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  • I need to remove Java Script tags using regular expressions and JRegex

    - by piotr
    I need to remove all the Java Script tags and the content in between and style tags from the HTML code of web pages.So far I've come up with this expression : "(<[ \r\n\t]script([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]noscript([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]style([ \r\n\t]|){1,}([ \r\n\t]|.)?)" I use JRegex library to work with regular expressions. When I test it in any regex tester it works just fine, but once I run my program - it all crashes down with this error report: Exception in thread "Thread-0" java.lang.StackOverflowError at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$BmpCharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) at java.util.regex.Pattern$GroupTail.match(Unknown Source) at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$CharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) .................................. And it keeps on going forever. If anyone can give me an advice on this one - I'll be very grateful.

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  • Silverlight MVVM Confusion: Updating Image Based on State

    - by senfo
    I'm developing a Silverlight application and I'm trying to stick to the MVVM principals, but I'm running into some problems changing the source of an image based on the state of a property in the ViewModel. For all intents and purposes, you can think of the functionality I'm implementing as a play/pause button for an audio app. When in the "Play" mode, IsActive is true in the ViewModel and the "Pause.png" image on the button should be displayed. When paused, IsActive is false in the ViewModel and "Play.png" is displayed on the button. Naturally, there are two additional images to handle when the mouse hovers over the button. I thought I could use a Style Trigger, but apparently they're not supported in Silverlight. I've been reviewing a forum post with a question similar to mine where it's suggested to use the VisualStateManager. While this might help with changing the image for hover/normal states, the part missing (or I'm not understanding) is how this would work with a state set via the view model. The post seems to apply only to events rather than properties of the view model. Having said that, I also haven't successfully completed the normal/hover affects, either. Below is my Silverlight 4 XAML. It should also probably be noted I'm working with MVVM Light. <UserControl x:Class="Foo.Bar.MyUserControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" mc:Ignorable="d" d:DesignHeight="100" d:DesignWidth="200"> <UserControl.Resources> <Style x:Key="MyButtonStyle" TargetType="Button"> <Setter Property="IsEnabled" Value="true"/> <Setter Property="IsTabStop" Value="true"/> <Setter Property="Background" Value="#FFA9A9A9"/> <Setter Property="Foreground" Value="#FF000000"/> <Setter Property="MinWidth" Value="5"/> <Setter Property="MinHeight" Value="5"/> <Setter Property="Margin" Value="0"/> <Setter Property="HorizontalAlignment" Value="Left" /> <Setter Property="HorizontalContentAlignment" Value="Center"/> <Setter Property="VerticalAlignment" Value="Top" /> <Setter Property="VerticalContentAlignment" Value="Center"/> <Setter Property="Cursor" Value="Hand"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="Button"> <Grid> <Image Source="/Foo.Bar;component/Resources/Icons/Bar/Play.png"> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="Active"> <VisualState x:Name="MouseOver"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Source" Storyboard.TargetName="/Foo.Bar;component/Resources/Icons/Bar/Play_Hover.png" /> </Storyboard> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> </Image> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="White"> <Button Style="{StaticResource MyButtonStyle}" Command="{Binding ChangeStatus}" Height="30" Width="30" /> </Grid> </UserControl> What is the proper way to update images on buttons with the state determined by the view model? Update I changed my Button to a ToggleButton hoping I could use the Checked state to differentiate between play/pause. I practically have it, but I ran into one additional problem. I need to account for two states at the same time. For example, Checked Normal/Hover and Unchecked Normal/Hover. Following is my updated XAML: <UserControl x:Class="Foo.Bar.MyUserControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity" mc:Ignorable="d" d:DesignHeight="100" d:DesignWidth="200"> <UserControl.Resources> <Style x:Key="MyButtonStyle" TargetType="ToggleButton"> <Setter Property="IsEnabled" Value="true"/> <Setter Property="IsTabStop" Value="true"/> <Setter Property="Background" Value="#FFA9A9A9"/> <Setter Property="Foreground" Value="#FF000000"/> <Setter Property="MinWidth" Value="5"/> <Setter Property="MinHeight" Value="5"/> <Setter Property="Margin" Value="0"/> <Setter Property="HorizontalAlignment" Value="Left" /> <Setter Property="HorizontalContentAlignment" Value="Center"/> <Setter Property="VerticalAlignment" Value="Top" /> <Setter Property="VerticalContentAlignment" Value="Center"/> <Setter Property="Cursor" Value="Hand"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ToggleButton"> <Grid> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="CommonStates"> <VisualState x:Name="Normal"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="Pause"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Collapsed</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="MouseOver"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="PlayHover"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Visible</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="Play"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Collapsed</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> <VisualStateGroup x:Name="CheckStates"> <VisualState x:Name="Checked"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="Pause"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Visible</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="Play"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Collapsed</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="PlayHover"> <DiscreteObjectKeyFrame KeyTime="0"> <DiscreteObjectKeyFrame.Value> <Visibility>Collapsed</Visibility> </DiscreteObjectKeyFrame.Value> </DiscreteObjectKeyFrame> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="Unchecked" /> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <Image x:Name="Play" Source="/Foo.Bar;component/Resources/Icons/Bar/Play.png" /> <Image x:Name="Pause" Source="/Foo.Bar;component/Resources/Icons/Bar/Pause.png" Visibility="Collapsed" /> <Image x:Name="PlayHover" Source="/Foo.Bar;component/Resources/Icons/Bar/Play_Hover.png" Visibility="Collapsed" /> <Image x:Name="PauseHover" Source="/Foo.Bar;component/Resources/Icons/Bar/Pause_Hover.png" Visibility="Collapsed" /> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="White"> <ToggleButton Style="{StaticResource MyButtonStyle}" IsChecked="{Binding IsPlaying}" Command="{Binding ChangeStatus}" Height="30" Width="30" /> </Grid> </UserControl>

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  • How do I bind arrays to columns in a WPF datagrid

    - by user1432917
    I have a Log object that contains a list of Curve objects. Each curve has a Name property and an array of doubles. I want the Name to be in the column header and the data below it. I have a user control with a datagid. Here is the XAML; <UserControl x:Class="WellLab.UI.LogViewer" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d" d:DesignHeight="500" d:DesignWidth="500"> <Grid> <StackPanel Height="Auto" HorizontalAlignment="Stretch" Margin="0" Name="stackPanel1" VerticalAlignment="Stretch" Width="Auto"> <ToolBarTray Height="26" Name="toolBarTray1" Width="Auto" /> <ScrollViewer Height="Auto" Name="scrollViewer1" Width="Auto" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Visible" CanContentScroll="True" Background="#E6ABA4A4"> <DataGrid AutoGenerateColumns="True" Height="Auto" Name="logDataGrid" Width="Auto" ItemsSource="{Binding}" HorizontalAlignment="Left"> </DataGrid> </ScrollViewer> </StackPanel> </Grid> In the code behind I have figured out how to create columns and name them, but I have not figured out how to bind the data. public partial class LogViewer { public LogViewer(Log log) { InitializeComponent(); foreach (var curve in log.Curves) { var data = curve.GetData(); var col = new DataGridTextColumn { Header = curve.Name }; logDataGrid.Columns.Add(col); } } } I wont even show the code I tried to use to bind the array "data", since nothing even came close. I am sure I am missing something simple, but after hours of searching the web, I have to come begging for an answer.

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  • Java: 2-assignments-2-initializations inside for-loop not allowed?

    - by HH
    $ javac MatchTest.java MatchTest.java:7: ')' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: not a statement for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: illegal start of expression for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ 5 errors $ cat MatchTest.java import java.util.*; import java.io.*; public class MatchTest { public static void main(String[] args){ String text = "hello0123456789hello0123456789hello1234567890hello3423243423232"; for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) System.out.println(i); } }

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  • Having trouble creating vectors of System::String^

    - by Justen
    So I have a regex expression to parse certain parts of a file name. I'm trying to store each part in its own vector until I use it later, but it won't let me. One error I get when I try making a vector of System::String^ is that error C3698: 'System::String ^' : cannot use this type as argument of 'new' Then, when I try just making a vector of std::string, it can't implicitly convert to type System::String^, and casting won't work either. void parseData() { System::String^ pattern = "(\\D+)(\\d+)(\\w{1})(\\d+)\\.(\\D{3})"; std::vector < System::String^ > x, y, filename, separator; Regex re( pattern ); for ( int i = 0; i < openFileDialog1->FileNames->Length; i++ ) { Match^ m = re.Match( openFileDialog1->FileNames[i] ); filename.push_back( m->Groups[0]->Value );/* x.push_back( m->Groups[1]->Value ); separator.push_back( m->Groups[2]->Value ); y.push_back( m->Groups[3]->Value );*/ } }

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  • Exception on inserting into Access 2010 in C Sharp

    - by slao.it
    Hello, I am getting this exception when inserting into a Access 2010 database. Ex: System.Data.OleDb.OleDbException (0x80040E14): Syntax error in string in query expression ''CityName ?'. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at ReadingData.Program.Main(String[] args) in C:\Users\user\documents\visual studio 2010\Projects\ReadingData\ReadingData\Program.cs:line 238 INSERT INTO CranbrookMain (ID,BlockNo,Plot,SubPlot,Code,Type,LastName,FirstName,ServiceHome,ServiceAddress,ServiceCity,Notes) VALUES ('1','Y','37','DS','C2','O','SMITH','John','Service Inc.','520B SLATER ROAD N.W.','CityName','CityName ? ') insertSQL = "INSERT INTO CranbrookMain (ID,BlockNo,Plot,SubPlot,Code,Type,LastName," + "FirstName,ServiceHome,ServiceAddress,ServiceCity,Notes) VALUES (" + "'"+id+ "','" + blockNo + "','" + plot + "','" + subPlot + "','" + code + "','" + type + "','" + lastname + "','" + firstname + "','" + serviceHome + "','" + serviceAddress + "','" + serviceCity + "','" + notes +"')"; Console.WriteLine(); OleDbCommand cmd = new OleDbCommand(insertSQL, con); // creating query command cmd.ExecuteNonQuery(); The error occurs in cmd.ExecuteNonQuery() function call. The above SQL INSERT statement works fine if I directly execute in the Access 2010 file.

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  • What's the best way to resolve this scope problem?

    - by Peter Stewart
    I'm writing a program in python that uses genetic techniques to optimize expressions. Constructing and evaluating the expression tree is the time consumer as it can happen billions of times per run. So I thought I'd learn enough c++ to write it and then incorporate it in python using cython or ctypes. I've done some searching on stackoverflow and learned a lot. This code compiles, but leaves the pointers dangling. I tried 'this_node = new Node(...' . It didn't seem to work. And I'm not at all sure how I'd delete all the references as there would be hundreds. I'd like to use variables that stay in scope, but maybe that's not the c++ way. What is the c++ way? class Node { public: char *cargo; int depth; Node *left; Node *right; } Node make_tree(int depth) { depth--; if(depth <= 0) { Node tthis_node("value",depth,NULL,NULL); return tthis_node; } else { Node this_node("operator" depth, &make_tree(depth), &make_tree(depth)); return this_node; } };

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  • Bind button visibility to the expresion (C#)

    - by drasto
    I have a delete button in each row of GridView (component ASP.NET). I want some of the delete buttons to be invisible. The visibility of the delete button should depend on the data that are back the row. GridView is backed by EntityDataSource. GridView displays entities called Category, one instance in each row. Entity Category has (besides others) also a field of type EntityCollection. Name of that field is Items. Basically I want to allow user to delete a row only if the Items field of backing Category entity is an empty collection. I cannot make up the binding of Visible property. I have no experience with bindings and Google does not really help. This is how the button looks right now: <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" Visible=??? ></asp:Button> I don't know what should replace ???. The button schold be visible only when this expression evaluates to true: ((SimpleEShop.Model.Category) dataItem).Items.LongCount() <= 0 where dataItem variable contains data of current row in the table. What is the binding that I need ?

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  • Calculate the year for ending month/day?

    - by Dave Jarvis
    Given: Start Year Start Month & Start Day End Month & End Day What SQL statement results in TRUE if a date lands between the Start and End days? 1st example: Start Date = 11-22 End Date = 01-17 Start Year = 2009 Specific Date = 2010-01-14 TRUE 2nd example: Start Date = 11-22 End Date = 11-16 Start Year = 2009 Specific Date = 2010-11-20 FALSE 3rd example: Start Date = 02-25 End Date = 03-19 Start Year = 2004 Specific Date = 2004-02-29 TRUE I was thinking of using the MySQL functions datediff and sign plus a CASE condition to determine whether the year wraps, but it seems rather expensive. Am looking for a simple, efficient calculation. Update 1 The problem is the end date cannot simply use the year. The year must be increased if the end month/day combination happens before the start date. The start date is easy: Start Date = date( concat_ws( '-', year, Start Month, Start Day ) ) The end date is not so simple. Update 2 Here is what I was thinking about for obtaining the end year: end_year = case sign( diff( date( concat_ws( year, start_month, start_day ) ), date( concat_ws( year, end_month, end_day ) ) ) ) when -1 then Start_Year + 1 else Start_Year end case Then wrap that expression (once syntactically correct) inside of another date, followed by BETWEEN statement. Update 3 To clear up some confusion: there is no end year. The end year must be calculated. Thank you!

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  • Operation is not valid due to the current state of the object?

    - by Bill
    I am programming in C#; the code was working about a week ago, however it throws an exception and I don't understand at all what could be wrong with it. Var root = new CalculationNode(); -> Throw exception. In the call stack thats the only thing listed, I've been told that it could be that I need a clean build, but I am open to any ideas or suggestions. Thanks, -Bill Update: Exception's Detail System.InvalidOperationException was unhandled by user code Message=Operation is not valid due to the current state of the object. Source=Calculator.Logic StackTrace: at ~.Calculator.Logic.MyBaseExpressionParser.Parse(String expression) in ~\Source\Calculator.Logic\MyBaseExpressionParser.cs:line 44 at ~.Calculator.Logic.Tests.MyBaseCalculatorServiceTests.BasicMathDivision() in ~\Projects\Tests\Calculator.Logic.Tests\MyBaseCalculatorServiceTests.cs:line 60 InnerException: CalculationNode's code: public sealed calss CalculationNode { public CalculationNode() { this.Left = null; this.Right = null; this.Element = new CalculationElement(); } public CalculationNode Left {get;set;} public CalculationNode Right {get;set;} public CalculationElement Element {get; set;} } CalculationElement's code: public sealed class CalculationElement { public CalculationElement() { Value = string.Empty; IsOperator = false; } public string Value {get; set} public bool IsOperator {get; set} }

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  • Regex: match a non nested code block

    - by Sylvanas Garde
    I am currently writing a small texteditor. With this texteditor users are able to create small scripts for a very simple scripting engine. For a better overview I want to highlight codeblocks with the same command like GoTo(x,y) or Draw(x,y). To achieve this I want to use Regular Expresions (I am already using it to highlight other things like variables) Here is my Expression (I know it's very ugly): /(?<!GoTo|Draw|Example)(^(?:GoTo|Draw|Example)\(.+\)*?$)+(?!GoTo|Draw|Example)/gm It matches the following: lala GoTo(5656) -> MATCH 1 sdsd GoTo(sdsd) --comment -> MATCH 2 GoTo(23329); -> MATCH 3 Test() GoTo(12) -> MATCH 4 LALA Draw(23) -> MATCH 5 Draw(24) -> MATCH 6 Draw(25) -> MATCH 7 But what I want to achieve is, that the complete "blocks" of the same command are matched. In this case Match 2 & 4 and Match 5 & 6 & 7 should be one match. Tested with http://regex101.com/, the programming lanuage is vb.net. Any advise would be very useful, Thanks in advance!

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  • Differences between Assembly Code output of the same program

    - by ultrajohn
    I have been trying to replicate the buffer overflow example3 from this article aleph one I'm doing this as a practice for a project in a computer security course i'm taking so please, I badly need your help. I've been the following the example, performing the tasks as I go along. My problem is the assembly code dumped by gdb in my computer (i'm doing this on a debian linux image running on VM Ware) is different from that of the example in the article. There are some constructs which I find confusing. Here is the one from my computer: here is the one from the article... Dump of assembler code for function main: 0x8000490 <main>: pushl %ebp 0x8000491 <main+1>: movl %esp,%ebp 0x8000493 <main+3>: subl $0x4,%esp 0x8000496 <main+6>: movl $0x0,0xfffffffc(%ebp) 0x800049d <main+13>: pushl $0x3 0x800049f <main+15>: pushl $0x2 0x80004a1 <main+17>: pushl $0x1 0x80004a3 <main+19>: call 0x8000470 <function> 0x80004a8 <main+24>: addl $0xc,%esp 0x80004ab <main+27>: movl $0x1,0xfffffffc(%ebp) 0x80004b2 <main+34>: movl 0xfffffffc(%ebp),%eax 0x80004b5 <main+37>: pushl %eax 0x80004b6 <main+38>: pushl $0x80004f8 0x80004bb <main+43>: call 0x8000378 <printf> 0x80004c0 <main+48>: addl $0x8,%esp 0x80004c3 <main+51>: movl %ebp,%esp 0x80004c5 <main+53>: popl %ebp 0x80004c6 <main+54>: ret 0x80004c7 <main+55>: nop As you can see, there are differences between the two. I'm confuse and I can't understand totally the assembly code from my computer. I would like to know the differences between the two. How is pushl different from push, mov vs movl , and so on... what does the expression 0xhexavalue(%register) means? I am sorry If I'm asking a lot, But I badly need your help. Thanks for the help really...

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  • Extension methods for encapsulation and reusability

    - by tzaman
    In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

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  • Is there a practical benefit to casting a NULL pointer to an object and calling one of its member fu

    - by zdawg
    Ok, so I know that technically this is undefined behavior, but nonetheless, I've seen this more than once in production code. And please correct me if I'm wrong, but I've also heard that some people use this "feature" as a somewhat legitimate substitute of a lacking aspect of the current C++ standard, namely, the inability to obtain the address (well, offset really) of a member function. For example, this is out of a popular implementation of a PCRE (Perl-compatible Regular Expression) library: #ifndef offsetof #define offsetof(p_type,field) ((size_t)&(((p_type *)0)->field)) #endif One can debate whether the exploitation of such a language subtlety in a case like this is valid or not, or even necessary, but I've also seen it used like this: struct Result { void stat() { if(this) // do something... else // do something else... } }; // ...somewhere else in the code... ((Result*)0)->stat(); This works just fine! It avoids a null pointer dereference by testing for the existence of this, and it does not try to access class members in the else block. So long as these guards are in place, it's legitimate code, right? So the question remains: Is there a practical use case, where one would benefit from using such a construct? I'm especially concerned about the second case, since the first case is more of a workaround for a language limitation. Or is it? PS. Sorry about the C-style casts, unfortunately people still prefer to type less if they can.

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  • Can't use Visual Studio 2008 Designer with MVVMLight V3 SP1

    - by mcauthorn
    I wish I knew what I did to cause this, but I cannot use the Visual Studio 2008 Designer at all with with MVVMLight templates. I receive a "Could not create an instance of type 'ViewModelLocator'. in any of my xaml pages. The application builds and runs fine but only the designer is broken. In the App.xaml is <Application x:Class="ExcelReportGenerator.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:vm="clr-namespace:ExcelReportGenerator.ViewModel" xmlns:res="clr-namespace:ExcelReportGenerator.Resources" Startup="Application_Startup" mc:Ignorable="d"> <Application.Resources> <!--Global View Model Locator--> <vm:ViewModelLocator x:Key="Locator" d:IsDataSource="True" /> </Application.Resources> I even receive the error when I create a brand new MVVMLight application. The interesting thing is if I use an express version of VS2010 I can view, edit and work in designer just fine. As much as I would love to go to VS2010, I can't right now convince IT to make that move.

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  • C# Attribute XmlIgnore and XamlWriter class - XmlIgnore not working

    - by Horst Walter
    I have a class, containing a property Brush MyBrush marked as [XmlIgnore]. Nevertheless it is serialized in the stream causing trouble when trying to read via XamlReader. I did some tests, e.g. when changing the visibility (to internal) of the Property it is gone in the stream. Unfortunately I cannot do this in my particular scenario. Did anybody have the same issue and? Do you see any way to work around this? Remark: C# 4.0 as far I can tell This is a method from my Unit Test where I do test the XamlSerialization: // buffer to a StringBuilder StringBuilder sb = new StringBuilder(); XmlWriter writer = XmlWriter.Create(sb, settings); XamlDesignerSerializationManager manager = new XamlDesignerSerializationManager(writer) {XamlWriterMode = XamlWriterMode.Expression}; XamlWriter.Save(testObject, manager); xml = sb.ToString(); Assert.IsTrue(!String.IsNullOrEmpty(xml) && !String.IsNullOrEmpty(xml), "Xaml Serialization failed for " + testObject.GetType() + " no xml string available"); xml = sb.ToString(); MemoryStream ms = xml.StringToStream(); object root = XamlReader.Load(ms); Assert.IsTrue(root != null, "After reading from MemoryStream no result for Xaml Serialization"); In one of my classes I use the Property Brush. In the above code this Unit Tests fails because of a Brush object not serializable is the value. When I remove the Setter (as below, the Unit Test passes. Using the XmlWriter (basically same test as above) it works. In the StringBuffer sb I can see that Property Brush is serialized when the Setter is there and not when removed (most likely another check ignoring the Property because of no setter). Other Properties with [XmlIgnore] are ignored as intended. [XmlIgnore] public Brush MyBrush { get { ..... } // removed because of problem with Serialization // set { ... } }

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  • d2: assigning ranges/iterators to array slices

    - by modchan
    Consider following code: enum size = 16; double[size] arr1 = [...]; double[size] arr2 = [...]; process = (double x) { return (x + 1); }; arr2[] = map!(process)(arr1[]); // here I have trouble converting results of map back to my plain array. Problem applies not only to map, but also to take, repeat and all those fine tools from std.algorithm and std.range that operate on ranges. On this assignment, I get Error: cannot implicitly convert expression (map(arr1[])) of type Result to double[]. How can I evaluate range to array without using uint i = 0; foreach (x; map!(process)(arr1[])) { arr2[i] = x; i++; } ? Additionally, can someone please explain, why I must call map!(process)(arr1[]) instead of map!(process)(arr1) with static arrays? Shouldn't static arrays be compatible with dynamic for means of iteration, or I don't get something? Also, it seems that straightforward enumeration syntax foreach (index, item; sequence) does not work for ranges - are there workarounds? I guess the reason is the same as why ranges cannot be assigned to array slices.

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  • Project management: Implementing custom errors in VS compilation process

    - by David Lively
    Like many architects, I've developed coding standards through years of experience to which I expect my developers to adhere. This is especially a problem with the crowd that believes that three or four years of experience makes you a senior-level developer.Approaching this as a training and code review issue has generated limited success. So, I was thinking that it would be great to be able to add custom compile-time errors to the build process to more strictly enforce this and other guidelines. For instance, we use stored procedures for ALL database access, which provides procedure-level security, db encapsulation (table structure is hidden from the app), and other benefits. (Note: I am not interested in starting a debate about this.) Some developers prefer inline SQL or parametrized queries, and that's fine - on their own time and own projects. I'd like a way to add a compilation check that finds, say, anything that looks like string sql = "insert into some_table (col1,col2) values (@col1, @col2);" and generates an error or, in certain circumstances, a warning, with a message like Inline SQL and parametrized queries are not permitted. Or, if they use the var keyword var x = new MyClass(); Variable definitions must be explicitly typed. Do Visual Studio and MSBuild provide a way to add this functionality? I'm thinking that I could use a regular expression to find unacceptable code and generate the correct error, but I'm not sure what, from a performance standpoint, is the best way to to integrate this into the build process. We could add a pre- or post-build step to run a custom EXE, but how can I return line- and file-specifc errors? Also, I'd like this to run after compilation of each file, rather than post-link. Is a regex the best way to perform this type of pattern matching, or should I go crazy and run the code through a C# parser, which would allow node-level validation via the parse tree? I'd appreciate suggestions and tales of prior experience.

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  • A weird crash...

    - by Nima
    Hi, I have a piece of code that runs in debug mode in VS2008, C++. The problem is that when I am debugging the code line by line, at a very weird point of the code, it crashes and says: debug assertion faild. Expression: _BLOCK_TYPE_IS_VALID(pHead-nBlockUse) The crash point is on the first closed curly bracket (after mesh-edges[e].needsUpdate=false;) I don't understand why on a curly bracket? does that make sense to you guys? Can anybody help me understanding what is going on..? for(int e=0; e<mesh->edges.size(); e++) { if(mesh->edges[e].valid && mesh->edges[e].v[0]>=0 && mesh->edges[e].v[1]>=0 && mesh->points[mesh->edges[e].v[0]].writable && mesh->points[mesh->edges[e].v[1]].writable) { //update v_hat and its corresponding error DecEdge Current = DecEdge(e); pair<Point, float> ppf = computeVhat(e); Current.v_hat = ppf.first; Current.error = ppf.second; edgeSoup.push(Current); mesh->edges[e].needsUpdate=false; } }

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  • Why do bind1st and bind2nd require constant function objects?

    - by rlbond
    So, I was writing a C++ program which would allow me to take control of the entire world. I was all done writing the final translation unit, but I got an error: error C3848: expression having type 'const `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>' would lose some const-volatile qualifiers in order to call 'void `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>::operator ()(const point::Point &,const int &)' with [ T=SideCounter, BinaryFunction=std::plus<int> ] c:\program files (x86)\microsoft visual studio 9.0\vc\include\functional(324) : while compiling class template member function 'void std::binder2nd<_Fn2>::operator ()(point::Point &) const' with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] c:\users\****\documents\visual studio 2008\projects\TAKE_OVER_THE_WORLD\grid_divider.cpp(361) : see reference to class template instantiation 'std::binder2nd<_Fn2>' being compiled with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] I looked in the specifications of binder2nd and there it was: it took a const AdaptibleBinaryFunction. So, not a big deal, I thought. I just used boost::bind instead, right? Wrong! Now my take-over-the-world program takes too long to compile (bind is used inside a template which is instantiated quite a lot)! At this rate, my nemesis is going to take over the world first! I can't let that happen -- he uses Java! So can someone tell me why this design decision was made? It seems like an odd decision. I guess I'll have to make some of the elements of my class mutable for now...

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  • Float addition promoted to double?

    - by Andreas Brinck
    I had a small WTF moment this morning. Ths WTF can be summarized with this: float x = 0.2f; float y = 0.1f; float z = x + y; assert(z == x + y); //This assert is triggered! (Atleast with visual studio 2008) The reason seems to be that the expression x + y is promoted to double and compared with the truncated version in z. (If i change z to double the assert isn't triggered). I can see that for precision reasons it would make sense to perform all floating point arithmetics in double precision before converting the result to single precision. I found the following paragraph in the standard (which I guess I sort of already knew, but not in this context): 4.6.1. "An rvalue of type float can be converted to an rvalue of type double. The value is unchanged" My question is, is x + y guaranteed to be promoted to double or is at the compiler's discretion? UPDATE: Since many people has claimed that one shouldn't use == for floating point, I just wanted to state that in the specific case I'm working with, an exact comparison is justified. Floating point comparision is tricky, here's an interesting link on the subject which I think hasn't been mentioned.

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  • Silverlight 3 data-binding child property doesn't update

    - by sonofpirate
    I have a Silverlight control that has my root ViewModel object as it's data source. The ViewModel exposes a list of Cards as well as a SelectedCard property which is bound to a drop-down list at the top of the view. I then have a form of sorts at the bottom that displays the properties of the SelectedCard. My XAML appears as (reduced for simplicity): <StackPanel Orientation="Vertical"> <ComboBox DisplayMemberPath="Name" ItemsSource="{Binding Path=Cards}" SelectedItem="{Binding Path=SelectedCard, Mode=TwoWay}" /> <TextBlock Text="{Binding Path=SelectedCard.Name}" /> <ListBox DisplayMemberPath="Name" ItemsSource="{Binding Path=SelectedCard.PendingTransactions}" /> </StackPanel> I would expect the TextBlock and ListBox to update whenever I select a new item in the ComboBox, but this is not the case. I'm sure it has to do with the fact that the TextBlock and ListBox are actually bound to properties of the SelectedCard so it is listening for property change notifications for the properties on that object. But, I would have thought that data-binding would be smart enough to recognize that the parent object in the binding expression had changed and update the entire binding. It bears noting that the PendingTransactions property (bound to the ListBox) is lazy-loaded. So, the first time I select an item in the ComboBox, I do make the async call and load the list and the UI updates to display the information corresponding to the selected item. However, when I reselect an item, the UI doesn't change! For example, if my original list contains three cards, I select the first card by default. Data-binding does attempt to access the PendingTransactions property on that Card object and updates the ListBox correctly. If I select the second card in the list, the same thing happens and I get the list of PendingTransactions for that card displayed. But, if I select the first card again, nothing changes in my UI! Setting a breakpoint, I am able to confirm that the SelectedCard property is being updated correctly. How can I make this work???

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  • ViewModel Views relation/link/syncroniztion

    - by mehran
    Third try to describing problem: Try 1: Sunchronizing view model and view Try2: WPF ViewModel not active presenter Try3: I have some class for view models: public class Node : INotifyPropertyChanged { Guid NodeId { get; set; } public string Name { get; set; } } public class Connection: INotifyPropertyChanged { public Node StartNode { get; set; } public Node EndNode { get; set; } } public class SettingsPackModel { public List<Node> Nodes { get; private set; } public List<Connection> Connections { get; private set; } } I also have some templates to displays these models: <DataTemplate DataType="{x:Type vm:Node}">…</DataTemplate> <DataTemplate DataType="{x:Type vm:Connection}"> <my:ConnectionElment StartNodeElment="???" EndNodeElment="???"> </my:ConnectionElment> <DataTemplate> But the problem is that DataTemplate for Connection need reference ot two element of type UIElement , how can I pass these two, how can I fill ??? in above expression?

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  • Weird splitter behaviour when moving it

    - by tomo
    My demo app displays two rectangles which should fill whole browser's screen. There is a vertical splitter between them. This looks like a basic scenario but I have no idea how to implement this in xaml. I cannot force this to fill whole screen and when moving splitter then whole screen grows. Can anybody help? <UserControl xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls" x:Class="SilverlightApplication1.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"> <Grid x:Name="LayoutRoot" VerticalAlignment="Stretch" HorizontalAlignment="Stretch"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="Auto"/> </Grid.ColumnDefinitions> <Border BorderBrush="Black" BorderThickness="1" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" MinWidth="50"> </Border> <controls:GridSplitter Grid.Column="1" VerticalAlignment="Stretch" Width="Auto" ></controls:GridSplitter> <Border BorderBrush="Blue" BorderThickness="1" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Grid.Column="2" MinWidth="50"></Border> </Grid> </UserControl>

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  • Unable to get values in ftl from value stack in custom Result Type

    - by Nagadev
    Hello, I am unable retrieve value from value stack in FTL file. Here is the code. Action class holds a property called 'name' private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } public String execute(){ setName("From value stack .. "); return SUCCESS; } FTL code: ${name} Custom result Type deExecute Method Configuration configuration = new Configuration(); String templatePath = "/ftl"; ServletContext context = ServletActionContext.getServletContext(); configuration.setServletContextForTemplateLoading(context, templatePath); configuration.setObjectWrapper(new DefaultObjectWrapper()); Template template = configuration.getTemplate("sample.ftl"); OutputStreamWriter out = new OutputStreamWriter(System.out); template.process(ActionContext.getContext().getValueStack(), out); I am passing the value Stack which contains recently executed Action as well. But FTL is throwing an exception Expression name is undefined on line 1, column 3 in sample.ftl I tried with passing session instead of value stack and I could get the value in FTL. Please suggest me a way to get values from Action class to FTL from value stack. Thanks inadvance.

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