined again. EDIT Thank you all for the quick answers. I completely forgot the fact that the classes actually are templates. Please, see the new examples below, which are actually compiling when including "this-" and are failing when omiting "this-" in the copy-constructor of the Derived-class: Base-class: #include <iostream> template<class T> class Base{ public: Base() : base_attr(0) {} Base( const Base& b) : base_attr(b.base_attr) {} void baseIncrement() { ++base_attr; } void printAttr() { std::cout << "Base Attribute: " << base_attr << std::endl; } protected: T base_attr; }; Derived-class: #include "base.hpp" template< class T > class Derived: public Base<T>{ public: Derived() : derived_attr(1) {} Derived( const Derived& d) : derived_attr(d.derived_attr) { this->base_attr = d.base_attr; } void derivedIncrement() { ++derived_attr; } protected: T derived_attr; }; and for completeness also the main function: #include "derived.hpp" int main() { Derived<int> d; d.printAttr(); d.baseIncrement(); d.printAttr(); Derived<int> d2(d); d2.printAttr(); return 0; }; I am using g++-4.3.4. Although I understood now that it seems to come from the fact that I use template-class definitions, I did not quite understand what is causing the problem when using templates and why it works when not using templates. Could someone please further clarify this?

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  • Modern alternatives to Java

    - by Ralph
    I have been a Java developer for 14 years and have written an enterprise-level (~500 kloc) Swing application that uses most of the standard library APIs. Recently, I have become disappointed with the progress that the language has made to "modernize" itself, and am looking for an alternative for ongoing development. I have considered moving to the .NET platform, but I have issues with using something the only runs well in Windows (I know about Mono, but that is still far behind Microsoft). I also plan on buying a new Macbook Pro as soon as Apple releases their new rumored Arrandale-based machines and want to develop in an environment that will feel "at home" in Unix/Linux. I have considered using Python or Ruby, but the standard Java library is arguably the largest of any modern language. In JVM-based languages, I looked at Groovy, but am disappointed with its performance. Rumor has it that with the soon-to-be released JDK7, with its InvokeDynamic instruction, this will improve, but I don't know how much. Groovy is also not truly a functional language, although it provides closures and some of the "functional" features on collections. It does not embrace immutability. I have narrowed my search down to two JVM-based alternatives: Scala and Clojure. Each has its strengths and weaknesses. I am looking for opinions. I am not an expert at either of these languages; I have read 2 1/2 books on Scala and am currently reading Stu Halloway's book on Clojure. Scala is strongly statically typed. I know the dynamic language folks claim that static typing is a crutch for not doing unit testing, but it does provide a mechanism for compile-time location of a whole class of errors. Scala is more concise than Java, but not as much as Clojure. Scala's inter-operation with Java seems to be better than Clojure's, in that most Java operations are easier to do in Scala than in Clojure. For example, I can find no way in Clojure to create a non-static initialization block in a class derived from a Java superclass. For example, I like the Apache commons CLI library for command line argument parsing. In Java and Scala, I can create a new Options object and add Option items to it in an initialization block as follows (Java code): final Options options = new Options() { { addOption(new Option("?", "help", false, "Show this usage information"); // other options } }; I can't figure out how to the same thing in Clojure (except by using (doit...)), although that may reflect my lack of knowledge of the language. Clojure's collections are optimized for immutability. They rarely require copy-on-write semantics. I don't know if Scala's immutable collections are implemented using similar algorithms, but Rich Hickey (Clojure's inventor) goes out of his way to explain how that language's data structures are efficient. Clojure was designed from the beginning for concurrency (as was Scala) and with modern multi-core processors, concurrency takes on more importance, but I occasionally need to write simple non-concurrent utilities, and Scala code probably runs a little faster for these applications since it discourages, but does not prohibit, "simple" mutability. One could argue that one-off utilities do not have to be super-fast, but sometimes they do tasks that take hours or days to complete. I know that there is no right answer to this "question", but I thought I would open it up for discussion. Are there other JVM-based languages that can be used for enterprise level development?

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  • Router 2wire, Slackware desktop in DMZ mode, iptables policy aginst ping, but still pingable

    - by skriatok
    I'm in DMZ mode, so I'm firewalling myself, stealthy all ok, but I get faulty test results from Shields Up that there are pings. Yesterday I couldn't make a connection to game servers work, because ping block was enabled (on the router). I disabled it, but this persists even due to my firewall. What is the connection between me and my router in DMZ mode (for my machine, there is bunch of others too behind router firewall)? When it allows router affecting if I'm pingable or not and if router has setting not blocking ping, rules in my iptables for this scenario do not work. Please ignore commented rules, I do uncomment them as I want. These two should do the job right? iptables -A INPUT -p icmp --icmp-type echo-request -j DROP echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all Here are my iptables: #!/bin/sh # Begin /bin/firewall-start # Insert connection-tracking modules (not needed if built into the kernel). #modprobe ip_tables #modprobe iptable_filter #modprobe ip_conntrack #modprobe ip_conntrack_ftp #modprobe ipt_state #modprobe ipt_LOG # allow local-only connections iptables -A INPUT -i lo -j ACCEPT # free output on any interface to any ip for any service # (equal to -P ACCEPT) iptables -A OUTPUT -j ACCEPT # permit answers on already established connections # and permit new connections related to established ones (eg active-ftp) iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT #Gamespy&NWN #iptables -A INPUT -p tcp -m tcp -m multiport --ports 5120:5129 -j ACCEPT #iptables -A INPUT -p tcp -m tcp --dport 6667 --tcp-flags SYN,RST,ACK SYN -j ACCEPT #iptables -A INPUT -p tcp -m tcp --dport 28910 --tcp-flags SYN,RST,ACK SYN -j ACCEPT #iptables -A INPUT -p tcp -m tcp --dport 29900 --tcp-flags SYN,RST,ACK SYN -j ACCEPT #iptables -A INPUT -p tcp -m tcp --dport 29901 --tcp-flags SYN,RST,ACK SYN -j ACCEPT #iptables -A INPUT -p tcp -m tcp --dport 29920 --tcp-flags SYN,RST,ACK SYN -j ACCEPT #iptables -A INPUT -p udp -m udp -m multiport --ports 5120:5129 -j ACCEPT #iptables -A INPUT -p udp -m udp --dport 6500 -j ACCEPT #iptables -A INPUT -p udp -m udp --dport 27900 -j ACCEPT #iptables -A INPUT -p udp -m udp --dport 27901 -j ACCEPT #iptables -A INPUT -p udp -m udp --dport 29910 -j ACCEPT # Log everything else: What's Windows' latest exploitable vulnerability? iptables -A INPUT -j LOG --log-prefix "FIREWALL:INPUT" # set a sane policy: everything not accepted > /dev/null iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP iptables -A INPUT -p icmp --icmp-type echo-request -j DROP # be verbose on dynamic ip-addresses (not needed in case of static IP) echo 2 > /proc/sys/net/ipv4/ip_dynaddr # disable ExplicitCongestionNotification - too many routers are still # ignorant echo 0 > /proc/sys/net/ipv4/tcp_ecn #ping death echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all # If you are frequently accessing ftp-servers or enjoy chatting you might # notice certain delays because some implementations of these daemons have # the feature of querying an identd on your box for your username for # logging. Although there's really no harm in this, having an identd # running is not recommended because some implementations are known to be # vulnerable. # To avoid these delays you could reject the requests with a 'tcp-reset': #iptables -A INPUT -p tcp --dport 113 -j REJECT --reject-with tcp-reset #iptables -A OUTPUT -p tcp --sport 113 -m state --state RELATED -j ACCEPT # To log and drop invalid packets, mostly harmless packets that came in # after netfilter's timeout, sometimes scans: #iptables -I INPUT 1 -p tcp -m state --state INVALID -j LOG --log-prefix \ "FIREWALL:INVALID" #iptables -I INPUT 2 -p tcp -m state --state INVALID -j DROP # End /bin/firewall-start Active ruleset: bash-4.1# iptables -L -n -v Chain INPUT (policy DROP 38 packets, 2228 bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 844 542K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 38 2228 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix `FIREWALL:INPUT' 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 38 2228 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix `FIREWALL:INPUT' Chain FORWARD (policy DROP 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy DROP 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 1158 111K ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 Active ruleset: (after editing iptables into below sugested form) bash-4.1# iptables -L -n -v Chain INPUT (policy DROP 2567 packets, 172K bytes) pkts bytes target prot opt in out source destination 49 4157 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 412K 441M ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 2567 172K LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 prefix `FIREWALL:INPUT' 0 0 DROP icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmp type 8 Chain FORWARD (policy DROP 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 312K packets, 25M bytes) pkts bytes target prot opt in out source destination ping and syslog simultaneous screenshots from phone (pinger) and from laptop (being pinged) http://dl.dropbox.com/u/4160051/slckwr/pingfrom%20mobile.jpg http://dl.dropbox.com/u/4160051/slckwr/tailsyslog.jpg

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  • When Clearing an ObservableCollection, There are No Items in e.OldItems

    - by cplotts
    I have something here that is really catching me off guard. I have an ObservableCollection of T that is filled with items. I also have an event handler attached to the CollectionChanged event. When you Clear the collection it causes an CollectionChanged event with e.Action set to NotifyCollectionChangedAction.Reset. Ok, that's normal. But what is weird is that neither e.OldItems or e.NewItems has anything in it. I would expect e.OldItems to be filled with all items that were removed from the collection. Has anyone else seen this? And if so, how have they gotten around it? Some background: I am using the CollectionChanged event to attach and detach from another event and thus if I don't get any items in e.OldItems ... I won't be able to detach from that event. CLARIFICATION: I do know that the documentation doesn't outright state that it has to behave this way. But for every other action, it is notifying me of what it has done. So, my assumption is that it would tell me ... in the case of Clear/Reset as well. Below is the sample code if you wish to reproduce it yourself. First off the xaml: <Window x:Class="ObservableCollection.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300" > <StackPanel> <Button x:Name="addButton" Content="Add" Width="100" Height="25" Margin="10" Click="addButton_Click"/> <Button x:Name="moveButton" Content="Move" Width="100" Height="25" Margin="10" Click="moveButton_Click"/> <Button x:Name="removeButton" Content="Remove" Width="100" Height="25" Margin="10" Click="removeButton_Click"/> <Button x:Name="replaceButton" Content="Replace" Width="100" Height="25" Margin="10" Click="replaceButton_Click"/> <Button x:Name="resetButton" Content="Reset" Width="100" Height="25" Margin="10" Click="resetButton_Click"/> </StackPanel> </Window> Next, the code behind: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Collections.ObjectModel; namespace ObservableCollection { /// <summary> /// Interaction logic for Window1.xaml /// </summary> public partial class Window1 : Window { public Window1() { InitializeComponent(); _integerObservableCollection.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(_integerObservableCollection_CollectionChanged); } private void _integerObservableCollection_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) { switch (e.Action) { case System.Collections.Specialized.NotifyCollectionChangedAction.Add: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Move: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Remove: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Replace: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Reset: break; default: break; } } private void addButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Add(25); } private void moveButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Move(0, 19); } private void removeButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.RemoveAt(0); } private void replaceButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection[0] = 50; } private void resetButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Clear(); } private ObservableCollection<int> _integerObservableCollection = new ObservableCollection<int> { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 }; } }

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