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  • Licensing WPF application

    - by Macros
    Does anyone have any guidance on the best way to manage licensing for a WPF application? I would like to have different levels of licensing (Free, Trial and Professional). The app itself will probably be distributed with a WiX installer (if that makes any difference)

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  • Best way to test for a variable's existence in PHP; isset() is clearly broken

    - by chazomaticus
    From the isset() docs: isset() will return FALSE if testing a variable that has been set to NULL. Basically, isset() doesn't check for whether the variable is set at all, but whether it's set to anything but NULL. Given that, what's the best way to actually check for the existence of a variable? I tried something like: if(isset($v) || @is_null($v)) (the @ is necessary to avoid the warning when $v is not set) but is_null() has a similar problem to isset(): it returns TRUE on unset variables! It also appears that: @($v === NULL) works exactly like @is_null($v), so that's out, too. How are we supposed to reliably check for the existence of a variable in PHP? Edit: there is clearly a difference in PHP between variables that are not set, and variables that are set to NULL: <?php $a = array('b' => NULL); var_dump($a); PHP shows that $a['b'] exists, and has a NULL value. If you add: var_dump(isset($a['b'])); var_dump(isset($a['c'])); you can see the ambiguity I'm talking about with the isset() function. Here's the output of all three of these var_dump()s: array(1) { ["b"]=> NULL } bool(false) bool(false) Further edit: two things. One, a use case. An array being turned into the data of an SQL UPDATE statement, where the array's keys are the table's columns, and the array's values are the values to be applied to each column. Any of the table's columns can hold a NULL value, signified by passing a NULL value in the array. You need a way to differentiate between an array key not existing, and an array's value being set to NULL; that's the difference between not updating the column's value and updating the column's value to NULL. Second, Zoredache's answer, array_key_exists() works correctly, for my above use case and for any global variables: <?php $a = NULL; var_dump(array_key_exists('a', $GLOBALS)); var_dump(array_key_exists('b', $GLOBALS)); outputs: bool(true) bool(false) Since that properly handles just about everywhere I can see there being any ambiguity between variables that don't exist and variables that are set to NULL, I'm calling array_key_exists() the official easiest way in PHP to truly check for the existence of a variable. (Only other case I can think of is for class properties, for which there's property_exists(), which, according to its docs, works similarly to array_key_exists() in that it properly distinguishes between not being set and being set to NULL.)

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  • vspace vs. vskip

    - by Geoff
    What is the difference between \vspace{-1em} and \vskip -1em, for example? I guess the first is LaTeX, and the latter is TeX. When is the proper time to use one and not the other, and why?

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  • Image Steganography

    - by Sridhar
    Hi, I'm working on Steganography application. I need to hide a message inside an image file and secure it with a password, with not much difference in the file size. I am using Least Significant Bit algorithm and could do it successfully with BMP files but it does not work with JPEG, PNG or TIFF files. Does this algorithm work with these files at all? Is there a better way to achieve this? Thanks.

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  • jQuery is not defined on my staging server but works fine on my local

    - by Tony
    If you pop open this page with your javascript console, you'll notice a bunch of JS errors. I don't get these errors in my local environment and it seems like it is happening because $ is not defined. I have tried to mimic my local environment exactly on staging by using the same environment.rb file and removing all JS caching but it is making no difference. Can anyone tell why jQuery is crapping out? It might be something really stupid, but I need a second pair of eyes.

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  • Is SQL DATEDIFF(year, ..., ...) an Expensive Computation?

    - by rlb.usa
    I'm trying to optimize up some horrendously complicated SQL queries because it takes too long to finish. In my queries, I have dynamically created SQL statements with lots of the same functions, so I created a temporary table where each function is only called once instead of many, many times - this cut my execution time by 3/4. So my question is, can I expect to see much of a difference if say, 1,000 datediff computations are narrowed to 100?

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  • Python tkInter text entry validation

    - by meade
    I'm trying to validate the entry of text using Python/tkInter def validate_text(): return False text = Entry(textframe, validate="focusout", validatecommand=validate_text) where validate_text is the function - I've tried always returning False and always returning True and there's no difference in the outcome..? Is there a set of arguments in the function that I need to include? Edit - changed from NONE to focusout...still not working

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  • what to do with a flawed C++ skills test

    - by Mike Landis
    In the following gcc.gnu.org post, Nathan Myers says that a C++ skills test at SANS Consulting Services contained three errors in nine questions: Looking around, one of fthe first on-line C++ skills tests I ran across was: http://www.geekinterview.com/question_details/13090 I looked at question 1... find(int x,int y) { return ((x<y)?0:(x-y)):} call find(a,find(a,b)) use to find (a) maximum of a,b (b) minimum of a,b (c) positive difference of a,b (d) sum of a,b ... immediately wondering why would anyone write anything so obtuse. Getting past the absurdity, I didn't really like any of the answers, immediately eliminating (a) and (b) because you can get back zero (which is neither a nor b) in a variety of circumstances. Sum or difference seemed more likely, except that you could also get zero regardless of the magnitudes of a and b. So... I put Matlab to work (code below) and found: when either a or b is negative you get zero; when b a you get a; otherwise you get b, so the answer is (b) min(a,b), if a and b are positive, though strictly speaking the answer should be none of the above because there are no range restrictions on either variable. That forces test takers into a dilemma - choose the best available answer and be wrong in 3 of 4 quadrants, or don't answer, leaving the door open to the conclusion that the grader thinks you couldn't figure it out. The solution for test givers is to fix the test, but in the interim, what's the right course of action for test takers? Complain about the questions? function z = findfunc(x,y) for i=1:length(x) if x(i) < y(i) z(i) = 0; else z(i) = x(i) - y(i); end end end function [b,d1,z] = plotstuff() k = 50; a = [-k:1:k]; b = (2*k+1) * rand(length(a),1) - k; d1 = findfunc(a,b); z = findfunc(a,d1); plot( a, b, 'r.', a, d1, 'g-', a, z, 'b-'); end

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  • post increment vs pre increment [closed]

    - by mousey
    Possible Duplicate: Difference between i++ and ++i in a loop? Hi, Can some one please help me when to use pre increment or post increment in a for loop. I am getting the same results for both the loops! I also would like to know when and where to choose one between the two. Thanks in advance.

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  • Should I use my models in a library?

    - by Piers
    I've got my auth library in codeigniter which accesses the database to check to see if the email/password combination is correct. If I'm sticking to the MVC practice, should I move the function that interacts with the database to my model, or is it best practice to leave it where it is so I can use it in the future? Doesn't make much difference to me, other than the fact I'd have to re-write the library and create the function in my model, but if that's the way it should be then so be it.

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  • The question regarding cerr cout and clog

    - by skydoor
    Can anybody explain the difference between cerr cout and clog and why does different objects are proposed? I know the differences are as below: 1) cout can redirected but cerr can't 2) clog can use buffer. I am confused about the point 2, I am grateful if anybody can elaborate it more.

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  • Two FullTextSqlQueries?

    - by SeeBees
    There are two FullTextSqlQueries, one in the namespace Microsoft.Office.Server.Search.Query, and the other in Microsoft.Office.Server.Search.Query. What's the difference between these two? Which one should I use?

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  • SQL Select queries

    - by sds
    Which is better and what is the difference? SELECT * FROM TABLE_A A WHERE A.ID IN (SELECT B.ID FROM TABLE_B B) or SELECT * FROM TABLE_A A, TABLE_B B WHERE A.ID = B.ID

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  • Why is my number being rounded incorrectly?

    - by izb
    This feels like the kind of code that only fails in-situ, but I will attempt to adapt it into a code snippet that represents what I'm seeing. float f = myFloat * myConstInt; /* Where myFloat==13.45, and myConstInt==20 */ int i = (int)f; int i2 = (int)(myFloat * myConstInt); After stepping through the code, i==269, and i2==268. What's going on here to account for the difference?

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  • Does the Python 3 interpreter have a JIT feature?

    - by guz
    I found that when I ask something more to Python, python doesn't use my machine resource at 100% and it's not really fast, it's fast if compared to many other interpreted languages, but when compared to compiled languages i think that the difference is really remarkable. It's possible to speedup things with a JIT compiler in Python 3 ? Usually a JIT compiler is the only thing that can improve performances in interpreted languages, so i'm referring to this one, if other solutions are available i would love to accept new answers.

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  • Can't access font resource in Silverlight class library

    - by Matt
    I have a reasonably large Silveright 3.0 project on the go, and I'm having issues accessing a couple of custom font resources from within one of the assemblies. I've got a working test solution where I have added a custom font as a resource, and can access it fine from XAML using: <TextBlock Text="Test" FontFamily="FontName.ttf#Font Name" /> The test solution consists of the TestProject.Application and the TestProject.Application.Web projects, with all the fun and games obviously in the TestProject.Application project However, when I try this in my main solution, the fonts refuse to show in the correct type face (instead showing in the default font). There's no difference in the way the font has been added to project between the test solution and the main solution, and the XAML is identical. However, there is a solution layout difference. In the main solution, as well as having a MainApp.Application and MainApp.Application.Web project, I also have a MainApp.Application.ViewModel project and a MainApp.Application.Views project, and the problem piece of XAML is the in the MainApp.Application.Views project (not the .Application project like the test solution). I've tried putting the font into either the .Application or .Application.Views project, tried changing the Build Action to Content, Embedded Resource etc, all to no avail. So, is there an issue accessing font resources from a child assembly that I don't know about, or has anyone successfully done this? My long term need will be to have the valid custom fonts being stored as resources in a separate .Application.FontLibrary assembly that will be on-demand downloaded and cached, and the XAML controls in the .Application.Views project will need to reference this FontLibrary assembly to get the valid fonts. I've also tried xcreating this separate font library assembly, and I can't seem to get the fonts from the second assembly. As some additional information, I've also tried the following font referencing approaches: <TextBlock Text="Test" FontFamily="/FontName.ttf#Font Name" /> <TextBlock Text="Test" FontFamily="pack:application,,,/FontName.ttf#Font Name" /> <TextBlock Text="Test" FontFamily="pack:application,,,/MainApp.Application.Views;/FontName.ttf#Font Name" /> <TextBlock Text="Test" FontFamily="pack:application,,,/MainApp.Application.Views;component/FontName.ttf#Font Name" /> And a few similar variants with different assembly references/sub directories/random semi colons. And so far nothing works... anyone struck this (and preferably solved it)?

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  • Equivalent of System.Windows.Forms.Cursor in Web Application

    - by Vishwa
    Hi I have a code in windows application now i am trying to implement in web Application but it is showimg that it ths no cursor class (System.Windows.Forms.Cursor )so..wat is the equivalent in web application. Here is my code private void btnGo_Click(System.Object sender, System.EventArgs e) { this.Cursor = Cursors.WaitCursor; Application.DoEvents(); // Load the images. Bitmap bm1 = (Bitmap) (Image.FromFile(txtFile1.Text)); Bitmap bm2 = (Bitmap) (Image.FromFile(txtFile2.Text)); // Make a difference image. int wid = Math.Min(bm1.Width, bm2.Width); int hgt = Math.Min(bm1.Height, bm2.Height); Bitmap bm3 = new Bitmap(wid, hgt); // Create the difference image. bool are_identical = true; int r1; int g1; int b1; int r2; int g2; int b2; int r3; int g3; int b3; Color eq_color = Color.White; Color ne_color = Color.Transparent; for (int x = 0; x <= wid - 1; x++) { for (int y = 0; y <= hgt - 1; y++) { if (bm1.GetPixel(x, y).Equals(bm2.GetPixel(x, y))) { bm3.SetPixel(x, y, eq_color); } else { bm1.SetPixel(x, y, ne_color); are_identical = false; } } } // Display the result. picResult.Image = bm1; Bitmap Logo = new Bitmap(picResult.Image); Logo.MakeTransparent(Logo.GetPixel(1, 1)); picResult.Image = (Image)Logo; this.Cursor = Cursors.Default; if ((bm1.Width != bm2.Width) || (bm1.Height != bm2.Height)) { are_identical = false; } if (are_identical) { MessageBox.Show("The images are identical"); } else { MessageBox.Show("The images are different"); } //bm1.Dispose() // bm2.Dispose() }

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  • Has anyone gotten VB highlighting to work in Emacs23?

    - by akoumjian
    I have found and installed the visual basic mode for emacs. It seems to be loading on emacs startup and the VB mode loads when I open a *.bas file. The code is not highlighted at all, however. I'm using Emacs23, tried it with 21 and saw no difference. Background for the curious: I am rewriting a set of codes from VB to Python. The syntax highlighting will make it much easier for me to see what's going on.

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  • What is the best way to declare sorted association in grails domain classes ?

    - by fabien7474
    It seems that there are two different ways of declaring sorted associations in Grails : Method 1 (see here) using default sort order class Book { String title } class Author { static hasMany = [books : Book] static mapping = { books sort: "title"} } Method 2 (see here) using SortedSet class Book implements Comparable { String title int compareTo(obj) { title <=> obj.title } } class Author { SortedSet books static hasMany = [books : Book] } I am not sure which one to use and what is the difference (if any), pros and cons between using one against the other. I would appreciate any clarification. Thank you

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  • what is the point of return in ruby?

    - by Sam
    What is the difference between return and just putting a variable such as the following: return def write_code(number_of_errors) if number_of_errors > 1 mood = "WTF" else mood = "No Problem" end mood end no return def write_code(number_of_errors) if number_of_errors > 1 mood = "WTF" else mood = puts "No Problem" end return mood end

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  • Managed DirectX as a starting point

    - by numerical25
    I know the difference between manage and unmanaged DirectX. My question is if I decided to do managed directX as a starting point, would it help me to better understand unmanaged DirectX. Honestly, the only thing I see different about the 2 is how you initiate and access resources. Matrix Math is Matrix no matter what so If I learn it in managed, then I should be fine in unmanaged

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