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  • Error while coping datacolumn with data from one table to another .

    - by Harikrishna
    I have one Datatable like DataTable addressAndPhones; And there are four columns name,address,phoneno,and other details and I only want two columns Name and address from that so I do for that is DataTable addressAndPhones2; addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["name"].ColumnName)); addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["address"].ColumnName)); But it gives me error so how can I copy fix no of columns data from one table to another table ? ERROR :Object reference not set to an instance of an object.

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  • how to generate large image in compact framework

    - by Buthrakaur
    I need to generate large images (A4 image at 200 DPI, PNG format would be fine) in my compact framework application. This is impossible to do in standard way due to memory limitations (such big image will throw OOMException). Is there any library which offers file-backed stream image generation? Or I could generate many smaller stripes of images (each stripe representing a row of the large image) using standard Bitmap approach, but I need to merge them together afterwards - is there any method how to merge many smaller images into one large without having to instantiate large Bitmap instance (which would again cause OOM)?

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  • How do I make PyScript work? Says it cant find python26.dll

    - by Alex
    I installed PyScript to try it out but it just wont start. It only gives me the error: "Error126: Could not open Dll "python26.dll" followed by: "Python could not be properly initialized. We must quit." I think this may have something to do with the PYTHONPATH but since I'm a newbie and dont know what it is or exactly what to put in the PYTHONPATH, after some googling, I ask here. Also, when I tried to install wxPython it was impossible becouse the PYTHONPATH could not be found. I have installed ActivePython 2.6 and the PATH is set so I can access python in cmd.

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  • c# GUI changing a listbox from another class

    - by SlowForce
    I've written a multithreaded server that uses tcplistener and a client handler class that controls input and output. I also have a GUI chat client. The chat client works fine and the console version of the server also works well. I have a start() method in the partial(?) Form class, which I run from a new thread when I click a button, that starts the TCP Listener and loops through and accepts socket requests. For every request a new ClientHandler object is created and the socket is passed to this object before being used in a new handler thread. The ClientHandler is a different class to the form and I'm having real problems writing data to the Listbox in the Form class from within the ClientHandler class. I've tried a few different ways of doing this but none of them work as they involve creating a new form class within the ClientHandler. Any help or advice on what I should be reading to help me would be really appreciated.

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  • How to invoke static method in C#4.0 with dynamic type?

    - by Morgan Cheng
    In C#4.0, we have dynamic type, but how to invoke static method of dynamic type object? Below code will generate exception at run time. class Foo { public static int Sum(int x, int y) { return x + y; } } class Program { static void Main(string[] args) { dynamic d = new Foo(); Console.WriteLine(d.Sum(1, 3)); } } IMHO, dynamic is invented to bridge C# and other programming language. There is some other language (e.g. Java) allows to invoke static method through object instead of type. BTW, The introduction of C#4.0 is not so impressive compared to C#3.0.

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  • Using C# to iterate form fields with same name

    - by itsatrp
    I have a section of a form that I need to handle differently from the rest of form results. In the section that needs special handling I need to iterate over 3 form fields that have the same name. They have to have the same name, I can't change it. The section of the form I am referring to looks something like this: <td><input name="Color" size="20" value="" type="text"></td> Using C# I try something like this: I try to handle it like this: int i; for (i = 1; i <= Request.Form["Color"][i]; i++) { colorName.Text += Request.Form["Color"]; } Which leads to the following exception: System.NullReferenceException: Object reference not set to an instance of an object. How should I be handling form fields with the same name?

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  • C++ memory management of reference types

    - by Russel
    Hello, I'm still a fairly novice programmer and I have a question about c++ memory management with refence types. First of all, my understanding of reference types: A pointer is put on the stack and the actual data that the pointer points to is created and placed on the heap. Standard arrays and user defined classes are refence types. Is this correct? Second, my main question is do c and c++'s memory management mechanisms (malloc, free and new, delete) always handle this properly and free the memory that a class or array is pointing to? Does everything still work if those pointers get reassigned somehow to other objects of the same size/type on the heap? What if a class has a pointer member that points to another object? I am assuming that delete/freeing the class object doesn't free what it's member pointer points to, is that correct? Thanks all! -R

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  • What are the most frustrating Python hacks to unwind, rewrite, etc.?

    - by Bialecki
    My impression of Python from the short time I've been developing with it is that it's incredible powerful and flexible, but I can't help but feel like "with great power comes great responsibility." So while I've read numerous blog posts about simple and elegant Python snippets that solve a problems, I wonder if there are design patterns or abuses of Python language features that, once built into an application or library, cause the code to be incredibly brittle and near impossible to refactor. So the question is basically what are the most frustrating, but somewhat common, Python "hacks" or language feature abuses that someone can introduce that will cause nightmares for future maintainers of that code?

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  • Does isolation frameworks (Moq, RhinoMock, etc) lead to test overspecification?

    - by Marius
    In Osherove's great book "The Art of Unit Testing" one of the test anti-patterns is over-specification which is basically the same as testing the internal state of the object instead of some expected output. To my experience, using Isolation frameworks can cause the same unwanted side effects as testing internal behavior because one tends to only implement the behavior necessary to make your stub interact with the object under test. Now if your implementation changes later on (but the contract remains the same), your test will suddenly break because you are expecting some data from the stub which was not implemented. So what do you think is the best approach to counter this? 1) Implement your stubs/mocks fully, this has the negative side-effect of potentially making your test less readable and also specifying more than necessary to make your test pass. 2) Favor manual, fully implemented fakes. 3) Implement your stubs/fakes so that they make your test just pass, and then deal with the brittleness that this might introduce.

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  • Simple Scala syntax - trying to define "==" operator - what am I missing?

    - by Alex R
    While experimenting with some stuff on the REPL, I got to a point where I needed something like this: scala class A(x:Int) { println(x); def ==(a:A) : Boolean = { this.x == a.x; } } Just a simple class with an "==" operator. Why doesn't it work??? Here's the result: :10: error: type mismatch; found : A required: ?{val x: ?} Note that implicit conversions are not applicable because they are ambiguous: both method any2ArrowAssoc in object Predef of type [A](x: A)ArrowAssoc[A] and method any2Ensuring in object Predef of type [A](x: A)Ensuring[A] are possible conversion functions from A to ?{val x: ?} class A(x:Int) { println(x); def ==(a:A) : Boolean = { this.x == a.x; } } ^ This is scala 2.8 RC1. Thanks

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  • Writing secure java code with RMI

    - by jtnire
    Hi Everyone, This may seem like a very broad question, but any help is appreciated. I have a client/server solution written in java which uses the Cajo project (which uses RMI). I just want to try and make my solution as secure as possible, given the sensitive data that will be transferred between server and client. So far, my ideas are to make all my classes "final" as well as throw a "non-serializable" exception for all my classes in the server (except for the object bound in the RMI registry, and any objects that actually do need to be transferred of course). Can anyone think of any other ideas? I know that someone could write a malicious client - this isn't hard to do as you can find out the remote object's API using reflection. However is there anything I can do to protect a malicious client access classes/objects within the server that they are not supposed to access? Many Thanks

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  • post data through httpWebRequest

    - by user304901
    Hello, everybody. I need to "Post" some data to an external website using HttpWebRequest object from my application(desktop) and get a response back into my application through HttpWebResponse object. But the webpage on which i m posting data have textboxes which have dynamic names. how can i get the name of those textboxes and post data in httpwebresquest. for example when i load the page the textbox name is like this "U2FsdGVkX183MTQyNzE0MrhLOmUpqd3eL60xF19RmCwLlSiG5nC1H6wvtBDhjI3uM1krX_B8Fwc" but when i refresh the page name change to this "U2FsdGVkX182MjMwNjIzMPAtotst_q9PP9TETomXB453Mq3M3ZY5HQt70ZeyxbRb118Y8GQbgP8" Thanks for any suggestions.

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  • C#.NET: FTP Several Files

    - by Steve Kiss
    Hi, I have what would seem like a common problem, but I cannot find an appropriate solution on any forums. I need to FTP an entire directory structure using .NET. I have found several code examples all of which show how you can FTP a single file by creating an FtpWebRequest object. Unfortunately, there is no information on how to deal with several files. Do I simply create a FtpWebRequest object for every single file? Any help would be appreciated. Thanks

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  • How to declare a warning on field with AspectJ

    - by Ralph
    I want to declare a warning on all fields Annotated with @org.jboss.weld.context.ejb.Ejb in AspectJ. But I do not find a way how to select that field. I guess the aspect should be something like that: public aspect WrongEjbAnnotationWarningAspect { declare warning : within(com.queomedia..*) && ??? (@org.jboss.weld.context.ejb.Ejb) : "WrongEjbAnnotationErrorAspect: use javax.ejb.EJB instead of weld Ejb!"; } Or is it impossible to declare warnings on fields at all?

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  • Looking for design patterns to isolate framework layers from each other

    - by T Reddy
    Hi, I'm wondering if anyone has any experience in "isolating" framework objects from each other (Spring, Hibernate, Struts). I'm beginning to see design "problems" where an object from one framework gets used in another object from a different framework. My fear is we're creating tightly coupled objects. For instance, I have an application where we have a DynaActionForm with several attributes...one of which is a POJO generated by the Hibernate Tools. This POJO gets used everywhere...the JSP populates data to it, the Struts Action sends it down to a Service Layer, the DAO will persist it...ack! Now, imagine that someone decides to do a little refactoring on that POJO...so that means the JSP, Action, Service, DAO all needs to be updated...which is kind of painful...There has got to be a better way?! There's a book called Core J2EE Patterns: Best Practices and Design Strategies (2nd Edition)...is this worth a look? I don't believe it touches on any specific frameworks, but it looks like it might give some insight on how to properly layer the application... Thanks!

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  • Always require a plugin to be loaded

    - by axon
    I am writing an application with RequireJS and Knockout JS. The application includes an extension to knockout that adds ko.protectedObservable to the main knockout object. I would like this to always be available on the require'd knockout object, and not only when I specify it in the dependencies. I could concat the files together, but that seems that it should be unnecessary. Additionally, I can put knockout-protectedObservable as a dependency for knockout in the requirejs shim configuration, but that just leads to a circular dependency and it all fails to load. Edit: I've solved me issue, but seems hacky, is there a better way? -- Main.html <script type="text/javascript" src="require.js"></script> <script type="text/javascript"> require(['knockout'], function(ko) { require(['knockout-protectedObservable']); }); </script> -- knockout-protectedObservable.js define(['knockout'], function(ko) { ko.protectedObservable = { ... }; });

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  • SWIG-Lua question on class returning another class

    - by John Smith
    I am concreting a question I had earlier. I have two classes in C++ and I use SWIG to wrap them. A method in one class can return a pointer to the other class. How can I get Lua to see it as more than just a userdata? More concretely: I have class fruit { int numberofseeds; //some other stuff about fruit constructors etc... public: getseedcount() { return numberofseeds; } } class tree { fruit * apple; public: //constructors and whatnot fruit * getfruit() { return apple; } } I wrap these two class with SWIG so I can access them in Lua So I can get in Lua the object x=pomona.tree(grannysmith). My question now is: How can I arrange for things so that when I type y=x:getfruit() I will get a pomona:fruit type object? Where I can write something line y:getseedcount()? At the moment all I get is userdata which not edible.

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  • Why can't I read session variables

    - by Marty Goetz
    I have a c# .net web application. I create session variables but when I try to read them after I leave the page that they were created from I can't. Created on page 1 Session["UserName"] = "WhatEver"; Then I do Response.Redirect("~/whatever.aspx"); and try to read to read the session variable in the Page_Load method of the new page string userName = Session["UserName"].ToString(); I receive "Object reference not set to an instance of an object." Why am I receiving this error and what can I do to fix the problem? I would greatly appreciate any help anyone can give me.

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  • Accessing contents of a file in a web-application without uploading.

    - by UniCoder
    As far as I can tell, it is impossible to access the content of files on the user's computer in a web application without first uploading to the server, then re-downloading to user, unless some sort of plug-in is used. (Flash, etc.) Ideally, the user would upload the file directly to localstorage and then scripts would have a chance to process/display/validate/filter without the user having to wait on an upload. Are there any features in upcoming web standards such as html5 that will allow this? If not, why has there been no effort to make this possible, and how can I work around it without getting stuck with plugins?

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  • Calling this[int index] via reflection

    - by tkutter
    I try to implement a reflection-based late-bound library to Microsoft Office. The properties and methods of the Offce COM objects are called the following way: Type type = Type.GetTypeFromProgID("Word.Application"); object comObject = Activator.CreateInstance(type); type.InvokeMember(<METHOD NAME>, <BINDING FLAGS>, null, comObject, new object[] { <PARAMS>}); InvokeMember is the only possible way because Type.GetMethod / GetProperty works improperly with the COM objects. Methods and properties can be called using InvokeMember but now I have to solve the following problem: Method in the office-interop wrapper: Excel.Workbooks wb = excel.Workbooks; Excel.Workbook firstWb = wb[0]; respectively foreach(Excel.Workbook w in excel.Workbooks) // doSmth. How can I call the this[int index] operator of Excel.Workbooks via reflection?

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  • Embeddable unit testing framework for mixed Windows app

    - by Andy Dent
    I want to test portions of a very complex app which includes both a major native Windows component and a substantial WPF GUI. Due to complexities I can't detail, it is impossible to run the native portion independently nor can I isolate the areas I want to test (spare me the lectures, we're talking a huge legacy code base and we do have refactoring plans). I'm looking for a unit test kit I can invoke on the native side but must be able to run with the app launched with the managed portion initialised. That seems to rule out the run executable feature of the cfix Windows unit test kit. I really like their philosophy, like WinUnit, of using DLL compilation as a way to add the reflective capabilities missing in C++ and gain a more NUnit-like experience. Ideally, I want something like WinUnit running within the application code and generating an HTML report. I'm trying to introduce more TDD and having things as lean as possible is important.

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  • ADO.NET - DataRead Error

    - by user560706
    Hi, I am trying to display data from a column in my database onto my rich textbox, but I am getting mixed up between DataSet and DataReader - I know the majority of the code below is correct, I just get two lines containing errors, and I'm not sure why: // Create a connection string string ConnectionString = ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source= C:\\Documents and Settings\\Harley\\Desktop\\Test.accdb"); string SQL = "SELECT * FROM Paragraph"; // create a connection object SqlConnection conn = new SqlConnection(ConnectionString); // Create a command object SqlCommand cmd = new SqlCommand(SQL, conn); conn.Open(); DataTable dt = new DataTable(); da.Fill(dt); //ERROR // Call ExecuteReader to return a DataReader SqlDataReader reader = cmd.ExecuteReader(); foreach(DataRow reader in dsRtn) //ERROR { richTextBox = richTextBox.Text + reader[0].ToString(); } //Release resources reader.Close(); conn.Close(); }

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  • Algorithm for calculating indefinite integrals

    - by mbac32768
    Suppose I have an integral that's bounded on one (or both) ends by (-)infinity. AFAICT, I can't analytically solve this problem, it takes brute force (e.g. using a Left Riemann Sum). I'm having trouble generalizing the algorithm so that it sets the proper subdivisions; I'll either do far too much work to calculate something trivial, or not do nearly enough and have huge aliasing errors. Answering in any language is cool, but maybe someone with better google-fu can end this quickly. :) Is what I'm looking for as impossible as trying to measure the British coastline?

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