Search Results

Search found 35523 results on 1421 pages for 'nullable string'.

Page 406/1421 | < Previous Page | 402 403 404 405 406 407 408 409 410 411 412 413  | Next Page >

• Deployment problems of asp.net 3.5 in iis 5.1

  - by peter

  i have microsoft.net 3.5 application and have IIS5.1,,for deploying website do i need to do any thing aother than this 1.In IIS i created virtual directory named SPA and i browsed in to the location where my project is lacated and i added entire project file there( Do i need to add only bin file and login page or i need to add all pages???) 2.In asp.net folder i selected tab version 2.0,, 3.when i browsed i can see all pages when i click login.aspx i am getting this error [SqlException (0x80131904): User does not have permission to perform this action.] System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +821651 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +186 System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +1932 System.Data.SqlClient.SqlInternalConnectionTds.CompleteLogin(Boolean enlistOK) +33 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +172 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +381 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +181 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +173 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +133 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +30 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +424 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +494 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +82 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +105 System.Data.SqlClient.SqlConnection.Open() +111 ChatTool.LoginForm.Page_Load(Object sender, EventArgs e) in D:\Chat tool_Ameya\ProjectCode\Unisys Project Testing\Unisys Project\Login.aspx.cs:25 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +15 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +33 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +47 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436

  Read the article

• Am I using handlers in the wrong way?

  - by superexsl

  Hey, I've never used HTTP Handlers before, and I've got one working, but I'm not sure if I'm actually using it properly. I have generated a string which will be saved as a CSV file. When the user clicks a button, I want the download dialog box to open so that the user can save the file. What I have works, but I keep reading about modifying the web.config file and I haven't had to do that. My Handler: private string _data; private string _title = "temp"; public void AddData(string data) { _data = data; } public bool IsReusable { get { return false; } } public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/csv"; context.Response.AddHeader("content-disposition", "filename=" + _title + ".csv"); context.Response.Write(_data); context.Response.Flush(); context.Response.Close(); } And this is from the page that allows the user to download: (on button click) string dataToConvert = "MYCSVDATA...."; csvHandler handler = new csvHandler(); handler.AddData(dataToConvert); handler.ProcessRequest(this.Context); This works fine, but no examples I've seen ever instantiate the handler and always seem to modify the web.config. Am I doing something wrong? Thanks

  Read the article

• PHP Doctrine - YAML syntax help. Default value for many to many relationship?

  - by Dan

  Hi, I have the following YAML schema for organising users in Doctrine: Person: tableName: people columns: id: type: integer primary: true autoincrement: true firstname: type: string notnull: true lastname: type: string notnull: true User: inheritance: extends: Person type: column_aggregation keyField: type keyValue: 1 Userdetails: columns: person_id: type: integer primary: true password: type: string notnull: true relations: User: foreignType: one local: person_id onDelete: CASCADE onUpdate: CASCADE Group: tableName: groups columns: id: type: integer primary: true autoincrement: true name: type: string notnull: true UserGroup: columns: group_id: type: integer primary: true person_id: type: integer primary: true relations: User: foreignType: many local: person_id Group: foreignType: many Basically, any people who are users will belong to one or more groups. Is there any way to add new users to a particular group by default? Any advice appreciated. Thanks

  Read the article

• How to properly document programming languages?

  - by roydukkey

  Where can I find information on how to properly document a programming language? What I mean is that there seems to be a standard way to document code. php.net and api.jquery.com seem to document there code the a similar way. For example, the trim() description on php.net. string trim ( string $str [, string $charlist ] ) And likewise on jquery.com .animate( properties, [ duration ], [ easing ], [ callback ] ) Does anyone even know what this syntax is called?

  Read the article

• Creating a blocking Queue<T> in .NET?

  - by spoon16

  I have a scenario where I have multiple threads adding to a queue and multiple threads reading from the same queue. If the queue reaches a specific size all threads that are filling the queue will be blocked on add until an item is removed from the queue. The solution below is what I am using right now and my question is: How can this be improved? Is there an object that already enables this behavior in the BCL that I should be using? internal class BlockingCollection<T> : CollectionBase, IEnumerable { //todo: might be worth changing this into a proper QUEUE private AutoResetEvent _FullEvent = new AutoResetEvent(false); internal T this[int i] { get { return (T) List[i]; } } private int _MaxSize; internal int MaxSize { get { return _MaxSize; } set { _MaxSize = value; checkSize(); } } internal BlockingCollection(int maxSize) { MaxSize = maxSize; } internal void Add(T item) { Trace.WriteLine(string.Format("BlockingCollection add waiting: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.WaitOne(); List.Add(item); Trace.WriteLine(string.Format("BlockingCollection item added: {0}", Thread.CurrentThread.ManagedThreadId)); checkSize(); } internal void Remove(T item) { lock (List) { List.Remove(item); } Trace.WriteLine(string.Format("BlockingCollection item removed: {0}", Thread.CurrentThread.ManagedThreadId)); } protected override void OnRemoveComplete(int index, object value) { checkSize(); base.OnRemoveComplete(index, value); } internal new IEnumerator GetEnumerator() { return List.GetEnumerator(); } private void checkSize() { if (Count < MaxSize) { Trace.WriteLine(string.Format("BlockingCollection FullEvent set: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.Set(); } else { Trace.WriteLine(string.Format("BlockingCollection FullEvent reset: {0}", Thread.CurrentThread.ManagedThreadId)); _FullEvent.Reset(); } } }

  Read the article

• Problem with LINQ in C#

  - by David Bonnici

  I am encountering a problem when using LINQ in C#, I am constantly getting "Specified cast is not valid". This is what I am trying to do. I create a class in which I declare all the columns of the table. [Table(Name="tbl_Aff")] public class Affiliate { [Column] public string name; [Column] public string firstname; [Column] public string surname; [Column] public string title; } I then declare a strongly typed DataContext in which I declare all Table collections as members of the context. public partial class Database : DataContext { public Table affiliate; public Database() : base(Settings.getConnectionString()) { } //This method gets the connection string by reading from an XML file. } public partial class Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Database database = new Database(); try { var q = from a in database.affiliate select a; foreach (var aff in q) // Here I get the error "Specified cast is not valid" { lblMessage.InnerHtml += aff.name + ""; } } catch (Exception ex) { System.Console.WriteLine(ex.Message); } } }

  Read the article

• Is there a standard Cyclic Iterator in C++

  - by Hippicoder

  Based on the following question: Check if one string is a rotation of other string I was thinking of making a cyclic iterator type that takes a range, and would be able to solve the above problem like so: std::string s1 = "abc" ; std::string s2 = "bca" ; std::size_t n = 2; // number of cycles cyclic_iterator it(s2.begin(),s2.end(),n); cyclic_iterator end; if (std::search(it, end, s1.begin(),s1.end()) != end) { std::cout << "s1 is a rotation of s2" << std::endl; } My question, Is there already something like this available? I've check Boost and STL doesn't have one. I've got a simple hand-written one but would rather use an already made/tested implementation.

  Read the article

• How to get a Class literal from a generically specific Class

  - by h2g2java

  There are methods like these which require Class literals as argument. Collection<EmpInfo> emps = SomeSqlUtil.select( EmpInfo.class, "select * from emps"); or GWT.create(Razmataz.class); The problem presents itself when I need to supply generic specific classes like EmpInfo<String> Razmataz<Integer> The following would be wrong syntax Collection<EmpInfo<String>> emps = SomeSqlUtil.select( EmpInfo<String>.class, "select * from emps"); or GWT.create(Razmataz<Integer>.class); Because you cannot do syntax like Razmataz<Integer>.class So, how would I be able to squeeze a class literal out of EmpInfo<String> Razmataz<Integer> so that I could feed them as arguments to methods requiring Class literals? Further info Okay, I confess that I am asking this primarily for GWT. I have a pair of GWT RPC interface Razmataz. (FYI, GWT RPC interface has to be defined in server-client pairs). I plan to use the same interface pair for communicating whether it be String, Integer, Boolean, etc. GWT.create(Razmataz) for Razmataz<T> complains that, since I did not specify T, GWT compiler treated it as Object. Then GWT compiler would not accept Object class. It needs to be more specific than being an Object. So, it seems there is no way for me to tell GWT.create what T is because a Class literal is a runtime concept while generics is a compile time concept, Right?

  Read the article

• what are all the Optimize tricks that you know for asp.net code ?

  - by Aristos

  After some time of many code programming on asp.net, I discover the very big speed different between string and StringBuilder. I know that is very common and known but I just mention it for start. The second think that I have found to speed up the code, is to use the const, and not the static, for declare my configuration constants value (especial the strings). With the const, the compiler not create new object, but just place the value, on the point that you have ask it, but with the static declaration, is create a new memory object and keep its on the memory. My third trick, is when I search for string, I use hash values, and not the string itself. For example, if I need a List<string SomeValues, and place inside strings that I need to search them, I prefer to use List<int SomeHashValue, and I use the hash value to locate the strings. My forth thought that I was wandering, is if is better to place big strings in one line, or separate them in different lines with the + symbol to be more easy to read out. I make some tests and see that the compiler make a good job is some split the string, in many lines, using the + symbol. What other tricks/tips do you know and use on your programming to make it run faster, and maybe use less memory. Well I know, that some times, to make something run faster, you need more memory, more cache. My priority is on speed. Because Speed Counts.

  Read the article

• Understanding Thread/BeginInvoke? [beginner]

  - by Moberg

  Consider the code: class Work { public void DoStuff(string s) { Console.WriteLine(s); // .. whatever } } class Master { private readonly Work work = new Work(); public void Execute() { string hello = "hello"; // (1) is this an ugly hack ? var thread1 = new Thread(new ParameterizedThreadStart(o => this.work.DoStuff((string)o))); thread1.Start(hello); thread1.Join(); // (2) is this similar to the one above? new Action<string>(s => this.work.DoStuff(s)).BeginInvoke(hello, null, null); } } Is (1) an acceptable way of easy starting some work in a seperate thread? If not a better alternative would be much appreciated. Is (2) doing the same? I guess what I ask is if a new thread is started, or.. Hope you can help a beginner to a better understanding :) /Moberg

  Read the article

• How can I parse a namespace using the SAX parser?

  - by Silvestri

  Hello, Using a twitter search URL ie. http://search.twitter.com/search.rss?q=android returns CSS that has an item that looks like: <item> <title>@UberTwiter still waiting for @ubertwitter android app!!!</title> <link>http://twitter.com/meals69/statuses/21158076391</link> <description>still waiting for an app!!!</description> <pubDate>Sat, 14 Aug 2010 15:33:44 +0000</pubDate> <guid>http://twitter.com/meals69/statuses/21158076391</guid> <author>Some Twitter User</author> <media:content type="image/jpg" height="48" width="48" url="http://a1.twimg.com/profile_images/756343289/me2_normal.jpg"/> <google:image_link>http://a1.twimg.com/profile_images/756343289/me2_normal.jpg</google:image_link> <twitter:metadata> <twitter:result_type>recent</twitter:result_type> </twitter:metadata> </item> Pretty simple. My code parses out everything (title, link, description, pubDate, etc.) without any problems. However, I'm getting null on: <google:image_link> I'm using Java to parse the RSS feed. Do I have to handle compound localnames differently than I would a more simple localname? This is the bit of code that parses out Link, Description, pubDate, etc: @Override public void endElement(String uri, String localName, String name) throws SAXException { super.endElement(uri, localName, name); if (this.currentMessage != null){ if (localName.equalsIgnoreCase(TITLE)){ currentMessage.setTitle(builder.toString()); } else if (localName.equalsIgnoreCase(LINK)){ currentMessage.setLink(builder.toString()); } else if (localName.equalsIgnoreCase(DESCRIPTION)){ currentMessage.setDescription(builder.toString()); } else if (localName.equalsIgnoreCase(PUB_DATE)){ currentMessage.setDate(builder.toString()); } else if (localName.equalsIgnoreCase(GUID)){ currentMessage.setGuid(builder.toString()); } else if (uri.equalsIgnoreCase(AVATAR)){ currentMessage.setAvatar(builder.toString()); } else if (localName.equalsIgnoreCase(ITEM)){ messages.add(currentMessage); } builder.setLength(0); } } startDocument looks like: @Override public void startDocument() throws SAXException { super.startDocument(); messages = new ArrayList<Message>(); builder = new StringBuilder(); } startElement looks like: @Override public void startElement(String uri, String localName, String name, Attributes attributes) throws SAXException { super.startElement(uri, localName, name, attributes); if (localName.equalsIgnoreCase(ITEM)){ this.currentMessage = new Message(); } } Tony

  Read the article

• Implementing an interface with interface members

  - by jstark

  What is the proper way to implement an interface that has its own interface members? (am I saying that correctly?) Here's what I mean: public Interface IFoo { string Forty { get; set; } string Two { get; set; } } public Interface IBar { // other stuff... IFoo Answer { get; set; } } public class Foo : IFoo { public string Forty { get; set; } public string Two { get; set; } } public class Bar : IBar { // other stuff public Foo Answer { get; set; } //why doesnt' this work? } I've gotten around my problem using explicit interface implementation, but I'm wondering if there is a better way?

  Read the article

• VBA How to find last insert id?

  - by Muiter

  I have this code: With shtControleblad Dim strsql_basis As String strsql_basis = "INSERT INTO is_calculatie (offerte_id) VALUES ('" & Sheets("controleblad").Range("D1").Value & "')" rs.Open strsql_basis, oConn, adOpenDynamic, adLockOptimistic Dim last_id As String last_id = "select last_insert_id()" End With The string last_id is not filled. What is wrong? I need to find te last_insert_id so I can use it in an other query.

  Read the article

• Scala traits and implicit conversion confusion

  - by pr1001

  The following lines work when I enter them by hand on the Scala REPL (2.7.7): trait myTrait { override def toString = "something" } implicit def myTraitToString(input: myTrait): String = input.toString object myObject extends myTrait val s: String = myObject However, if I try to compile file with it I get the following error: [error] myTrait.scala:37: expected start of definition [error] implicit def myTraitToString(input: myTrait): String = input.toString [error] ^ Why? Thanks!

  Read the article

• JSON.Net: deserializing polymorphic types without specifying the assembly

  - by Frank Schwieterman

  I see that using JSON.Net, I can decode polymorphic objects if a $type attribute specifies the specific type of the JSON object. In all the examples I've seen, $type includes the namespace. Is it possible to make this work including just a simple typename without the assembly? I'd be happy to specify a default assembly to the JsonSerializer if thats possible I am able to deserialize the JSON using: public class SingleAssemblyJsonTypeBinder : SerializationBinder { private readonly Assembly _assembly; private Dictionary _typesBySimpleName = new Dictionary(StringComparer.OrdinalIgnoreCase); private Dictionary _simpleNameByType = new Dictionary(); public SingleAssemblyJsonTypeBinder(Assembly assembly) { _assembly = assembly; _typesBySimpleName = new Dictionary<string, Type>(); foreach (var type in _assembly.GetTypes().Where(t => t.IsPublic)) { if (_typesBySimpleName.ContainsKey(type.Name)) throw new InvalidOperationException("Cannot user PolymorphicBinder on a namespace where multiple public types have same name."); _typesBySimpleName[type.Name] = type; _simpleNameByType[type] = type.Name; } } public override Type BindToType(string assemblyName, string typeName) { Type result; if (_typesBySimpleName.TryGetValue(typeName.Trim(), out result)) return result; return null; } public override void BindToName(Type serializedType, out string assemblyName, out string typeName) { string name; if (_simpleNameByType.TryGetValue(serializedType, out name)) { typeName = name; assemblyName = null;// _assembly.FullName; } else { typeName = null; assemblyName = null; } } } ... public static JsonSerializerSettings GetJsonSerializationSettings() { var settings = new JsonSerializerSettings(); settings.Binder = new SingleAssemblyJsonTypeBinder(typeof(MvcApplication).Assembly); settings.TypeNameHandling = TypeNameHandling.Objects; return settings; } .... var serializer = JsonSerializer.Create(settings); I haven't been able to make this work with MVC though, I'm configuring json deserialization per the code below in Application_Start, and the object is deserialized, but using the base type one. GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.Binder = new SingleAssemblyJsonTypeBinder(this.GetType().Assembly); GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.TypeNameHandling = TypeNameHandling.All; GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.TypeNameAssemblyFormat = FormatterAssemblyStyle.Simple;

  Read the article

• is there a downside to putting N in front of strings in scripts? Is it considered a "best practice"?

  - by jcollum

  Let's say I have a table that has a varchar field. If I do an insert like this: INSERT MyTable SELECT N'the string goes here' Is there any fundamental difference between that and: INSERT MyTable SELECT 'the string goes here' My understanding was that you'd only have a problem if the string contained a Unicode character and the target column wasn't unicode. Other than that, SQL deals with it just fine and converts the string with the N'' into a varchar field (basically ignores the N). I was under the impression that N in front of strings was a good practice, but I'm unable to find any discussion of it that I'd consider definitive. Title may need improvement, feel free.

  Read the article

• How to get some xml that comes before and a little from after a DOM Node.

  - by startoftext

  I am using java and I am pretty open to using w3c DOM or DOM4J at this point. So lets say I have a Node like a text node that I have found something interesting in, like say an occurrence of a substring in the nodes text. If I want to get a string with a number characters preceding that node and a few characters after that node how may I do that? Basically I need to be able to display a snippet of the original xml around the occurrence of that string. The problem I have with getting the parent node for example and then calling asXML is that I no longer know the exact location of the substring in the text node. If I search again for that string value in the parents xml then I may find 2 occurrences or many more if the parent has other children that contain an occurrence of that string. Much appreciation if any one can answer this question.

  Read the article

• How to define a collection in a POCO in Entity Framework 4?

  - by Stef

  Lets say I've a Team class which contains 0 or more Players. The Player class is easy: public class Player { public long Id { get; set; } public string Name { get; set; } public Team Team { get; set; } } But whats the best to define the Team class? Option 1 public class Team { public long Id { get; set; } public string Name { get; set; } public ICollection<Player> Players { get; set; } } Option 2: public class Team { public Team() { Players = new Collection<Player>(); } public long Id { get; set; } public string Name { get; set; } public ICollection<Player> Players { get; set; } } Option 3: public class Team { public long Id { get; set; } public string Name { get; set; } public IQueryable<Player> Players { get; set; } } Option 4: public class Team { public long Id { get; set; } public string Name { get; set; } public ObjectSet<Player> Players { get; set; } }

  Read the article

• Cleaning up a dynamic array of Objects in C++

  - by Dr. Monkey

  I'm a bit confused about handling an array of objects in C++, as I can't seem to find information about how they are passed around (reference or value) and how they are stored in an array. I would expect an array of objects to be an array of pointers to that object type, but I haven't found this written anywhere. Would they be pointers, or would the objects themselves be laid out in memory in an array? In the example below, a custom class myClass holds a string (would this make it of variable size, or does the string object hold a pointer to a string and therefore take up a consistent amount of space. I try to create a dynamic array of myClass objects within a myContainer. In the myContainer.addObject() method I attempt to make a bigger array, copy all the objects into it along with a new object, then delete the old one. I'm not at all confident that I'm cleaning up my memory properly with my destructors - what improvements could I make in this area? class myClass { private string myName; public unsigned short myAmount; myClass(string name, unsigned short amount) { myName = name; myAmount = amount; } //Do I need a destructor here? I don't think so because I don't do any // dynamic memory allocation within this class } class myContainer { int numObjects; myClass * myObjects; myContainer() { numObjects = 0; } ~myContainer() { //Is this sufficient? //Or do I need to iterate through myObjects and delete each // individually? delete [] myObjects; } void addObject(string name, unsigned short amount) { myClass newObject = new myClass(name, amount); myClass * tempObjects; tempObjects = new myClass[numObjects+1]; for (int i=0; i<numObjects; i++) tempObjects[i] = myObjects[i]); tempObjects[numObjects] = newObject; numObjects++; delete newObject; //Will this delete all my objects? I think it won't. //I'm just trying to delete the old array, and have the new array hold // all the objects plus the new object. delete [] myObjects; myObjects = tempObjects; } }

  Read the article

• using xpath get the correct value in selectName

  - by Sangeeta

  Below I have written the code. I need help to get the right value in selectName. I am new to XPath. Basically with this code I am trying to achieve if employeeName = Chris I need to return 23549 to the calling function. Please help. Part of the code: public static string getEmployeeeID(string employeeName) { Cache cache = HttpContext.Current.Cache; string cacheNameEmployee = employeeName + "Tech"; if (cache[cacheNameEpm] == null) { XPathDocument doc = new XPathDocument(HttpContext.Current.Request.MapPath("inc/xml/" + SiteManager.Site.ToString() + "TechToolTip.xml")); XPathNavigator navigator = doc.CreateNavigator(); string selectName = "/Technologies/Technology[FieldName='" + fieldName + "']/EpmId"; XPathNodeIterator nodes = navigator.Select(selectName); if (nodes.Count > 0) { if (nodes.Current.Name.Equals("FieldName")) //nodes.Current.MoveToParent(); //nodes.Current.MoveToParent(); //nodes.Current.MoveToChild("//EpmId"); cache.Add(cacheNameEpm, nodes.Current.Value, null, DateTime.Now + new TimeSpan(4, 0, 0), System.Web.Caching.Cache.NoSlidingExpiration, CacheItemPriority.Default, null); } } return cache[cacheNameEpm] as string; } XML file <?xml version="1.0" encoding="utf-8" ?> <Employees> <Employee> <EName>Chris</EName> <ID>23556</ID> </Employee> <Employee> <EName>CBailey</EName> <ID>22222</ID> </Employee> <Employee> <EName>Meghan</EName> <ID>12345</ID> </Employee> </Employees> PLEASE NOTE:This XML file has 100 nodes. I just put 1 to indicate the structure.

  Read the article

• Break a class in twain, or impose an interface for restricted access?

  - by bedwyr

  What's the best way of partitioning a class when its functionality needs to be externally accessed in different ways by different classes? Hopefully the following example will make the question clear :) I have a Java class which accesses a single location in a directory allowing external classes to perform read/write operations to it. Read operations return usage stats on the directory (e.g. available disk space, number of writes, etc.); write operations, obviously, allow external classes to write data to the disk. These methods always work on the same location, and receive their configuration (e.g. which directory to use, min disk space, etc.) from an external source (passed to the constructor). This class looks something like this: public class DiskHandler { public DiskHandler(String dir, int minSpace) { ... } public void writeToDisk(String contents, String filename) { int space = getAvailableSpace(); ... } public void getAvailableSpace() { ... } } There's quite a bit more going on, but this will do to suffice. This class needs to be accessed differently by two external classes. One class needs access to the read operations; the other needs access to both read and write operations. public class DiskWriter { DiskHandler diskHandler; public DiskWriter() { diskHandler = new DiskHandler(...); } public void doSomething() { diskHandler.writeToDisk(...); } } public class DiskReader { DiskHandler diskHandler; public DiskReader() { diskHandler = new DiskHandler(...); } public void doSomething() { int space = diskHandler.getAvailableSpace(...); } } At this point, both classes share the same class, but the class which should only read has access to the write methods. Solution 1 I could break this class into two. One class would handle read operations, and the other would handle writes: // NEW "UTILITY" CLASSES public class WriterUtil { private ReaderUtil diskReader; public WriterUtil(String dir, int minSpace) { ... diskReader = new ReaderUtil(dir, minSpace); } public void writeToDisk(String contents, String filename) { int = diskReader.getAvailableSpace(); ... } } public class ReaderUtil { public ReaderUtil(String dir, int minSpace) { ... } public void getAvailableSpace() { ... } } // MODIFIED EXTERNALLY-ACCESSING CLASSES public class DiskWriter { WriterUtil diskWriter; public DiskWriter() { diskWriter = new WriterUtil(...); } public void doSomething() { diskWriter.writeToDisk(...); } } public class DiskReader { ReaderUtil diskReader; public DiskReader() { diskReader = new ReaderUtil(...); } public void doSomething() { int space = diskReader.getAvailableSpace(...); } } This solution prevents classes from having access to methods they should not, but it also breaks encapsulation. The original DiskHandler class was completely self-contained and only needed config parameters via a single constructor. By breaking apart the functionality into read/write classes, they both are concerned with the directory and both need to be instantiated with their respective values. In essence, I don't really care to duplicate the concerns. Solution 2 I could implement an interface which only provisions read operations, and use this when a class only needs access to those methods. The interface might look something like this: public interface Readable { int getAvailableSpace(); } The Reader class would instantiate the object like this: Readable diskReader; public DiskReader() { diskReader = new DiskHandler(...); } This solution seems brittle, and prone to confusion in the future. It doesn't guarantee developers will use the correct interface in the future. Any changes to the implementation of the DiskHandler could also need to update the interface as well as the accessing classes. I like it better than the previous solution, but not by much. Frankly, neither of these solutions seems perfect, but I'm not sure if one should be preferred over the other. I really don't want to break the original class up, but I also don't know if the interface buys me much in the long run. Are there other solutions I'm missing?

  Read the article

• BackgroundWorker and foreach loop

  - by tomfox66

  I have to process a loop with backgroundworkers. Before I start a new loop iteration I need to wait until the provious backgroundworker has finished. A while loop inside my foreach loop with isbusy flag doesn's seem like a good idea to me. How should I design this loop so it waits for the bg-worker to end before iterating the loop public void AutoConnect() { string[] HardwareList = new string[] { "d1", "d4", "ds1_2", "ds4_2" }; foreach (string HW in HardwareList) { if (backgroundWorker1.IsBusy != true) { backgroundWorker1.RunWorkerAsync(HW); // Wait here until backgroundWorker1 finished } } } private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) { BackgroundWorker worker = sender as BackgroundWorker; string FileName = e.Argument as string; try { if ((worker.CancellationPending == true)) { e.Cancel = true; } else { // Time consuming operation ParseFile(Filename); } } catch { } } private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) { label1.Text = e.ProgressPercentage.ToString() + " lines"; } private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { if(e.Cancelled == true) { //this.tbProgress.Text = "Canceled!"; } else if(!(e.Error == null)) { //this.tbProgress.Text = ("Error: " + e.Error.Message); } else { label1.text = "Done!"; } }

  Read the article

• Azure table storage: maximum variable size ?

  - by Egon

  I will be using the table storage to store a lot of blob names, in a single string, appended to each other using some special character. This string will sky rockets pretty soon. But is there a maximum size to the length of a property for a particular entity ? in my case the string ?

  Read the article

• P/Invoke a Function Passed a StringBuilder

  - by andrew

  in a C# file i have a class Archiver { [DllImport("Archiver.dll")] public static extern void archive(string data, StringBuilder response); } string data is an input, and StringBuilder response is where the function writes something the archive function prototype (written in C) looks like this: void archive(char * dataChr, char * outChr); and it receives a string in dataChr, and then does a strcpy(outChr,"some big text"); from C# i call it something like this: string message = "some text here"; StringBuilder response = new StringBuilder(10000); Archiver.archive(message,response); this works, but the problem, as you might see is that i give a value to the StringBuilder size, but the archive function might give back a (way) larger text than the size i've given to my StringBuilder. any way to fix this?

  Read the article

• ASP.NET WebMethod Returns JSON wrapped in quotes

  - by CL4NCY

  Hi, I have an asp.net page with a WebMethod on it to pass JSON back to my javascript. Bellow is the web method: [WebMethod] public static string getData(Dictionary<string, string> d) { string response = "{ \"firstname\": \"John\", \"lastname\": \"Smith\" }"; return response; } When this is returned to the client it is formatted as follows: { \"d\": \"{ \"firstname\": \"John\", \"lastname\": \"Smith\" }\" } The problem is the double quotes wrapping everything under 'd'. Is there something I've missed in the web method or some other means of returning the data without the quotes? I don't really want to be stripping it out on the client everytime. Also I've seen other articles where this doesn't happen. Any help would be appreciated thanks.

  Read the article

< Previous Page | 402 403 404 405 406 407 408 409 410 411 412 413  | Next Page >