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• How can I draw a Rectangle on a PictureBox?

  - by TooFat

  I am trying to just draw a Rectangle on a PictureBox that is on a Form. Writing text like shown here works fine. private void pictureBox1_Paint(object sender, PaintEventArgs e) { using (Font myFont = new Font("Arial", 14)) { e.Graphics.DrawString("Hello .NET Guide!", myFont, Brushes.Green, new Point(2, 2)); } } but when I try to draw a rectangle like so nothing shows up. private void pictureBox1_Paint(object sender, PaintEventArgs e) { Rectangle rect = new Rectangle(); rect.Location = new Point(25, 25); rect.Width = 50; using (Pen pen = new Pen(Color.Red, 2)) { e.Graphics.DrawRectangle(pen, rect); } } What am I missing?

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• net c# lock statement in data access layer

  - by Pedro Rivera

  I saw a code where they have the data access layer like this: public class CustomerDA{ private static readonly object _sync = new object(); private static readonly CustomerDA _mutex = new CustomerDA(); private CustomerDA(){ } public CustomerDA GetInstance(){ lock(_sync){ return _mutex; } } public DataSet GetCustomers(){ //database SELECT //return a DataSet } public int UpdateCustomer(some parameters){ //update some user } } public class CustomerBO{ public DataSet GetCustomers(){ //some bussiness logic return CustomerDA.GetInstance().GetCustomers(); } } I was using it, but start thinking... "and what if had to build a facebook like application where there are hundreds of thousands of concurrent users? would I be blocking each user from doing his things until the previous user ends his database stuff? and for the Update method, is it useful to LOCK THREADS in the app when database engines already manage concurrency at database server level?" Then I started to think about moving the lock to the GetCustomers and UpdateCustomer methods, but think again: "is it useful at all?"

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• datatable works in C# winform but not ASP.NET

  - by Charles Gargent

  Hi I have created a class that returns a datatable, when I use the class in a c# winform the dataGridView is populted corectly using the following code dataGridView1.DataSource = dbLib.GetData(); However when I try the same thing with ASP.NET I get a Object reference not set to an instance of an object. using the following code GridView1.DataSource = dbLib.GetData(); GridView1.DataBind(); What am I doing wrong / missing Thanks EDIT for the curios here is the dbLib class public static DataTable GetData() { SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db"); SQLiteCommand cmd = new SQLiteCommand("SELECT count(Message) AS Occurances, Message FROM evtlog GROUP BY Message ORDER BY Occurances DESC LIMIT 25", cnn); cnn.Open(); SQLiteDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection); DataTable dt = new DataTable(); dt.Load(dr); return dt; }

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• Return database messages on successful SQL execution when using ADO

  - by peacedog

  I'm working on a legacy VB6 app here at work, and it has been a long time since I've looked at VB6 or ADO. One thing the app does is to executes SQL Tasks and then to output the success/failure into an XML file. If there is an error it inserts the text the task node. What I have been asked to do is try and do the same with the other mundane messages that result from succesfully executed tasks, like (323 row(s) affected). There is no command object being used, it's just an ADODB.Connection object. Here is the gist of the code: Dim sqlStatement As String Set sqlStatement = /* sql for task */ Dim sqlConn As ADODB.Connection Set sqlConn = /* connection magic */ sqlConn.Execute sqlStatement, , adExecuteNoRecords What is the best way for me to capture the non-error messages so I can output them? Or is it even possible?

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• Keyboard event issue

  - by Petar Minchev

  Hello guys! I have to capture the following keyboard event in a TextBox - SHIFT + 8(on the numpad). This also means the NumLock will be on. When I try the following, nothing is printed: private void textBox1_KeyDown(object sender, KeyEventArgs e) { if (e.Shift && e.KeyCode == Keys.NumPad8) Console.WriteLine("SHIFT + UP"); } But CTRL + 8(on the numpad) is working. private void textBox1_KeyDown(object sender, KeyEventArgs e) { if (e.Control && e.KeyCode == Keys.NumPad8) Console.WriteLine("CTRL + UP"); } Could someone explain me, why SHIFT + 8 isn't fired, but CTRL + 8 is working? P.S. I wrote + UP, because the user wants to navigate with the numpad arrows and the SHIFT key, but his NumLock will also be on. That's why I catch Keys.NumPad8. All the best, Petar

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• Conseqences of assigning self

  - by Vegar

  Hi, Found a piece of code today, that I find a little smelly... TMyObject.LoadFromFile(const filename: String); begin if fileExists(filename) then self := TSomeObjectStreamer.ReadObjectFromFile(filename); end; If this code works, it will atleast leak some memory, but does it work? Is OK to assign to self in this manner? What if the streamed object is of a different subclass then the original self? What if the streamed object is of a different class with no common ancestore to the original self?

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• How to effectively draw on desktop in C#?

  - by Lazlo

  I want to draw directly on the desktop in C#. From searching a bit, I ended up using a Graphics object from the Desktop HDC (null). Then, I painted normally using this Graphics object. The problem is that my shapes get lost when any part of the screen is redrawn. I tried a While loop, but it actually ends up drawing as fast as the application can, which is not the update rate of the desktop. Normally, I would need to put my drawing code in a "OnPaint" event, but such thing does not exist for the desktop. How would I do it? Example code: http://stackoverflow.com/questions/1536141/how-to-draw-directly-on-the-windows-desktop-c

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• How to let users edit list<T> content?

  - by iTayb

  I'm making an aspx page that can edit books. A book is an complex class with lots of properties. I've made an edit page for most of them, however I'm having trouble with showing edit options for my Sellers Proprety. It is an list<Seller> object. Seller is as follows: public class Seller { private string sellerName; private double price; } How can I print a list to the screen, and let the clinet edit it, then load it back to the object? Thank you very much.

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• Ruby: "do this task eventually"

  - by marienbad

  I hope this question is clear enough -- if not let me know :) What API would I use when I want to write a procedure at runtime and then just run it eventually at low priority while continuing to do the important stuff right now? Example: link checker 1. I write a blog post with links represented by Link objects. I publish the post. 2. Eventually (at very low priority) the system gets around to fetching the URL of each Link object to make sure it's not broken and indicates that in a property of the Link object. 3. When a user visits my blog post, the render code that turns Link objects into HTML knows whether the links have been checked. I'm assuming there's a very general purpose API for doing this kind of "eventually/low priority" stuff.

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• Does Ruby on Rails "has_many" array provide data on a "need to know" basis?

  - by Jian Lin

  On Ruby on Rails, say, if the Actor model object is Tom Hanks, and the "has_many" fans is 20,000 Fan objects, then actor.fans gives an Array with 20,000 elements. Probably, the elements are not pre-populated with values? Otherwise, getting each Actor object from the DB can be extremely time consuming. So it is on a "need to know" basis? So does it pull data when I access actor.fans[500], and pull data when I access actor.fans[0]? If it jumps from each record to record, then it won't be able to optimize performance by doing sequential read, which can be faster on the hard disk because those records could be in the nearby sector / platter layer -- for example, if the program touches 2 random elements, then it will be faster just to read those 2 records, but what if it touches all elements in random order, then it may be faster just to read all records in a sequential way, and then process the random elements. But how will RoR know whether I am doing only a few random elements or all elements in random?

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• Simplest way to flatten document to a view in RavenDB

  - by degorolls

  Given the following classes: public class Lookup { public string Code { get; set; } public string Name { get; set; } } public class DocA { public string Id { get; set; } public string Name { get; set; } public Lookup Currency { get; set; } } public class ViewA // Simply a flattened version of the doc { public string Id { get; set; } public string Name { get; set; } public string CurrencyName { get; set; } // View just gets the name of the currency } I can create an index that allows client to query the view as follows: public class A_View : AbstractIndexCreationTask<DocA, ViewA> { public A_View() { Map = docs => from doc in docs select new ViewA { Id = doc.Id, Name = doc.Name, CurrencyName = doc.Currency.Name }; Reduce = results => from result in results group on new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName } into g select new ViewA { Id = g.Key.Id, Name = g.Key.Name, CurrencyName = g.Key.CurrencyName }; } } This certainly works and produces the desired result of a view with the data transformed to the structure required at the client application. However, it is unworkably verbose, will be a maintenance nightmare and is probably fairly inefficient with all the redundant object construction. Is there a simpler way of creating an index with the required structure (ViewA) given a collection of documents (DocA)? FURTHER INFORMATION The issue appears to be that in order to have the index hold the data in the transformed structure (ViewA), we have to do a Reduce. It appears that a Reduce must have both a GROUP ON and a SELECT in order to work as expected so the following are not valid: INVALID REDUCE CLAUSE 1: Reduce = results => from result in results group on new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName } into g select g.Key; This produces: System.InvalidOperationException: Variable initializer select must have a lambda expression with an object create expression Clearly we need to have the 'select new'. INVALID REDUCE CLAUSE 2: Reduce = results => from result in results select new ViewA { Id = result.Id, Name = result.Name, CurrencyName = result.CurrencyName }; This prduces: System.InvalidCastException: Unable to cast object of type 'ICSharpCode.NRefactory.Ast.IdentifierExpression' to type 'ICSharpCode.NRefactory.Ast.InvocationExpression'. Clearly, we also need to have the 'group on new'. Thanks for any assistance you can provide. (Note: removing the type (ViewA) from the constructor calls has no effect on the above)

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• Are there any nasty side affects if i lock the HttpContext.Current.Cache.Insert method

  - by Ekk

  Apart from blocking other threads reading from the cache what other problems should I be thinking about when locking the cache insert method for a public facing website. The actual data retrieval and insert into the cache should take no more than 1 second, which we can live with. More importantly i don't want multiple thread potentially all hitting the Insert method at the same time. The sample code looks something like: public static readonly object _syncRoot = new object(); if (HttpContext.Current.Cache["key"] == null) { lock (_syncRoot) { HttpContext.Current.Cache.Insert("key", "DATA", null, DateTime.Now.AddMinutes(5), Cache.NoSlidingExpiration, CacheItemPriority.Normal, null); } } Response.Write(HttpContext.Current.Cache["key"]);

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• Does std::multiset guarntee insertion order?

  - by Naveen

  I have a std::multiset which stores elements of class A. I have provided my own implementation of operator< for this class. My question is if I insert two equivalent objects into this multiset is their order guaranteed? For example, first I insert a object a1 into the set and then I insert an equivalent object a2 into this set. Can I expect the a1 to come before a2 when I iterate through the set? If no, is there any way to achieve this using multiset?

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• Onclick not firing

  - by user320588

  I have a set of buttons on my master page (I have attached the code below) but no onclick event is being raised. I pulled the final page source and no onclick event was present. As you can see I tried a few different approaches to solve the problem. I am looking for a normal postback to the server but I am getting nothing when I click any of these buttons. What am I not doing? --Master --Master Code Behind Protected Sub Button_Command(ByVal sender As Object, ByVal e As CommandEventArgs) Handles btnCancel.Command, btnClear.Command Session("ButtonClicked") = e.CommandArgument End Sub Protected Sub Button_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click, btnSubmit.Click Session("ButtonClicked") = CType(sender, Button).CommandArgument End Sub --Page Source

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• Analysis and Design for Functional Programming

  - by edalorzo

  How do you deal with analysis and design phases when you plan to develop a system using a functional programming language like Haskell? My background is in imperative/object-oriented programming languages, and therefore, I am used to use case analysis and the use of UML to document the design of program. But the thing is that UML is inherently related to the object-oriented way of doing software. And I am intrigued about what would be the best way to develop documentation and define software designs for a system that is going to be developed using functional programming. Would you still use use case analysis or perhaps structured analysis and design instead? How do software architects define the high-level design of the system so that developers follow it? What do you show to you clients or to new developers when you are supposed to present a design of the solution? How do you document a picture of the whole thing without having first to write it all? Is there anything comparable to UML in the functional world?

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• Retrieve Value From Xml Attributes

  - by Chong

  hi everyone, i want to get some value from xml file filtering with xml attribute. my xml format is like below. <Object type="System.Windows.Forms.TextBox"> <Property name="Name">RadioButton1</Property> <Property name="Size">86, 24</Property> <Property name="Text">RadioButton1</Property> <Property name="Location">175, 126</Property> </Object> for example, if name = "Name" then i will add its value to name textbox. if name = "Size" then i will add its value to size textbox. regards Chong

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• Zoom image using delphi

  - by Himadri

  Hello All, I am working with delphi. I have TImage, to which I assign a bitmap. imgmain.Picture.Bitmap := bmpMain; imgmain.Picture.Bitmap.PixelFormat := pf24bit; imgmain is object of TImage and bmpMain is object of TBitmap I want to zoom my image. I have one trackbar on my form and as I click on trackbar the image should get zoom. What should I do? Thank You.

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• Concatenating databases with Squeryl

  - by Pengin

  I'm trying to use Squeryl to take the contents of a table from one database, and append it to the equivalent table in another database. The primary key will have to be reassigned in the process, but I'm getting the error NULL not allowed for column "SIMID". Why is this? object Concatenator { def main(args: Array[String]) { Class.forName("org.h2.Driver"); val seshA = Session.create( java.sql.DriverManager.getConnection("jdbc:h2:file:data/resultsA", "sa", "password"), new H2Adapter ) val seshB = Session.create( java.sql.DriverManager.getConnection("jdbc:h2:file:data/resultsB", "sa", "password"), new H2Adapter ) using(seshA){ import Library._ from(sims){s => select(s)}.foreach{item => using(seshB){ sims.insert(item); } } } } case class Simulation( @Column("SIMID") var id: Long, val date: Date ) extends KeyedEntity[Long] object Library extends Schema { val sims = table[Simulation] on(sims)(s => declare( s.id is(unique, indexed, autoIncremented) )) } }

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• How can I dynamically override a classes "each" method?

  - by rewbs

  Groovy adds each() and a number of other methods to java.lang.Object. I can't figure out how to use the Groovy metaclass to dynamically replace the default each() on a Java class. I can see how to add new methods: MyJavaClass.metaClass.myNewMethod = { closure -> /* custom logic */ } new MyJavaClass().myNewMethod { item -> println item } // runs custom logic But it seems the same approach doesn't work when overriding methods: MyJavaClass.metaClass.each = { closure -> /* custom logic */ } new MyJavaClass().each { item -> println item } // runs Object.each() What am I doing wrong? How can I dynamically override each() in Groovy?

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• Web2py controllers with parameters?

  - by nickfranceschina

  I am building an app using Web2py framework... I don't want to have to use the request object to get all of the querystring parameters, instead I'd like to build my controller with named parameters and have the router unpack the querystring (or form data) dictionary into the named parameters and call my controller. so instead of a controller method of create_user(): where I would use the global request() object and look through the vars list... I would prefer instead to have create_user(first_name, last_name, email): like I see in other MVC platforms. is this possible in Web2py already? or is there a plugin for it? or do I need to add that myself?

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• How to pass an event to a method and then subscribe to it?

  - by Ryan Peschel

  Event Handler public void DeliverEvent(object sender, EventArgs e) { } #1: This Works public void StartListening(Button source) { source.Click += DeliverEvent; } #2: And so does this.. public void StartListening(EventHandler eventHandler) { eventHandler += DeliverEvent; } But in #2, you cannot call the method because if you try something like this: StartListening(button.Click); You get this error: The event 'System.Windows.Forms.Control.Click' can only appear on the left hand side of += or -= Is there any way around that error? I want to be able to pass the event and not the object housing the event to the StartListening method.

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• Simple Moq ? - Problem with .Verify

  - by user127954

  Hi, just a simple question here. I've used Moq for awhile but, as of yet, have only used it for stubbing and not for mocking. I am trying to introduce our developers to unit testing. I set up a simple example to explain the concepts but i can't seem to get it working. Probably something simple so i thought i would just ask you all to see what i'm doing wrong: <Test()> _ Public Sub Divide_DivideByZero_LogsError() Dim mock = New Mock(Of ILogger) With mock Dim calc = New MyCalculator(New CalculatorData, .Object) calc.Divide(55, 0) mock.Object.WriteError("test", "Test") .Verify(Function(x) CType(x,ILogger).WriteError(it.IsAny(of String),It.IsAny(Of String)))) End With End Sub I'm using Moq version 3.2.416.3. I get an error on the .verify telling me that i'm calling it with incorrect arguments. I'm just trying to verify that .WriteError was called. any help would be appreciated.

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• Memory leak while using emoticons on CRichEditCtrl

  - by Jorg B Jorge

  I'm developing a text editor class (for a chat application) based on CRichEditCtrl (MFC) with emoticon support. After i load the emoticon's bitmap, I use the function OleCreateStaticFromData to insert it into CRichEditCtrl. After that i just delete the bitmap object allocated by myself. I can verify (using a GDIView utility) that all resources i allocate have been properly released. This works perfectly: the bitmap (emoticon) is drawn on the CRichEditCtrl window and is handled just like a character. My problem is that I don't know how to deallocate the memory (internal) allocated by OleCreateStaticFromData to manage the bitmap (emoticon). The memory allocated for any emoticon used is never released, even if i delete the CRichEditCtrl object. I'd like to know how to fix that issue. Is that a MFC's issue or i'm doing something wrong ? Thx.

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• Why does C# not implement GetHashCode for Collections?

  - by Peterdk

  I am porting something from Java to C#. In Java the hashcode of a ArrayList depends on the items in it. In C# I always get the same hashcode from a List... Why is this? For some of my objects the hashcode needs to be different because the objects in their list property make the objects non-equal. I would expect that a hashcode is always unique for the object's state and only equals another hashcode when the object is equal. Am I wrong?

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• Looking for RESTful Suggestions In Porting ASP.NET to MVC.NET

  - by DaveDev

  I've been tasked with porting/refactoring a Web Application Platform that we have from ASP.NET to MVC.NET. Ideally I could use all the existing platform's configurations to determine the properties of the site that is presented. Is it RESTful to keep a SiteConfiguration object which contains all of our various page configuration data in the System.Web.Caching.Cache? There are a lot of settings that need to be loaded when the user acceses our site so it's inefficient for each user to have to load the same settings every time they access. Some data the SiteConfiguration object contains is as follows and it determines what Master Page / site configuration / style / UserControls are available to the client, public string SiteTheme { get; set; } public string Region { private get; set; } public string DateFormat { get; set; } public string NumberFormat { get; set; } public int WrapperType { private get; set; } public string LabelFileName { get; set; } public LabelFile LabelFile { get; set; } // the following two are the heavy ones // PageConfiguration contains lots of configuration data for each panel on the page public IList<PageConfiguration> Pages { get; set; } // This contains all the configurations for the factsheets we produce public List<ConfiguredFactsheet> ConfiguredFactsheets { get; set; } I was thinking of having a URL structure like this: www.MySite1.com/PageTemplate/UserControl/ the domain determines the SiteConfiguration object that is created, where MySite1.com is SiteId = 1, MySite2.com is SiteId = 2. (and in turn, style, configurations for various pages, etc.) PageTemplate is the View that will be rendered and simply defines a layout for where I'm going to inject the UserControls Can somebody please tell me if I'm completely missing the RESTful point here? I'd like to refactor the platform into MVC because it's better to work in but I want to do it right but with a minimum of reinventing-the-wheel because otherwise it won't get approval. Any suggestions otherwise? Thanks

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