Search Results

Search found 19136 results on 766 pages for 'library understanding'.

Page 376/766 | < Previous Page | 372 373 374 375 376 377 378 379 380 381 382 383  | Next Page >

  • C# -Closure -Clarification

    - by nettguy
    I am learning C#.Can I mean closure as a construct that can adopt the changes in the environment in which it is defined. Example : List<Person> gurus = new List<Person>() { new Person{id=1,Name="Jon Skeet"}, new Person{id=2,Name="Marc Gravell"}, new Person{id=3,Name="Lasse"} }; void FindPersonByID(int id) { gurus.FindAll(delegate(Person x) { return x.id == id; }); } The variable id is declared in the scope of FindPersonByID() but t we still can access the local variable id inside the anonymous function (i.e) delegate(Person x) { return x.id == id; } (1) Is my understanding of closure is correct ? (2) What are the aditional advantages can we get from closures?

    Read the article

  • Windows code pages, what are they?

    - by Mike D
    I'm trying to gain a basic understanding of what is meant by a Windows code page. I kind of get the feeling it's a translation between a given 8 bit value and some 'abstraction' for a given character graphic. I made the following experiment. I created a "" character literal with two versions of the letter u with an umlaut. One created using the ALT 129 (uses code page 437) value and one using the ALT 0252 (uses code page 1252) value. When I examined the literal both characters had the value 252. Is 252 the universal 8 bit abstraction for u with an umlaut? Is it the Unicode value? Aside from keyboard input are there any library routines or system calls that use code pages? For example is there a function to translate a string using a given code table (as above for the ALT 129 value)?

    Read the article

  • Why does this window object not have the eval function?

    - by Motti
    I ran into an interesting (?) problem in the YUI rich edit demo on IE. When looking at the window object for the content editable frame used as the browser I see that the eval function is undefined (by running the following). javascript:alert(document.getElementById("editor_editor").contentWindow.eval) This only happens on IE (I checked on IE6 and IE8), and it doesn't happen on Firefox or Chrome. All the other window functions and properties seem to be in order, now I realise that eval is not really defined on the window but on the global object but my understanding was that in browsers the window is the global object (also eval does appear on all other windows so why not on this one?). Does anyone know if this is a know bug/limitation in IE and how I can get to eval in the context of the global object of this frame? (I need the side effects to be available to anything running from within this frame).

    Read the article

  • django app organization

    - by iHeartDucks
    I have been reading some django tutorial and it seems like all the view functions have to go in a file called "views.py" and all the models go in "models.py". I fear that I might end up with a lot of view functions in my view.py file and the same is the case with models.py. Is my understanding of django apps correct? Django apps lets us separate common functionality into different apps and keep the file size of views and models to a minimum? For example: My project can contain an app for recipes (create, update, view, and search) and a friend app, the comments app, and so on. Can I still move some of my view functions to a different file? So I only have the CRUD in one single file?

    Read the article

  • Parsing JPEG file format: Format of entropy-coded segment (ECS) segments?

    - by me2
    I'm having difficulty understanding the ITU-T T.81 spec for the JPEG file format. Hopefully someone else here has tried to parse JPEG files and/or knows about the details of this file format. The spec indiates that the ECS0 segment starts after the SOS segment but I can't find where in the spec it actually talks about the format of the ECS0 segment or how do detect its start. Simple JPEG implementations online are of limited help because they assume many things about the JPEGs they parse. Can anyone point me in the right direction?

    Read the article

  • Code Signing Services

    - by bogdan
    I'm developing a System Preference Pane that runs a background application. I'm planning on codesigning the background application and I'll be using the kill flag of codesign (http://gemma.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man1/codesign.1.html). From my understanding, this kill flag will not allow the background application to be run if it's signature doesn't match. My problem with this approach is that it doesn't provide any feedback to the user and, for somewhat reason, the application gets corrupted, it will refuse to launch without any information. I'd like to use the Code Signing Service from the System Preference Pane to check the validity of the background application. However, I couldn't find how to use it to check the validity of an external file. Is this possible using the Code Signing Service or should I NSTask codesign directly? My application is targeted for 10.6 so it doesn't matter which I use. Thank you!

    Read the article

  • Accessing structure elements using pointers

    - by Arun Nadesh
    Hi Everybody, Greetings! I got surprised when the following program did not crash. typedef struct _x{ int a; char b; int c; }x; main() { x *ptr=0; char *d=&ptr->b; } As per my understanding the -> operator has higher precedence over & operator. So I expected the program to crash at the below statement when we try to dereference the NULL pointer tr. char *d=&ptr->b; But the statement &ptr->b evaluates to a valid address. Could somebody please explain where I'm wrong? Thanks & Regards, Arun

    Read the article

  • Select from multiple tables, remove duplicates

    - by staze
    I have two tables in a SQLite DB, and both have the following fields: idnumber, firstname, middlename, lastname, email, login One table has all of these populated, the other doesn't have the idnumber, or middle name populated. I'd LIKE to be able to do something like: select idnumber, firstname, middlename, lastname, email, login from users1,users2 group by login; But I get an "ambiguous" error. Doing something like: select idnumber, firstname, middlename, lastname, email, login from users1 union select idnumber, firstname, middlename, lastname, email, login from users2; LOOKS like it works, but I see duplicates. my understanding is that union shouldn't allow duplicates, but maybe they're not real duplicates since the second user table doesn't have all the fields populated (e.g. "20, bob, alan, smith, [email protected], bob" is not the same as "NULL, bob, NULL, smith, [email protected], bob"). Any ideas? What am I missing? All I want to do is dedupe based on "login". Thanks!

    Read the article

  • ado.net managing connections

    - by madlan
    Hi, I'm populating a listview with a list of databases on a selected SQL instance, then retrieving a value from each database (It's internal product version, column doesn't always exist) I'm calling the below function to populate the second column of the listview: item.SubItems.Add(DBVersionCheck(serverName, database.Name)) Function DBVersionCheck(ByVal SelectedInstance As String, ByVal SelectedDatabase As String) Dim m_Connection As New SqlConnection("Server=" + SelectedInstance + ";User Id=sa;Password=password;Database=" + SelectedDatabase) Dim db_command As New SqlCommand("select Setting from SystemSettings where [Setting] = 'version'", m_Connection) Try m_Connection.Open() Return db_command.ExecuteScalar().trim m_Connection.Dispose() Catch ex As Exception 'MessageBox.Show(ex.Message) Return "NA" Finally m_Connection.Dispose() End Try End Function This works fine except it's creating a connection to each database and leaving it open. My understanding is the close()\dispose() releases only the connection from the pool in ado rather than the actual connection to sql. How would I close the actual connections after I've retrieved the value? Leaving these open will create hundreds of connections to databases that will probably not be used for that session.

    Read the article

  • Binding Linq To Entities query results to a datagridview

    - by Nickson
    I just started playing with Linq to entities in a windows forms application and am not understanding one behavior that looks so simple though. If i type code below, i get ReadOnly records in my dataGridView Dim x = From n in Table1 _ Select n.FirstName, n.LastName, N.Department DataGridView1.DataSource = x But if i type the following code, i get editable rows in my dataGridView Dim x = From n in Table1 _ Select n DataGridView1.DataSource = x So, basically if i specify the column names to select and databind to my DataGridView1, the rows are readonly but if i do not specify the column names and databind to the DataGridView, the rows are editable and i don't understand why.

    Read the article

  • Strange thing about .NET 4.0 filesystem enumeration functionality

    - by codymanix
    I just read a page of "Whats new .NET Framework 4.0". I have trouble understanding the last paragraph: To remove open handles on enumerated directories or files Create a custom method (or function in Visual Basic) to contain your enumeration code. Apply the MethodImplAttribute attribute with the NoInlining option to the new method. For example: [MethodImplAttribute(MethodImplOptions.NoInlining)] Private void Enumerate() Include the following method calls, to run after your enumeration code: * The GC.Collect() method (no parameters). * The GC.WaitForPendingFinalizers() method. Why the attribute NoInlining? What harm would inlining do here? Why call the garbage collector manually, why not making the enumerator implement IDisposable in the first place? I suspect they use FindFirstFile()/FindNextFile() API calls for the imlementation, so FindClose() has to be called in any case if the enumeration is done.

    Read the article

  • A question about some code from TBB book, Thanks.

    - by Jackie
    I am reading the book: Intel Threading Building Blocks. I often have difficulties understanding them. For example,the following code is from the book(page 112): Node* AllocateNode() { Node* n; FreeListMutexType::scoped_lock lock; lock.acquire(FreeListMutex); n=FreeList; if(n) Freelist=n->next; lock.release(); if(!n) n=new Node(); return n; } There is other introduction regarding this code. I can not understand it. What does it means? How can I understand this book better? Thanks.

    Read the article

  • How does this ruby custom accessor work

    - by ennuikiller
    So the method below in class_eval dynamically creates accessors for attributes defined at runtime. It can be used, for example, to create configuration objects with attributes read from a config file (and unknown until runtime). I understanding all of it except for the else branch. If I am correct the else branch returns the attribute value (val[0]) if there is one value passed in *val. However the way its written I would expect it to return an array (val) if there is more then one value passed in *var. In particular, if I have something like the following: value = 5 then from reading the code I would expect "#{@value}" to be [=,5]. However "#{@value}" returns 5 and not the array [=,5]. How is this possible? class Module def dsl_accessor(*symbols) symbols.each do |sym| class_eval %{ def #{sym}(*val) if val.empty? @#{sym} else @#{sym} = val.size == 1 ? val[0] : val end end } end end end

    Read the article

  • Expression Tree

    - by nettguy
    My understanding of expression tree is : Expression trees are in-memory representation of expression like arithmetic or boolean expression.The expressions are stored into the parsed tree.so we can easily transalate into any other language. Linq to SQL uses expression tree.Normally in LINQ to SQL query the compiler translates it into parsed expression trees.These are passed to Sql Server as T-SQL Statements.The Sql server executes the T-SQL query and sends down the result back.That is why when you execute LINQ to SQL you gets IQueryable<T> not IEnumetrable<T>.Because IQuerybale contains public IQueryable:IEnumerable { Type Element {get;} Expression Expression {get;} IQueryaleProvider Provider {get;} } Questions : Microsoft uses Expression trees to play with LINQ-to-Sql.What are the different ways can i use expression trees to boost my code. Apart from LINQ to SQL,Linq to amazon ,who used expression trees in their applications? Linq to Object return IEnumerable,Linq to SQL return IQueryable ,What does LINQ to XML return?

    Read the article

  • Difference between 'scope' and 'namespace'?

    - by katriel
    What is the difference, in general, between the concepts of namespaces and scope? To my understanding, both describe the parts of a program in which a variable/object/method/function will be accessible. I understand that 'scope' tends to be a property of the variable (e.g., "This variable has global scope"), while a 'namespace' is a property of the program (e.g., "A Python function creates a local namespace"). Are there other differences? Global scope vs global namespace addresses a slightly narrower question: global namespaces in C++. http://www.alan-g.me.uk/tutor/tutname.htm states, There are a few very subtle differences between the terms but only a Computer Scientist pedant would argue with you, and for our purposes namespace and scope are identical. What are those subtle differences? Under what circumstances or with which kinds of languages do people use each concept?

    Read the article

  • How do I create SEO-Friendly urls in ASP.Net-MVC

    - by blesh
    I'm getting myself acquainted with ASP.Net-MVC, and I was trying to accomplish some common tasks I've accomplished in the past with webforms and other functionality. On of the most common tasks I need to do is create SEO-friendly urls, which in the past has meant doing some url rewriting to build the querystring into the directory path. for example: www.somesite.com/productid/1234/widget rather than: www.somesite.com?productid=1234&name=widget What method do I use to accomplish this in ASP.Net-MVC? I've search around, and all I've found is this, which either I'm not understanding properly, or doesn't really answer my question: http://stackoverflow.com/questions/734583/seo-urls-with-asp-net-mvc

    Read the article

  • concurrency in Java

    - by p1
    1]What is Non-blocking Concurrency and how is it different. 2] I have heard that this is available in Java. Are there any particular scenarios we should use this feature 3] Is there a difference/advantage of using one of these methods for a collection. What are the trade offs class List { private final ArrayList<String> list = new ArrayList<String>(); void add(String newValue) { synchronized (list) { list.add(newValue); } } } OR private final ArrayList<String> list = Collections.synchronizedMap(); The questions are more from a learning/understanding point of view. Thanks for attention.

    Read the article

  • Why & When should I use SPARSE COLUMN? (SQL SERVER 2008)

    - by priyanka.sarkar
    After going thru some tutorials on SQL SERVER 2008's new feature SPARSE COLUMN, I have found that it doesn't take any space if the column value is 0 or null but when there is a value, it takes 4 times the space a regular(non sparse) column holds. If my understanding is correct, then why I will go for that at the time of database design? And if I use that, then at what situation so I be? Also out of curiosity, how come no space get's reserve when a column is defined as sparse column(I mean to say, what is the internal implementation for that) Thanks in advance

    Read the article

  • java keytool question

    - by user384706
    Hi, I created a java keystore programmatically of type jks (i.e. default type). It is initially empty so I created a DSA certificate. keytool -genkey -alias myCert -v -keystore trivial.keystore How can I see the public and private keys? I.e. is there a command that prints the private key of my certificate? I could only find keytool -certreq which in my understanding prints the certificate as a whole: -----BEGIN NEW CERTIFICATE REQUEST----- MIICaTCCAicCAQAwZTELMAkGA1UEBhMCR1IxDzANBgNVBAgTBkdyZWVjZTEPMA0GA1UEBxMGQXRo BQADLwAwLAIUQZbY/3Qq0G26fsBbWiHMbuVd3VICFE+gwtUauYiRbHh0caAtRj3qRTwl -----END NEW CERTIFICATE REQUEST----- I assume this is the whole certificate. How can I see private (or public key) via keytool? Thank you

    Read the article

  • WHERE clause confusion with PDO

    - by Greg
    I'm having some trouble understanding how to use prepared statements, when you need to match one value against several columns at once. In other words what instead of doing this: $stmt = $dbh-prepare("SELECT * FROM REGISTRY where name = ?"); $stmt-bindParam(':name', $name); I wanted to do this: $stmt = $dbh-prepare("SELECT * FROM REGISTRY where firstname = ? or lastname = ?"); with both '?' representing the same string.

    Read the article

  • Separation of logic from presentation: HTTP variable names?

    - by Allan Jardine
    Hello all, This could probably be considered an academic question, rather than a real world one - but throwing it out to see if anyone has any great ideas! We all know that keeping the business logic of an application separate from the presentation is a good idea (I'm looking at web-apps atm), but there needs to be an understanding between the business logic for what HTTP variables to expect (and then process) and the variable names which are sent by the presentation layer. Is this simply a matter of telling the designer what variable names to use in a template? The template doesn't need to know what the variable names are (unless using them for JS/CSS selectors), so why should they be 'hardcoded' in there. Or should the business logic put the names into variables to be printed out? Another layer of complexity for the templates? Does anyone have any experience of this, or thoughts on how to deal with it? Thanks, Allan

    Read the article

  • Front End Developer positions for Recent Graduates

    - by Rajat
    Is it just me or there is a serious dearth of Front End Web Developer positions for recent grads. I have been working as one for the last 6 months now after my graduation and I understand that most of the front-end skills are not taught at academia and the profession requires a lot of discipline and patience to learn them on your own. I see a plethora of opportunities for recent grads for back-end positions but very few for front end positions. Does the industry have an understanding that Front-End positions require more expertise than back-end positions? Just my thoughts but not many people seem to keen to hire recent grads for front-end positions.

    Read the article

  • Can someone explain me implicit parameters in Scala?

    - by Oscar Reyes
    And more specifically how does the BigInt works for convert int to BigInt? In the source code it reads: ... implicit def int2bigInt(i: Int): BigInt = apply(i) ... How is this code invoked? I can understand how this other sample: "Date literals" works. In. val christmas = 24 Dec 2010 Defined by: implicit def dateLiterals(date: Int) = new { import java.util.Date def Dec(year: Int) = new Date(year, 11, date) } When int get's passed the message Dec with an int as parameter, the system looks for another method that can handle the request, in this case Dec(year:Int) Q1. Am I right in my understanding of Date literals? Q2. How does it apply to BigInt? Thanks

    Read the article

  • PHP app with cookie less session does not work

    - by iama
    I am trying to use PHP session without using cookies. I have enabled session.use_trans_sid and disabled session.use_cookies in my php.ini file. I have also disabled cookies in my firefox browser. Now, when I browse my home page, I do not see the HTTP set cookie header in the server response to my page request (using Live HTTP headers). My understanding is that PHP will append session IDs to my request URL when cookies are disabled. Am I doing something wrong? BTW, I am aware using session IDs is not a recommended approach.

    Read the article

  • Unreachable code detected by using const variables

    - by Anton Roth
    I have following code: private const FlyCapture2Managed.PixelFormat f7PF = FlyCapture2Managed.PixelFormat.PixelFormatMono16; public PGRCamera(ExamForm input, bool red, int flags, int drawWidth, int drawHeight) { if (f7PF == FlyCapture2Managed.PixelFormat.PixelFormatMono8) { bpp = 8; // unreachable warning } else if (f7PF == FlyCapture2Managed.PixelFormat.PixelFormatMono16){ bpp = 16; } else { MessageBox.Show("Camera misconfigured"); // unreachable warning } } I understand that this code is unreachable, but I don't want that message to appear, since it's a configuration on compilation which just needs a change in the constant to test different settings, and the bits per pixel (bpp) change depending on the pixel format. Is there a good way to have just one variable being constant, deriving the other from it, but not resulting in an unreachable code warning? Note that I need both values, on start of the camera it needs to be configured to the proper Pixel Format, and my image understanding code needs to know how many bits the image is in. So, is there a good workaround, or do I just live with this warning?

    Read the article

< Previous Page | 372 373 374 375 376 377 378 379 380 381 382 383  | Next Page >