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• USB windows xp final USB access issues

  - by Lex Dean

  I basically understand you C++ people, Please do not get distracted because I'm writing in Delphi. I have a stable USB Listing method that accesses all my USB devices I get the devicepath, and this structure: TSPDevInfoData = packed record Size: DWORD; ClassGuid: TGUID; DevInst: DWORD; // DEVINST handle Reserved: DWord; end; I get my ProductID and VenderID successfully from my DevicePath Lists all USB devices connected to the computer at the time That enables me to access the registry data to each device in a stable way. What I'm lacking is a little direction Is friendly name able to be written inside the connected USB Micro chips by the firmware programmer? (I'm thinking of this to identify the device even further, or is this to help identify Bulk data transfer devices like memory sticks and camera's) Can I use SPDRP_REMOVAL_POLICY_OVERRIDE to some how reset these polices What else can I do with the registry details. Identifying when some one unplugs a device The program is using (in windows XP standard) I used a documented windows event that did not respond. Can I read a registry value to identify if its still connected? using CreateFileA (DevicePath) to send and receive data I have read when some one unplugs in the middle of a data transfer its difficult clearing resources. what can IoCreateDevice do for me and how does one use it for that task This two way point of connection status and system lock up situations is very concerning. Has some one read anything about this subject recently? My objectives are to 1. list connected USB devices identify a in development Micro Controller from everything else send and receive data in a stable and fast way to the limits of the controller No lock up's transferring data Note I'm not using any service packs I understand everything USB is in ANSI when windows xp is not and .Net is all about ANSI (what a waste of memory) I plan to continue this project into a .net at a later date as an addition. MSDN gives me Structures and Functions and what should link to what ok but say little to what they get used for. What is available in my language Delphi is way over priced that it needs a major price drop.

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• Array Sorting Question for News System

  - by lemonpole

  Hello all. I'm currently stuck trying to figure out how to sort my array files. I have a simple news posting system that stores the content in seperate .dat files and then stores them in an array. I numbered the files so that my array can sort them from lowest number to greatest; however, I have run into a small problem. To begin here is some more information on my system so that you can understand it better. The function that gathers my files is: function getNewsList() { $fileList = array(); // Open the actual directory if($handle = opendir(ABSPATH . ADMIN . "data")) { // Read all file from the actual directory while($file = readdir($handle)) { if(!is_dir($file)) { $fileList[] = $file; } } } // Return the array. return $fileList; } On a seperate file is the programming that processes the news post. I didn't post that code for simplicity's sake but I will explain how the files are named. The files are numbered and the part of the post's title is used... for the numbering I get a count of the array and add "1" as an offset. I get the title of the post, encode it to make it file-name-friendly and limit the amount of text so by the end of it all I end up with: // Make the variable that names the file that will contain // the post. $filename = "00{$newnumrows}_{$snipEncode}"; When running print_r on the above function I get: Array ( [0] => 0010_Mira_mi_Soledad.dat [1] => 0011_WOah.dat [2] => 0012_Sinep.dat [3] => 0013_Living_in_Warfa.dat [4] => 0014_Hello.dat [5] => 001_AS.dat [6] => 002_ASASA.dat [7] => 003_SSASAS.dat ... [13] => 009_ASADADASADAFDAF.dat ) And this is how my content is displayed. For some reason according to the array sorting 0010 comes before 001...? Is there a way I can get my array to sort 001 before 0010?

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• Best practices regarding equals: to overload or not to overload?

  - by polygenelubricants

  Consider the following snippet: import java.util.*; public class EqualsOverload { public static void main(String[] args) { class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } public boolean equals(Thing other) { return this.x == other.x; } } List<Thing> myThings = Arrays.asList(new Thing(42)); System.out.println(myThings.contains(new Thing(42))); // prints "false" } } Note that contains returns false!!! We seems to have lost our things!! The bug, of course, is the fact that we've accidentally overloaded, instead of overridden, Object.equals(Object). If we had written class Thing as follows instead, then contains returns true as expected. class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } @Override public boolean equals(Object o) { return (o instanceof Thing) && (this.x == ((Thing) o).x); } } Effective Java 2nd Edition, Item 36: Consistently use the Override annotation, uses essentially the same argument to recommend that @Override should be used consistently. This advice is good, of course, for if we had tried to declare @Override equals(Thing other) in the first snippet, our friendly little compiler would immediately point out our silly little mistake, since it's an overload, not an override. What the book doesn't specifically cover, however, is whether overloading equals is a good idea to begin with. Essentially, there are 3 situations: Overload only, no override -- ALMOST CERTAINLY WRONG! This is essentially the first snippet above Override only (no overload) -- one way to fix This is essentially the second snippet above Overload and override combo -- another way to fix The 3rd situation is illustrated by the following snippet: class Thing { final int x; Thing(int x) { this.x = x; } public int hashCode() { return x; } public boolean equals(Thing other) { return this.x == other.x; } @Override public boolean equals(Object o) { return (o instanceof Thing) && (this.equals((Thing) o)); } } Here, even though we now have 2 equals method, there is still one equality logic, and it's located in the overload. The @Override simply delegates to the overload. So the questions are: What are the pros and cons of "override only" vs "overload & override combo"? Is there a justification for overloading equals, or is this almost certainly a bad practice?

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• OpenGL Projection matrix won't allow displaying anything

  - by user272973

  I'm trying to get some basic OpenGL-ES with Shaders to run on the iPhone, based on some examples. For some reason my projection matrix refuses to result in something on the screen. It feels like a clipping plane is set very near but that contradicts with the values I supply. If I render the same scene with an Orthogonal projection matrix I see my object just no perspective obviously. Here's the code that generates the projection matrix: esPerspective(&proj, 45.f, 768.0/1024.0, 1.f, 10000.f); void esPerspective(ESMatrix *result, float fovy, float aspect, float nearZ, float farZ) { float frustumW, frustumH; frustumH = tanf( fovy / 360.0f * PI ) * nearZ; frustumW = frustumH * aspect; esFrustum( result, -frustumW, frustumW, -frustumH, frustumH, nearZ, farZ ); } void esFrustum(ESMatrix *result, float left, float right, float bottom, float top, float nearZ, float farZ) { float deltaX = right - left; float deltaY = top - bottom; float deltaZ = farZ - nearZ; ESMatrix frust; if ( (nearZ <= 0.0f) || (farZ <= 0.0f) || (deltaX <= 0.0f) || (deltaY <= 0.0f) || (deltaZ <= 0.0f) ) return; frust.m[0][0] = 2.0f * nearZ / deltaX; frust.m[0][1] = frust.m[0][2] = frust.m[0][3] = 0.0f; frust.m[1][1] = 2.0f * nearZ / deltaY; frust.m[1][0] = frust.m[1][2] = frust.m[1][3] = 0.0f; frust.m[2][0] = (right + left) / deltaX; frust.m[2][1] = (top + bottom) / deltaY; frust.m[2][2] = -(nearZ + farZ) / deltaZ; frust.m[2][3] = -1.0f; frust.m[3][2] = -2.0f * nearZ * farZ / deltaZ; frust.m[3][0] = frust.m[3][1] = frust.m[3][3] = 0.0f; esMatrixMultiply(result, &frust, result); } My projection matrix comes out as: [3.21, 0, 0, 0] [0, 2.41, 0, 0] [0, 0, -1, -1] [0, 0, -2, 0] Even if I manually set the [3][3] cell to 1 I still don't see anything. Any ideas?

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• CSS: Javascript code out there that could draw form squares to copy to a real form?

  - by Dr. Zim

  I end up doing a lot of this to draw forms in boxes. This does an address block: position: absolute;top: .2em; left: .2em; width: 2.4em;height: 1.2em; position: absolute;top: .2em; left: 3em; width: 12.4em; height: 1.2em; position: absolute;top: 1.7em; left: 3em; width: 12.4em;height: 1.2em; position: absolute;top: 3.2em; left: 3em; width: 12.4em;height: 1.2em; position: absolute;top: 4.7em; left: 3em; width: 12.4em;height: 1.2em; position: absolute;top: 6.2em; left: 3em; width: 7.6em; height: 1.2em; position: absolute;top: 6.2em; left: 10.9em; width: 1.6em; height: 1.2em; position: absolute;top: 6.2em; left: 12.8em; width: 2.5em; height: 1.2em; position: absolute;top: 7.7em; left: 3em; width: 7.6em;height: 1.2em; position: absolute;top: 9.2em; left: 3em; width: 7.6em;height: 1.2em; position: absolute;top: 10.7em; left: 3em; width: 1.2em;height: 1.2em; position: absolute;top: 10.7em; left: 4.5em; width: 10.9em; height: 1.2em; but what I really need is some Javascript that allows me to draw my forms on screen, then generate the CSS for my real ASP.NET MVC 2 partial views, allowing nudge and cell resizing with keystrokes. Anyone have any suggestions for something like this?

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• In a PHP project, how do you organize and access your helper objects?

  - by Pekka

  How do you organize and manage your helper objects like the database engine, user notification, error handling and so on in a PHP based, object oriented project? Say I have a large PHP CMS. The CMS is organized in various classes. A few examples: the database object user management an API to create/modify/delete items a messaging object to display messages to the end user a context handler that takes you to the right page a navigation bar class that shows buttons a logging object possibly, custom error handling etc. I am dealing with the eternal question, how to best make these objects accessible to each part of the system that needs it. my first apporach, many years ago was to have a $application global that contained initialized instances of these classes. global $application; $application->messageHandler->addMessage("Item successfully inserted"); I then changed over to the Singleton pattern and a factory function: $mh =&factory("messageHandler"); $mh->addMessage("Item successfully inserted"); but I'm not happy with that either. Unit tests and encapsulation become more and more important to me, and in my understanding the logic behind globals/singletons destroys the basic idea of OOP. Then there is of course the possibility of giving each object a number of pointers to the helper objects it needs, probably the very cleanest, resource-saving and testing-friendly way but I have doubts about the maintainability of this in the long run. Most PHP frameworks I have looked into use either the singleton pattern, or functions that access the initialized objects. Both fine approaches, but as I said I'm happy with neither. I would like to broaden my horizon on what is possible here and what others have done. I am looking for examples, additional ideas and pointers towards resources that discuss this from a long-term, real-world perspective. Also, I'm interested to hear about specialized, niche or plain weird approaches to the issue. Bounty I am following the popular vote in awarding the bounty, the answer which is probably also going to give me the most. Thank you for all your answers!

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• Insane CPU usage in QT 5.0

  - by GravityScore

  I'm having trouble using the QT framework, particularly with the paintEvent of QWidget. I have a QWidget set up, and am overriding the paintEvent of it. I need to render a bunch of rectangles (grid system), 51 by 19, leading to 969 rectangles being drawn. This is done in a for loop. Then I also need to draw an image on each on of these grids. The QWidget is added to a QMainWindow, which is shown. This works nicely, but it's using up 47% of CPU per window open! And I want to allow the user to open multiple windows like this, likey having 3-4 open at a time, which puts the CPU close to 150%. Why does this happen? Here is the paintEvent contents. The JNI calls don't cause the CPU usage, commenting them out doesn't lower it, but commenting out the p.fillRect and Renderer::renderString (which draws the image) lowers the CPU to about 5%. // Background QPainter p(this); p.fillRect(0, 0, this->width(), this->height(), QBrush(QColor(0, 0, 0))); // Lines for (int y = 0; y < Global::terminalHeight; y++) { // Line and color method ID jmethodID lineid = Manager::jenv->GetMethodID(this->javaClass, "getLine", "(I)Ljava/lang/String;"); error(); jmethodID colorid = Manager::jenv->GetMethodID(this->javaClass, "getColorLine", "(I)Ljava/lang/String;"); error(); // Values jstring jl = (jstring) Manager::jenv->CallObjectMethod(this->javaObject, lineid, jint(y)); error(); jstring cjl = (jstring) Manager::jenv->CallObjectMethod(this->javaObject, colorid, jint(y)); error(); // Convert to C values const char *l = Manager::jenv->GetStringUTFChars(jl, 0); const char *cl = Manager::jenv->GetStringUTFChars(cjl, 0); QString line = QString(l); QString color = QString(cl); // Render line for (int x = 0; x < Global::terminalWidth; x++) { QColor bg = Renderer::colorForHex(color.mid(x + color.length() / 2, 1)); // Cell location on widget int cellx = x * Global::cellWidth + Global::xoffset; int celly = y * Global::cellHeight + Global::yoffset; // Background p.fillRect(cellx, celly, Global::cellWidth, Global::cellHeight, QBrush(bg)); // String // Renders the image to the grid Renderer::renderString(p, tc, text, cellx, celly); } // Release Manager::jenv->ReleaseStringUTFChars(jl, l); Manager::jenv->ReleaseStringUTFChars(cjl, cl); }

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• I have to select the checkbox two times to check/uncheck in jTable

  - by 117526709403775781607

  I have a jTable code i intend to use, but the problem with it is that when i click on the checkbox once it doesn't select/deselect it, instead i have to click twice. But if i select any other cell in the row except the one containing the checkbox the purpose is solved. HERE IS MY CODE : public class TableSelectionTest extends JFrame implements ListSelectionListener { private final int COLUMN_COUNT = 5; private TblModel model; public TableSelectionTest() { initialize(); setDefaultCloseOperation(EXIT_ON_CLOSE); pack(); } private void initialize() { List data = new ArrayList(); for (int i = 0; i < 10; i++) { Object record[] = new Object[COLUMN_COUNT]; record[0] = Boolean.FALSE; for (int j = 1; j < COLUMN_COUNT; j++) { record[j] = new Integer(j); } data.add(record); } model = new TblModel(data); JTable table = new JTable(model); table.getSelectionModel().setSelectionMode(ListSelectionModel.SINGLE_SELECTION); table.getSelectionModel().addListSelectionListener (this); JScrollPane scroll = new JScrollPane(table); getContentPane().add(scroll, BorderLayout.CENTER); } public static void main(String[] args) { TableSelectionTest f = new TableSelectionTest(); f.show(); } class TblModel extends AbstractTableModel { private List data; public TblModel(List data) { this.data = data; } public int getColumnCount() { return COLUMN_COUNT; } public int getRowCount() { return data == null ? 0 : data.size(); } public void setValueAt(Object value, int rowIndex, int columnIndex) { getRecord(rowIndex)[columnIndex] = value; super.fireTableCellUpdated(rowIndex, columnIndex); } public Object getValueAt(int rowIndex, int columnIndex) { return getRecord(rowIndex)[columnIndex]; } public boolean isCellEditable(int rowIndex, int columnIndex) { if(columnIndex == 0) return true; else return false; } public Class getColumnClass(int columnIndex) { if (data == null || data.size() == 0) { return Object.class; } Object o = getValueAt(0, columnIndex); return o == null ? Object.class : o.getClass(); } private Object[] getRecord(int rowIndex) { return (Object[]) data.get(rowIndex); } } public void valueChanged(ListSelectionEvent e) { if (!e.getValueIsAdjusting()) { ListSelectionModel lsm = (ListSelectionModel) e.getSource(); int index = lsm.getMinSelectionIndex(); if(model.getRecord(index)[0] == Boolean.FALSE) model.setValueAt(Boolean.TRUE, index, 0); else if(model.getRecord(index)[0] == Boolean.TRUE) model.setValueAt(Boolean.FALSE, index, 0); } } } Please reply soon as it is bugging me a lot Thank you in advance :)

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• I want to set the AutoCompleteMode property in ApplyCellStyleToEditingControl subroutine

  - by Ranjan Gupta

  Hi, I am creating a DataGridView Column. and it is working well. now I want to customise this column with AutoCompleteMode, and AutoCompleteSource properties to show the customised data. I made the properties for this columns, and these are also working well. but these properties are not working in the "ApplyCellStyleToEditingControl" subroutine. Please help me to use these column properties in the "ApplyCellStyleToEditingControl" subroutine. Public Class DataGridViewDataValueColumn Inherits DataGridViewColumn Dim m_AutoCompleteMode As AutoCompleteMode, _ m_AutoCompleteSource As AutoCompleteSource, _ m_AutoCompleteStringCollection As AutoCompleteStringCollection Public Sub New() MyBase.New(New DataValueCell()) End Sub Public Overrides Property CellTemplate() As DataGridViewCell Get Return MyBase.CellTemplate End Get Set(ByVal value As DataGridViewCell) ' Ensure that the cell used for the template is a DataValueCell. If (value IsNot Nothing) AndAlso _ Not value.GetType().IsAssignableFrom(GetType(DataValueCell)) _ Then Throw New InvalidCastException("Must be a DataValueCell") End If MyBase.CellTemplate = value End Set End Property Region "User Defined Properties" '&*--------------------------------------*&' <Description("Indicates the text completion behaviour of the combo box."), DefaultValue(AutoCompleteMode.None)> _ Public Property AutoCompleteMode() As AutoCompleteMode Get Return m_AutoCompleteMode End Get Set(ByVal value As AutoCompleteMode) m_AutoCompleteMode = value End Set End Property <Description("The source of complete strings used to automatic completion."), DefaultValue(AutoCompleteSource.None)> _ Public Property AutoCompleteSource() As AutoCompleteSource Get Return m_AutoCompleteSource End Get Set(ByVal value As AutoCompleteSource) m_AutoCompleteSource = value End Set End Property <Description("The autocomplete custom source.")> _ Public Property AutoCompleteCustomSource() As AutoCompleteStringCollection Get Return m_AutoCompleteStringCollection End Get Set(ByVal value As AutoCompleteStringCollection) m_AutoCompleteStringCollection = value End Set End Property End Region End Class '&*--------------------------------------*&' Class DataValueCell Inherits DataGridViewTextBoxCell Public Sub New() ' End Sub Public Overrides ReadOnly Property EditType As Type Get Return GetType(PCLDataGridViewTextBoxEditingControl) End Get End Property End Class '&*--------------------------------------*&' '&* Edit DataGridView Columns *&' '&*--------------------------------------*&' Class PCLDataGridViewTextBoxEditingControl Inherits DataGridViewTextBoxEditingControl Public Overrides Function EditingControlWantsInputKey(ByVal keyData As Keys, ByVal dataGridViewWantsInputKey As Boolean) As Boolean Select Case ((keyData And Keys.KeyCode)) Case Keys.Prior, Keys.Next, Keys.End, Keys.Home, Keys.Left, Keys.Up, Keys.Right, Keys.Down, Keys.Delete Return True End Select Return MyBase.EditingControlWantsInputKey(keyData, dataGridViewWantsInputKey) End Function Public Overrides Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As DataGridViewCellStyle) With DirectCast(Me, TextBox) '.AutoCompleteMode = DataGridViewDataValueColumn.AutoCompleteMode_Value '.AutoCompleteSource = DataGridViewDataValueColumn.AutoCompleteSource_Value '.AutoCompleteCustomSource = MyBase.AutoCompleteCustomSource End With End Sub End Class

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• Updating DetailViewController from RootController

  - by Stefano Salmaso

  I'm trying to create an iPad application with a similar user interface to Apple's Mail application, i.e: RootView controller (table view) on the left hand side of the split view for navigation with a multiple view hierarchy. When a table cell is selected a new table view is pushed on the left hand side The new view on the left side can update the detail view. I can accomplish both tasks BUT NOT TOGETHER. I mean I can make a multi-level table view in the RootController.(HERE you can find the working source code). Or I can make a single-level table view in the RootController which can update the detailViewController (here there is the source code:http://www.megaupload.com/?d=D6L0463G). Can anyone tell me how to make a multi-level table in the RootController which can update a detailViewController? There is more source code at the link but below is the method in which I presume I have to declare a new detailViewController (which has to be put in the UISplitViewController): - (void)tableView:(UITableView *)TableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSDictionary *dictionary = [self.tableDataSource objectAtIndex:indexPath.row]; //Get the children of the present item. NSArray *Children = [dictionary objectForKey:@"Children"]; // if([Children count] == 0) { /* Create and configure a new detail view controller appropriate for the selection. */ NSUInteger row = indexPath.row; UIViewController <SubstitutableDetailViewController> *detailViewController = nil; if (row == 0) { FirstDetailViewController *newDetailViewController = [[FirstDetailViewController alloc]initWithNibName:@"FirstDetailView" bundle:nil]; detailViewController = newDetailViewController; } if (row == 1) { SecondDetailViewController *newDetailViewController = [[SecondDetailViewController alloc]initWithNibName:@"SecondDetailView" bundle:nil]; detailViewController = newDetailViewController; } // Update the split view controller's view controllers array. NSArray *viewControllers = [[NSArray alloc] initWithObjects:self.navigationController, detailViewController, nil]; splitViewController.viewControllers = viewControllers//nothing happens..... [viewControllers release];// } else { //Prepare to tableview. RootViewController *rvController = [[RootViewController alloc]initWithNibName:@"RootViewController" bundle:[NSBundle mainBundle]]; //Increment the Current View rvController.current_level += 1; //Set the title; rvController.current_title = [dictionary objectForKey:@"Title"]; //Push the new table view on the stack [self.navigationController pushViewController:rvController animated:YES]; rvController.tableDataSource = Children; [rvController.tableView reloadData]; //without this instrucion,items won't be loaded inside the second level of the table [rvController release]; } }

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• How to bind grid in ASP.NET?

  - by Abid Ali

  I cant bind my Grid. I dont know what I am doing wrong, the grid appears empty when I run the program. here is my code :: protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) this.BindGrid(this.GridView1); } private void BindGrid(GridView grid) { SqlCommand cmd = new SqlCommand("Select * from Person", cn); SqlDataAdapter da = new SqlDataAdapter(cmd); DataTable dt = new DataTable(); da.Fill(dt); grid.DataSource = dt; grid.DataBind(); } <body> <form id="form1" runat="server"> <div style="margin-left: 240px"> <asp:GridView ID="GridView1" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None" Width="856px" AutoGenerateColumns = "false" ShowFooter = "true" ShowHeader="true" BorderStyle="Groove" CaptionAlign="Top" HorizontalAlign="Center" onrowdatabound="GridView1_RowDataBound" > <RowStyle BackColor="#F7F6F3" ForeColor="#333333" /> <Columns> <asp:BoundField HeaderText="ID" /> <asp:BoundField HeaderText="First Name" /> <asp:BoundField HeaderText="Last Name" /> <asp:BoundField HeaderText="Home Phone #" /> <asp:BoundField HeaderText="Cell #" /> <asp:BoundField HeaderText="Email Address" /> <asp:BoundField HeaderText="NIC #" /> <asp:TemplateField HeaderText="Action"> <ItemTemplate> <asp:Button ID="Button1" runat="server" Text="Button" /> <asp:Button ID="Button2" runat="server" Text="Button" /> </ItemTemplate> </asp:TemplateField> </Columns> <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" /> <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#999999" /> <AlternatingRowStyle BackColor="White" ForeColor="#284775" /> </asp:GridView> </div> </form> </body>

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• How to efficently build an interpreter (lexer+parser) in C?

  - by Rizo

  I'm trying to make a meta-language for writing markup code (such as xml and html) wich can be directly embedded into C/C++ code. Here is a simple sample written in this language, I call it WDI (Web Development Interface): /* * Simple wdi/html sample source code */ #include <mySite> string name = "myName"; string toCapital(string str); html { head { title { mySiteTitle; } link(rel="stylesheet", href="style.css"); } body(id="default") { // Page content wrapper div(id="wrapper", class="some_class") { h1 { "Hello, " + toCapital(name) + "!"; } // Lists post ul(id="post_list") { for(post in posts) { li { a(href=post.getID()) { post.tilte; } } } } } } } Basically it is a C source with a user-friendly interface for html. As you can see the traditional tag-based style is substituted by C-like, with blocks delimited by curly braces. I need to build an interpreter to translate this code to html and posteriorly insert it into C, so that it can be compiled. The C part stays intact. Inside the wdi source it is not necessary to use prints, every return statement will be used for output (in printf function). The program's output will be clean html code. So, for example a heading 1 tag would be transformed like this: h1 { "Hello, " + toCapital(name) + "!"; } // would become: printf("<h1>Hello, %s!</h1>", toCapital(name)); My main goal is to create an interpreter to translate wdi source to html like this: tag(attributes) {content} = <tag attributes>content</tag> Secondly, html code returned by the interpreter has to be inserted into C code with printfs. Variables and functions that occur inside wdi should also be sorted in order to use them as printf parameters (the case of toCapital(name) in sample source). I am searching for efficient (I want to create a fast parser) way to create a lexer and parser for wdi. Already tried flex and bison, but as I am not sure if they are the best tools. Are there any good alternatives? What is the best way to create such an interpreter? Can you advise some brief literature on this issue?

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• centering a div without setting width

  - by Daniel

  Is there a way to do this? When using navigation that can change the number of items often, it would be nice not having to calculate the with and updating the css, but just having a solution that works. if that's impossible (I'm assuming it is) can anyone point me to a javascript that can do this? edit re: provide code some code basically I'm working with, what I think is, the most typical setup <div class="main"> <div class="nav"> <ul> <li>short title</li> <li>Item 3 Long title</li> <li>Item 4 Long title</li> <li>Item 5 Long title</li> <li>Item 6 Extra Long title</li> </ul> </div> </div> edit .main { width:100%; text-align:center; } .nav { margin:0 auto; } .nav ul li { display:inline; text-align:left; } the issue I've found with this/these solutions is that the content is nudged to the right adding some right padding (of 40px) seems to fix this across the browsers I'm checking on (O FF IE). .nav { margin:0 auto; padding-right:40px; } I don't know where this value is coming from though and why 40px fixes this. Does anyone know where this is coming from? it's not a margin or padding but no matter what I do the first about 40px can not be used for placement. Maybe it's the ul or li that's adding this. I've had a look at the display:table-cell way of doing this, but there's that complication with IE and it still has the same issue as the other solution edit (final) okay I've tried some things in regard to the indent. I've reset all padding to 0 *{padding:0;} that fixed it, and I don't need to offset the padding (I think I'll leave my whole process up so if anyone comes across this, it'll save them some time) thanks for the comments and replies

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• Call phpexcel from joomla

  - by Oscar Calderon

  i have a problem about phpexcel and joomla. I'm developing some filter form to load excel reports, so i used phpexcel library to do this. Right now i have only a report, it works fine, but after that i upload inside joomla using PHP pages component that allows me to put php files inside joomla and call it. When i put them, i change a little bit the form that calls the php that generates the excel report, i call the php using a link like this: h**p://www.whiblix.com/index.php?option=com_php&Itemid=24 That is, calling it from Joomla, not directly the php. If i wanna call the php directly i could use this path: h**p://www.whiblix.com/components/com_php/files/repImportaciones.php What's the problem? The problem is, when i call the php that generates the excel through joomla, the excel that is downloaded is corrupt and only shows symbols in one cell when i open it. But if i call the php directly the report is generated fine. I could call the php directly, the problem is that if i call it directly i can't use this line of code: defined( '_JEXEC' ) or die( 'Restricted access' ); That is used to deny the direct access to php from call it directly, because it doesn' work because the security. Where's the problem? This is the code of php that generates the report (ommiting the code where generates the rows and cells): <?php //defined( '_JEXEC' ) or die( 'Restricted access' ); /** Error reporting */ error_reporting(E_ALL); date_default_timezone_set('Europe/London'); require_once 'Classes/PHPExcel.php'; // Create new PHPExcel object $objPHPExcel = new PHPExcel(); // Set properties $objPHPExcel->getProperties()->setCreator("Maarten Balliauw") ->setLastModifiedBy("Maarten Balliauw") ->setTitle("Office 2007 XLSX Test Document") ->setSubject("Office 2007 XLSX Test Document") ->setDescription("Test document for Office 2007 XLSX, generated using PHP classes.") ->setKeywords("office 2007 openxml php") ->setCategory("Test result file"); // Rename sheet $objPHPExcel->getActiveSheet()->setTitle('Reporte de Importaciones'); // Set active sheet index to the first sheet, so Excel opens this as the first sheet $objPHPExcel->setActiveSheetIndex(0); // Redirect output to a client’s web browser (Excel5) header('Content-Type: application/vnd.ms-excel'); header('Content-Disposition: attachment;filename="repPrueba.xls"'); header('Cache-Control: max-age=0'); $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5'); $objWriter->save('php://output'); exit;

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• Releasing the keyboard stops shake events. Why?

  - by Moshe

  1) How do I make a UITextField resign the keyboard and hide it? The keyboard is in a dynamically created subview whose superview looks for shake events. Resigning first responder seems to break the shake event handler. 2) how do you make the view holding the keyboard transparent, like see through glass? I have seen this done before. This part has been taken care of thanks guys. As always, code samples are appreciated. I've added my own to help explain the problem. EDIT: Basically, - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event; gets called in my main view controller to handle shaking. When a user taps on the "edit" icon (a pen, in the bottom of the screen - not the traditional UINavigationBar edit button), the main view adds a subview to itself and animates it on to the screen using a custom animation. This subview contains a UINavigationController which holds a UITableView. The UITableView, when a cell is tapped on, loads a subview into itself. This second subview is the culprit. For some reason, a UITextField in this second subview is causing problems. When a user taps on the view, the main view will not respond to shakes unless the UITextField is active (in editing mode?). Additional info: My Motion Event Handler: - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event { NSLog(@"%@", [event description]); SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"shake" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); [self genRandom:TRUE]; } The genRandom: Method: /* Generate random label and apply it */ -(void)genRandom:(BOOL)deviceWasShaken{ if(deviceWasShaken == TRUE){ decisionText.text = [NSString stringWithFormat: (@"%@", [shakeReplies objectAtIndex:(arc4random() % [shakeReplies count])])]; }else{ SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"string" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); decisionText.text = [NSString stringWithFormat: (@"%@", [pokeReplies objectAtIndex:(arc4random() % [pokeReplies count])])]; } } shakeReplies and pokeReplies are both NSArrays of strings. One is used for when a certain part of the screen is poked and one is for when the device is shaken. The app will randomly choose a string from the NSArray and display onscreen. For those of you who work graphically, here is a diagram of the view hierarchy: Root View -> UINavigationController -> UITableView -> Edit View -> Problem UITextfield

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• How does Sentry aggregate errors?

  - by Hugo Rodger-Brown

  I am using Sentry (in a django project), and I'd like to know how I can get the errors to aggregate properly. I am logging certain user actions as errors, so there is no underlying system exception, and am using the culprit attribute to set a friendly error name. The message is templated, and contains a common message ("User 'x' was unable to perform action because 'y'"), but is never exactly the same (different users, different conditions). Sentry clearly uses some set of attributes under the hood to determine whether to aggregate errors as the same exception, but despite having looked through the code, I can't work out how. Can anyone short-cut my having to dig further into the code and tell me what properties I need to set in order to manage aggregation as I would like? [UPDATE 1: event grouping] This line appears in sentry.models.Group: class Group(MessageBase): """ Aggregated message which summarizes a set of Events. """ ... class Meta: unique_together = (('project', 'logger', 'culprit', 'checksum'),) ... Which makes sense - project, logger and culprit I am setting at the moment - the problem is checksum. I will investigate further, however 'checksum' suggests that binary equivalence, which is never going to work - it must be possible to group instances of the same exception, with differenct attributes? [UPDATE 2: event checksums] The event checksum comes from the sentry.manager.get_checksum_from_event method: def get_checksum_from_event(event): for interface in event.interfaces.itervalues(): result = interface.get_hash() if result: hash = hashlib.md5() for r in result: hash.update(to_string(r)) return hash.hexdigest() return hashlib.md5(to_string(event.message)).hexdigest() Next stop - where do the event interfaces come from? [UPDATE 3: event interfaces] I have worked out that interfaces refer to the standard mechanism for describing data passed into sentry events, and that I am using the standard sentry.interfaces.Message and sentry.interfaces.User interfaces. Both of these will contain different data depending on the exception instance - and so a checksum will never match. Is there any way that I can exclude these from the checksum calculation? (Or at least the User interface value, as that has to be different - the Message interface value I could standardise.) [UPDATE 4: solution] Here are the two get_hash functions for the Message and User interfaces respectively: # sentry.interfaces.Message def get_hash(self): return [self.message] # sentry.interfaces.User def get_hash(self): return [] Looking at these two, only the Message.get_hash interface will return a value that is picked up by the get_checksum_for_event method, and so this is the one that will be returned (hashed etc.) The net effect of this is that the the checksum is evaluated on the message alone - which in theory means that I can standardise the message and keep the user definition unique. I've answered my own question here, but hopefully my investigation is of use to others having the same problem. (As an aside, I've also submitted a pull request against the Sentry documentation as part of this ;-)) (Note to anyone using / extending Sentry with custom interfaces - if you want to avoid your interface being use to group exceptions, return an empty list.)

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• Proper HTML technique to create an web form out of an image

  - by Lars

  I plan to create an interactive golf score card for my website (XHTML). (Btw. thats how such a scorecard looks like: ScoreCard). So at the end one should be able to insert a score for each hole in the appropriated input field in the virtual scorecard on the website. For me it is very important that the interactive scorecard really looks the same as the original (paper-) scorecard does and so my first approach was to scan and slice the scorecard image to reach that appearance. Here you can see the way I sliced the image: The idea was to insert HTML text input for each score field ending up with something like this: After I sliced the image I reconstructed it using the HTML . To do that I put the image slices as the cell background. <table> <tr> <td style="background: url("slice1.jpg") width="58px" height="25px"> <input type="text"></inputText> </td> </tr> ... </table> At the first moment this worked fine (as Gimp offers quite a nice feature for this). Then the problem was that I had to create a HTML table to create the exact layout. As you can see the lower part of the layout is split up into 3 columns. The middle column is split up into several (for each hole) rows. So the left and right column have to be spanned over those rows. Ok finally that worked, but it lead to some kind of scaling problem. If I zoom in or out on the table the middle column (and only that one) is not scaled the right way. Iam not able to fix this, and so I start doubting if this is the right technique for html image virtualization. Iam really no specialist in the area of creating websites, so I would really appriciate any help on this. Maybe there is a complete other and better technique to do that, as I think it is a common job in webcreation. I couldnt find any nice examples or tuts on that.

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• using a Singleton to pass credentials in a multi-tenant application a code smell?

  - by Hans Gruber

  Currently working on a multi-tenant application that employs Shared DB/Shared Schema approach. IOW, we enforce tenant data segregation by defining a TenantID column on all tables. By convention, all SQL reads/writes must include a Where TenantID = '?' clause. Not an ideal solution, but hindsight is 20/20. Anyway, since virtually every page/workflow in our app must display tenant specific data, I made the (poor) decision at the project's outset to employ a Singleton to encapsulate the current user credentials (i.e. TenantID and UserID). My thinking at the time was that I didn't want to add a TenantID parameter to each and every method signature in my Data layer. Here's what the basic pseudo-code looks like: public class UserIdentity { public UserIdentity(int tenantID, int userID) { TenantID = tenantID; UserID = userID; } public int TenantID { get; private set; } public int UserID { get; private set; } } public class AuthenticationModule : IHttpModule { public void Init(HttpApplication context) { context.AuthenticateRequest += new EventHandler(context_AuthenticateRequest); } private void context_AuthenticateRequest(object sender, EventArgs e) { var userIdentity = _authenticationService.AuthenticateUser(sender); if (userIdentity == null) { //authentication failed, so redirect to login page, etc } else { //put the userIdentity into the HttpContext object so that //its only valid for the lifetime of a single request HttpContext.Current.Items["UserIdentity"] = userIdentity; } } } public static class CurrentUser { public static UserIdentity Instance { get { return HttpContext.Current.Items["UserIdentity"]; } } } public class WidgetRepository: IWidgetRepository{ public IEnumerable<Widget> ListWidgets(){ var tenantId = CurrentUser.Instance.TenantID; //call sproc with tenantId parameter } } As you can see, there are several code smells here. This is a singleton, so it's already not unit test friendly. On top of that you have a very tight-coupling between CurrentUser and the HttpContext object. By extension, this also means that I have a reference to System.Web in my Data layer (shudder). I want to pay down some technical debt this sprint by getting rid of this singleton for the reasons mentioned above. I have a few thoughts on what an better implementation might be, but if anyone has any guidance or lessons learned they could share, I would be much obliged.

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• cellForRowAtIndexPath called too late

  - by Mihai Fonoage

  Hi, I am trying to re-load a table every time some data I get from the web is available. This is what I have: SearchDataViewController: - (void)parseDatatXML { parsingDelegate = [[XMLParsingDelegate alloc] init]; parsingDelegate.searchDataController = self; // CONTAINS THE TABLE THAT NEEDS RE-LOADING; ImplementedSearchViewController *searchController = [[ImplementedSearchViewController alloc] initWithNibName:@"ImplementedSearchView" bundle:nil]; ProjectAppDelegate *delegate = [[UIApplication sharedApplication] delegate]; UINavigationController *nav = (UINavigationController *)[delegate.splitViewController.viewControllers objectAtIndex: 0]; NSArray *viewControllers = [[NSArray alloc] initWithObjects:nav, searchController, nil]; self.splitViewController.viewControllers = viewControllers; [viewControllers release]; // PASS A REFERENCE TO THE PARSING DELEGATE SO THAT IT CAN CALL reloadData on the table parsingDelegate.searchViewController = searchController; [searchController release]; // Build the url request used to fetch data ... NSURLRequest *dataURLRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:dataURL]]; parsingDelegate.feedConnection = [[[NSURLConnection alloc] initWithRequest:dataURLRequest delegate:parsingDelegate] autorelease]; } ImplementedSearchViewController: - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { NSLog(@"count = %d", [keys count]); // keys IS A NSMutableArray return [self.keys count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { ... cell.textLabel.text = [keys objectAtIndex:row]; ... } XMLParsingDelgate: -(void) updateSearchTable:(NSArray *)array { ... [self.currentParseBatch addObject:(NSString *)[array objectAtIndex:1]]; // RELOAD TABLE [self.searchViewController.table reloadData]; } - (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict { if ([elementName isEqualToString:@"..."]) { self.currentParseBatch = [NSMutableArray array]; searchViewController.keys = self.currentParseBatch; ... } ... } - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName { if ([elementName isEqualToString:@"..."]) { ... [self performSelectorOnMainThread:@selector(updateSearchTable:) withObject:array waitUntilDone:NO]; } ... } My problem is that when I debug, the calls go between reloadData and numberOfRowsInSection until the keys array is filled with the last data, time at which the cellForRowAtIndexPath gets called. I wanted the table to be updated for each element I send, one by one, instead of just in the end. Any ideas why this behavior? Thank you!

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• What common routines do you put in your Program.cs for C#

  - by Rick

  I'm interested in any common routine/procedures/methods that you might use in you Program.cs when creating a .NET project. For instance I commonly use the following code in my desktop applications to allow easy upgrades, single instance execution and friendly and simple reporting of uncaught system application errors. using System; using System.Diagnostics; using System.Threading; using System.Windows.Forms; namespace NameoftheAssembly { internal static class Program { /// <summary> /// The main entry point for the application. Modified to check for another running instance on the same computer and to catch and report any errors not explicitly checked for. /// </summary> [STAThread] private static void Main() { //for upgrading and installing newer versions string[] arguments = Environment.GetCommandLineArgs(); if (arguments.GetUpperBound(0) > 0) { foreach (string argument in arguments) { if (argument.Split('=')[0].ToLower().Equals("/u")) { string guid = argument.Split('=')[1]; string path = Environment.GetFolderPath(Environment.SpecialFolder.System); var si = new ProcessStartInfo(path + "\\msiexec.exe", "/x" + guid); Process.Start(si); Application.Exit(); } } //end of upgrade } else { bool onlyInstance = false; var mutex = new Mutex(true, Application.ProductName, out onlyInstance); if (!onlyInstance) { MessageBox.Show("Another copy of this running"); return; } AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException; Application.ThreadException += ApplicationThreadException; Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { try { var ex = (Exception) e.ExceptionObject; MessageBox.Show("Whoops! Please contact the developers with the following" + " information:\n\n" + ex.Message + ex.StackTrace, " Fatal Error", MessageBoxButtons.OK, MessageBoxIcon.Stop); } catch (Exception) { //do nothing - Another Exception! Wow not a good thing. } finally { Application.Exit(); } } public static void ApplicationThreadException(object sender, ThreadExceptionEventArgs e) { try { MessageBox.Show("Whoops! Please contact the developers with the following" + " information:\n\n" + e.Exception.Message + e.Exception.StackTrace, " Error", MessageBoxButtons.OK, MessageBoxIcon.Stop); } catch (Exception) { //do nothing - Another Exception! Wow not a good thing. } } } } I find these routines to be very helpful. What methods have you found helpful in Program.cs?

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• go programming POST FormValue can't be printed

  - by poor_programmer

  Before I being a bit of background, I am very new to go programming language. I am running go on Win 7, latest go package installer for windows. I'm not good at coding but I do like some challenge of learning a new language. I wanted to start learn Erlang but found go very interesting based on the GO I/O videos in youtube. I'm having problem with capturing POST form values in GO. I spend three hours yesterday to get go to print a POST form value in the browser and failed miserably. I don't know what I'm doing wrong, can anyone point me to the right direction? I can easily do this in another language like C#, PHP, VB, ASP, Rails etc. I have search the entire interweb and haven't found a working sample. Below is my sample code. Here is Index.html page {{ define "title" }}Homepage{{ end }} {{ define "content" }} <h1>My Homepage</h1> <p>Hello, and welcome to my homepage!</p> <form method="POST" action="/"> <p> Enter your name : <input type="text" name="username"> </P> <p> <button>Go</button> </form> <br /><br /> {{ end }} Here is the base page <!DOCTYPE html> <html lang="en"> <head> <title>{{ template "title" . }}</title> </head> <body> <section id="contents"> {{ template "content" . }} </section> <footer id="footer"> My homepage 2012 copy </footer> </body> </html> now some go code package main import ( "fmt" "http" "strings" "html/template" ) var index = template.Must(template.ParseFiles( "templates/_base.html", "templates/index.html", )) func GeneralHandler(w http.ResponseWriter, r *http.Request) { index.Execute(w, nil) if r.Method == "POST" { a := r.FormValue("username") fmt.Fprintf(w, "hi %s!",a); //<-- this variable does not rendered in the browser!!! } } func helloHandler(w http.ResponseWriter, r *http.Request) { remPartOfURL := r.URL.Path[len("/hello/"):] fmt.Fprintf(w, "Hello %s!", remPartOfURL) } func main() { http.HandleFunc("/", GeneralHandler) http.HandleFunc("/hello/", helloHandler) http.ListenAndServe("localhost:81", nil) } Thanks! PS: Very tedious to add four space before every line of code in stackoverflow especially when you are copy pasting. Didn't find it very user friendly or is there an easier way?

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• Rails 3: How do I call a javascript function from a js.erb file

  - by user321775

  Now that I've upgraded to Rails 3, I'm trying to figure out the proper way to separate and reuse pieces of javascript. Here's the scenario I'm dealing with: I have a page with two areas: one with elements that should be draggable, the other with droppables. When the page loads I use jQuery to setup the draggables and droppables. Currently I have the script in the head portion of application.html.erb, which I'm sure is not the right solution but at least works. When I press a button on the page, an ajax call is made to my controller that replaces the draggables with a new set of elements that should also be draggable. I have a js.erb file that renders a partial in the correct location. After rendering I need to make the new elements draggable, so I'd like to reuse the code that currently lives in application.html.erb, but I haven't found the right way to do it. I can only make the new elements draggable by pasting the code directly into my js.erb file (yuck). What I'd like to have: - a javascript file that contains the functions prepdraggables() and prepdroppables() - a way to call either function from application.html.erb or from a js.erb file I've tried using :content_for to store and reuse the code, but can't seem to get it working correctly. What I currently have in the head section of application.html.erb <% content_for :drag_drop_prep do %> <script type="text/javascript" charset="utf-8"> $(document).ready(function () { // declare all DOM elements with class draggable to be draggable $( ".draggable" ).draggable( { revert : 'invalid' }); // declare all DOM elements with class legal to be droppable $(".legal").droppable({ hoverClass : 'legal_hover', drop : function(event, ui) { var c = new Object(); c['die'] = ui.draggable.attr("id"); c['cell'] = $(this).attr("id"); c['authenticity_token'] = encodeURIComponent(window._token); $.ajax({ type: "POST", url: "/placeDie", data: c, timeout: 5000 }); }}); }); </script> <% end %> undo.js.erb $("#board").html("<%= escape_javascript(render :partial => 'shared/board', :locals => { :playable => true, :restartable => !session[:challenge]}) %>") // This is where I want to prepare draggables. <%= javascript_include_tag "customdragdrop.js" %> // assuming this file had the draggables code from above in a prepdraggables() function prepdraggables();

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• jQuery + Dialog Form Validation

  - by Panther24

  Hi, I have a jQuery Dialog form and on submit I'm trying to validate the fields. I'm using http://docs.jquery.com/Plugins/Validation to validate. In this I'm facing an issue, the validate function is not being called. I'm posting some snippet of my code $("#register-dialog-form").dialog({ autoOpen: false, height: 350, width: 450, modal: true, buttons: { 'Register': function() { $("#registerFrm").validate({ rules: { accountid: "required", name: { required: true, minlength: 5 }, username: { required: true, minlength: 5 }, password: { required: true, minlength: 5 } }, messages: { firstname: "Please enter your firstname", accountid: "Please enter the lastname", name: "Please enter a user friendly name", username: { required: "Please enter a username", minlength: jQuery.format("Enter at least {0} characters") }, password: { required: "Please provide a password", minlength: jQuery.format("Password must be at least {0} characters long") } } }); //****************** //TODO: Need to submit my form here //****************** $(this).dialog('close'); }, Cancel: function() { $(this).dialog('close'); } }, close: function() { //$('registerFrm').clearForm(); } }); Can someone please tell me what I'm doing wrong here. I've also tried to put the validation into $(document).ready(function() {}, but with no success. Here is the html code <div id="register-dialog-form" title="Register Account - Master" align="center" style="display: none"> <s:form name="registerFrm" id="registerFrm" action="registermaster" method="POST"> <table width="90%" border="0" class="ui-widget"> <tr> <td> <s:textfield label="Account Id" name="accountid" id="accountid" cssClass="text ui-widget-content ui-corner-all" /> </td> </tr> <tr> <td> <s:textfield label="Name" name="name" id="name" cssClass="text ui-widget-content ui-corner-all" /> </td> </tr> <tr> <td> <s:textfield label="Username" name="username" id="username" cssClass="text ui-widget-content ui-corner-all" /> </td> </tr> <tr> <td> <s:password label="Password" name="password" id="password" cssClass="text ui-widget-content ui-corner-all" /> </td> </tr> </table> </s:form> </div><!--End of RegisterAcc form-->

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• Why do we have reinterpret_cast in C++ when two chained static_cast can do it's job?

  - by Nawaz

  Say I want to cast A* to char* and vice-versa, we have two choices (I mean, many of us think we've two choices, because both seems to work! Hence the confusion!): struct A { int age; char name[128]; }; A a; char *buffer = static_cast<char*>(static_cast<void*>(&a)); //choice 1 char *buffer = reinterpret_cast<char*>(&a); //choice 2 Both work fine. //convert back A *pA = static_cast<A*>(static_cast<void*>(buffer)); //choice 1 A *pA = reinterpret_cast<A*>(buffer); //choice 2 Even this works fine! So why do we have reinterpret_cast in C++ when two chained static_cast can do it's job? Some of you might think this topic is a duplicate of the previous topics such as listed at the bottom of this post, but it's not. Those topics discuss only theoretically, but none of them gives even a single example demonstrating why reintepret_cast is really needed, and two static_cast would surely fail. I agree, one static_cast would fail. But how about two? If the syntax of two chained static_cast looks cumbersome, then we can write a function template to make it more programmer-friendly: template<class To, class From> To any_cast(From v) { return static_cast<To>(static_cast<void*>(v)); } And then we can use this, as: char *buffer = any_cast<char*>(&a); //choice 1 char *buffer = reinterpret_cast<char*>(&a); //choice 2 //convert back A *pA = any_cast<A*>(buffer); //choice 1 A *pA = reinterpret_cast<A*>(buffer); //choice 2 Also, see this situation where any_cast can be useful: Proper casting for fstream read and write member functions. So my question basically is, Why do we have reinterpret_cast in C++? Please show me even a single example where two chained static_cast would surely fail to do the same job? Which cast to use; static_cast or reinterpret_cast? Cast from Void* to TYPE* : static_cast or reinterpret_cast

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• How do I 'globally' catch exceptions thrown in object instances.

  - by SleepyBobos

  I am currently writing a winforms application (C#). I am making use of the Enterprise Library Exception Handling Block, following a fairly standard approach from what I can see. IE : In the Main method of Program.cs I have wired up event handler to Application.ThreadException event etc. This approach works well and handles the applications exceptional circumstances. In one of my business objects I throw various exceptions in the Set accessor of one of the objects properties set { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum trim..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message..."); _minimumTrim = value; } My logic for this approach (without turning this into a 'when to throw exceptions' discussion) is simply that the business objects are responsible for checking business rule constraints and throwing an exception that can bubble up and be caught as required. It should be noted that in the UI of my application I do explictly check the values that the public property is being set to (and take action there displaying friendly dialog etc) but with throwing the exception I am also covering the situation where my business object may not be used by a UI eg : the Property is being set by another business object for example. Anyway I think you all get the idea. My issue is that these exceptions are not being caught by the handler wired up to Application.ThreadException and I don't understand why. From other reading I have done the Application.ThreadException event and it handler "... catches any exception that occurs on the main GUI thread". Are the exceptions being raised in my business object not in this thread? I have not created any new threads. I can get the approach to work if I update the code as follows, explicity calling the event handler that is wired to Application.ThreadException. This is the approach outlined in Enterprise Library samples. However this approach requires me to wrap any exceptions thrown in a try catch, something I was trying to avoid by using a 'global' handler to start with. try { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message"); _minimumTrim = value; } catch (Exception ex) { Program.ThreadExceptionHandler.ProcessUnhandledException(ex); } I have also investigated using wiring a handler up to AppDomain.UnhandledException event but this does not catch the exceptions either. I would be good if someone could explain to me why my exceptions are not being caught by my global exception handler in the first code sample. Is there another approach I am missing or am I stuck with wrapping code in try catch, shown above, as required?

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