Search Results

Search found 4993 results on 200 pages for 'conversion operator'.

Page 142/200 | < Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >

• How to make Databinding type safe and support refactoring

  - by Ian Ringrose

  When I wish to bind a control to a property of my object, I have to provide the name of the property as a string. This is not very good because: If the property is removed or renamed, I don’t get a compiler warning. If a rename the property with a refactoring tool, it is likely the data binding will not be updated. I don’t get an error until runtime if the type of the property is wrong, e.g. binding an integer to a date chooser. Is there a design-paten that gets round this, but still has the ease of use of data-binding? (This is a problem in WinForm, Asp.net and WPF and most likely lots of other systems) I have now found "workarounds for nameof() operator in C#: typesafe databinding" that also has a good starting point for a solution.

  Read the article

• valueOf() vs. toString() in Javascript

  - by brainjam

  In Javascript every object has a valueOf() and toString() method. I would have thought that the toString() method got invoked whenever a string conversion is called for, but apparently it is trumped by valueOf(). For example, the code var x = {toString: function() {return "foo"; }, valueOf: function() {return 42; }}; window.console.log ("x="+x); window.console.log ("x="+x.toString()); will print x=42 x=foo This strikes me as backwards .. if x were a complex number, for example, I would want valueOf() to give me its magnitude (so that zero would become special), but whenever I wanted to convert to a string I would want something like "a+bi". And I wouldn't want to have to call toString() explicitly in contexts that implied a string. Is this just the way it is?

  Read the article

• Load binary file using fstream

  - by Kirill V. Lyadvinsky

  I'm trying to load binary file using fstream in the following way: #include <iostream #include <fstream #include <iterator #include <vector using namespace std; int main() { basic_fstream<uint32_t file( "somefile.dat", ios::in|ios::binary ); vector<uint32_t buffer; buffer.assign( istream_iterator<uint32_t, uint32_t( file ), istream_iterator<uint32_t, uint32_t() ); cout << buffer.size() << endl; return 0; } But it doesn't work. In Ubuntu it crashed with std::bad_cast exception. In MSVC++ 2008 it just prints 0. I know that I could use file.read to load file, but I want to use iterator and operator>> to load parts of the file. Is that possible? Why the code above doesn't work?

  Read the article

• Type casting needed for byte = byte - byte?

  - by Vaccano

  I have the following code: foreach (byte b in bytes) { byte inv = byte.MaxValue - b; // Add the new value to a list.... } When I do this I get the following error: Cannot implicitly convert type 'int' to 'byte'. An explicit conversion exists (are you missing a cast?) Each part of this statement is a byte. Why does C# want to convert the byte.MaxValue - b to an int? Shouldn't you be able to do this some how without casting? (i.e. I don't want to have to do this: byte inv = (byte) (byte.MaxValue - b);)

  Read the article

• Create method to handle multiple types of controls

  - by Praesagus

  I am trying to create a method that accepts multiple types of controls - in this case Labels and Panels. The conversion does not work because IConvertible doesn't convert these Types. Any help would be so appreciated. Thanks in advance public void LocationsLink<C>(C control) { if (control != null) { WebControl ctl = (WebControl)Convert.ChangeType(control, typeof(WebControl)); Literal txt = new Literal(); HyperLink lnk = new HyperLink(); txt.Text = "If you prefer a map to the nearest facility please "; lnk.Text = "click here"; lnk.NavigateUrl = "/content/Locations.aspx"; ctl.Controls.Add(txt); ctl.Controls.Add(lnk); } }

  Read the article

• Practical differences between classes and structs in .net (not conceptual)?

  - by Gulshan

  Whenever I tried to search about differences between classes and structs in C# or .net, I ended up with the conceptual overview of the two things like value type or the reference type, where the variables are allocated etc. But I need some practical differences. I have found some like different behavior of assignment operator, having constructors etc. Can anybody provide some more practical differences which will be directly useful while coding? Like the things works with one but not with other or same operation showing different behavior. And some common mistakes regarding these two. Also please suggest where to consider using a struct instead of a class. And where the structs should not be used.

  Read the article

• Converting python objects for rpy2

  - by bgbg

  The following code is supposed to created a heatmap in rpy2 import numpy as np from rpy2.robjects import r data = np.random.random((10,10)) r.heatmap(data) However, it results in the following error Traceback (most recent call last): File "z.py", line 8, in <module> labRow=rowNames, labCol=colNames) File "C:\Python25\lib\site-packages\rpy2\robjects\__init__.py", line 418, in __call__ new_args = [conversion.py2ri(a) for a in args] File "C:\Python25\lib\site-packages\rpy2\robjects\__init__.py", line 93, in default_py2ri raise(ValueError("Nothing can be done for the type %s at the moment." %(type(o)))) ValueError: Nothing can be done for the type <type 'numpy.ndarray'> at the moment. From the documentation I learn that r.heatmap expects "a numeric matrix". How do I convert np.array to the required data type?

  Read the article

• How to apply custom BidirectionalGraph from QuickGraph to GraphLayout from Graph#?

  - by Dmitry

  Whats wrong? using QuickGraph; using GraphSharp; public class State { public string Name { get; set; } public override string ToString() { return Name; } } public class Event { public string Name; public override string ToString() { return Name; } } BidirectionalGraph<State, TaggedEdge<State, Event>> x = new BidirectionalGraph<State, TaggedEdge<State, Event>>(); GraphLayout graphLayout = new GraphLayout(); graphLayout.Graph = x; Error: Cannot implicitly convert type 'QuickGraph.BidirectionalGraph' to 'QuickGraph.IBidirectionalGraph'. An explicit conversion exists (are you missing a cast?) If I put the cast, then application gets fault error on start without any information Whats wrong?

  Read the article

• Convert the ada code to its C .

  - by maddy

  HI All, I have a piece of ada code shown below which is a simple switch case statements.Is there any better way to convert this into C. for I in 1..100 loop case I is when 100 => Dollars := Dollars + 1; when 25|50|75 => Quarters := Quarters + 1; when 10|20|30|40|60|70|80|90 => Dimes := Dimes + 1; when 5|15|35|45|55|65|85|95 => Nickles := Nickles + 1; when others => Pennies := Pennies + 1; end case; end loop; Now by adding the switch and the case for each values in the case,i can do that conversion,But it seems tyo make the code too big.Is there anywa other simple and compact way.Please get back to me if the question is not clear? Regards maddy

  Read the article

• [Cocoa] NSTask string encoding problem

  - by ryyst

  Hi, In my program, I'm grep-ing via NSTask. For some reason, sometimes I would get no results (even though the code was apparently the same as the command run from the CLI which worked just fine), so I checked through my code and found, in Apple's documentation, that when adding arguments to an NSTask object, "the NSTask object converts both path and the strings in arguments to appropriate C-style strings (using fileSystemRepresentation) before passing them to the task via argv[]" (snip). The problem is that I might grep terms like "Río Gallegos". Sadly (as I checked with fileSystemRepresentation), that undergoes the conversion and turns out to be "RiÃÅo Gallegos". How can I solve this? -- Ry

  Read the article

• pthread_create from non-static member function

  - by Stanislav Palatnik

  This is somewhat similiar to this : http://stackoverflow.com/questions/1151582/pthread-function-from-a-class But the function that's getting called in the end is referencing the this pointer, so it cannot be made static. void * Server::processRequest() { std::string tmp_request, outRequest; tmp_request = this->readData(); outRequest = this->parse(tmp_request); this->writeReply(outRequest); } void * LaunchMemberFunction(void * obj) { return ((Server *)obj)->processRequest(); } and then the pthread_create pthread_create(&handler[tcount], &attr, (void*)LaunchMemberFunction,(void*)&SServer); errors: SS_Twitter.cpp:819: error: invalid conversion from void* to void* ()(void) SS_Twitter.cpp:819: error: initializing argument 3 of int pthread_create(pthread_t*, const pthread_attr_t*, void* ()(void), void*)

  Read the article

• How do I copy object in Qt?

  - by Martin

  I'm using Qt and have some real basic problems. I have created my own widget MyTest that have a variable obj. I need to set this variable obj from an object outside of the widget so that the variable is copied not just a pointer to another object. I get an error message and can't figure out how to do this basic stuff. This is the code I'm using: MyTest.h: class MyTest : public QWidget { Q_OBJECT public: void setObj(QObject &inobj); QObject obj; .... } MyTest.cpp: void MyTest::setObj(QObject &inobj) { obj = inobj; //HERE I get the error message: "illegal access from 'QObject' to protected/private member 'QObject::operator=(const QObject &)'" } main.cpp: int main(int argc, char *argv[]) { QApplication a(argc, argv); QObject *ob = new QObject(); MyTest w; w.setObj(*ob); } Thanks for your help!

  Read the article

• Java 'Prototype' pattern - new vs clone vs class.newInstance

  - by Guillaume

  In my project there are some 'Prototype' factories that create instances by cloning a final private instance. The author of those factories says that this pattern provides better performance than calling 'new' operator. Using google to get some clues about that, I've found nothing really relevant about that. Here is a small excerpt found in a javdoc from an unknown project javdoc from an unknown project Sadly, clone() is rather slower than calling new. However it is a lot faster than calling java.lang.Class.newInstance(), and somewhat faster than rolling our own "cloner" method. For me it's looking like an old best practice of the java 1.1 time. Does someone know more about this ? Is this a good practice to use that with 'modern' jvm ?

  Read the article

• LINQ Quicksort is Unstable Except When Cascading

  - by Mystagogue

  On page 64 of "LINQ To Objects Using C# 4.0" (Tony Magennis) he states that LINQ's quicksort ordering algorithm is unstable... ...although this is simply solved by cascading the result into a ThenBy or ThenByDescending operator. Huh? Why would cascading an unstable sortation into another sortation fix the result? In fact, I'd say that isn't possible. The original order, once passed through an unstable sort, is simply lost. What am I missing here?

  Read the article

• Segmentation Fault when using "mov" in Assembly

  - by quithakay207

  I am working on a simple assembly program for a class, and am encountering an odd segmentation fault. It's a pretty simple program to convert bytes into kilobytes. However, within the function that does the conversion, I get a segmentation fault when I try to move the value 1024 into the ebx register. I've never had this kind of problem before when working with registers. Does someone know what could be causing this? I imagine it is something simple that I'm overlooking. Thank you! asm_main: enter 0,0 pusha mov eax, 0 mov ebx, 0 call read_int push eax call functionA popa mov leave ret functionA: mov eax, [esp + 4] call print_int call print_nl mov ebx, 1024 ;segmentation fault occurs here div ebx call print_int ret UPDATE: One interesting discovery is that if I delete the lines interacting with the stack, push eax and mov eax, [esp + 4], there is no longer a segmentation fault. However, I get a crazy result in eax after performing div ebx.

  Read the article

• Creating a Rails query from a hash of user input

  - by Jamie

  I'm attempting to create a fairly complex search engine for a project using a variable number of search criteria. The user input is sorted into an array of hashes. The hashes contain the following information: { :column => "", :value => "", :operator => "", # Such as: =, !=, <, >, etc. :and_or => "", # Two possible values: "and" and "or" } How can I loop through this array and use the information in these hashes to make an ActiveRecord WHERE query?

  Read the article

• How does this C# asp.net random password code work?

  - by quakkels

  Hello all, I'm new to .NET and C# and I'm trying to figure out how this code works: public static string CreateRandomPassword(int PasswordLength) { String _allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ23456789"; Byte[] randomBytes = new Byte[PasswordLength]; RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider(); rng.GetBytes(randomBytes); char[] chars = new char[PasswordLength]; int allowedCharCount = _allowedChars.Length; for(int i = 0;i<PasswordLength;i++) { /// /// I don't understand how this line works: /// chars[i] = _allowedChars[(int)randomBytes[i] % allowedCharCount]; } return new string(chars); } I think I've got a pretty good handle on most of this. I haven't been able to understand the following line: chars[i] = _allowedChars[(int)randomBytes[i] % allowedCharCount]; I understand that the code generates random binary numbers and uses those random numbers in the for loop to select a character from the _allowedChars string. What I don't get is why this code uses the modulous operator (%) to get the _allowedChars index value. Thanks for any help

  Read the article

• Error while excuting a simple boost thread program

  - by Eternal Learner

  Hi All, Could you tell mw what is the problem with the below boost::thread program #include<iostream> #include<boost/thread/thread.hpp> boost::mutex mutex; class A { public: A() : a(0) {} void operator()() { boost::mutex::scoped_lock lock(mutex); } private: int a; }; int main() { boost::thread thr1(A()); boost::thread thr2(A()); thr1.join(); thr2.join(); } I get the error message: error: request for member 'join' in 'thr1', which is of non-class type 'boost::thread()(A ()())' BoostThread2.cpp:30: error: request for member 'join' in 'thr2', which is of non-class type 'boost::thread ()(A ()())'

  Read the article

• Error when using SharpDevelop

  - by Sebastian

  I have some code: Outlook.Application outLookApp = new Outlook.Application(); Outlook.Inspector inspector = outLookApp.ActiveInspector(); Outlook.NameSpace nameSpace = outLookApp.GetNamespace("MAPI"); Outlook.MAPIFolder inbox = nameSpace.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox); String sCriteria = "[SenderEmailAddress] = '[email protected]'"; Outlook.Items filteredItems = inbox.Items.Restrict(sCriteria); // totaly sure that count > 0; Outlook.MailItem item = filteredItems[1]; In the last line I have error: "Cannot implicitly convert type 'object' to 'Microsoft.Office.Interop.Outlook.MailItem'. An explicit conversion exists (are you missing a cast?)". I don't know why. Previous I used VisualStudio 2010 but my trial has expired. Is there any hope to run this on SharpDevelop?

  Read the article

• VIrtual class problem

  - by ugur

  What i think about virtual class is, if a derived class has a public base, let's say, class base, then a pointer to derived can be assigned to a variable of type pointer to base without use of any explicit type conversion. But what if, we are inside of base class then how can we call derived class's functions. I will give an example: class Graph{ public: Graph(string); virtual bool addEdge(string,string); } class Direct:public Graph{ public: Direct(string); bool addEdge(string,string); } Direct::Direct(string filename):Graph(filename){}; When i call constructor of Direct class then it calls Graph. Now lets think Graph function calls addedge. Graph(string str){ addedge(str,str); } When it calls addedge, even if the function is virtual, it calls Graph::edge. What i want is, to call Direct::addedge. How can it be done?

  Read the article

• Virtual class problem

  - by ugur

  What i think about virtual class is, if a derived class has a public base, let's say, class base, then a pointer to derived can be assigned to a variable of type pointer to base without use of any explicit type conversion. But what if, we are inside of base class then how can we call derived class's functions. I will give an example: class Graph{ public: Graph(string); virtual bool addEdge(string,string); } class Direct:public Graph{ public: Direct(string); bool addEdge(string,string); } Direct::Direct(string filename):Graph(filename){}; When i call constructor of Direct class then it calls Graph. Now lets think Graph function calls addedge. Graph(string str){ addedge(str,str); } When it calls addedge, even if the function is virtual, it calls Graph::edge. What i want is, to call Direct::addedge. How can it be done?

  Read the article

• How do encrypt a long or int using the Bouncy Castle crypto routines for BlackBerry?

  - by DanG

  How do encrypt/decrypt a long or int using the Bouncy Castle crypto routines for BlackBerry? I know how to encrypt/decrypt a String. I can encrypt a long but can't get a long to decrypt properly. Some of this is poorly done, but I'm just trying stuff out at the moment. I've included my entire crypto engine here: import org.bouncycastle.crypto.BufferedBlockCipher; import org.bouncycastle.crypto.DataLengthException; import org.bouncycastle.crypto.InvalidCipherTextException; import org.bouncycastle.crypto.engines.AESFastEngine; import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher; import org.bouncycastle.crypto.params.KeyParameter; public class CryptoEngine { // Global Variables // Global Objects private static AESFastEngine engine; private static BufferedBlockCipher cipher; private static KeyParameter key; public static boolean setEncryptionKey(String keyText) { // adding in spaces to force a proper key keyText += " "; // cutting off at 128 bits (16 characters) keyText = keyText.substring(0, 16); keyText = HelperMethods.cleanUpNullString(keyText); byte[] keyBytes = keyText.getBytes(); key = new KeyParameter(keyBytes); engine = new AESFastEngine(); cipher = new PaddedBufferedBlockCipher(engine); // just for now return true; } public static String encryptString(String plainText) { try { byte[] plainArray = plainText.getBytes(); cipher.init(true, key); byte[] cipherBytes = new byte[cipher.getOutputSize(plainArray.length)]; int cipherLength = cipher.processBytes(plainArray, 0, plainArray.length, cipherBytes, 0); cipher.doFinal(cipherBytes, cipherLength); String cipherString = new String(cipherBytes); return cipherString; } catch (DataLengthException e) { Logger.logToConsole(e); } catch (IllegalArgumentException e) { Logger.logToConsole(e); } catch (IllegalStateException e) { Logger.logToConsole(e); } catch (InvalidCipherTextException e) { Logger.logToConsole(e); } catch (Exception ex) { Logger.logToConsole(ex); } // else return "";// default bad value } public static String decryptString(String encryptedText) { try { byte[] cipherBytes = encryptedText.getBytes(); cipher.init(false, key); byte[] decryptedBytes = new byte[cipher.getOutputSize(cipherBytes.length)]; int decryptedLength = cipher.processBytes(cipherBytes, 0, cipherBytes.length, decryptedBytes, 0); cipher.doFinal(decryptedBytes, decryptedLength); String decryptedString = new String(decryptedBytes); // crop accordingly int index = decryptedString.indexOf("\u0000"); if (index >= 0) { decryptedString = decryptedString.substring(0, index); } return decryptedString; } catch (DataLengthException e) { Logger.logToConsole(e); } catch (IllegalArgumentException e) { Logger.logToConsole(e); } catch (IllegalStateException e) { Logger.logToConsole(e); } catch (InvalidCipherTextException e) { Logger.logToConsole(e); } catch (Exception ex) { Logger.logToConsole(ex); } // else return "";// default bad value } private static byte[] convertLongToByteArray(long longToConvert) { return new byte[] { (byte) (longToConvert >>> 56), (byte) (longToConvert >>> 48), (byte) (longToConvert >>> 40), (byte) (longToConvert >>> 32), (byte) (longToConvert >>> 24), (byte) (longToConvert >>> 16), (byte) (longToConvert >>> 8), (byte) (longToConvert) }; } private static long convertByteArrayToLong(byte[] byteArrayToConvert) { long returnable = 0; for (int counter = 0; counter < byteArrayToConvert.length; counter++) { returnable += ((byteArrayToConvert[byteArrayToConvert.length - counter - 1] & 0xFF) << counter * 8); } if (returnable < 0) { returnable++; } return returnable; } public static long encryptLong(long plainLong) { try { String plainString = String.valueOf(plainLong); String cipherString = encryptString(plainString); byte[] cipherBytes = cipherString.getBytes(); long returnable = convertByteArrayToLong(cipherBytes); return returnable; } catch (Exception e) { Logger.logToConsole(e); } // else return Integer.MIN_VALUE;// default bad value } public static long decryptLong(long encryptedLong) { byte[] cipherBytes = convertLongToByteArray(encryptedLong); cipher.init(false, key); byte[] decryptedBytes = new byte[cipher.getOutputSize(cipherBytes.length)]; int decryptedLength = cipherBytes.length; try { cipher.doFinal(decryptedBytes, decryptedLength); } catch (DataLengthException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalStateException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvalidCipherTextException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } long plainLong = convertByteArrayToLong(decryptedBytes); return plainLong; } public static boolean encryptBoolean(int plainBoolean) { return false; } public static boolean decryptBoolean(int encryptedBoolean) { return false; } public static boolean testLongToByteArrayConversion() { boolean returnable = true; // fails out of the bounds of an integer, the conversion to long from byte // array does not hold, need to figure out a better solution for (long counter = -1000000; counter < 1000000; counter++) { long test = counter; byte[] bytes = convertLongToByteArray(test); long result = convertByteArrayToLong(bytes); if (result != test) { returnable = false; Logger.logToConsole("long conversion failed"); Logger.logToConsole("test = " + test + "\n result = " + result); } // regardless } // the end Logger.logToConsole("final returnable result = " + returnable); return returnable; } }

  Read the article

• Qt SDk 4.6.2 on mac os x: invoke ffmpeg ??

  - by varunmagical

  Hello, I am writing an FFmpeg frontend in Qt & testing it on linux, windows & Mac. (FFmpeg is a popular command line tool for video operations) My project is working well on Linux & windows but I cannot invoke FFmpeg on Mac! I have compiled it from svn source on Mac & I have ensured that it is working properly by running it in Mac terminal. In my project, I have created a widget that shows FFmpeg output during conversion, but on mac, It always stays blank. Need help!

  Read the article

• ActiveRecord model with datetime stamp with timezone support attribute.

  - by jtarchie

  Rails is great that it will support timezone overall in the application with Time.zone. I need to be able to support the timezone a user selects for a record. The user will be able to select date, time, and timezone for the record and I would like all calculations to be done with respect to the user selected timezone. My question is what is the best practice to handle user selected timezones. The model is using a time_zone_select and datetime_select for two different attributes timezone and scheduled_at. When the model saves, the scheduled_at attribute gets converted to the locally defined Time.zone. When a user goes back to edit the scheduled_at attribute with the datetime_select the datetime is set to the converted Time.zone timezone and not the timezone attribute. Is there a nice way to handle to the conversion to the user selected timezone?

  Read the article

• Convert varchar to numeric in Informix

  - by user302705

  Hi All I have problem while converting varchar type to Int type in Informix. Actually I dont know if the value is really varchar or not which I want to convert to INT. Its a sandbox system. As Example: I am trying to run this kind of Select telnumber from numbers n where Cast(n.telnumber AS INT) between 1234 and 9999 I got this error: "Character to numeric conversion error" If I run this query like this: Select telnumber from numbers n where n.telnumber between '1234' and '9999' it brings a resultset but not in the range that I defined. 130987 130710 130723 How can I convert telnumber to a numeric value and use it in "between" 1234 and 9999 range Thanks in advance.

  Read the article

< Previous Page | 138 139 140 141 142 143 144 145 146 147 148 149  | Next Page >