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  • How can I create a SQL table using excel columns?

    - by Phsika
    I need to help to generate column name from excel automatically. I think that: we can do below codes: CREATE TABLE [dbo].[Addresses_Temp] ( [FirstName] VARCHAR(20), [LastName] VARCHAR(20), [Address] VARCHAR(50), [City] VARCHAR(30), [State] VARCHAR(2), [ZIP] VARCHAR(10) ) via C#. How can I learn column name from Excel? private void Form1_Load(object sender, EventArgs e) { ExcelToSql(); } void ExcelToSql() { string connectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Source\MPD.xlsm;Extended Properties=""Excel 12.0;HDR=YES;"""; // if you don't want to show the header row (first row) // use 'HDR=NO' in the string string strSQL = "SELECT * FROM [Sheet1$]"; OleDbConnection excelConnection = new OleDbConnection(connectionString); excelConnection.Open(); // This code will open excel file. OleDbCommand dbCommand = new OleDbCommand(strSQL, excelConnection); OleDbDataAdapter dataAdapter = new OleDbDataAdapter(dbCommand); // create data table DataTable dTable = new DataTable(); dataAdapter.Fill(dTable); // bind the datasource // dataBingingSrc.DataSource = dTable; // assign the dataBindingSrc to the DataGridView // dgvExcelList.DataSource = dataBingingSrc; // dispose used objects if (dTable.Rows.Count > 0) MessageBox.Show("Count:" + dTable.Rows.Count.ToString()); dTable.Dispose(); dataAdapter.Dispose(); dbCommand.Dispose(); excelConnection.Close(); excelConnection.Dispose(); }

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  • drawing to a JPanel without inheritance

    - by g.rocket
    Right now I'm working on a program that throws up a bunch of separate (generated at runtime) images, each in their own window. To do this i've tried this approach: public void display(){ JFrame window = new JFrame("NetPart"); JPanel canvas = new JPanel(); window.getContentPane().add(canvas); Graphics g = canvas.getGraphics(); Dimension d = getSize(); System.out.println(d); draw(g,new Point(d.minX*50,d.maxY*50), 50); window.setSize(d.size(50)); window.setResizable(false); window.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE); window.setVisible(true); } public void draw(Graphics g, Point startLoc, int scale){ // generate and draw the image } public Dimension getSize(){ //returns my own dimensions class } However, this throws a NullPointerException in draw, claiming that the graphics is null. is there any way to externally draw to a JPanel from outside it (not inherit from JPanel and override PaintComponent)? Any help would be appreciated.

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  • Another C question

    - by maddy
    Hi all, I have a piece of code shown below #include <stdio.h> #include <stdlib.h> void Advance_String(char [2],int ); int Atoi_val; int Count22; int Is_Milestone(char [2],int P2); char String[2] = "00"; main() { while(1) { if(Is_Milestone(S,21==1) { if(atoi(S)==22) { Count_22 = Count_22 + 1; } } Atoi_val = atoi(S); Advance_String(S,Atoi_val); } } int Is_Milestone(char P1[2],int P2) { int BoolInit; char *Ptr = P1; int value = atoi(Ptr); BoolInit = (value > P2); return BoolInit; } void Advance_String(char P1[2],int Value) { if(Value!=7) { P1[1] = P1[1]+1; } else { P1[1] = '0'; P1[0] = P1[0]+1 ; } } Now my problem is Count22 never increments as the char increments never achieves the value 21 or above.Could anyone please tell me the reason for this unexpected behaviour?My question here is to find the value of Count22.Is there any problem with the code? Thanks and regards Maddy

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  • What do I name this class whose sole purpose is to report failure?

    - by Blair Holloway
    In our system, we have a number of classes whose construction must happen asynchronously. We wrap the construction process in another class that derives from an IConstructor class: class IConstructor { public: virtual void Update() = 0; virtual Status GetStatus() = 0; virtual int GetLastError() = 0; }; There's an issue with the design of the current system - the functions that create the IConstructor-derived classes are often doing additional work which can also fail. At that point, instead of getting a constructor which can be queried for an error, a NULL pointer is returned. Restructuring the code to avoid this is possible, but time-consuming. In the meantime, I decided to create a constructor class which we create and return in case of error, instead of a NULL pointer: class FailedConstructor : public IConstructor public: virtual void Update() {} virtual Status GetStatus() { return STATUS_ERROR; } virtual int GetLastError() { return m_errorCode; } private: int m_errorCode; }; All of the above this the setup for a mundane question: what do I name the FailedConstructor class? In our current system, FailedConstructor would indicate "a class which constructs an instance of Failed", not "a class which represents a failed attempt to construct another class". I feel like it should be named for one of the design patterns, like Proxy or Adapter, but I'm not sure which.

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  • How to produce output using show function.

    - by wilson88
    I am trying to use sho to show the output of another function.The first function was used to do sorting, and returned a List. now I want to make a function that uses show() to display the output.This is how I had tried it only to get an error. Its to diplay the results of two the two sorted lists which used this function. map Auctioneer::compareBidList(map& one, map& two) and //**return Sorted.** void show(const char *msg, map<int, Bid*>& Sorted) { cout << msg << endl; show(Sorted); } void compare(map<int, Bid*>& sellers, map<int, Bid*>& buyers) { compare(sellers.begin(), sellers.end(), buyers.begin(),buyers.end(),compareBidList); } //my call in the main after declaration was as follows map<int, Bid*> buyers, sellers; Auctioneer auctioneer; auctioneer.compare(sellers,buyers); show(("Bids after sorting:", sellers,buyers);)

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  • proper use of volatile keyword

    - by luke
    I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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  • ListBox and Listview problem

    - by Anu
    Hi, I have listbox in my applcation and corresponding coding.. XAML: <DataTemplate x:Key="menuItemTemplate"> <WrapPanel> <TextBlock Text="{Binding Path = Menu}" /> </WrapPanel> </DataTemplate> <ListBox x:Name="menubox" ItemsSource="{Binding}" ItemTemplate="{StaticResource menuItemTemplate}" Margin="0,5,0,0"> .CS : public void Add(string[] menu) { ItemList items = ItemList.Load(menu); DataContext = items; } It works fine.Later i add Listview for another purpose and i coded like the same way of listbox XAML: <DataTemplate x:Key="ListItemTemplate"> <WrapPanel> <TextBlock Text="{Binding Path = Title}" /> </WrapPanel> </DataTemplate> <ListView ItemsSource="{Binding}" ItemTemplate="{StaticResource ListItemTemplate}" Name="listView1" /> .cs coding: public void SetTree(string Title,int BoxNo ) { TreeList items1 = TreeList.Load(Title,BoxNo); DataContext = items1; } After adding Listview,what happended this ListView show data,but Listbox didnot show anything.When i click the listbox it perfectly executing the clicking event of listbox.Only problem it doesnot display the text.What can i do for that. Here i added corresponding list class pls see tht. namespace Tabcontrol { public class TreeList : Collection<TreeItems> { public int size; public TreeList() { size = 0; } public int Count { get { return size; } } public static TreeList Load(string pmenu,int Box) { TreeList result = new TreeList(); TreeItems item = TreeItems.Load(pmenu,Box); result.Add(item); return result; } } } The ItemList class also the same thing, only variable names are getting differred.

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  • ZipArchive on the iPhone unzips files but they are empty

    - by user345131
    I'm trying to use ZipArchive on the iPhone to unzip a simple text file. It returns with no error but the file is empty. I would love to know why this doesn't work. I am using the following methods: -(void)alert:(NSString*)message { UIAlertView *myAlert = [[UIAlertView alloc] initWithTitle:@"" message:message delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [myAlert show]; [myAlert release]; } -(void)unzip { NSString *sourcepath = [[NSBundle mainBundle] pathForResource:@"secret" ofType:@"zip"]; NSString*filename = @"secret.txt"; NSArray *docPaths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES); NSString *destinationpath = [docPaths objectAtIndex: 0]; if (filename != nil ) destinationpath = [destinationpath stringByAppendingPathComponent: filename]; ZipArchive* za = [[ZipArchive alloc] init]; if( [za UnzipOpenFile:sourcepath Password:@""] ) { BOOL ret = [za UnzipFileTo:destinationpath overWrite:YES]; if( NO==ret ) [self alert:@"Problem"]; else [self alert:@"Success"]; [za UnzipCloseFile]; } [za release]; NSString *test = [[NSString alloc] initWithContentsOfFile:destinationpath encoding:NSASCIIStringEncoding error:nil]; [self alert:test]; }

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  • Images from SQL Server JPG/PNG Image Column not being Type Converted to Bitmap in HttpHandlers (cons

    - by kanchirk
    Our Silverlight 3.0 Client consumes Images stored/retrieved on the File System thorough ASP.NET HttpHandlers successfully. We are trying to store and read back Images using a SQL Server 2008 Database. Please find the stripped down code pasted below with the Exception. "Bitmap is not Valid" //Store document to the database private void SaveImageToDatabaseKK(HttpContext context, string pImageFileName) { try { //ADO.NET Entity Framework ImageTable documentDB = new ImageTable(); int intLength = Convert.ToInt32(context.Request.InputStream.Length); //Move the file contents into the Byte array Byte[] arrContent = new Byte[intLength]; context.Request.InputStream.Read(arrContent, 0, intLength); //Insert record into the Document table documentDB.InsertDocument(pImageFileName, arrContent, intLength); } catch { } } =The method to Read Back the Row from the Table and Send it back is below.= private void RetrieveImageFromDatabaseTableKK(HttpContext context, string pImageName) { try { ImageTable documentDB = new ImageTable(); var docRow = documentDB.GetDocument(pImageName); //based on Imagename which is unique //DocData column in table is **Image** if (docRow!=null && docRow.DocData != null && docRow.DocData.Length > 0) { Byte[] bytImage = docRow.DocData; if (bytImage != null && bytImage.Length > 0) { Bitmap newBmp = ConvertToBitmap(context, bytImage ); if (newBmp != null) { newBmp.Save(context.Response.OutputStream, ImageFormat.Jpeg); newBmp.Dispose(); } } } } catch (Exception exRI) { } } // Convert byte array to Bitmap (byte[] to Bitmap) protected Bitmap ConvertToBitmap(byte[] bmp) { if (bmp != null) { try { TypeConverter tc = TypeDescriptor.GetConverter(typeof(Bitmap)); Bitmap b = (Bitmap)tc.ConvertFrom(bmp); **//This is where the Exception Occurs.** return b; } catch (Exception) { } } return null; }

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  • Receiving generic typed <T> custom objects through remote object in Flex

    - by Aaron
    Is it possible to receive custom generic typed objects through AMF? I'm trying to integrate a flex app with an existing C# service but flex is choking on custom generic typed objects. As far as I can tell Flex doesn't even support generics, but I'd like to be able to even just read in the object and cast its members as necessary. I basically just want flex to ignore the <T>. I'm hopeful that there's a way to do this, since flex doesn't complain about typed collections (a server call returning List works fine and flex converts it to an ArrayCollection just like an un-typed List). Here's a trimmed down example of what's going on for me: The custom C# typed class public class TypeTest<T> { public T value { get; set; } public TypeTest () { } } The server method returning the typeTest public TypeTest<String> doTypeTest() { TypeTest<String> theTester = new TypeTest<String>("grrrr"); return theTester; } The corresponding flex value object: [RemoteClass(alias="API.Model.TypeTest")] public class TypeTest { private var _value:Object; public function get value():Object { return _value; } public function set value(theValue:Object):void { _value = value; } public function TypeTest() { } } and the result handler code: public function doTypeTest(result:TypeTest):void { var theString:String = result.value as String; trace(theString); } When the result handler is called I get the runtime error: TypeError: Error #1034: Type Coercion failed: cannot convert mx.utils::ObjectProxy@11a98041 to com.model.vos.TypeTest. Irritatingly if I change the result handler to take parameter of type Object it works fine. Anyone know how to make this work with the value object? I feel like i'm missing something really obvious.

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  • Passing data back from detailViewController to Uitableview

    - by jsetting32
    I am currently at the issue where I have a UITableviewCell that needs to be updated. When the user presses on the uitableviewcell - THERES ONLY 1!!, the user is pushed to a UITABLEVIEWCONTROLLER where the user is allowed to select 1 of multiple cells with their own titles. I need to get the clicked tableviewcells title and pass the value back to the parentviewcontroller and update the 1 tableviewcell's name to the one the user clicked in the pushed uitableivewcontroller. Here is a picture of the parent viewcontroller... And heres the picture of the pushed viewcontroller.... I was told earlier yesterday that delegation would be needed but I am unsure what to do at this point :/. Heres some code I use in the parent viewcontroller... - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [tableView deselectRowAtIndexPath:indexPath animated:YES]; ProblemTypes *view = [[ProblemTypes alloc] init]; [self.navigationController pushViewController:view animated:YES]; } I am also NOT USING storyboards, just a few xibs. Also heres the code for the pushedviewcontroller to pop to the parent viewcontroller when a cell is selected... #pragma mark - Table view delegate - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; NSLog(@"Cell's text: %@",cell.textLabel.text); [self.navigationController popViewControllerAnimated:YES]; } Thank you guys!

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  • Reducing Time Complexity in Java

    - by Koeneuze
    Right, this is from an older exam which i'm using to prepare my own exam in january. We are given the following method: public static void Oorspronkelijk() { String bs = "Dit is een boodschap aan de wereld"; int max = -1; char let = '*'; for (int i=0;i<bs.length();i++) { int tel = 1; for (int j=i+1;j<bs.length();j++) { if (bs.charAt(j) == bs.charAt(i)) tel++; } if (tel > max) { max = tel; let = bs.charAt(i); } } System.out.println(max + " keer " + let); } The questions are: what is the output? - Since the code is just an algorithm to determine the most occuring character, the output is "6 keer " (6 times space) What is the time complexity of this code? Fairly sure it's O(n²), unless someone thinks otherwise? Can you reduce the time complexity, and if so, how? Well, you can. I've received some help already and managed to get the following code: public static void Nieuw() { String bs = "Dit is een boodschap aan de wereld"; HashMap<Character, Integer> letters = new HashMap<Character, Integer>(); char max = bs.charAt(0); for (int i=0;i<bs.length();i++) { char let = bs.charAt(i); if(!letters.containsKey(let)) { letters.put(let,0); } int tel = letters.get(let)+1; letters.put(let,tel); if(letters.get(max)<tel) { max = let; } } System.out.println(letters.get(max) + " keer " + max); } However, I'm uncertain of the time complexity of this new code: Is it O(n) because you only use one for-loop, or does the fact we require the use of the HashMap's get methods make it O(n log n) ? And if someone knows an even better way of reducing the time complexity, please do tell! :)

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  • Drupal htaccess redirect - all files in directory to new directory

    - by hfidgen
    Hiya, I've moved a site to Drupal, but am now getting a lot of 404 errors due to the search engines taking their time to update the indexes. The 404 paths all look similar to this: recipedata/ccp1300006/633_L.jpg recipedata/ccp1500005/risotto.jpg recipedata/ccp1500006/haddock.jpg So I'd like to do some htaccess redirection with mod_rewrite to take care of this lot. All the images DO exist - the path has just changed to /sites/default/files/images/ I've edited a lot of redirects into my htaccess already, but because the ccpXXXXXX directory changes I can't quite figure out the regex. This was my last attempt, but yeah - doesn't work :) Can anyone give me some pointers? RewriteRule ^recipedata/(ccp+)/(.+)$ http://domain.co.uk/sites/default/files/images/$2 [R=301,L] This has to be in the context of the Drupal mod_rewrite rules which already exist <IfModule mod_rewrite.c> RewriteEngine on # Rewrite URLs of the form 'x' to the form 'index.php?q=x'. RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_URI} !=/favicon.ico RewriteRule ^(.*)$ index.php?q=$1 [L,QSA] </IfModule> Thanks!

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  • iPhone slide view passing variables

    - by sebastyuiop
    Right, I'm trying to make an app that has a calculation that involves a stopwatch. When a button on the calculation view is clicked a stopwatch slides in from the bottom. This all works fine, the problem I can't get my head around is how to send the recorded time back to the previous controller to update a textfield. I've simplified the code and stripped out most irrelevant stuff. Many thanks. CalculationViewController.h #import <UIKit/UIKit.h> @interface CalculationViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> { IBOutlet UITextField *inputTxt; } @property (nonatomic, retain) UITextField *inputTxt; - (IBAction)showTimer:(id)sender; @end CalculationViewController.m #import "CalculationViewController.h" #import "TimerViewController.h" @implementation CalculationViewController - (IBAction)showTimer:(id)sender { TimerViewController *timerView = [[TimerViewController alloc] init]; [self.navigationController presentModalViewController:timerView animated:YES]; } TimerViewController.h #import <UIKit/UIKit.h> @interface TimerViewController : UIViewController { IBOutlet UILabel *time; NSTimer *myTicker; } - (IBAction)start; - (IBAction)stop; - (IBAction)reset; - (void)showActivity; @end TimerViewController.m #import "TimerViewController.h" #import "CalculationViewController.h" @implementation TimerViewController - (IBAction)start { myTicker = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(showActivity) userInfo:nil repeats:YES]; } - (IBAction)stop { [myTicker invalidate]; #Update inputTxt on calculation view here [self dismissModalViewControllerAnimated:YES]; } - (IBAction)reset { time.text = @"0"; } - (void)showActivity { int currentTime = [time.text intValue]; int newTime = currentTime + 1; time.text = [NSString stringWithFormat:@"%d", newTime]; } @end

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  • Looks like COM object is created, but JScript fails to get a reference

    - by damix911
    I'm using the following code to create a COM component that I have developed and registered. var mycom = new ActiveXObject("Mirabilis.ComponentServices.1"); mycom.SetFirstNumber(5); mycom.SetSecondNumber(3); The first line runs fine, while if I alter the ProgID (that is, the string passed to ActiveXObject) I get the message Automation server can't create object. This suggests that at least the basics of the registration mechanism are working properly. I integrated some logging calls into the DLL. When I run the script I get the proof into the log file that both this call to QueryInterface: STDAPI DllGetClassObject( const CLSID &clsid, const IID &iid, void **ppv) { ... CAddFactory *pAddFact = new CAddFactory; ... HRESULT hr = pAddFact->QueryInterface(iid, ppv); if (hr == S_OK) writeToLogFile("Class QueryInterface returned S_OK"); else writeToLogFile("Class QueryInterface failed"); return hr; ... } and this one: HRESULT __stdcall CAddFactory::CreateInstance( IUnknown *pUnknownOuter, const IID &iid, void **ppv) { ... CAddObj *pObject = new CAddObj; ... HRESULT hr = pObject->QueryInterface(iid, ppv); if (hr == S_OK) writeToLogFile("Object QueryInterface returned S_OK"); else writeToLogFile("Object QueryInterface failed"); return hr; ... } return S_OK. However, when JScript gets to line 3 of the script, I get the following error message: 'mycom' is null or not an object Why is this happening? It looks like JScript should be able to obtain a reference. Some attempts I made I tried to return S_FALSE from DllCanUnloadNow to be sure that the DLL will not be unloaded, just in case, but with no luck.

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  • Intel IA-32 Assembly

    - by Kay
    I'm having a bit of difficulty converting the following java code into Intel IA-32 Assembly: class Person() { char name [8]; int age; void printName() {...} static void printAdults(Person [] list) { for(int k = 0; k < 100; k++){ if (list[k].age >= 18) { list[k].printName(); } } } } My attempt is: Person: push ebp; save callers ebp mov ebp, esp; setup new ebp push esi; esi will hold name push ebx; ebx will hold list push ecx; ecx will hold k init: mov esi, [ebp + 8]; mov ebx, [ebp + 12]; mov ecx, 0; k=0 forloop: cmp ecx, 100; jge end; if k>= 100 then break forloop cmp [ebx + 4 * ecx], 18 ; jl auxloop; if list[k].age < 18 then go to auxloop jmp printName; printName: auxloop: inc ecx; jmp forloop; end: pop ecx; pop ebx; pop esi; pop ebp; Is my code correct? NOTE: I'm not allowed to use global variables.

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  • Spring 3 - Custom Security

    - by Eqbal
    I am in the process of converting a legacy application from proprietary technology to a Spring based web app, leaving the backend system as is. The login service is provided by the backend system through a function call that takes in some parameter (username, password plus some others) and provides an output that includes the authroizations for the user and other properties like firstname, lastname etc. What do I need to do to weave this into Spring 3.0 security module. Looks like I need to provide a custom AuthenticationProvider implementation (is this where I call the backend function?). Do I also need a custom User and UserDetailsService implementation which needs loadUserByName(String userName)? Any pointers on good documentation for this? The reference that came with the download is okay, but doesn't help too much in terms of implementing custom security.

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  • Update C# Chart using BackgroundWorker

    - by Mark
    I am currently trying to update a chart which is on my form to the background worker using: bwCharter.RunWorkerAsync(chart1); Which runs: private void bcCharter_DoWork(object sender, DoWorkEventArgs e) { System.Windows.Forms.DataVisualization.Charting.Chart chart = null; // Convert e.Argument to chart //.. // Converted.. chart.Series.Clear(); e.Result=chart; setChart(c.chart); } private void setChart(System.Windows.Forms.DataVisualization.Charting.Chart arg) { if (chart1.InvokeRequired) { chart1.Invoke(new MethodInvoker(delegate { setChart(arg); })); return; } chart1 = arg; } However, at the point of clearing the series, an exception is thrown. Basically, I want to do a whole lot more processing after clearing the series, which slows the GUI down completely - so wanted this in another thread. I thought that by passing it as an argument, I should be safe, but apparently not! Interestingly, the chart is on a tab page. I can run this over and over if the tabpage is in the background, but if I run this, look at the chart, hide it again, and re-run, it throws the exception. Obviously, it throws if the chart is in the foreground as well. Can anyone suggest what I can do differently? Thanks!

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  • lambda traits inconsistency across C++0x compilers

    - by Sumant
    I observed some inconsistency between two compilers (g++ 4.5, VS2010 RC) in the way they match lambdas with partial specializations of class templates. I was trying to implement something like boost::function_types for lambdas to extract type traits. Check this for more details. In g++ 4.5, the type of the operator() of a lambda appears to be like that of a free standing function (R (*)(...)) whereas in VS2010 RC, it appears to be like that of a member function (R (C::*)(...)). So the question is are compiler writers free to interpret any way they want? If not, which compiler is correct? See the details below. template <typename T> struct function_traits : function_traits<decltype(&T::operator())> { // This generic template is instantiated on both the compilers as expected. }; template <typename R, typename C> struct function_traits<R (C::*)() const> { // inherits from this one on VS2010 RC typedef R result_type; }; template <typename R> struct function_traits<R (*)()> { // // inherits from this one g++ 4.5 typedef R result_type; }; int main(void) { auto lambda = []{}; function_traits<decltype(lambda)>::result_type *r; // void * } This program compiles on both g++ 4.5 and VS2010 but the function_traits that are instantiated are different as noted in the code.

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  • Recommended way to manage persistent PHP script processes?

    - by BigglesZX
    First off - hello, this is my first Stack Overflow question so I'll try my best to communicate properly. The title of my question may be a bit ambiguous so let me expand upon it immediately: I'm planning a project which involves taking data inputs from several "streaming" APIs, Twitter being one example. I've got a basic script coded up in PHP which runs indefinitely from the command line, taking input from the Twitter streaming API and doing very basic things with it. My eventual objective is to have several such processes running (perhaps daemonized using the System Daemon PEAR class), and I would like to be able to manage them from some governing process (also a PHP script). By manage I mean basic operations such as stop/start and (most crucially) automatically restarting a process that crashes. I would appreciate any pointers on how best to approach this process management angle. Again, apologies if this question is too expansive - tips on more tightly focused lines of enquiry would be appreciated if necessary. Thanks for reading and I look forward to your answers.

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  • Custom spring interceptor

    - by Hari
    Hi, I want to convert some of our internal API into a spring bean spring interceptor that we can use in other projects. This API needs some instantiation and other logic which I want to encapsulate in this bean so that we can just put the bean into our app context with necessary propoerties alone, and this will then apply the logic. I remember having read an article on this somewhere in the past - but cant find it now. Any pointers to something similar will be helpful EDIT: Sorry, I meant a spring interceptor, not a bean - my bad - please see my edit. I want to apply this interceptor to another bean dealing in XML messages.

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  • Refresher on Java classes in separate files

    - by JohnFaig
    I need a refresher on moving classes from one file into two files. My sample code is in one file called "external_class_file_main". The program runs fine and the code is shown below: Public class external_class_file_main { public static int get_a_random_number (int min, int max) { int n; n = (int)(Math.random() * (max - min +1)) + min; return (n); } public static void main(String[] args) { int r; System.out.println("Program starting..."); r = get_a_random_number (1, 5); System.out.println("random number = " + r); System.out.println("Program ending..."); } } I move the get_a_random_number class to a separate file called "external_class_file". When I do this, I get the following error: Exception in thread "main" java.lang.Error: Unresolved compilation problem: The method get_a_random_number(int, int) is undefined for the type external_class_file_main at external_class_file_main.main(external_class_file_main.java:20) The "external_class_file_main" now contains: public class external_class_file_main { public static void main(String[] args) { int r; System.out.println("Program starting..."); r = get_a_random_number (1, 5); System.out.println("random number = " + r); System.out.println("Program ending..."); } } The "external_class_file" now contains: public class external_class_file { public static int get_a_random_number (int min, int max) { int n; n = (int)(Math.random() * (max - min +1)) + min; return (n); } }

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  • Java assignment issues - Is this atomic?

    - by Bob
    Hi, I've got some questions about Java's assigment. Strings I've got a class: public class Test { private String s; public synchronized void setS(String str){ s = s + " - " + str; } public String getS(){ return s; } } I'm using "synchronized" in my setter, and avoiding it in my getter, because in my app, there are a tons of data gettings, and very few settings. Settings must be synchronized to avoid inconsistency. My question is: is getting and setting a variable atomic? I mean, in a multithreaded environment, Thread1 is about to set variable s, while Thread2 is about to get "s". Is there any way the getter method could get something different than the s's old value or the s's new value (suppose we've got only two threads)? In my app it is not a problem to get the new value, and it is not a problem to get the old one. But could I get something else? What about HashMap's getting and putting? considering this: public class Test { private Map<Integer, String> map = Collections.synchronizedMap(new HashMap<Integer, String>()); public synchronized void setMapElement(Integer key, String value){ map.put(key, value); } public String getValue(Integer key){ return map.get(key); } } Is putting and getting atomic? How does HashMap handle putting an element into it? Does it first remove the old value and put the now one? Could I get other than the old value or the new value? Thanks in advance!

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  • actionscript-3: refactor interface inheritance to get rid of ambiguous reference error

    - by maxmc
    hi! imagine there are two interfaces arranged via composite pattern, one of them has a dispose method among other methods: interface IComponent extends ILeaf { ... function dispose() : void; } interface ILeaf { ... } some implementations have some more things in common (say an id) so there are two more interfaces: interface ICommonLeaf extends ILeaf { function get id() : String; } interface ICommonComponent extends ICommonLeaf, IComponent { } so far so good. but there is another interface which also has a dispose method: interface ISomething { ... function dispose() : void; } and ISomething is inherited by ICommonLeaf: interface ICommonLeaf extends ILeaf, ISomething { function get id() : String; } As soon as the dispose method is invoked on an instance which implements the ICommonComponent interface, the compiler fails with an ambiguous reference error because ISomething has a method called dispose and ILeaf also has a dispose method, both living in different interfaces (IComponent, ISomething) within the inheritace tree of ICommonComponent. I wonder how to deal with the situation if the IComponent, the ILeaf and the ISomething can't change. the composite structure must also work for for the ICommonLeaf & ICommonComponent implementations and the ICommonLeaf & ICommonComponent must conform to the ISomething type. this might be an actionscript-3 specific issue. i haven't tested how other languages (for instance java) handle stuff like this.

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  • Choice of programming language for learning data structures and algorithms

    - by bguiz
    Which programming language would you recommend to learn about data structures and algorithms in? Considering the follwing: Personal experience Language features (pointers, OO, etc) Suitability for learning DS & A concepts I ask because there are some books out there that are programming language-agnostic (written from a Mathematical perspective, and use pseudocode). If I learn from one of these I would like to work out the algorithms in a chosen language. Then, there are other books which introduce DS & A concepts with examples in a particular programming laguage - and I would follow these examples as well. Either way, I have to choose a language, and I would like to stick to one throughout. Which one best fits the bill.

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